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Nair HRCR, Budhavant K, Manoj MR, Kirillova EN, Satheesh SK, Gustafsson Ö. Roles of water-soluble aerosol coatings for the enhanced radiative absorption of black carbon over south asia and the northern indian ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171721. [PMID: 38494028 DOI: 10.1016/j.scitotenv.2024.171721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/22/2024] [Accepted: 03/12/2024] [Indexed: 03/19/2024]
Abstract
Black Carbon (BC), formed by incomplete combustion, absorbs solar radiation and heats the atmosphere. We investigated the enhancement in optical absorption of BC due to coatings of water-soluble (WS) species in the polluted South Asian atmosphere. The BC Mass Absorption Cross-section (MAC; 678 nm) was estimated before and after removal of the WS components. Wintertime samples were collected from three South Asian receptor observatories intercepting large-footprint outflow: Bangladesh Climate Observatory Bhola (BCOB; integrating outflow of the Indo-Gangetic Plain), Maldives Climate Observatories at Hanimaadhoo (MCOH) and at Gan (MCOG), both reflecting outflow from the South Asian region. The ambient MAC observed at BCOB, MCOH and MCOG were 4.2 ± 1.4, 7.9 ± 1.9 and 7.1 ± 1.5 m2 g-1, respectively. The average enhancement of the BC MAC due to WS coatings (i.e., ws-EMAC) was identical at all three sites (1.6 ± 0.5) indicating that the anthropogenic aerosols had already evolved to a fully coated morphology at BCOB and/or that subsequent aging involved two compensating evolution processes of the coating. Inspecting the key coating component sulfate; the sulfate-to-BC ratio increased threefold when transitioning from BCOB to MCOH and by about 1.5 times from BCOB to MCOG. Conversely, both WS organic carbon (WSOC)/BC and water-insoluble OC (WIOC)/BC ratios declined with distance: WSOC/BC diminished by 84 % from BCOB to MCOH and by 80 % from BCOB to MCOG, while WIOC/BC dropped by about 63 % and 59 %, respectively. Such declines in WSOC and WIOC reflect a combination of photochemical oxidation and more efficient washout of OC compared to BC. The observed changes in the SO42-/BC and WSOC/BC ratios across South Asia highlight the significant impact of aerosol composition on the optical properties of Black Carbon (BC). These findings emphasize the need for detailed studies on aerosol composition to improve climate models and develop effective strategies for reducing the impact of anthropogenic aerosols on the climate.
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Affiliation(s)
- H R C R Nair
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Krishnakant Budhavant
- Maldives Climate Observatory at Hanimaadhoo, H. Dh. Hanimaadhoo, Maldives; Divecha Centre for Climate Change, Indian Institute of Science, Bangalore, India
| | - M R Manoj
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Elena N Kirillova
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden; Institute of Medicine, Ecology and Physical Education, Ulyanovsk State University, Ulyanovsk, Russia
| | - S K Satheesh
- Divecha Centre for Climate Change, Indian Institute of Science, Bangalore, India; Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore, India; DST-Centre of Excellence in Climate Change, Indian Institute of Science, Bangalore, India
| | - Örjan Gustafsson
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden.
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Boreddy SKR, Nair VS, Babu SS. Assessment of submicron aerosol liquid water content and mass-based growth factors in South Asian outflow over the Indian Ocean. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:166461. [PMID: 37607630 DOI: 10.1016/j.scitotenv.2023.166461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/18/2023] [Accepted: 08/18/2023] [Indexed: 08/24/2023]
Abstract
Aerosol-bound water, a ubiquitous and abundant component of atmospheric aerosols, has an impact on regional climate, visibility, human health, the hydrological cycle, and atmospheric chemistry. Yet, the intricate relationship between aerosol liquid water (ALWC) and chemical composition and relative humidity (RH) was not well understood. The present study explores ALWC derived from the ISORROPIA II model using real-time, high-resolution data of non-refractory submicron chemical species and meteorological parameters (temperature and RH) collected over the Indian Ocean as part of the ICARB (Integrated Campaign for Aerosols, Gases, and Radiation Budget)-2018 experiment. Results show that ALWC values over the South Eastern Arabian Sea (SEAS) were found to be higher by 4-6 times than those observed over the Equatorial Indian Ocean (EIO) due to a large decrease in aerosol loading from SEAS to EIO. ALWC peaked in the early morning hours (4:00-7:00), with greater values during the nighttime and lower values during the daytime across SEAS, which is comparable with RH variation. While the ratio of organics-to-SO42- mass fraction linearly decreased with increasing mass-based growth factors (MGFs) over EIO, such a scenario was not observed over SEAS. The latitudinal gradient of mass fraction of ALWC had shown a decrease towards EIO, consistent with organic fraction. The extinction coefficient of the dry mass of submicron particles is noticeably increased by 40 % by ALWC over SEAS and EIO. Moreover, ALWC could enhance the aerosol negative forcing by an average of 66 % (64 %) over SEAS (EIO) at the top of the atmosphere during the cruise period. These inferences imply that ALWC is the key factor in assessing the role of aerosols on atmospheric radiative forcing. Overall, the present study highlights the serious need to consider the ALWC in climate forcing simulations, particularly in moist tropical environments where their effect can be significant.
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Affiliation(s)
- Suresh K R Boreddy
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022, India.
| | - Vijayakumar S Nair
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022, India
| | - S Suresh Babu
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695022, India
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3
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Kalisa W, Zhang J, Igbawua T, Henchiri M, Mulinga N, Nibagwire D, Umuhoza M. Spatial and temporal heterogeneity of air pollution in East Africa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 886:163734. [PMID: 37120019 DOI: 10.1016/j.scitotenv.2023.163734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/01/2023] [Accepted: 04/21/2023] [Indexed: 05/20/2023]
Abstract
East Africa's air pollution levels are deteriorating due to anthropogenic and biomass burning emissions and unfavorable weather conditions. This study investigates the changes and influencing factors of air pollution in East Africa from 2001 to 2021. The study found that air pollution in the region is heterogeneous, with increasing trends observed in pollution hot spots (PHS) while it decreased in pollution cold spots (PCS). The analysis identified four major pollution periods: High Pollution period 1, Low Pollution period 1, High Pollution period 2, and Low Pollution period 2, which occur during Feb-Mar, Apr-May, Jun-Aug and Oct-Nov, respectively. The study also revealed that long range transport of pollutants to the study area is primarily influenced by distant sources from the eastern, western, southern, and northern part of the continent. The seasonal meteorological conditions, such as high sea level pressure in the upper latitudes, cold air masses from the northern hemisphere, dry vegetation, and a dry and less humid atmosphere from boreal winter, further impact the transport of pollutants. The concentrations of pollutants were found to be influenced by climate factors, such as temperature, precipitation, and wind patterns. The study identified different pollution patterns in different seasons, with some areas having minimal anthropogenic pollution due to high vegetation vigor and moderate precipitation. Using Ordinary Least Square (OLS) regression and Detrended Fluctuation Analysis (DFA), the study quantified the magnitude of spatial variation in air pollution. The OLS trends indicated that 66 % of pixels exhibited decreasing trends while 34 % showed increasing trends, and DFA results indicating that 36 %, 15 %, and 49 % of pixels exhibited anti-persistence, random, and persistence in air pollution, respectively. Areas in the region experiencing increasing or decreasing trends in air pollution, which can be used to prioritize interventions and resources for improving air quality, were also highlighted. It also identifies the driving forces behind air pollution trends, such as anthropogenic or biomass burning, which can inform policy decisions aimed at reducing air pollution emissions from these sources. The findings on the persistence, reversibility, and variability of air pollution can inform the development of long-term policies for improving air quality and protecting public health.
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Affiliation(s)
- Wilson Kalisa
- Remote Sensing and Digital Earth Center, School of Computer Science and Technology, Qingdao University, Qingdao 266071, China; Global Change and Disaster, Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China
| | - Jiahua Zhang
- Remote Sensing and Digital Earth Center, School of Computer Science and Technology, Qingdao University, Qingdao 266071, China; Global Change and Disaster, Key Laboratory of Digital Earth Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China.
| | - Tertsea Igbawua
- Department of Physics, Federal University of Agriculture, Makurdi, Nigeria
| | - Malak Henchiri
- Remote Sensing and Digital Earth Center, School of Computer Science and Technology, Qingdao University, Qingdao 266071, China
| | - Narcisse Mulinga
- Department of Agricultural Economics and Rural development, University of Rwanda, Rwanda
| | - Deborah Nibagwire
- Department of Environmental Management, Pan African University of Life and Earth Sciences (PAULESI), Nigeria
| | - Mycline Umuhoza
- UNEP-Tongji Institute of environment for Sustainable Development, Shanghai 200092, China
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4
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Li Q, Dai J, Zhang H, Wan Z, Xu J. Potentially toxic elements in lake sediments in China: Spatial distribution, ecological risks, and influencing factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161596. [PMID: 36646219 DOI: 10.1016/j.scitotenv.2023.161596] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/07/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Potentially toxic elements (PTEs) pollution in lake sediments is a serious threat to the ecological safety of lake water and human health, owing to anthropogenic activities. Studies on the distribution of pollution, the differences in lake types, and the influencing factors in China as a whole are lacking. This study collected data on PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in Chinese lake sediments published from 2005 to 2021, and aimed to evaluate pollution levels and spatial distribution characteristics of PTEs in lake sediments, differences in pollution in different types of lakes, and influencing factors. The results showed that (1) All metals in the lake sediments accumulated to different degrees, when compared to the background values. (2) The lake type pollution levels were ranked: urban lakes > reservoirs > plateau lakes > natural lakes. (3) The geoaccumulation and potential ecological risk indexes both indicated that Cd and Hg are the main pollutants, and that the overall ecological risk level of lake sediments in China is high. (4) The degree of economic and population growth is highly correlated with the concentrations of eight PTEs; the amount of fertilizer and pesticide used in agricultural activities are the main factors affecting As and Hg; industrial activities and traffic pollution emissions are the predominant factors affecting Cu and Ni. (5) In the interaction detection analysis, the Cr content was mainly influenced by natural factors; Cd, Pb, and Zn contents were affected more by human activities. This study provides a reference for understanding the current status and influencing factors of PTE pollution in Chinese lakes.
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Affiliation(s)
- Qi Li
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Junfeng Dai
- Guangxi Collaborative Innovation Center for Water Pollution Control and Safety in Karst Area, Guilin University of Technology, Guilin 541004, China.
| | - Hongyan Zhang
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China
| | - Zupeng Wan
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Jingxuan Xu
- Guilin Water and Resources Bureau, Guilin 541199, China
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5
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Bikkina P, Bikkina S, Kawamura K. Tracing the biomass burning emissions over the Arabian Sea in winter season: Implications from the molecular distributions and relative abundances of sugar compounds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157643. [PMID: 35908715 DOI: 10.1016/j.scitotenv.2022.157643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/02/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
The widespread haze pollution over South Asia typically occurs in winter, affecting the abundance of organic aerosols (OA) over the Arabian Sea due to prevailing meteorology. We determined the concentrations of biomass burning (BB) derived anhydrosugars (levoglucosan: Lev, galactosan: Gal, and mannosan: Man), sugars (glucose, fructose, sucrose, and trehalose) and sugar alcohols (arabitol, mannitol, erythritol, and inositol) over the Arabian Sea during a winter cruise (6-24 December 2018). Molecular distributions revealed predominance of levoglucosan or sucrose. Besides, levoglucosan strongly correlated with mannosan, galactosan, sugar alcohols and elemental carbon, emphasizing their BB-origin. Backward air mass trajectories intercepted by the satellite-based fire counts over the Indo-Gangetic Plain together with relationship between stable carbon isotopic composition of TC (δ13CTC) and levoglucosan-C to organic carbon (%), confirmed the impact of BB-derived OA. A comparison of Lev/Man (av. 16.2) and Lev/K+ (av. 0.27) ratios over the Arabian Sea with the source-emissions revealed their origin from crop-residue burning. Rather high concentrations of Lev over the Arabian Sea compared to those documented over the Bay of Bengal, East China Sea, Sea of Japan and the western North Pacific further suggests a stronger impact of BB in the continental outflow over this marine basin. Besides, Lev/K+ ratios in marine aerosols exponentially decreased with an apparent increase in ambient relative humidity and temperature over the Arabian Sea during the South Asian outflow, implying a photochemical oxidation of BBOA. Such field-based relationship of Lev with the meteorological parameters can be useful for modelling the impact of BBOA on the surface Ocean. Besides, the aeolian input of sugar-C and water-soluble organic carbon (WSOC) accounted for 83 % and 92 % of that riverine supply to the Arabian Sea, respectively. This means atmospheric dry-deposition of sugars is an important external source of dissolved organic compounds to the surface water.
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Affiliation(s)
- Poonam Bikkina
- CSIR National Institute of Oceanography, Dona Paula 403004, Goa, India.
| | - Srinivas Bikkina
- CSIR National Institute of Oceanography, Dona Paula 403004, Goa, India
| | - Kimitaka Kawamura
- Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan
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6
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Goetz JD, Giordano MR, Stockwell CE, Bhave PV, Puppala PS, Panday AK, Jayarathne T, Stone EA, Yokelson RJ, DeCarlo PF. Aerosol Mass Spectral Profiles from NAMaSTE Field-Sampled South Asian Combustion Sources. ACS EARTH & SPACE CHEMISTRY 2022; 6:2619-2631. [PMID: 36425341 PMCID: PMC9677502 DOI: 10.1021/acsearthspacechem.2c00173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Unit mass resolution mass spectral profiles of nonrefractory submicron aerosol were retrieved from undersampled atmospheric emission sources common to South Asia using a "mini" aerosol mass spectrometer. Emission sources including wood- and dung-fueled cookstoves, agricultural residue burning, garbage burning, engine exhaust, and coal-fired brick kilns were sampled during the 2015 Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign. High-resolution peak fitting estimates of the mass spectra were used to characterize ions found within each source profile and help identify mass spectral signatures unique to aerosol emissions from the investigated source types. The first aerosol mass spectral profiles of dung burning, charcoal burning, garbage burning, and brick kilns are provided in this work. The online aerosol mass spectra show that organics were generally the dominant component of the nonrefractory aerosol. However, inorganic aerosol components including ammonium and chloride were significant in dung- and charcoal-fired cookstove emissions and sulfate compounds were major components of the coal-fired brick kiln emissions. Organic mass spectra from both the charcoal burning and zigzag brick kiln were dominated by nitrogen-containing ions thought to be from the electron ionization of amines and amides contained in the emissions. The mixed garbage burning emissions profiles were dominated by plastic combustion with very low fractions of organic markers associated with biomass burning. The plastic burning emissions were associated with enhanced organic signal at mass-to-charge (m/z) 104 and m/z 166, which could be useful fragment ion indicators for garbage burning in ambient aerosol profiles. Finally, a framework for the identification of emission sources using the unit mass resolution organic mass fractions at m/z 55 (f 55), m/z 57 (f 57), and m/z 60 (f 60) is proposed in this work. Plotting the ratio of f 55 to f 57 versus f 60 is found to be effective for the identification of emissions by the fuel type and even useful in separating emissions of similar source types. Although the sample size was limited, these results give further context to the aerosol and gas-phase emission factors presented in other NAMaSTE works and provide a critical reference for future aerosol composition measurements in South Asia.
