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Srivastava P, Naja M, Bhardwaj P, Kumar R, Rajwar MC, Seshadri TR. Utilising BC observations to estimate CO contributions from fossil fuel and biomass burning in the Central Himalayan region. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122975. [PMID: 37992951 DOI: 10.1016/j.envpol.2023.122975] [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: 07/31/2023] [Revised: 10/14/2023] [Accepted: 11/14/2023] [Indexed: 11/24/2023]
Abstract
The Himalayan region is adversely affected by the increasing anthropogenic emissions from the adjacent Indo-Gangetic plain. However, source apportionment studies for the Himalayan region that are crucial for estimating CO concentration, are grossly insufficient, to say the least. It is in this context that our study reported here assumes significance. This study utilizes five years (2014-2018) of ground-based observations of eBC and multiple linear regression framework (MLR) to estimate CO and segregate its fossil fuel and biomass emission fractions at a high-altitude (1958 m) site in the Central Himalayas. The results show that MERRA2 always underestimates the observed CO; MOPITT has a high monthly difference ranging from -32% to +57% while WRF-Chem simulations underestimate CO from February to June and overestimate in other months. In contrast, CO estimated from MLR replicates diurnal and monthly variations and estimates CO with an r2 > 0.8 for 2014-2017. The CO predicted during 2018 closely follows the observed variations, and its mixing ratios lie within ±17% of the observed CO. The results reveal a unimodal diurnal variation of CO, COff (ff: fossil fuel) and CObb (bb: biomass burning) governed by the boundary layer evolution and upslope winds. COff has a higher diurnal amplitude (39.1-67.8 ppb) than CObb (5.7-33.5 ppb). Overall, COff is the major contributor (27%) in CO after its background fraction (58%). CObb fraction reaches a maximum (28%) during spring, a period of increased agricultural and forest fires in Northern India. In comparison, WRF-Chem tracer runs underestimate CObb (-38% to -98%) while they overestimate the anthropogenic CO during monsoon. This study thus attempts to address the lack of continuous CO monitoring and the need to segregate its fossil fuel and biomass sources, specifically over the Central Himalayas, by employing a methodology that utilizes the existing network of eBC observations.
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Affiliation(s)
- Priyanka Srivastava
- National Institute for Environmental Studies (NIES), Tsukuba, 305-8506, Japan
| | - M Naja
- Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital, 263001, India.
| | - P Bhardwaj
- Center for Study of Science, Technology and Policy (CSTEP), Bengaluru, 560094, India
| | - R Kumar
- National Center for Atmospheric Research (NCAR), Boulder, CO, 80307-3000, USA
| | - M C Rajwar
- Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital, 263001, India
| | - T R Seshadri
- Department of Physics and Astrophysics, University of Delhi, Delhi, 110007, India
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2
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Singh P, Vaishya A, Rastogi S. Investigating changes in atmospheric aerosols properties over the Indo-Gangetic Plain during different phases of COVID-19-induced lockdowns. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:100215-100232. [PMID: 37632617 DOI: 10.1007/s11356-023-29449-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: 03/27/2023] [Accepted: 08/18/2023] [Indexed: 08/28/2023]
Abstract
Impact of COrona VIrus Diseases 2019 (COVID-19) restrictive measures on aerosol optical depth (AOD) and black carbon (BC) concentration is investigated for the western, central, and eastern Indo-Gangetic Plain (IGP) using satellite-based observations. Due to COVID-19-induced lockdown measures, a noticeable decline in AOD and BC concentrations was observed across the IGP when compared to pre-lockdown period of 2020 and the lockdown concurrent period of 2015-2019. During the total lockdown period, a maximum drop in AOD and BC was observed in the central IGP (26.5 % and 10.1 %), followed by western IGP (24.9% and 5.2%) and eastern IGP (23.2 % and 4.9 %) with respect to the same period of 2015-2019. We have removed seasonal influences on aerosol properties during the COVID-19 lockdown, by taking average seasonal variations during the period of 2015-2019 as reference and projecting the hypothetical AOD and BC for the lockdown period under normal scenario. The difference between the hypothetical AOD and BC (under normal scenario) and the retrieved AOD and BC for the lockdown period is the absolute percentage change in AOD and BC concentration due to the lockdown alone. This elimination of seasonal influence is a novel approach. Central IGP showed an absolute decrease in AOD and BC of 38.5% and 18.2% during the lockdown period followed by western IGP (34.6% and 7.7%) and eastern IGP (25.9% and 11.5%). The observed absolute reduction in AOD, 26-39 %, is significantly higher than the global average reduction in AOD of 2-5%. CALIPSO-derived aerosol sub-types over major location of the western, central, and eastern IGP suggests prevalence of anthropogenic activities during pre- and post-lockdown periods. During the lockdown, IGP was influenced by aerosols from natural sources, with mineral dust and polluted dust in the western and central IGP, and aerosols from marine regions in the eastern IGP. Replenishment of aerosols within the boundary layer were far quicker when compared to total column during post-lockdown. Overall, the study reveals a reduction in anthropogenic emissions during the COVID-19-induced lockdowns, leading to temporary improvements in air quality over the IGP. Our study presents a comprehensive analysis of COVID-19 lockdown impact on aerosols properties over the IGP and highlights unprecedented reductions in AOD (~ 40 %) and BC (~ 20 %), due to imposition of lockdown and subsequent cessation of aerosol sources, by removing seasonal influences.