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Affiliation(s)
- J. Douglas Goetz
- Laboratory
for Atmospheric and Space Physics, University
of Colorado at Boulder, Boulder, Colorado 80303, United States
| | - Michael R. Giordano
- Department
of Civil, Architectural, and Environmental Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Chelsea E. Stockwell
- Department
of Chemistry, University of Montana, Missoula, Montana 59812, United States
| | - Prakash V. Bhave
- International
Centre for Integrated Mountain Development (ICIMOD), Lalitpur 44700, Nepal
| | - Praveen S. Puppala
- International
Centre for Integrated Mountain Development (ICIMOD), Lalitpur 44700, Nepal
| | - Arnico K. Panday
- International
Centre for Integrated Mountain Development (ICIMOD), Lalitpur 44700, Nepal
| | - Thilina Jayarathne
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Elizabeth A. Stone
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Robert J. Yokelson
- Department
of Chemistry, University of Montana, Missoula, Montana 59812, United States
| | - Peter F. DeCarlo
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21205, United States
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Sarma VVSS, Sridevi B, Kumar A, Bikkina S, Kumari VR, Bikkina P, Yadav K, Rao VD. Impact of atmospheric anthropogenic nitrogen on new production in the northern Indian Ocean: constrained based on satellite aerosol optical depth and particulate nitrogen levels. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1895-1911. [PMID: 36148795 DOI: 10.1039/d2em00234e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Aerosols are one of the significant external sources of soluble reactive nitrogen to the surface ocean and their deposition affects the primary productivity. Owing to rapid industrialization over South and Southeast Asia, an increasing trend in atmospheric pollutants was observed over the northern Indian Ocean (NIO). To assess the contribution of the aeolian supply of inorganic nitrogen to the NIO, the available compositional data of marine aerosols collected over this basin between 2001 and 2020 were compiled. Based on the observed relationship of mass load, and particulate nitrate and ammonium concentrations with the corresponding satellite-derived anthropogenic aerosol optical depth (AAOD), the temporal, spatial, and long-term variabilities were derived for the past two decades. In particular, high aerosol mass load, nitrate and ammonium levels were observed in the coastal aerosols of peninsular India during fall and winter and they were low in summer. The atmospheric input of inorganic nitrogen to the Arabian Sea is higher (AS; 1.7 TgN per year) compared to that of the Bay of Bengal (BoB; 0.9 TgN per year) and accounts for ∼30% of the total external sources of nitrogen to the NIO. The new production, supported by external sources of nitrogen, contributes to ∼23 and 53% of export production to the oxygen minimum zone (OMZ) in the AS and BoB respectively. A significant rate of increase in the aerosol mass load (0.05-1.67 μg per m3 per year), and nitrate (0.003-0.04 μg per m3 per year) and ammonium (0.006-0.11 μg per m3 per year) concentrations was observed between 2001 and 2020, likely because of the increased emission of anthropogenic pollutants over South and Southeast Asia and their subsequent long-range atmospheric transport to the NIO. Overall, these results suggest that an enhanced contribution of atmospheric nitrogen may potentially increase (1) the N/P ratio of the surface ocean that impacts phytoplankton composition, (2) export production to the OMZ leads to intensification, and (3) sequestration of atmospheric CO2. A decrease in primary production due to global warming is reported due to a decrease in vertical nutrient supply; however, the increase in atmospheric deposition of nutrients may compensate for this. Therefore, ocean models must be coupled with atmospheric models to better constrain the oceanic response to climate change in the NIO.
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Affiliation(s)
- V V S S Sarma
- National Institute of Oceanography, Regional Centre, 176 Lawsons Bay Colony, Visakhapatnam, India.
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - B Sridevi
- National Institute of Oceanography, Regional Centre, 176 Lawsons Bay Colony, Visakhapatnam, India.
| | - Ashwini Kumar
- National Institute of Oceanography, Dona Paula, Goa, India
| | - S Bikkina
- National Institute of Oceanography, Dona Paula, Goa, India
| | - V R Kumari
- National Institute of Oceanography, Regional Centre, 176 Lawsons Bay Colony, Visakhapatnam, India.
| | - P Bikkina
- National Institute of Oceanography, Dona Paula, Goa, India
| | - K Yadav
- National Institute of Oceanography, Regional Centre, 176 Lawsons Bay Colony, Visakhapatnam, India.
| | - V D Rao
- National Centre for Coastal Research, Ministry of Earth Science, Velacherry, Chennai, India
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8
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Singh A, Singh S, Srivastava AK, Payra S, Pathak V, Shukla AK. Climatology and model prediction of aerosol optical properties over the Indo-Gangetic Basin in north India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:827. [PMID: 36156160 DOI: 10.1007/s10661-022-10440-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
The current research focuses on the use of different simulation techniques in the future prediction of the crucial aerosol optical properties over the highly polluted Indo-Gangetic Basin in the northern part of India. The time series model was used to make an accurate forecast of aerosol optical depth (AOD) and angstrom exponent (AE), and the statistical variability of both cases was compared in order to evaluate the effectiveness of the model (training and validation). For this, different models were used to simulate the monthly average AOD and AE over Jaipur, Kanpur and Ballia during the period from 2003 to 2018. Further, the study was aimed to construct a comparative model that will be used for time series statistical analysis of MODIS-derived AOD550 and AE412-470. This will provide a more comprehensive information about the levels of AOD and AE that will exist in the future. To test the validity and applicability of the developed models, root-mean-square error (RMSE), mean absolute error (MAE), mean absolute percent error (MAPE), fractional bias (FB), and Pearson coefficient (r) were used to show adequate accuracy in model performance. From the observation, the monthly mean values of AOD and AE were found to be nearly similar at Kanpur and Ballia (0.62 and 1.26) and different at Jaipur (0.25 and 1.14). Jaipur indicates that during the pre-monsoon season, the AOD mean value was found to be highest (0.32 ± 0.15), while Kanpur and Ballia display higher AOD mean values during the winter season (0.72 ± 0.26 and 0.83 ± 0.32, respectively). Among the different methods, the autoregressive integrated moving average (ARIMA) model was found to be the best-suited model for AOD prediction at Ballia based on fitted error (RMSE (0.22), MAE (0.15), MAPE (24.55), FB (0.05)) and Pearson coefficient r (0.83). However, for AE, best prediction was found at Kanpur based on RMSE (0.24), MAE (0.21), MAPE (22.54), FB (-0.09) and Pearson coefficient r (0.82).
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Affiliation(s)
- Amarendra Singh
- Institute of Engineering and Technology, Lucknow, India.
- Ministry of Earth Sciences, Indian Institute of Tropical Meteorology, New Delhi, India.
| | - Sumit Singh
- Institute of Engineering and Technology, Lucknow, India
| | - A K Srivastava
- Ministry of Earth Sciences, Indian Institute of Tropical Meteorology, New Delhi, India.
| | - Swagata Payra
- Department of Remote Sensing, Birla Institute of Technology, Mesra, Ranchi, India
| | | | - A K Shukla
- Institute of Engineering and Technology, Lucknow, India
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9
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Al-Abadleh HA, Motaghedi F, Mohammed W, Rana MS, Malek KA, Rastogi D, Asa-Awuku AA, Guzman MI. Reactivity of aminophenols in forming nitrogen-containing brown carbon from iron-catalyzed reactions. Commun Chem 2022; 5:112. [PMID: 36697654 PMCID: PMC9814260 DOI: 10.1038/s42004-022-00732-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/07/2022] [Indexed: 01/28/2023] Open
Abstract
Nitrogen-containing organic carbon (NOC) in atmospheric particles is an important class of brown carbon (BrC). Redox active NOC like aminophenols received little attention in their ability to form BrC. Here we show that iron can catalyze dark oxidative oligomerization of o- and p-aminophenols under simulated aerosol and cloud conditions (pH 1-7, and ionic strength 0.01-1 M). Homogeneous aqueous phase reactions were conducted using soluble Fe(III), where particle growth/agglomeration were monitored using dynamic light scattering. Mass yield experiments of insoluble soot-like dark brown to black particles were as high as 40%. Hygroscopicity growth factors (κ) of these insoluble products under sub- and super-saturated conditions ranged from 0.4-0.6, higher than that of levoglucosan, a prominent proxy for biomass burning organic aerosol (BBOA). Soluble products analyzed using chromatography and mass spectrometry revealed the formation of ring coupling products of o- and p-aminophenols and their primary oxidation products. Heterogeneous reactions of aminophenol were also conducted using Arizona Test Dust (AZTD) under simulated aging conditions, and showed clear changes to optical properties, morphology, mixing state, and chemical composition. These results highlight the important role of iron redox chemistry in BrC formation under atmospherically relevant conditions.
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Affiliation(s)
- Hind A. Al-Abadleh
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Fatemeh Motaghedi
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Wisam Mohammed
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Md Sohel Rana
- grid.266539.d0000 0004 1936 8438Department of Chemistry, University of Kentucky, Kentucky, 40506 USA
| | - Kotiba A. Malek
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Dewansh Rastogi
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Akua A. Asa-Awuku
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Marcelo I. Guzman
- grid.266539.d0000 0004 1936 8438Department of Chemistry, University of Kentucky, Kentucky, 40506 USA
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Bikkina P, Bikkina S, Kawamura K, Sarma VVSS, Deshmukh DK. Unraveling the sources of atmospheric organic aerosols over the Arabian Sea: Insights from the stable carbon and nitrogen isotopic composition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154260. [PMID: 35248629 DOI: 10.1016/j.scitotenv.2022.154260] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
The isotopic composition of stable carbon (δ13C) and nitrogen (δ15N) in marine aerosols influenced by the continental outflows are useful proxies for understanding the aging and secondary formation processes. Every winter, the haze pollutants transported from South Asia significantly affect the chemical composition of marine atmospheric boundary layer of the Arabian Sea. Here, we assessed the δ13C of total carbon (TC) and δ15N of total nitrogen (TN) in marine aerosols collected over the Arabian Sea during a winter cruise (6-24 December 2018). TC (2.1-13.4 μg m-3) is strongly correlated with TN (0.9-5.0 μg m-3), likely because of their common source-emissions, biomass burning and fossil-fuel combustion in the Indo-Gangetic Plain and South Asia (corroborated by backward-air mass trajectories and satellite fire counts). Besides, the linear relationship between the mass ratios of water-soluble organic carbon (WSOC) to TC (0.04-0.65) and δ13CTC (-25.1‰ to -22.9‰) underscores the importance of aging process. This means oxidation of organic aerosols during transport not only influences the WSOC levels but also affects their δ13CTC. Likewise, the prevalent inverse linear relationship between the equivalent mass ratio of (NH4+/non-sea-salt- or nss-SO42-) and δ15NTN (+15.3‰ to +25.1‰) emphasizes the overall significance of neutralization reactions between major acidic ([nss-SO42-] ≫ [NO3-]) and alkaline species (NH4+) in aerosols. Higher δ15NTN values in winter than the spring inter-monsoon clearly emphasizes the significance of the anthropogenic combustion sources (i.e., biomass burning) in the South Asian outflow. A comparison of δ13CTC and δ15NTN with the source emissions revealed that crop-residue burning emissions followed by the coal fired power plants mostly dictate the atmospheric abundance of organic aerosols in the wider South Asian outflow.
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Affiliation(s)
- Poonam Bikkina
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India.
| | - Srinivas Bikkina
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India; Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
| | - Kimitaka Kawamura
- Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
| | - V V S S Sarma
- CSIR-National Institute of Oceanography, Regional Cente Waltair, Visakhapatnam 530017, India
| | - Dhananjay K Deshmukh
- Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
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11
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Niu H, Lu X, Zhang G, Sarangi C. Investigation of water-soluble organic constituents and their spatio-temporal heterogeneity over the Tibetan Plateau. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 302:119093. [PMID: 35245621 DOI: 10.1016/j.envpol.2022.119093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/24/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Investigating the migration and transformation of carbonaceous and nitrogenous matter in the cryosphere areas is crucial for understanding global biogeochemical cycle and earth's climate system. However, water-soluble organic constituents and their transformation in multiple water bodies are barely investigated. Water-soluble organic carbon (WSOC) and organic nitrogen (WSON), and particulate black carbon (PBC) in multiple types of water bodies in eastern Tibetan Plateau (TP) cryosphere for the first time have been systematically investigated. Statistical results exhibited that from south to north and from east to west of this region, WSOC concentrations in alpine river runoff were gradually elevated. WSOC and nitrogenous matter in the alpine river runoff and precipitation in the glacier region presented distinct seasonal variations. WSON was the dominant component (63.4%) of water-soluble total nitrogen in precipitation over high-altitude southeastern TP cryosphere. Water-soluble carbonaceous matter dominated the carbon cycle in the TP cryosphere, but particulate carbonaceous matter in the alpine river runoff had a small fraction of the cryospheric carbon cycle. Analysis of optical properties illustrated that PBC had a much stronger light absorption ability (MAC-PBC: 2.28 ± 0.37 m2 g-1) than WSOC in the alpine river runoff (0.41 ± 0.26 m2 g-1). Ionic composition was dominated by SO42-, NO3-, and NH4+ (average: 45.13 ± 3.75%) in the snow of glaciers, implying important contribution of (fossil fuel) combustion sources over this region. The results of this study have essential implications for understanding the carbon and nitrogen cycles in high altitude cryosphere regions of the world. Future work should be performed based on more robust in-situ observations and measurements from multiple environmental medium over the cryosphere areas, to ensure ecological protection and high-quality development of the high mountain Asia.
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Affiliation(s)
- Hewen Niu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - Xixi Lu
- Department of Geography, National University of Singapore, 1 Arts Link, 117570, Singapore
| | - Guotao Zhang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chandan Sarangi
- Department of Civil Engineering, Indian Institute of Technology, Madras, Chennai, India; Laboratory for Atmospheric and Climate Sciences, Indian Institute of Technology Madras, Chennai, India
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He H, Wei H, Wang Y, Wang L, Qin Z, Li Q, Shan F, Fan Q, Du Y. Geochemical and Statistical Analyses of Trace Elements in Lake Sediments from Qaidam Basin, Qinghai-Tibet Plateau: Distribution Characteristics and Source Apportionment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19042341. [PMID: 35206531 PMCID: PMC8872242 DOI: 10.3390/ijerph19042341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 12/05/2022]
Abstract
The safety of lake ecosystems on the Qinghai-Tibet Plateau (QTP) has attracted increasing attention, owing to its unique location and ecological vulnerability. Previous studies have shown that the aquatic systems on the QTP have been polluted to varying degrees by trace elements. However, little is known of the distribution and sources of trace elements in lakes in the northeast QTP. Here, 57 sediment samples were collected from six lakes (Dasugan Lake, Xiaoqaidam Lake, Kreuk Lake, Toson Lake, Gahai Lake and Xiligou Lake) in the Qaidam Basin, northeast QTP, and the trace elements (V, Cr, Ni, Cu, Zn, As, Ba, Tl, Cd, Pb, and U) were analyzed. The results indicated that Ba, Zn, V, and Cr had a higher content and a wider distribution relative to the other tested elements. Correlation coefficient matrix results showed that the trace elements in the study area were strongly correlated, revealing their source of similarity. Self-organizing maps (SOM, an artificial neural network algorithm) results indicated that the degree of pollution in Xiaoqaidam Lake was the highest, and that of Dasugan Lake was the lowest. Furthermore, all sampling points were clustered into four categories through K-means clustering. The positive matrix factorization (PMF) results indicated that atmospheric deposition and anthropogenic inputs were the main trace elements sources in these lakes, followed by traffic emission and geological sources. Collectively, trace elements of six lakes in Qinghai-Tibet Plateau presented high-content and pollution characteristics. This research provides a scientific basis for better water environment management and ecological protection on the QTP.
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Affiliation(s)
- Haifang He
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haicheng Wei
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
- Correspondence: (H.W.); (L.W.)
| | - Yong Wang
- Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
| | - Lingqing Wang
- Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
- Correspondence: (H.W.); (L.W.)
| | - Zhanjie Qin
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
| | - Qingkuan Li
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
| | - Fashou Shan
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
| | - Qishun Fan
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
| | - Yongsheng Du
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China; (H.H.); (Z.Q.); (Q.L.); (F.S.); (Q.F.); (Y.D.)
- Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, China
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Nayak G, Kumar A, Bikkina S, Tiwari S, Sheteye SS, Sudheer AK. Carbonaceous aerosols and their light absorption properties over the Bay of Bengal during continental outflow. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:72-88. [PMID: 34897330 DOI: 10.1039/d1em00347j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The marine atmosphere of the Bay of Bengal (BoB) is prone to get impacted by anthropogenic aerosols from the Indo-Gangetic Plain (IGP) and Southeast Asia (SEA), particularly during the northeast monsoon (NEM). In this study, we quantify and characterize carbonaceous aerosols and their absorption properties collected in two cruise campaigns onboard ORV Sindhu Sadhana during the continental outflow period over the BoB. Aerosol samples were classified based on the air mass back trajectory analyses, wherein samples were impacted by the continental air parcel (CAP), marine air parcel (MAP), and mix of both (CAP + MAP). Significant variability in the PM10 mass concentration (in μg m-3) is found with a maximum value for MAP samples (75.5 ± 36.4) followed by CAP + MAP (58.5 ± 27.3) and CAP (58.5 ± 27.3). The OC/EC ratio (>2) and diagnostic tracers i.e. nss-K+/EC (0.2-0.96) and nss-K+/OC (0.11-1.32) along with the absorption angstrom exponent (AAE: 4.31-6.02) and MODIS (Moderate Resolution Imaging Spectroradiometer) derived fire counts suggest the dominance of biomass burning emission sources. A positive correlation between OC and EC (i.e. r = 0.86, 0.70, and 0.42 for CAP, MAP, and CAP + MAP, respectively) further confirmed the similar emission sources of carbonaceous species. Similarly, a significant correlation between estimated secondary organic carbon (SOC) and water-soluble organic carbon (WSOC; r = 0.99, 0.96, and 0.97 for CAP, MAP, and CAP + MAP, respectively) indicate their similar chemical nature as well as dominant contribution of SOC to WSOC. The absorption coefficient (babs-365) and mass absorption efficiency (MAEBrC-365) of the soluble fraction were estimated at 365 nm wherein, babs-365 showed a linear relationship with WSOC and nss-K+, signifying the contribution of water soluble brown carbon from biomass burning emissions. The estimated MAEBrC-365 (0.30-0.93 m2 g-1), during this study, was consistent with the earlier observations over the BoB, particularly during the continental outflow season.
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Affiliation(s)
- Gourav Nayak
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004, India.
| | - Ashwini Kumar
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Srinivas Bikkina
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004, India.
| | - Shani Tiwari
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004, India.
| | - Suhas S Sheteye
- Geological Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa-403 004, India.
| | - A K Sudheer
- Physical Research Laboratory, Department of Space, Ahmedabad, India
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Gole PK, Midya SK. Association of pre-monsoon CG lightning activity and some surface pollutants in different Indian cities around the COVID-19 lockdown year 2020. PROCEEDINGS OF THE INDIAN NATIONAL SCIENCE ACADEMY 2021. [PMCID: PMC8485116 DOI: 10.1007/s43538-021-00052-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In this paper, pre-monsoon (March – May) Cloud to Ground (CG) lightning activity over 6 mega cities (New Delhi, Kolkata, Mumbai, Chennai, Bengaluru and Hyderabad) in India is analysed with concentrations of four surface pollutants namely particulate matters (PM2.5, PM10), Sulphur dioxide (SO2) and Ozone for a period of 2018 to 2021 that includes the lockdown year 2020. Pollution greatly reduced with an enhancement of air quality in this year. Lightning data for the analysis is derived from the ground based lightning Network -Earth Networks Global Lightning Network (ENGLN). Among the mega cities, Kolkata faces most lightning whereas Mumbai receives the least. CG lightning flash counts significantly decrease in 2020 for Kolkata, Bengaluru, New Delhi and increase for Chennai, Hyderabad and Mumbai though the increase for the last two cities are very insignificant. This increase may be due to greater impact of meteorological factors on lightning than the pollutant concentrations. The lightning activity averaged over all the mega cities follows the trend of pollutant concentrations and average CG lightning flash counts go to minimum in the COVID-19 lockdown year 2020. Analysis also reveals that average seasonal CG lightning flash counts, average positive CG lightning flash counts and maximum peak CG currents show positive correlations with the concentration of all the four pollutants. The overall study shows that control of pollution may reduce the lightning activity in some lightning prone urban areas.
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Affiliation(s)
- P. K. Gole
- Department of Atmospheric Sciences, University of Calcutta, Kolkata, 700019 India
| | - S. K. Midya
- Department of Atmospheric Sciences, University of Calcutta, Kolkata, 700019 India
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15
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Tlili S, Mouneyrac C. New challenges of marine ecotoxicology in a global change context. MARINE POLLUTION BULLETIN 2021; 166:112242. [PMID: 33706213 DOI: 10.1016/j.marpolbul.2021.112242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 02/23/2021] [Accepted: 02/28/2021] [Indexed: 05/27/2023]
Abstract
Currently, research agenda in marine ecotoxicology is facing new challenges with the emergence of newly and complex synthetized chemicals. The study of the fate and adverse effects of toxicants remains increasingly complicated with global change events. Ecotoxicology had provided for a decades, precious scientific data and knowledge but also technical and management tools for the environmental community. Regarding those, it is necessary to update methodologies dealing with these issues such as combined effect of conventional and emergent stressors and global changes. In this point of view article, we discuss one hand the new challenges of ecotoxicology in this context, and in the other hand, the need of updating agenda and methodologies currently used in monitoring programs and finally recommendations and future research needs. Among recommendations, it could be cited the necessity to perform long-term experiments, the standardization of sentinel species and taking benefit from baseline studies and omics technologies.
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Affiliation(s)
- Sofiene Tlili
- Laboratoire Mer, Molécules, Santé (MMS, EA 2160), Université Catholique, de l'Ouest, 49000 Angers, France.
| | - Catherine Mouneyrac
- Laboratoire Mer, Molécules, Santé (MMS, EA 2160), Université Catholique, de l'Ouest, 49000 Angers, France
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16
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Roy SS, Balling RC. Impact of the COVID-19 lockdown on air quality in the Delhi Metropolitan Region. APPLIED GEOGRAPHY (SEVENOAKS, ENGLAND) 2021; 128:102418. [PMID: 36536956 PMCID: PMC9753935 DOI: 10.1016/j.apgeog.2021.102418] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 01/04/2021] [Accepted: 01/27/2021] [Indexed: 05/08/2023]
Abstract
With the rapid spread of COVID-19 related cases globally, national governments took different lockdown approaches to limit the spread of the virus. Among them, the Government of India imposed a complete nationwide lockdown starting on March 25, 2020. This presented a unique opportunity to explore how a complete standstill in regular daily activities might impact the local environment. In this study, we have analyzed the change in the air quality levels stemming from the reduced anthropogenic activities in one of the most polluted cities in the world, the Delhi Metropolitan Region (DMR). We analyzed station-level changes in particulate matter, PM10 and PM2.5, across the DMR between April 2019 and 2020. The results of our study showed widespread reduction in the levels of both pollutants, with substantial spatial variations. The largest decreases in particulate matter were associated with industrial and commercial areas. Highest levels of PM10 and PM2.5 were observed near sunrise with little change in the time of maximum between 2019 and 2020. The results of our study highlight the role of anthropogenic activities on the air quality at the local level.
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Affiliation(s)
- Shouraseni Sen Roy
- Department of Geography and Regional Studies, University of Miami, FL, USA
| | - Robert C Balling
- School of Geographical Sciences and Urban Planning, Arizona State University, AZ, USA
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17
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Yin S. Biomass burning spatiotemporal variations over South and Southeast Asia. ENVIRONMENT INTERNATIONAL 2020; 145:106153. [PMID: 33002702 DOI: 10.1016/j.envint.2020.106153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 05/27/2023]
Abstract
In this study, Moderate Resolution Imaging Spectroradiometer active fire and land use products were integrated to extract and classify biomass burning (BB) data for South Asia (SA) and Southeast Asia (SEA). Several trend and geographic distribution analyses were conducted at the grid (0.25° × 0.25°) and regional scales. As the principal local form of BB, crop residue burning (CRB) in SA increased by 844 spots/yr, and the Mann-Kendall (MK) τ reached 0.61. Additionally, the CRB in Punjab-Haryana, a region a well-known for severest CRB, presented a significant declining trend. BB in mainland SEA was much more intense and was dominated by forest and shrubland fires. Forest fires in mainland SEA declined at a rate of -209 spots/yr, and shrubland fire conversely grew at a rate of 803 spots/yr, which was likely related to the dramatic land cover change induced by the local swidden agriculture. Unlike other regions, BB in equatorial SEA primarily occurred in the second half of the year (August to October), and it was extremely vulnerable to El Niño events. When the annual sea surface temperature anomalies within the Niño 3 region improved by 1 °C, the annual BB spots and fire radiative power in equatorial SEA increased by 5.18 × 104 and 2.40 × 106 MW, respectively. Although the interannual variations in equatorial SEA were dramatic, the robust Siegel's repeated median estimator still revealed that equatorial SEA BB significantly declined by -1825 spots/yr. This regional decline reflects government endeavors to curb indigenous BB. However, regions with enhanced BB still need to draw more attention, and it is imperative for the Indonesian government to take substantial measures to reduce anthropogenic fire sources during El Niño events.
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Affiliation(s)
- Shuai Yin
- Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba 3058506, Japan.
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Liu Z, Hu B, Yang Y, Zhang D, Li W, Wen T, Xin J, Wang Y. Evaluating the size distribution characteristics and sources of atmospheric trace elements at two mountain sites: comparison of the clean and polluted regions in China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:42713-42726. [PMID: 32720022 DOI: 10.1007/s11356-020-10213-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Size-resolved trace metal concentrations at two background sites were assessed during a 1-year observation campaign, with the measurements performed in parallel at two mountain sites, where Mt. Dinghu (DHS) located in the rural region of Pearl River Delta (PRD) and Mt. Gongga (GGS) located in the Tibetan Plateau region. In total, 15 selected trace elements (Mg, Al, K, V, Mn, Fe, Cu, Zn, As, Mo, Ag, Cd, Ba, Tl, and Pb) in aerosol samples were determined using inductively coupled plasma mass spectrometry (ICPMS). The major metals in these two mountain sites were Fe, K, Mg, and Ca with concentrations ranging between 241 and 1452 ng/m3, 428 and 1351 ng/m3, 334 and 875 ng/m3, and 376 and 870 ng/m3, respectively, while the trace metals with the lowest concentrations were Mo, Ag, Cd, and Tl with concentrations lower than 4 ng/m3 in DHS and 2 ng/m3 in GGS. The pronounced seasonal variability in the trace elements was observed in DHS, with lower concentrations in spring and summer and relatively high in winter and autumn, whereas seasonal variance of trace elements is hardly observed in Mt. Gongga. The size distribution pattern of crustal elements of Al, Mg, K, Ba, and Fe was quite similar in DHS and GGS, which were mainly found in coarse particles peaked at 4.7-5.8 μm. In addition, V, Mo, Ag, and Tl were also concentrated in coarse particles, although the high enrichment factor (EF > 100) of which suggested anthropogenic origin, whereas trace metals of Cd, Mn, Zn, As, Cu, and Pb concentrated in fine mode particles. Specifically, these trace metals peak at approximately 1.5 μm in DHS, while those in GGS peaked at diameter smaller than 0.3 μm, indicating the responsible for long-range transport from the far urban and industrialized areas. Multivariate receptor model combined with the enrichment factor results demonstrated that the trace elemental components at these two background sites were largely contributed from the fossil fuel combustion (55.4% in DHS and 44.0% in GGS) and industrial emissions factors (20.1% vs. 26.5%), which are associated with long distance transport from the coastal area of Southeast China and the Northwestern India, respectively, as suggested by the backward air mass trajectory analysis. Local sources from soil dust contributed a minor variance for trace elements in DHS (9.7%) and GGS (13.8%), respectively.
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Affiliation(s)
- Zirui Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100191, China.
| | - Bo Hu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100191, China
| | - Yongjie Yang
- National Research Center for Environmental Analysis and Measurement, Beijing, 100029, China
| | - Deqiang Zhang
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Wei Li
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Tianxue Wen
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100191, China
| | - Jinyuan Xin
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100191, China
| | - Yuesi Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100191, China.
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Takahashi M, Feng Z, Mikhailova TA, Kalugina OV, Shergina OV, Afanasieva LV, Heng RKJ, Majid NMA, Sase H. Air pollution monitoring and tree and forest decline in East Asia: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140288. [PMID: 32721711 DOI: 10.1016/j.scitotenv.2020.140288] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 05/03/2023]
Abstract
Air pollution and atmospheric deposition have adverse effects on tree and forest health. We reviewed studies on tree and forest decline in Northeast and Southeast Asia, Siberia, and the Russian Far East (hereafter referred to as East Asia). This included studies published in domestic journals and languages. We identified information about the locations, causes, periods, and tree species exhibiting decline. Past air pollution was also reviewed. Most East Asian countries show declining trends in SO2 concentration in recent years, although Mongolia and Russia show increasing trends. Ozone (O3) concentrations are stable or gradually increasing in the East Asia region, with high maxima. Wet nitrogen (N) deposition was high in China and tropical countries, but low in Russia. The decline of trees and forests primarily occurred in the mid-latitudes of Japan, Korea, China, and Russia. Long-term large N deposition resulted in the N saturation phenomenon in Japan and China, but no clear forest health response was observed. Thereafter, forest decline symptoms, suspected to be caused by O3, were observed in Japan and China. In East Russia, tree decline occurred around industrial centers in Siberia. Haze events have been increasing in tropical and boreal forests, and particulate matter inhibits photosynthesis. In recent years, chronically high O3 concentrations, in conjunction with climate change, are likely have adverse effects on tree physiology. The effects of air pollution and related factors on tree decline are summarized. Recently, the effects of air pollution on tree decline have not been apparent under the changing climate, however, monitoring air pollution is indispensable for identifying the cause of tree decline. Further economic growth is projected in Southeast Asia and therefore, the monitoring network should be expanded to tropical and boreal forest zones. Countermeasures such as restoring urban trees and rural forests are important for ensuring future ecosystem services.
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Affiliation(s)
- Masamichi Takahashi
- Forestry and Forest Products Research Institute, Tsukuba, Japan; Japan International Forestry Promotion and Cooperation Center, Tokyo, Japan.
| | - Zhaozhong Feng
- School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
| | - Tatyana A Mikhailova
- Siberian Institute of Plant Physiology & Biochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.
| | - Olga V Kalugina
- Siberian Institute of Plant Physiology & Biochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.
| | - Olga V Shergina
- Siberian Institute of Plant Physiology & Biochemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.
| | - Larisa V Afanasieva
- Institute of General & Experimental Biology, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia.
| | - Roland Kueh Jui Heng
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, Sarawak, Malaysia.
| | - Nik Muhamad Abd Majid
- Faculty of Agriculture and Food Sciences, Universiti Putra Malaysia Bintulu Sarawak Campus, Sarawak, Malaysia; Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, Selangor, Malaysia.
| | - Hiroyuki Sase
- Asia Center for Air Pollution Research, Niigata, Japan.
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20
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Shi L, Li A, Zhang W, Wu H, Chi Y. Endowing chloroplasts with artificial "cell walls" using metal-organic frameworks. NANOSCALE 2020; 12:11582-11592. [PMID: 32432290 DOI: 10.1039/d0nr02206c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Biological photosynthesis via chloroplasts (CHs) is widely recognized as the most appropriate and effective method to convert solar energy and simultaneously supply nutrition to maintain life on earth. It is of great significance to prepare CH-based biohybrids which not only can artificially simulate the photocatalytic functionality of CH-containing plants and bacteria, but also can be easily prepared, stored for a long period and conveniently utilized when needed. In this work, for the first time, CHs were encapsulated into metal-organic frameworks (MOFs), namely zeolitic imidazolate frameworks (ZIF-8), under very gentle reaction conditions, i.e. in aqueous solution and at room temperature. Without the negative effects of organic solvents and high temperature on synthesis, the obtained CH@ZIF-8 biohybrids not only have shells maintaining the porous structure of ZIF-8, but also well preserve the biological activity of CHs inside. The porous ZIF-8 coating on CHs acts as a "cell wall" to allow mass and energy exchange between CHs and the environment, and protect CHs from microbiological degradation, which significantly prolong the lifetime of CHs in vitro (raised from several days to >300 days). The CH@ZIF-8 biohybrids may have promising applications in "living" artificial leaves and even artificial trees capable of photosynthesis in the future.
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Affiliation(s)
- Lei Shi
- MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, and College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China.
| | - Ailing Li
- MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, and College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China.
| | - Weiwei Zhang
- MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, and College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China.
| | - Haishan Wu
- MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, and College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China.
| | - Yuwu Chi
- MOE Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, and College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, P. R. China.
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Molecular Markers in Ambient Air Associated with Biomass Burning in Morelos, México. ATMOSPHERE 2020. [DOI: 10.3390/atmos11050491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Atmospheric particles with an aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5) were collected at two sites located in the urban area of the city of Cuernavaca (Morelos) during a season when a large number of forest fires occurred. Three dicarboxylic acids (malonic, glutaric and succinic) and levoglucosan were analyzed by liquid chromatography coupled with mass spectrometry (ESI-Q-TOF) and soluble potassium (K+) was analyzed by ion chromatography. The concentration of PM2.5 increased on the days when the highest number of forest fires occurred. A strong correlation was observed between levoglucosan and K+, confirming the hypothesis that both are tracers of biomass burning (r = 0.57, p < 0.05). Levoglucosan (average 367.6 ng m−3, Site 2) was the most abundant compound, followed by succinic acid (average 101.7 ng m−3, Site 2), glutaric acid (average 63.2 ng m−3, Site 2), and malonic acid (average 46.9 ng m−3, Site 2), respectively. The ratio of C3/C4 concentrations ranged from 0.5 to 1.2, with an average of 0.8, which suggests great photochemical activity in the Cuernavaca atmosphere. The ratio of K+/levoglucosan concentrations (0.44) indicates that open fires are the main source of these tracers. The positive correlations between PM2.5 and levoglucosan and succinic and malonic acids suggest that such compounds are contributing to secondary organic aerosol particle formation.
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Aswini AR, Hegde P, Aryasree S, Girach IA, Nair PR. Continental outflow of anthropogenic aerosols over Arabian Sea and Indian Ocean during wintertime: ICARB-2018 campaign. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:135214. [PMID: 31836221 DOI: 10.1016/j.scitotenv.2019.135214] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Chemical characterisation of atmospheric aerosols over Arabian Sea (AS) and Indian Ocean (IO) have been carried out during the winter period (January to February 2018) as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018). Mass concentrations of organic carbon (OC), elemental carbon (EC), water soluble and insoluble OC (WSOC, WIOC), primary and secondary OC (POC, SOC), water-soluble inorganic ions and trace metals have been estimated with a view to identify and quantify the major anthropogenic pollutants affecting the oceanic environments. Aerosol mass loading was found to exhibit strong spatial heterogeneity (varying from 13 to 84 μg m-3), significantly modulated by the origin of air-mass trajectories. Chemical analysis of aerosols revealed the presence of an intense pollution plume over south-eastern coastal Arabian Sea, near to south-west Indian peninsula (extending from ~ 12°N to 0° at 75°E) with a strong latitudinal gradient (~3 μg m-3/deg. from north to south) dominated by anthropogenic species contributing as high as 73% (38% nss-SO42-, 24.2% carbonaceous aerosols (21% Organic Matter, 3.2% EC) and 10% NH4+). Anthropogenic signature over oceanic environment was also evident from the dominance and high enrichment of elements like Zn, Cu, Mn and Pb in trace metals. Long-range transport of air-masses originating from Indo Gangetic Plains and its outflow regions in Bay of Bengal, has been seen over Arabian Sea during winter, that imparted such strong anthropogenic signatures over this oceanic environment. Comparison with previous cruise studies conducted nearly two decades ago shows a more than two-fold increase in the concentration of nss-SO42-, over the continental outflow region in Arabian Sea.
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Affiliation(s)
- A R Aswini
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India; Cochin University of Science and Technology, Cochin, India
| | - Prashant Hegde
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India.
| | - S Aryasree
- Institute for applied Geosciences, Technical University Darmstadt, Darmstadt, Germany
| | - Imran A Girach
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India
| | - Prabha R Nair
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India
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Ojha N, Sharma A, Kumar M, Girach I, Ansari TU, Sharma SK, Singh N, Pozzer A, Gunthe SS. On the widespread enhancement in fine particulate matter across the Indo-Gangetic Plain towards winter. Sci Rep 2020; 10:5862. [PMID: 32246046 PMCID: PMC7125076 DOI: 10.1038/s41598-020-62710-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/09/2020] [Indexed: 11/20/2022] Open
Abstract
Fine particulate matter (PM2.5, aerodynamic diameter ≤2.5 µm) impacts the climate, reduces visibility and severely influences human health. The Indo-Gangetic Plain (IGP), home to about one-seventh of the world's total population and a hotspot of aerosol loading, observes strong enhancements in the PM2.5 concentrations towards winter. We performed high-resolution (12 km × 12 km) atmospheric chemical transport modeling (WRF-Chem) for the post-monsoon to winter transition to unravel the underlying dynamics and influences of regional emissions over the region. Model, capturing the observed variations to an extent, reveals that the spatial distribution of PM2.5 having patches of enhanced concentrations (≥100 µgm-3) during post-monsoon, evolves dramatically into a widespread enhancement across the IGP region during winter. A sensitivity simulation, supported by satellite observations of fires, shows that biomass-burning emissions over the northwest IGP play a crucial role during post-monsoon. Whereas, in contrast, towards winter, a large-scale decline in the air temperature, significantly shallower atmospheric boundary layer, and weaker winds lead to stagnant conditions (ventilation coefficient lower by a factor of ~4) thereby confining the anthropogenic influences closer to the surface. Such changes in the controlling processes from post-monsoon to winter transition profoundly affect the composition of the fine aerosols over the IGP region. The study highlights the need to critically consider the distinct meteorological processes of west-to-east IGP and changes in dominant sources from post-monsoon to winter in the formulation of future pollution mitigation policies.
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Affiliation(s)
- Narendra Ojha
- Space and Atmospheric Sciences division, Physical Research Laboratory, Ahmedabad, India.
| | - Amit Sharma
- EWRE Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India
- Laboratory for Atmospheric Research, Washington State University, Pullman, USA
| | - Manish Kumar
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Imran Girach
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, India
| | - Tabish U Ansari
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Som K Sharma
- Space and Atmospheric Sciences division, Physical Research Laboratory, Ahmedabad, India
| | - Narendra Singh
- Aryabhatta Research Institute of observational sciencES (ARIES), Nainital, India
| | - Andrea Pozzer
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Sachin S Gunthe
- EWRE Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India.
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Maji S, Beig G, Yadav R. Winter VOCs and OVOCs measured with PTR-MS at an urban site of India: Role of emissions, meteorology and photochemical sources. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 258:113651. [PMID: 31806461 DOI: 10.1016/j.envpol.2019.113651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 11/10/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
Within the outline of air quality studies at metropolitan city, the mixing ratios of seven selected volatile organic compounds (VOCs) were measured during December 2015 (winter) at an urban site of Pune. The measurement of VOCs was conducted using a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). The study represents daily variability of ambient VOCs and their various associated emission sources. Diurnal profiles have differed from one VOC to another as the result of their different origins and the influence of different meteorological parameters (i.e. solar radiation, temperature) and planetary boundary layer height (PBL-H). The hourly mixing ratios of Oxygenated-VOCs (OVOCs) and aromatics were in the ranges of 0.6-29 ppbv and 0.13-14 ppbv, respectively with OVOCs accounted for up to 75% of total measured VOCs. The role of long-range transport from the clear Thar Desert and polluted Indo-Gangetic Plain (IGP) was observed during the episodes of 1-15 and 17-31 December 2015, respectively. VOCs showed the strong diurnal variations with peaks during morning and evening hours and lowest in the afternoon. In the evening period, high levels of aromatics coincided with the lowest OVOCs suggests the role of fresh vehicular emissions. Emission ratios of various VOCs as a function of temperature showed the role of different sources including the biogenic and photochemical production as well as the anthropogenic sources, respectively. The higher emission ratio of Δmethanol/Δacetonitrile at the study site suggests the long range transport of biomass burning plumes from the Indo-Gangetic Plain (IGP) during the 17-31, Dec. 2015. In addition to the pattern of emission, the diurnal and day-to-day variations of VOCs were influenced by the local meteorological conditions and depth of planetary boundary layer (PBL-H).
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Affiliation(s)
- Sujit Maji
- Atmospheric Pollution and Transport Modeling (APTM) Division, Indian Institute of Tropical Meteorology Pune, India.
| | - Gufran Beig
- Atmospheric Pollution and Transport Modeling (APTM) Division, Indian Institute of Tropical Meteorology Pune, India
| | - Ravi Yadav
- Atmospheric Pollution and Transport Modeling (APTM) Division, Indian Institute of Tropical Meteorology Pune, India.
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25
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Li J, Han Z, Li J, Liu R, Wu Y, Liang L, Zhang R. The formation and evolution of secondary organic aerosol during haze events in Beijing in wintertime. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:134937. [PMID: 31767292 DOI: 10.1016/j.scitotenv.2019.134937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 10/10/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
A regional air quality model system (RAQMS) with a volatility basis set approach for secondary organic aerosol (SOA) formation and an emission inventory of semi-volatile (SVOC) and intermediate volatile organic compounds (IVOC) are applied to investigate the distribution and evolution of organic aerosols over the Beijing-Tianjin-Hebei (BTH) region in winter 2014, with focus on Beijing. Model validation demonstrates the model is capable of reproducing meteorological variables and major aerosol components, and the model significantly improves SOA and organic aerosol (OA) simulations by taking S/IVOCs (SVOC + IVOC) and relevant aging processes into account. SVOC and IVOC emissions in the BTH region are estimated to be 0.47 Tg and in a range of 0.09-0.36 Tg, respectively, which are about 18% and 4-14% of the emission amounts of volatile organic compounds (VOCs). The distribution of mean organic aerosols is characterized by a high concentration belt oriented southwest-northeast from southern Hebei to Beijing, with the maximum concentration up to 50 μg m-3 in Beijing and Shijiazhuang. The simulated SOA concentration is comparable in magnitude to primary organic aerosol (POA) concentration, and the SOA/OA ratio is around 50% in most areas of the BTH region. In terms of domain average, the percentage contributions to SOA mass concentration from anthropogenic volatile organic compounds (AVOCs), SVOCs, IVOCs and biogenic VOCs are estimated to be 46.1%, 40.1%, 9.4% and 4.4%, respectively, in the BTH region during the study period, which indicates an important role of S/IVOCs in SOA formation. From clean to haze periods, both POA and SOA concentrations apparently increase, with an increasing (decreasing) trend of the SOA/OA (POA/OA) ratio. SOA dominates over POA in fine organic aerosols during the haze periods. The increase of POA in hazy days is mainly due to the weakened vertical diffusion and accumulation near the surface, whereas the increase of SOA is likely attributed to both the reduced diffusivity and a series of competing chemical processes, in which the decreased photolysis rate by aerosol attenuation tends to decrease SOA concentration by about 6% during the most severe haze day, whereas the lower surface air temperature and higher POA and S/IVOC concentrations in haze days both enhance gas to particle partition, and consequently lead to higher SOA concentration.
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Affiliation(s)
- Jie Li
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Han
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jiawei Li
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China
| | - Ruiting Liu
- Institute of Urban Meteorology, China Meteorological Administration, Beijing 100089, China
| | - Yunfei Wu
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China
| | - Lin Liang
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Renjian Zhang
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS), Beijing 100029, China
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26
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Wu G, Wan X, Ram K, Li P, Liu B, Yin Y, Fu P, Loewen M, Gao S, Kang S, Kawamura K, Wang Y, Cong Z. Light absorption, fluorescence properties and sources of brown carbon aerosols in the Southeast Tibetan Plateau. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 257:113616. [PMID: 31761583 DOI: 10.1016/j.envpol.2019.113616] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/10/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Brown carbon (BrC) has been proposed as an important driving factor in climate change due to its light absorption properties. However, our understanding of BrC's chemical and optical properties are inadequate, particularly at remote regions. This study conducts a comprehensive investigation of BrC aerosols in summer (Aug. 2013) and winter (Jan. 2014) at Southeast Tibetan Plateau, which is ecologically fragile and sensitive to global warming. The concentrations of methanol-soluble BrC (MeS-BrC) are approximately twice of water-soluble BrC (WS-BrC), demonstrating the environmental importance of water-insoluble BrC are previously underestimated with only WS-BrC considered. The mass absorption efficiency of WS-BrC (0.27-0.86 m2 g-1) is lower than those in heavily polluted South Asia, indicating a distinct contrast between the two sides of Himalayas. Fluorescence reveals that the absorption of BrC is mainly attributed to humic-like and protein-like substances, which broaden the current knowledge of BrC's chromophores. Combining organic tracer, satellite MODIS data and air-mass backward trajectory analysis, this study finds BrC is mainly derived from bioaerosols and secondary formation in summer, while long-range transport of biomass burning emissions in winter. Our study provides new insights into the optical and chemical properties of BrC, which may have implications for environmental effect and sources of organic aerosols.
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Affiliation(s)
- Guangming Wu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Wan
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kirpa Ram
- Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi 221005, India
| | - Peilin Li
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Liu
- Chongqing Jinfo Mountain Field Scientific Observation and Research Station for Kaster Ecosystem, School of Geographical Sciences, Southwest University, Chongqing 400715, China
| | - Yongguang Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, CAS, Beijing 100085, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Mark Loewen
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Shaopeng Gao
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China; Center for Excellence in Tibetan Plateau Earth Sciences, CAS, Beijing 100101, China
| | - Kimitaka Kawamura
- Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan
| | - Yongjie Wang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Zhiyuan Cong
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; Center for Excellence in Tibetan Plateau Earth Sciences, CAS, Beijing 100101, China.
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Stockwell WR, Saunders E, Goliff WS, Fitzgerald RM. A perspective on the development of gas-phase chemical mechanisms for Eulerian air quality models. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2020; 70:44-70. [PMID: 31750791 DOI: 10.1080/10962247.2019.1694605] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 10/21/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
An essential component of a three-dimensional air quality model is its gas-phase mechanism. We present an overview of the necessary atmospheric chemistry and a discussion of the types of mechanisms with some specific examples such as the Master Chemical Mechanism, the Carbon Bond, SAPRC and the Regional Atmospheric Chemistry Mechanism (RACM). The first versions of the Carbon Bond and SAPRC mechanisms were developed through a hierarchy of chemical species approach that relied heavily on chemical environmental chamber data. Now a new approach has been proposed where the first step is to develop a highly detailed explicit mechanism such as the Master Chemical Mechanism and the second step is to test the detailed explicit mechanism against laboratory and field data. Finally, the detailed mechanism is condensed for use in a three-dimensional air quality model. Here it is argued that the development of highly detailed explicit mechanisms is very valuable for research, but we suggest that combining the hierarchy of chemical species and the detailed explicit mechanism approaches would be better than either alone.Implication: Many gas-phase mechanisms are available for urban, regional and global air quality modeling. A "hierarchy of chemical species approach," relying heavily on smog-chamber data was used for the development of the early series of mechanisms. Now the development of large, explicit master mechanisms that may be condensed is a significant, trend. However, a continuing problem with air quality mechanism development is due to the high complexity of atmospheric chemistry and the current availability of laboratory measurements. This problem requires a balance between completeness and speculation so that models maintain their utility for policymakers.
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Affiliation(s)
- William R Stockwell
- Department of Physics, University of Texas El Paso, El Paso, TX, USA
- Division of Atmospheric Sciences, Desert Research Institute, Nevada System of Higher Education, Reno, NV, USA
| | - Emily Saunders
- Science Systems and Applications, Inc. and Global Modeling Assimilation Office (GMAO), NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Wendy S Goliff
- Chemistry Department, Riverside City College, Riverside, CA, USA
| | - Rosa M Fitzgerald
- Department of Physics, University of Texas El Paso, El Paso, TX, USA
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Abstract
The atmosphere is composed of nitrogen, oxygen and argon, a variety of trace gases, and particles or aerosols from a variety of sources. Reactive, trace gases have short mean residence time in the atmosphere and large spatial and temporal variations in concentration. Many trace gases are removed by reaction with hydroxyl radical and deposition in rainfall or dryfall at the Earth's surface. The upper atmosphere, the stratosphere, contains ozone that screens ultraviolet light from the Earth's surface. Chlorofluorocarbons released by humans lead to the loss of stratospheric ozone, which might eventually render the Earth's land surface uninhabitable. Changes in the composition of the atmosphere, especially rising concentrations of CO2, CH4, and N2O, will lead to climatic changes over much of the Earth's surface.
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Multi-Model Evaluation of Meteorological Drivers, Air Pollutants and Quantification of Emission Sources over the Upper Brahmaputra Basin. ATMOSPHERE 2019. [DOI: 10.3390/atmos10110703] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The temporal distributions of meteorological drivers and air pollutants over Dibrugarh, a location in the upper Brahmaputra basin, are studied using observations, models and reanalysis data. The study aims to assess the performance of the Weather Research and Forecasting model coupled with chemistry (WRF-Chem), the WRF coupled with Sulfur Transport dEposition Model (WRF-STEM), and Copernicus Atmosphere Monitoring Service (CAMS) model over Dibrugarh for the first time. The meteorological variables and air pollutants viz., black carbon(BC), carbon monoxide(CO), sulphur dioxide(SO2), Ozone(O3), and oxides of Nitrogen(NOx) obtained from WRF-Chem, WRF-STEM and CAMS are evaluated with observations. The source region tagged CO simulated by WRF-STEM delineate the regional contribution of CO. The principal source region of anthropogenic CO over Dibrugarh is North-Eastern India with a 59% contribution followed by that from China (17%), Indo-Gangetic Plains (14%), Bangladesh (6%), other parts of India (3%) and other regions (1%). Further, the BC-CO regression analysis is used to delineate the local emission sources. The BC-CO correlations estimated from models (0.99 for WRF-Chem, 0.96 for WRF-STEM, 0.89 for CAMS), and reanalysis (0.8 for Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA2) are maximum in pre-monsoon whereas surface observations show highest correlations (0.81) in winter. In pre-monsoon season, 90% of the modeled CO is due to biomass burning over Dibrugarh.
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Wei T, Dong Z, Kang S, Zong C, Rostami M, Shao Y. Atmospheric deposition and contamination of trace elements in snowpacks of mountain glaciers in the northeastern Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:754-764. [PMID: 31280157 DOI: 10.1016/j.scitotenv.2019.06.455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 06/09/2023]
Abstract
To investigate the large-scale trace element deposition and anthropogenic pollution in mountain glaciers of the northeastern Tibetan Plateau (TP) and its surrounding regions, we analyzed Al and 13 trace elements (As, Cd, Co, Cr, Cs, Cu, Mn, Mo, Ni, Pb, Sb, V, and Zn) in glacier snowpacks collected at the Yuzhufeng, Laohugou No.12, and Qiyi glaciers (YG, LG12, and QG, respectively) in the northeastern TP as well as in the Miaoergou Glacier (MG) in the eastern Tianshan Mountains in June 2017. The concentrations and enrichment factors (EFs) of most trace elements (e.g., As, Cd, Co, Cr, Cu, Ni, and Sb) showed that the largest value appeared in the MG, followed by LG12, and the lowest value appeared in the QG, thereby implying a decreasing influence of anthropogenic emissions on these elements from the west (MG) to the east (QG). The YG inversely exhibited high concentrations but low EFs for As, Cd, Co, Cr, Cs, Cu, Pb, and Sb. Compared to the surrounding regions of the southern and western TP (e.g., NamCo, Mt. Everest, and Pamirs), Japan, and Kathmandu, the trace element concentrations were relatively higher at the YG and MG but relatively lower at the LG12 and QG. The spatial distribution characteristics of trace elements (e.g., Pb and Sb) exhibited a gradually decreasing concentration from west to east in the Tianshan Mountains, and from south to north in the TP, implying two potential transport routes of atmospheric pollutants from Central and South Asia to the northeastern TP. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations/Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO/CALIOP) data reflected that these trace elements in the MG, LG12, and QG predominately originated from the western and surrounding areas, whereas in the YG they were mainly derived from a local source and South Asia through long-distance transport.
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Affiliation(s)
- Ting Wei
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwen Dong
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences (CAS), Beijing 100101, China; Institute for Geophysics and Meteorology, University of Cologne, Cologne D-50923, Germany.
| | - Shichang Kang
- State Key Laboratory of Cryosphere Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Chunlei Zong
- State Key Laboratory of Continental Dynamics, Northwest University, Xi'an 710069, China
| | - Masoud Rostami
- Institute for Geophysics and Meteorology, University of Cologne, Cologne D-50923, Germany
| | - Yaping Shao
- Institute for Geophysics and Meteorology, University of Cologne, Cologne D-50923, Germany
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Sun Y, Xu F, Li X, Zhang Q, Gu Y. Mechanisms and kinetic studies of OH-initiated atmospheric oxidation of methoxyphenols in the presence of O 2 and NO x. Phys Chem Chem Phys 2019; 21:21856-21866. [PMID: 31553018 DOI: 10.1039/c9cp03246k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methoxyphenols, as the main products and tracers of biomass burning, have been demonstrated to play an important role in the formation of secondary organic aerosols. However, their chemical transformation and migration in the atmosphere haven't been well characterized. In this study, detailed gas-phase reaction mechanisms and kinetics of three representative methoxyphenols (guaiacol, creosol and syringol) with OH radicals were investigated by using density functional theory (DFT). The initial reactions of methoxyphenols with OH radicals proceed via two different patterns, including OH-addition and H-atom abstraction. Subsequent reaction schemes of the active intermediates in the presence of O2/NOx are thoughtfully modeled. Catechol, methyl glyoxylate, malealdehyde and carbonyl or carboxyl compounds were confirmed as the dominant oxidation products for guaiacol. As a supplementary study, the formation pathways for the expected products nitroguaiacol and nitrocatechol were presented in high-NO2 conditions. Total and individual rate coefficients are calculated using the MESMER program at 294 K and 1 atm. The lifetimes of guaiacol, creosol and syringol were estimated to be 4.27, 3.56 and 2.98 hours, respectively, which are strongly competitive with the solar photolysis of methoxyphenols.
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Affiliation(s)
- Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, P. R. China.
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An Z, Sun J, Han D, Mei Q, Wei B, Wang X, He M. Theoretical study on the mechanisms, kinetics and ecotoxicity assessment of OH-initiated reactions of guaiacol in atmosphere and wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 685:729-740. [PMID: 31234135 DOI: 10.1016/j.scitotenv.2019.06.229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/31/2019] [Accepted: 06/15/2019] [Indexed: 06/09/2023]
Abstract
The OH-initiated transformation mechanisms, kinetics and ecotoxicity assessment of guaiacol (2-methoxyphenol) in the presence of O2/NOx were investigated both in atmosphere and wastewater. The solvent effect lowers the energy barriers of initial OH-addition reactions more than H-abstraction reactions, leading to much higher addition branching ratio (Γadd) of 0.92 in aqueous solution than that of 0.42 in gas-phase. At 298 K, the overall rate constants of the title reactions in atmosphere and wastewater are 5.56 × 10-12 and 1.41 × 10-11 cm3 molecule-1 s-1 with corresponding half-lives of 34.6 h and 0.82 s, respectively. In atmosphere, all the proposed favorable products including nitroguaiacols, methoxybenzoquinone, 2-hydroxyphenyl formate, 2-methoxybenzene-1, 3-diol and dialdehyde could contribute to secondary organic aerosols (SOAs). In wastewater, NO2 addition reactions lead to higher toxicity of products (nitroguaiacols and 2-methoxybenzene-1, 4-diol) than that of parental guaiacol. However, O2/NO addition pathways may generate less harmful products except for methoxybenzoquinone (P3) which is with higher toxicity than guaiacol. Therefore, more attention should be focused on the products formed from OH-initiated reactions of guaiacol both in atmosphere and wastewater.
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Affiliation(s)
- Zexiu An
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Jianfei Sun
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Dandan Han
- School of Chemistry and Chemical Engineering, Heze University, Heze 274015, PR China
| | - Qiong Mei
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Bo Wei
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Xueyu Wang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Maoxia He
- Environment Research Institute, Shandong University, Qingdao 266237, PR China.
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Mechanistic and Kinetic Investigations on the Ozonolysis of Biomass Burning Products: Guaiacol, Syringol and Creosol. Int J Mol Sci 2019; 20:ijms20184492. [PMID: 31514377 PMCID: PMC6770092 DOI: 10.3390/ijms20184492] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 08/26/2019] [Accepted: 09/07/2019] [Indexed: 02/01/2023] Open
Abstract
The lignin pyrolysis products generated by biomass combustion make an essential contribution to the formation of secondary organic aerosols (SOAs). The ozone-initiated oxidation of guaiacol, syringol and creosol, major constituents of biomass burning, were investigated theoretically by using the density functional theory (DFT) method at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. Six primary addition reaction pathways and further decomposition routes with corresponding thermodynamic values were proposed. The Criegee intermediates can be excited by small molecules, such as NOx, H2O in the atmosphere, and would further proceed via self-decomposition or isomerization. The most predominant product for ozonation of guaiacol is the monomethyl muconate (P1). At 295 K and atmospheric pressure, the rate constant is 1.10 × 10-19 cm3 molecule-1 s-1, which is lies a factor of 4 smaller than the previous experimental study. The branching ratios of the six channels are calculated based on corresponding rate coefficient. The present work mainly provides a more comprehensive and detailed theoretical research on the ozonation of methoxyphenol, which aspires to offer novel insights and reference for future experimental and theoretical work and control techniques of SOAs caused by lignin pyrolysis products.
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He X, Zhang YH. Influence of relative humidity on SO 2 oxidation by O 3 and NO 2 on the surface of TiO 2 particles: Potential for formation of secondary sulfate aerosol. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 219:121-128. [PMID: 31030039 DOI: 10.1016/j.saa.2019.04.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 04/14/2019] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
The heterogeneous reactions of SO2/O3 and SO2/NO2 with TiO2 particles were studied as a function of relative humidities (RHs). An in situ microscopic Fourier transform infrared (micro-FTIR) spectrometer was used to monitor the reaction kinetics. Rapid conversion of SO2 to sulfate occurs on the surface of TiO2 particles in the presence of O3 or NO2, which is sensitive to RHs. For unreacted (fresh) particles, the uptake coefficients for SO2 in initial stage are both obviously enhanced over four times with the increasing RH from ~4% to ~85%. Moreover, the uptake coefficient in the system of SO2/O3 is about 40% higher than that of SO2/NO2 on TiO2 particles at the similar RH conditions. For TiO2 after exposure to SO2/O3 or SO2/NO2 (sulfated) particles, the uptake coefficients for SO2 in moisture absorption stage are all higher than that on fresh particles in initial stage at the similar RH, indicating rapid mixture gases adsorption with particle hygroscopic growth. The high production of the secondary sulfate for heterogeneous reaction of mixture gases on TiO2 surface from arid region to humid region provides new insights for better understanding the severe haze under the humid condition.
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Affiliation(s)
- Xiang He
- College of Resource and Environment Sciences, Xinjiang University, Urumqi 830046, PR China; Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, PR China
| | - Yun-Hong Zhang
- Institute of Chemical Physics, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, PR China.
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Gao M, Sherman P, Song S, Yu Y, Wu Z, McElroy MB. Seasonal prediction of Indian wintertime aerosol pollution using the ocean memory effect. SCIENCE ADVANCES 2019; 5:eaav4157. [PMID: 31328156 PMCID: PMC6636995 DOI: 10.1126/sciadv.aav4157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 06/11/2019] [Indexed: 05/26/2023]
Abstract
As China makes every effort to control air pollution, India emerges as the world's most polluted country, receiving worldwide attention with frequent winter (boreal) haze extremes. In this study, we found that the interannual variability of wintertime aerosol pollution over northern India is regulated mainly by a combination of El Niño and the Antarctic Oscillation (AAO). Both El Niño sea surface temperature (SST) anomalies and AAO-induced Indian Ocean Meridional Dipole SST anomalies can persist from autumn to winter, offering prospects for a prewinter forecast of wintertime aerosol pollution over northern India. We constructed a multivariable regression model incorporating El Niño and AAO indices for autumn to predict wintertime AOD. The prediction exhibits a high degree of consistency with observation, with a correlation coefficient of 0.78 (P < 0.01). This statistical model could allow the Indian government to forecast aerosol pollution conditions in winter and accordingly improve plans for pollution control.
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Affiliation(s)
- Meng Gao
- Department of Geography, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Peter Sherman
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Shaojie Song
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Yueyue Yu
- Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Zhiwei Wu
- Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
| | - Michael B. McElroy
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
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36
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Bikkina S, Sarin M. Brown carbon in the continental outflow to the North Indian Ocean. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:970-987. [PMID: 31089643 DOI: 10.1039/c9em00089e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this paper, we synthesize the size distribution and optical properties of the atmospheric water-soluble fraction of light-absorbing organic carbon (brown carbon; BrC) in the continental outflow from the Indo-Gangetic Plain (IGP) in South Asia to the North Indian Ocean. A comparison of the mass absorption coefficient of water-soluble BrC (babs-WSBrC-365nm) in PM2.5 with that in PM10 sampled over the Bay of Bengal reveals the dominance of BrC in fine mode. Furthermore, the babs-BrC-365nm shows a significant linear relationship with mass concentrations of airborne particulate matter, water-soluble organic carbon and non-sea-salt-K+ in the continental outflow from the IGP. This observation emphasizes the ubiquitous nature and significant contribution of water-soluble BrC from biomass burning emissions (BBEs). Comparing the absorption properties from this study with global datasets, it is discernible that BBEs dominate BrC absorption. Furthermore, the imaginary refractive index of water-soluble BrC (kWSBrC-365nm) in marine aerosols sampled over the North Indian Ocean during November is significantly higher than during December to January. Thus, significant temporal variability is associated with crop-residue burning emissions in the IGP on the composition of BrC over the North Indian Ocean. Our estimates show that the babs-WSBrC-365nm and kWSBrC-365nm from post-harvest crop-residue burning emissions in the IGP are much higher than the BBEs from the southeastern United States and Amazonian forest fires. Another major finding of this study is the lack of significant relationship between kWSBrC-365nm and the mass ratio of elemental carbon to particulate organic matter, as previously suggested by chamber experiments to model varying BrC absorption properties in ambient aerosols. Therefore, considerable spatio-temporal variability prevails among emission sources (wood burning vs. crop-residue burning), which needs to be considered when assessing the regional radiative forcing of BrC relative to major absorbing elemental carbon.
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Affiliation(s)
- Srinivas Bikkina
- Geosciences Division, Physical Research Laboratory, Ahmedabad-380 009, India.
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Wu G, Ram K, Fu P, Wang W, Zhang Y, Liu X, Stone EA, Pradhan BB, Dangol PM, Panday AK, Wan X, Bai Z, Kang S, Zhang Q, Cong Z. Water-Soluble Brown Carbon in Atmospheric Aerosols from Godavari (Nepal), a Regional Representative of South Asia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:3471-3479. [PMID: 30848122 DOI: 10.1021/acs.est.9b00596] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Brown carbon (BrC) has recently emerged as an important light-absorbing aerosol. This study provides interannual and seasonal variations in light absorption properties, chemical composition, and sources of water-soluble BrC (WS-BrC) based on PM10 samples collected in Godavari, Nepal, from April 2012 to May 2014. The mass absorption efficiency of WS-BrC at 365 nm (MAE365) shows a clear seasonal variability, with the highest MAE365 of 1.05 ± 0.21 m2 g-1 in premonsoon season and the lowest in monsoon season (0.59 ± 0.16 m2 g-1). The higher MAE365 values in nonmonsoon seasons are associated with fresh biomass burning emissions. This is further substantiated by a strong correlation ( r = 0.79, P < 0.01) between Abs365 (light absorption coefficient at 365 nm) and levoglucosan. We found, using fluorescence techniques, that humic-like and protein-like substances are the main chromophores in WS-BrC and responsible for 80.2 ± 4.1% and 19.8 ± 4.1% of the total fluorescence intensity, respectively. BrC contributes to 8.78 ± 3.74% of total light absorption over the 300-700 nm wavelength range. Considering the dominant contribution of biomass burning to BrC over Godavari, this study suggests that reduction in biomass burning emission may be a practical method for climate change mitigation in South Asia.
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Affiliation(s)
- Guangming Wu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes , Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Kirpa Ram
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes , Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China
- Institute of Environment and Sustainable Development , Banaras Hindu University , Varanasi 221005 , India
| | - Pingqing Fu
- Institute of Surface-Earth System Science , Tianjin University , Tianjin 300072 , China
| | - Wan Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment , Chinese Research Academy of Environmental Sciences , Beijing 100012 , China
| | - Yanlin Zhang
- Yale-NUIST Center on Atmospheric Environment , Nanjing University of Information Science and Technology , Nanjing 210044 , China
| | - Xiaoyan Liu
- Yale-NUIST Center on Atmospheric Environment , Nanjing University of Information Science and Technology , Nanjing 210044 , China
| | - Elizabeth A Stone
- Department of Chemistry , University of Iowa , Iowa City , Iowa 52246 , United States
| | - Bidya Banmali Pradhan
- International Centre for Integrated Mountain Development , Khumaltar , Lalitpur 009771 , Nepal
| | - Pradeep Man Dangol
- International Centre for Integrated Mountain Development , Khumaltar , Lalitpur 009771 , Nepal
| | - Arnico K Panday
- International Centre for Integrated Mountain Development , Khumaltar , Lalitpur 009771 , Nepal
| | - Xin Wan
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes , Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Zhipeng Bai
- State Key Laboratory of Environmental Criteria and Risk Assessment , Chinese Research Academy of Environmental Sciences , Beijing 100012 , China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources , Chinese Academy of Sciences , Lanzhou 730000 , China
- Center for Excellence in Tibetan Plateau Earth Sciences , Chinese Academy of Sciences , Beijing 100101 , China
| | - Qianggong Zhang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes , Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China
- Center for Excellence in Tibetan Plateau Earth Sciences , Chinese Academy of Sciences , Beijing 100101 , China
| | - Zhiyuan Cong
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes , Institute of Tibetan Plateau Research, Chinese Academy of Sciences , Beijing 100101 , China
- Center for Excellence in Tibetan Plateau Earth Sciences , Chinese Academy of Sciences , Beijing 100101 , China
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Gadi R, Sharma SK, Mandal TK. Source apportionment and health risk assessment of organic constituents in fine ambient aerosols (PM 2.5): A complete year study over National Capital Region of India. CHEMOSPHERE 2019; 221:583-596. [PMID: 30665088 DOI: 10.1016/j.chemosphere.2019.01.067] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 05/28/2023]
Abstract
Fine ambient aerosols (PM2.5) levels in the atmosphere are continuously worsening over Delhi and National Capital Region (NCR) of India. Complete source profiles are required to be assessed for implementation of proper mitigation measures over the NCR. In this study, emission sources of PM2.5 are reported for the NCR of India for samples collected during December 2016 to December 2017 at three sampling sites in Delhi, Uttar Pradesh and Haryana. Organic constituents (n-alkanes, isoprenoid hydrocarbons, polycyclic aromatic hydrocarbons, phthalates, levoglucosan and n-alkanoic acids) in PM2.5 were measured to apportion the sources over the study area. Source apportionment of PM2.5 was performed using organic constituents by Positive Matrix Factorization (PMF) and Principal Component Analysis (PCA). Health risk associated with organic pollutants [PAHs and carcinogen BEHP bis(2-ethylhexyl) phthalate] demonstrated the threat of PM2.5 exposure via inhalation. Transport pathways of air masses were evaluated using 3-day backward trajectories and observed that some air masses originated from local sources along with long-range transport which influenced the PAHs concentration during most of the study period over the NCR. PMF and PCA resulted in the five major emission sources [vehicular emissions (32.2%), biomass burning (30%), cooking emissions (16.8%), plastic burning (13.4%), mixed sources (7.6%) including biogenic and industrial emissions] for PM2.5 over the sampling sites. The present study reveals that transport sector is a major source to be targeted to reduce the vehicular emissions and consequent health risks associated with organic pollutants especially PAHs.
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Affiliation(s)
- Ranu Gadi
- Indira Gandhi Delhi Technical University for Women, New Delhi, 110006, India.
| | - Sudhir Kumar Sharma
- National Physical Laboratory, Council of Scientific and Industrial Research (CSIR), New Delhi, 110012, India
| | - Tuhin Kumar Mandal
- National Physical Laboratory, Council of Scientific and Industrial Research (CSIR), New Delhi, 110012, India
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Tripathee L, Guo J, Kang S, Paudyal R, Huang J, Sharma CM, Zhang Q, Chen P, Ghimire PS, Sigdel M. Spatial and temporal distribution of total mercury in atmospheric wet precipitation at four sites from the Nepal-Himalayas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 655:1207-1217. [PMID: 30577113 DOI: 10.1016/j.scitotenv.2018.11.338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 06/09/2023]
Abstract
The studies on global pollutant mercury (Hg), which is of public concern due to its high toxicity and capacity to long-range transport via atmospheric circulation, is poorly characterized in wet deposition over the Nepal-Himalayas region. Therefore, in order to understand the concentration levels, spatial distribution and seasonal variation of total Hg, 333 precipitation samples were collected from south to north: Kathmandu (1314 m a.s.l.), Dhunche (2065 m a.s.l.), Dimsa (3078 m a.s.l.) and Gosainkunda (4417 m a.s.l.) characterized as urban, rural, remote forest and remote alpine sites, respectively, for over one-year period. The highest Hg concentration was found in Kathmandu comparable to the urban sites worldwide, and significantly lower concentrations at other three sites demonstrated similar levels as in rural and remote alpine sites worldwide. Higher wet deposition fluxes of 34.91 and 15.89 μg m-2 year-1 were found in Kathmandu and Dhunche respectively, due to higher precipitation amount. Clear and distinct seasonal differences were observed with higher concentrations in non-monsoon and lower values in monsoon periods due to less scavenging and high pollutant concentration loadings during the dry period. The positive correlation of Hg flux and precipitation amount with Hg concentration suggested that both precipitation amount and Hg concentration plays a vital role in Hg deposition in the central Himalayan region. Enrichment factor (EFHg) indicated that the anthropogenic emission sources play a significant role for Hg enrichment and a high ratio of EFmonsoon to EFnon-monsoon (>2.18) suggested that the anthropogenic atmospheric mercury could likely be long-range transported from south Asian regions to the Himalayas during the monsoon season. In addition, our results showed that the major ionic compositions (e.g., SO42-, NO3-, NH4+, K+, Ca2+) could influence Hg concentration in wet precipitation. The anthropogenic sources of Hg such as biomass and fossil fuel combustion, crustal aerosols may contribute to the Hg concentration in wet precipitation over the central Himalayas.
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Affiliation(s)
- Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal
| | - Junming Guo
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China.
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rukumesh Paudyal
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Huang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Chhatra Mani Sharma
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal; Central Department of Environmental Science, Tribhuvan University, Kathmandu, Nepal
| | - Qianggong Zhang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100085, China; Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Pengfei Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Prakriti Sharma Ghimire
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal
| | - Madan Sigdel
- Central Department of Hydrology and Meteorology, Tribhuvan University, Kathmandu, Nepal
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40
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Lee CSL, Chou CCK, Cheung HC, Tsai CY, Huang WR, Huang SH, Chen MJ, Liao HT, Wu CF, Tsao TM, Tsai MJ, Su TC. Seasonal variation of chemical characteristics of fine particulate matter at a high-elevation subtropical forest in East Asia. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 246:668-677. [PMID: 30611943 DOI: 10.1016/j.envpol.2018.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 10/01/2018] [Accepted: 11/11/2018] [Indexed: 06/09/2023]
Abstract
The aim of this study was to chemically characterize the fine particulate matter (PM2.5) at a subtropical forest in East Asia under the influences of anthropogenic and biogenic sources and a complex topographic setting. Four seasonal campaigns were conducted at the Xitou Experimental Forest in central Taiwan from the winter of 2013 to the autumn of 2014. The results indicated that the ambient levels and chemical features of PM2.5 exhibited pronounced seasonal variations. Non-sea-salt sulfate (nss-SO42-) constituted the major component of PM2.5, followed by ammonium (NH4+) and nitrate (NO3-) during winter, summer and autumn. However, it was revealed that the mass fraction of NO3- increased to be comparable with that of nss-SO42- in springtime. The mass contribution of secondary organic carbon (SOC) to PM2.5 peaked in summer (13.2%), inferring the importance of enhanced photo-oxidation reactions in SOC formation. Diurnal variations of O3 and SO2 coincided with each other, suggesting the transport of aged pollutants from distant sources, whereas CO and NOx were shown to be under the influences of both local and regional sources. Notably high sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were observed, which were 0.93 ± 0.05 and 0.39 ± 0.20, respectively. Precursor gases (i.e. SO2 and NOx) could be converted to sulfate and nitrate during the transport by the uphill winds. Furthermore, due to the high relative humidity at Xitou, enhanced aqueous-phase and/or heterogeneous reactions could further contribute to the formation of sulfate and nitrate at the site. This study demonstrated the significant transport of urban pollutants to a subtropical forest by the mountain-valley circulations as well as the long-range transport from regional sources, whereas the implications of which for regional climate change necessitated further investigation.
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Affiliation(s)
- Celine S L Lee
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - C C-K Chou
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan.
| | - H C Cheung
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - C-Y Tsai
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - W-R Huang
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - S-H Huang
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - M-J Chen
- Research Center for Environmental Changes, Academia Sinica, Taipei, Taiwan
| | - H-T Liao
- Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan
| | - C-F Wu
- Department of Public Health, National Taiwan University, Taipei, Taiwan
| | - T-M Tsao
- School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan
| | - M-J Tsai
- School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan
| | - T-C Su
- Department of Internal Medicine and Cardiovascular Center, National Taiwan University Hospital, Taipei, Taiwan
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Xu R, Tie X, Li G, Zhao S, Cao J, Feng T, Long X. Effect of biomass burning on black carbon (BC) in South Asia and Tibetan Plateau: The analysis of WRF-Chem modeling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 645:901-912. [PMID: 30032086 DOI: 10.1016/j.scitotenv.2018.07.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 06/08/2023]
Abstract
The focus of this study is to evaluate the impact of biomass burning (BB) from South Asia and Southeast Asia on the glaciers over the Tibetan Plateau. The seasonality and long-term trend of biomass fires measured by Terra and Aqua satellite data from 2010 to 2016 are used in this study. The analysis shows that the biomass burnings were widely dispersed in the continental of Indian and Southeast Asia and existed a strong seasonal variation. The biomass burnings in winter (January) were relatively weak and scattered and were significantly enhanced in spring (April). The highest biomass burnings located in two regions. One was along the foothill of Himalayas, where is a dense population area, and the second located in Southeast Asia. Because these two high biomass burning regions are close to the Tibetan Plateau, they could have important effects on the BC deposition over the glaciers of the Tibetan Plateau. In order to study the effect of BB emissions on the deposition over the glaciers in the Tibetan Plateau, a regional chemical model (WRF-Chem; Weather Research and Forecasting Chemical model) was applied to simulate the BC distributions and the transport from BB emission regions to the glaciers in Tibetan Plateau. The result shows that in winter (January), due to the relatively weak BB emissions, the effect of BB emissions on BC concentrations was not significant. The BC concentrations resulted from BB emissions ranged from 0.1 to 2.0 μg/m3, with high concentrations distributed along the foothill of Himalayas and the southeastern Asia region. Due to the relative low BC concentrations, there was insignificant effect of BB emissions on the deposition over the glaciers in the Tibetan Plateau in winter. However, the BB emissions were highest in spring (April), producing high BC concentrations. For example, along the Himalayas Mountain and in the southeastern Asia region, The BC concentrations ranged from 2.0 to 6.0 μg/m3. In addition to the high BC concentrations, there were also west and south prevailing winds in these regions. As a result, the BC particles were transported to the glaciers in the Tibetan Plateau, causing significant deposition of BC particles on the snow surface of the glaciers. This study suggests that the biomass burning emissions have important effects on the BC deposition over the glaciers in the Tibetan Plateau, and the contaminations of glaciers could have significant impact on the melting of snow in the Tibetan Plateau, causing some severe environmental problems, such as the water resources.
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Affiliation(s)
- Ruiguang Xu
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; College of Energy and Environmental Engineering, Hebei University of Engineering, Handan 056038, China; Postdoctoral Research Station of Xi'an Chan-Ba Ecological District(CBE) Management Committee, Xi'an 710024, China
| | - Xuexi Tie
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; National Center for Atmospheric Research (NCAR), Boulder, CO 80303, USA.
| | - Guohui Li
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Shuyu Zhao
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Junji Cao
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Tian Feng
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Xin Long
- State Kay Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
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Gadi R, Sharma SK, Mandal TK, Kumar R, Mona S, Kumar S, Kumar S. Levels and sources of organic compounds in fine ambient aerosols over National Capital Region of India. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:31071-31090. [PMID: 30187408 DOI: 10.1007/s11356-018-3044-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/22/2018] [Indexed: 06/08/2023]
Abstract
The study presents the spatial and temporal variation of fine ambient aerosols (PM2.5) over National Capital Region (NCR), India, during January to June 2016. The investigation includes three sampling sites, one in Delhi and two in the adjoining states of Delhi (Uttar Pradesh and Haryana), across NCR, India. The average PM2.5 concentration was highest for Delhi (128.5 ± 51.5 μg m-3) and lowest for Mahendragarh, Haryana (74.5 ± 28.7 μg m-3), during the study period. Seasonal variation was similar for all the sites with highest concentration during winter and lowest in summer. PM2.5 samples were analysed for organic compounds using gas chromatograph (GC). The concentration of three organic compound classes, n-alkanes (C11-C35), polycyclic aromatic hydrocarbons (PAHs), and phthalates, present in PM2.5 samples has been reported. Diagnostic ratios for n-alkanes demonstrated that biogenic emissions were dominant over Mahendragarh while major contributions were observed from petrogenic emissions over Delhi and Modinagar, Uttar Pradesh. Molecular diagnostic ratios were calculated to distinguish between different sources of PAHs, which revealed that the fossil fuel combustion (diesel and gasoline emissions), traffic emissions, and biomass burning are the major source contributors. Health risk associated with human exposure of phthalates and PAHs was also assessed as daily intake (DI, ng kg-1 day-1) and lung cancer risk, respectively. Backward trajectory analysis explained the local, regional, and long-range transport routes of PM2.5 for all sites. Principal component analysis (PCA) results summarized that the vehicular emissions, biomass burning, and plastic burning were the major sources of the PAHs and phthalates over the sampling sites.
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Affiliation(s)
- Ranu Gadi
- Indira Gandhi Delhi Technical University for Women, New Delhi, 110006, India.
| | - Sudhir Kumar Sharma
- National Physical Laboratory, Council of Scientific and Industrial Research (CSIR), New Delhi, 110012, India
| | - Tuhin Kumar Mandal
- National Physical Laboratory, Council of Scientific and Industrial Research (CSIR), New Delhi, 110012, India
| | - Ravi Kumar
- Multanimal Modi College, Modinagar, Uttar Pradesh, 201204, India
| | - Sharma Mona
- Central University of Haryana, Mahendragarh, Haryana, 123031, India
| | - Sachin Kumar
- Multanimal Modi College, Modinagar, Uttar Pradesh, 201204, India
| | - Sanchit Kumar
- Central University of Haryana, Mahendragarh, Haryana, 123031, India
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Sen A, Karapurkar SG, Saxena M, Shenoy DM, Chaterjee A, Choudhuri AK, Das T, Khan AH, Kuniyal JC, Pal S, Singh DP, Sharma SK, Kotnala RK, Mandal TK. Stable carbon and nitrogen isotopic composition of PM 10 over Indo-Gangetic Plains (IGP), adjoining regions and Indo-Himalayan Range (IHR) during a winter 2014 campaign. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:26279-26296. [PMID: 29978315 DOI: 10.1007/s11356-018-2567-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 06/14/2018] [Indexed: 06/08/2023]
Abstract
For source identification, a field campaign involving simultaneous sampling of particulate matter (PM10) was conducted at eight sampling sites in the Indian mainland during winter 2014. The sampling sites include Delhi (upper IGP), Lucknow (middle IGP), and Kolkata (lower IGP) in the Indo-Gangetic Plains (IGP); Mohal-Kullu and Darjeeling in the Indo-Himalayan Range (IHR). In addition, Ajmer, located upwind of the IGP in NW-India and Giridih and Bhubaneswar, in the downwind to the IGP has also been chosen. To characterize the sources of the ambient PM10, stable isotope ratios of carbon (δ13CTC) and nitrogen (δ15NTN) for the total carbon (TC) and total nitrogen (TN) fractions have been considered. Ancillary chemical parameters, such as organic carbon (OC), elemental carbon (EC), and water-soluble ionic components (WSIC) mass concentrations are also presented in this paper. There was very small variation in the daily average δ13CTC ratios (- 24.8 to - 25.9‰) among the sites. Comparison with end-member stable C isotopic signatures of major typical sources suggests that the PM10 at the sites was mainly from fossil fuel and biofuel and biomass combustion. Daily average δ15NTN ratios were not observed to vary much between sites either (8.3 to 11.0‰), and the low δ15NTN levels also indicate substantial contributions from biofuel and biomass burning of primarily C3 andC4 plant matter. Graphical abstract Scatter plot of the average (± 1 standard deviation (SD)) δ13CTC (‰) compared to δ15NTN (‰) at the sampling sites.
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Affiliation(s)
- Avirup Sen
- Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi, 110012, India
| | | | - Mohit Saxena
- Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi, 110012, India
| | - Damodar M Shenoy
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Abhijit Chaterjee
- Centre for Astroparticle Physics and Space Sciences, Bose Institute, Darjeeling, Kolkata, West Bengal, India
| | | | - Trupti Das
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha, India
| | - Altaf H Khan
- CSIR-Indian Institute of Toxicology Research, Lucknow, Uttar Pradesh, India
| | - Jagdish Chandra Kuniyal
- G.B. Pant National Institute of Himalayan Environment and Sustainable Development, Himachal Unit, Mohal, Kullu, Himachal Pradesh, India
| | - Srimata Pal
- Indian Statistical Institute, B.T. Road, Kolkata, West Bengal, India
| | | | - Sudhir Kumar Sharma
- Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi, 110012, India
| | - Ravindra Kumar Kotnala
- Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi, 110012, India
| | - Tuhin Kumar Mandal
- Environmental Sciences and Biomedical Metrology Division, CSIR-National Physical Laboratory, Dr. K S Krishnan Road, New Delhi, 110012, India.
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Lelieveld J, Bourtsoukidis E, Brühl C, Fischer H, Fuchs H, Harder H, Hofzumahaus A, Holland F, Marno D, Neumaier M, Pozzer A, Schlager H, Williams J, Zahn A, Ziereis H. The South Asian monsoon-pollution pump and purifier. Science 2018; 361:270-273. [PMID: 29903882 DOI: 10.1126/science.aar2501] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 05/30/2018] [Indexed: 11/02/2022]
Abstract
Air pollution is growing fastest in monsoon-affected South Asia. During the dry winter monsoon, the fumes disperse toward the Indian Ocean, creating a vast pollution haze, but their fate during the wet summer monsoon has been unclear. We performed atmospheric chemistry measurements by aircraft in the Oxidation Mechanism Observations campaign, sampling the summer monsoon outflow in the upper troposphere between the Mediterranean and the Indian Ocean. The measurements, supported by model calculations, show that the monsoon sustains a remarkably efficient cleansing mechanism by which contaminants are rapidly oxidized and deposited to Earth's surface. However, some pollutants are lofted above the monsoon clouds and chemically processed in a reactive reservoir before being redistributed globally, including to the stratosphere.
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Affiliation(s)
- J Lelieveld
- Max Planck Institute for Chemistry, 55128 Mainz, Germany. .,The Cyprus Institute, 1645 Nicosia, Cyprus
| | | | - C Brühl
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - H Fischer
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - H Fuchs
- Institute for Energy and Climate Research, Research Center Jülich, 52425 Jülich, Germany
| | - H Harder
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - A Hofzumahaus
- Institute for Energy and Climate Research, Research Center Jülich, 52425 Jülich, Germany
| | - F Holland
- Institute for Energy and Climate Research, Research Center Jülich, 52425 Jülich, Germany
| | - D Marno
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - M Neumaier
- Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - A Pozzer
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - H Schlager
- Institute of Atmospheric Physics, Germany Aerospace Center, 82234 Oberpfaffenhofen, Germany
| | - J Williams
- Max Planck Institute for Chemistry, 55128 Mainz, Germany.,The Cyprus Institute, 1645 Nicosia, Cyprus
| | - A Zahn
- Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - H Ziereis
- Institute of Atmospheric Physics, Germany Aerospace Center, 82234 Oberpfaffenhofen, Germany
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Sweileh WM, Al-Jabi SW, Zyoud SH, Sawalha AF. Outdoor air pollution and respiratory health: a bibliometric analysis of publications in peer-reviewed journals (1900 - 2017). Multidiscip Respir Med 2018; 13:15. [PMID: 29881545 PMCID: PMC5984296 DOI: 10.1186/s40248-018-0128-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/18/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Outdoor air pollution is a major threat to global public health that needs responsible participation of researchers at all levels. Assessing research output is an important step in highlighting national and international contribution and collaboration in a certain field. Therefore, the aim of this study was to analyze globally-published literature in outdoor air pollution - related respiratory health. METHOD Outdoor air pollution documents related to respiratory health were retrieved from Scopus database. The study period was up to 2017. Mapping of author keywords was carried out using VOSviewer 1.6.6. RESULTS Search query yielded 3635 documents with an h-index of 137. There was a dramatic increase in the number of publications in the last decade of the study period. The most frequently encountered author keywords were: air pollution (835 occurrences), asthma (502 occurrences), particulate matter (198 occurrences), and children (203 occurrences). The United States of America ranked first (1082; 29.8%) followed by the United Kingdom (279; 7.7%) and Italy (198; 5.4%). Annual research productivity stratified by income and population size indicated that China ranked first (22.2) followed by the USA (18.8). Analysis of regional distribution of publications indicated that the Mediterranean, African, and South-East Asia regions had the least contribution. Harvard University (92; 2.5%) was the most active institution/organization followed the US Environmental Protection Agency (89; 2.4%). International collaboration was restricted to three regions: Northern America, Europe, and Asia. The top ten preferred journals were in the field of environmental health and respiratory health. Environmental Health Perspective was the most preferred journal for publishing documents in outdoor pollution in relation to respiratory health. CONCLUSION Research on the impact of outdoor air pollution on respiratory health had accelerated lately and is receiving a lot of interest. Global research networks that include countries with high level of pollution and limited resources are highly needed to create public opinion in favor of minimizing outdoor air pollution and investing in green technologies.
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Affiliation(s)
- Waleed M. Sweileh
- Division of Biomedical Sciences, Department of Physiology, Pharmacology and Toxicology, College of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Samah W. Al-Jabi
- Department of Clinical and Community Pharmacy, College of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Sa’ed H. Zyoud
- Department of Clinical and Community Pharmacy, College of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Ansam F. Sawalha
- Division of Biomedical Sciences, Department of Physiology, Pharmacology and Toxicology, College of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
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Guo B, Liu Y, Zhang F, Hou J, Zhang H, Li C. Heavy metals in the surface sediments of lakes on the Tibetan Plateau, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:3695-3707. [PMID: 29168132 DOI: 10.1007/s11356-017-0680-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Heavy metal contamination has affected many regions in the world, particularly the developing countries of Asia. We investigated 8 heavy metals (Cu, Zn, Cd, Pb, Cr, Co, Ni, and As) in the surface sediments of 18 lakes on the Tibetan Plateau. It was found that the distributions of the heavy metals showed no clear spatial pattern on the plateau. The results indicated that the mean concentrations of these metals in the sediment samples diminished as follows: Cr > As > Zn > Ni > Pb > Cu > Co > Cd. The results of geoaccumulation index (I geo) and potential ecological risk factor (E ir ) assessments showed that the sediments were moderately polluted by Cd and As, which posed much higher risks than the other metals. The values of the potential ecological risk index (RI) showed that lake Bieruoze Co has been severely polluted by heavy metals. Principal component analysis, hierarchical cluster analysis, and Pearson correlation analysis results indicated that the 8 heavy metals in the lake surface sediments of the Tibetan Plateau could be classified into four groups. Group 1 included Cu, Zn, Pb, Co, and Ni which were mainly derived from both natural and traffic sources. Group 2 included Cd which mainly originated from anthropogenic sources like alloying, electroplating, and dyeing industries and was transported to the Tibetan Plateau by atmospheric circulation. Group 3 included Cr and it might mainly generate from parent rocks of watersheds. The last Group (As) was mainly from manufacturing, living, and the striking deterioration of atmospheric environment of the West, Central Asia, and South Asia.
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Affiliation(s)
- Bixi Guo
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Colledge of Resources and Environment, Beijing, 10049, China
| | - Yongqin Liu
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Colledge of Resources and Environment, Beijing, 10049, China.
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Fan Zhang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Juzhi Hou
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hongbo Zhang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chaoliu Li
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
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Dumka UC, Kaskaoutis DG, Sagar R, Chen J, Singh N, Tiwari S. First results from light scattering enhancement factor over central Indian Himalayas during GVAX campaign. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 605-606:124-138. [PMID: 28662426 DOI: 10.1016/j.scitotenv.2017.06.138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/17/2017] [Indexed: 06/07/2023]
Abstract
The present work examines the influence of relative humidity (RH), physical and optical aerosol properties on the light-scattering enhancement factor [f(RH=85%)] over central Indian Himalayas during the Ganges Valley Aerosol Experiment (GVAX). The aerosol hygroscopic properties were measured by means of DoE/ARM (US Department of Energy, Atmospheric Radiation Measurement) mobile facility focusing on periods with the regular instrumental operation (November-December 2011). The measured optical properties include aerosol light-scattering (σsp) and absorption (σap) coefficients and the intensive parameters i.e., single scattering albedo (SSA), scattering Ångström exponent (SAE), absorption Ångström exponent (AAE) and light scattering enhancement factor (f(RH)=σsp(RH, λ)/σsp(RHdry, λ)). The measurements were separated for sub-micron (<1μm, D1μm) and particles with diameter<10μm (D10μm) in order to examine the influence of particle size on f(RH) and enhancement rate (γ). The particle size affects the aerosol hygroscopicity since mean f(RH=85%) of 1.27±0.12 and 1.32±0.14 are found for D10μm and D1μm, respectively. These f(RH) values are relatively low suggesting the enhanced presence of soot and carbonaceous particles from biomass burning activities, which is verified via backward air-mass trajectories. Similarly, the light-scattering enhancement rates are ~0.20 and 0.17 for the D1μm and D10μm particles, respectively. However, a general tendency for increasing f(RH) and γ is shown for higher σsp and σap values indicating the presence of rather aged smoke plumes, coated with industrial aerosols over northern India, with mean SSA, SAE and AAE values of 0.92, 1.00 and 1.15 respectively. On the other hand, a moderate-to-small dependence of f(RH) and γ on SAE, AAE, and SSA was observed for both particle sizes. Furthermore, f(RH) exhibits an increasing tendency with the number of cloud condensation nuclei (NCCN) indicating larger particle hygroscopicity but without significant dependence on the activation ratio.
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Affiliation(s)
- U C Dumka
- Aryabhatta Research Institute of observational Sciences, Nainital 263 001, India.
| | - D G Kaskaoutis
- Atmospheric Research Team, Institute for Environmental Research and Sustainable Development, National Observatory of Athens, 118 10 Athens, Greece
| | - Ram Sagar
- Aryabhatta Research Institute of observational Sciences, Nainital 263 001, India; NASI-Senior Scientist Platinum Jubilee Fellow, Indian Institute of Astrophysics, Bangalore 560 034, India
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200 433, China; Collaborative Innovation Center of Climate Change, School of Atmospheric Sciences, Nanjing University, Nanjing 210 023, China
| | - Narendra Singh
- Aryabhatta Research Institute of observational Sciences, Nainital 263 001, India
| | - Suresh Tiwari
- Indian Institute of Tropical Meteorology, Pune, New Delhi Branch, New Delhi 110 060, India
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Tripathee L, Kang S, Rupakheti D, Cong Z, Zhang Q, Huang J. Chemical characteristics of soluble aerosols over the central Himalayas: insights into spatiotemporal variations and sources. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:24454-24472. [PMID: 28895029 DOI: 10.1007/s11356-017-0077-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/01/2017] [Indexed: 06/07/2023]
Abstract
In order to investigate the spatial and temporal variations of aerosols and its soluble chemical compositions of the data gap zone in the central Himalayan region, aerosol samples were collected at four sites. The sampling location were characterized by four different categories, such as urban (Bode), semi-urban site in the northern Indo-Gangetic Plain (Lumbini), rural (Dhunche), and semiarid rural (Jomsom). A total of 230 aerosol samples were collected from four representative sites for a yearlong period and analyzed for water-soluble inorganic ions (WSIIs). The annual average aerosol mass concentration followed the sequence as Bode (238.24 ± 162.24 μg/m3)> Lumbini (161.14 ± 105.95 μg/m3)> Dhunche (112.40 ± 40.30 μg/m3)> Jomsom (78.85 ± 34.28 μg/m3), suggesting heavier particulate pollution in the urban and semi-urban sites. The total soluble ions contributed to 12.61-28.19% of TSP aerosol mass. The results revealed that SO42- and NO3- were the major anion and Ca2+ and NH4+ were the major cation influencing the aerosol composition over the central Himalayas. Calcium played a major role in neutralizing aerosol acidity followed by NH4+ at all the sites. The major compound of aerosol was (NH4)2SO4 and NH4HSO4 in the central Himalayas. Clear seasonality was observed at three observation sites, with higher concentrations during non-monsoon (dry periods) and lower during monsoon (wet period), suggesting washing out of aerosol particles by heavy precipitation during monsoon. In contrast, semiarid sites did not show the clear seasonal trend due to limited precipitation. Stationary sources were predominant over the mobile sources mostly in the remote sites. Principal component analysis confirmed that the major sources of WSIIs in the region were industrial emissions, fossil fuel and biomass burning, and crustal fugitive dusts. Nevertheless, transboundary aerosol transport over the region from polluted cities from south Asia could not be ignored as indicated by the clusters of air mass backward trajectory analysis.
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Affiliation(s)
- Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Himalayan Environment Research Institute (HERI), Kathmandu, Nepal.
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Dipesh Rupakheti
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, Beijing, 100101, China
| | - Zhiyuan Cong
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, Beijing, 100101, China
| | - Qianggong Zhang
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, Beijing, 100101, China
| | - Jie Huang
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese, Academy of Sciences, Beijing, 100101, China
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Shang D, Hu M, Guo Q, Zou Q, Zheng J, Guo S. Effects of continental anthropogenic sources on organic aerosols in the coastal atmosphere of East China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 229:350-361. [PMID: 28609736 DOI: 10.1016/j.envpol.2017.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/30/2017] [Accepted: 05/04/2017] [Indexed: 06/07/2023]
Abstract
Although organic compounds in marine atmospheric aerosols have significant effects on climate and marine ecosystems, they have rarely been studied, especially in the coastal regions of East China. To assess the origins of the organic aerosols in the East China coastal atmosphere, PM2.5 samples were collected from the atmospheres of the Yellow Sea, the East China Sea, and Changdao Island during the CAPTAIN (Campaign of Air PolluTion At INshore Areas of Eastern China) field campaign in the spring of 2011. The marine atmospheric aerosol samples that were collected were grouped based on the backward trajectories of their air masses. The organic carbon concentrations in the PM2.5 samples from the marine and Changdao Island atmospheres were 5.5 ± 3.1 μgC/m3 and 6.9 ± 2.4 μgC/m3, respectively, which is higher than in other coastal water atmospheres. The concentration of polycyclic aromatic hydrocarbons (PAHs) in the marine atmospheric PM2.5 samples was 17.0 ± 20.2 ng/m3, indicating significant continental anthropogenic influences. The influences of fossil fuels and biomass burning on the composition of organic aerosols in the coastal atmosphere of East China were found to be highly dependent on the origins of the air masses. Diesel combustion had a strong impact on air masses from the Yangtze River Delta (YRD), and gasoline emissions had a more significant impact on the "North China" marine atmospheric samples. The "Northeast China" marine atmospheric samples were most impacted by biomass burning. Coal combustion contributed significantly to the compositions of all of the atmospheric samples. The proportions of secondary compounds increased as samples aged in the marine atmosphere indicating that photochemical oxidation occured during transport. Our results quantified ecosystem effects on marine atmospheric aerosols and highlighted the uncertainties that arise when modeling marine atmospheric PM2.5 without considering high spatial resolution source data and meteorological parameters.
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Affiliation(s)
- Dongjie Shang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Beijing Innovation Center for Engineering Sciences and Advanced Technology, Peking University, Beijing, China.
| | - Qingfeng Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Qi Zou
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jing Zheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Ahmad W, Coeur C, Tomas A, Fagniez T, Brubach JB, Cuisset A. Infrared spectroscopy of secondary organic aerosol precursors and investigation of the hygroscopicity of SOA formed from the OH reaction with guaiacol and syringol. APPLIED OPTICS 2017; 56:E116-E122. [PMID: 28414388 DOI: 10.1364/ao.56.00e116] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) synchrotron analyses supplemented by density functional theory (DFT) anharmonic calculations have been undertaken to study the fundamental vibrational signatures of guaiacol and syringol, two methoxyphenol compounds found at the highest concentrations in fresh wood smoke and precursors of secondary organic aerosols (SOA) affecting the radiative balance and chemistry of the atmosphere. Nitroderivatives of these two compounds have also been studied experimentally for nitroguaiacol and theoretically for nitrosyringol. All the active fundamental vibrational bands have been assigned and compared to available gas phase measurements, providing a vibrational database of the main precursors for the analysis of SOA produced by atmospheric oxidation of methoxyphenols. In addition, the SOA formed in an atmospheric simulation chamber from the OH reaction with guaiacol and syringol were analyzed using the ATR-FTIR synchrotron spectroscopy and their hygroscopic properties were also investigated. The vibrational study confirms that nitroguaiacol and nitrosyringol are the main oxidation products of methoxyphenols by OH and are key intermediates in SOA production. The hydration experiments highlight the hydrophilic and hydrophobic characters of nitrosyringol and nitroguaiacol, respectively.
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