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Affiliation(s)
- Prayagraj Singh
- Department of Physics, Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur, 273009, India
| | - Aditya Vaishya
- School of Arts and Sciences, Ahmedabad University, Ahmedabad, 380 009, India.
- Global Centre for Environment and Energy, Ahmedabad University, Ahmedabad, 380 009, India.
| | - Shantanu Rastogi
- Department of Physics, Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur, 273009, India
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Singh RD, Gumber S, Sundriyal RC, Ram J, Singh SP. Chir pine forest and pre-monsoon drought determine spatial, and temporal patterns of forest fires in Uttarakhand Himalaya. Trop Ecol 2023:1-11. [PMID: 37362779 PMCID: PMC10240464 DOI: 10.1007/s42965-023-00306-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/28/2023] [Accepted: 05/15/2023] [Indexed: 06/28/2023]
Abstract
Associated with farming practices (between 300 and 2000 m elevations), human-ignited small, and patchy surface forest fires occur almost every year in Uttarakhand (between 28°43`- 31°27` N and 77°34`- 81°02`E; area 51,125 km2), a Himalayan state of India. Using fire incidence data of 19 years (2002-2020) generated by MODIS, we analysed the factors which drive temporal and spatial patterns of fire in the region. The fire incidence data were organized by 24 forest divisions, the unit of state forest management and administration. The standardized regression model showed that pre-monsoon temperature (March to May or mid-June), proportional area of the forest division under chir pine (Pinus roxburghii) forest (positive effect), and pre-monsoon and winter precipitation (negative effect) accounted for 56% of the variance in fire incidence density (FID). The pre-monsoon temperature (warmer) and precipitation (lower) were significantly different in 2009, 2012, 2016 and 2019, the years with high FID (average 54.9 fire/100 km2) than the rest of years with low FID (average 20.9 fire/100 km2). During the two decades of warming, high FID (> 30 incidence per year /100 km2) occurred after every three to four years, and fire peaks tended to increase with time. The study suggests that effective fire management can be attained by improving pre-monsoon precipitation forecasting and targeting forest compartments with a higher occurrence of chir pine and fire-vulnerable oaks. Furthermore, since fires are human-ignited, periodical analysis of changes in population distribution and communities' dependence on forests would need to be conducted. Supplementary Information The online version contains supplementary material available at 10.1007/s42965-023-00306-9.
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Affiliation(s)
- Ripu Daman Singh
- Department of Forestry and Environmental Science, DSB Campus, Kumaun University, Nainital, 263001 India
| | - Surabhi Gumber
- Department of Forestry and Environmental Science, DSB Campus, Kumaun University, Nainital, 263001 India
| | - R. C. Sundriyal
- Department of Forestry and Natural Resources, HNB Garhwal University, Srinagar, 246174 India
| | - Jeet Ram
- Department of Forestry and Environmental Science, DSB Campus, Kumaun University, Nainital, 263001 India
| | - Surendra P. Singh
- INSA, Honorary Scientist Central Himalayan Environment Association (CHEA), Dehradun, 248006 India
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Nair HRCR, Budhavant K, Manoj MR, Andersson A, Satheesh SK, Ramanathan V, Gustafsson Ö. Aerosol demasking enhances climate warming over South Asia. NPJ CLIMATE AND ATMOSPHERIC SCIENCE 2023; 6:39. [PMID: 37252186 PMCID: PMC10199435 DOI: 10.1038/s41612-023-00367-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/03/2023] [Indexed: 05/31/2023]
Abstract
Anthropogenic aerosols mask the climate warming caused by greenhouse gases (GHGs). In the absence of observational constraints, large uncertainties plague the estimates of this masking effect. Here we used the abrupt reduction in anthropogenic emissions observed during the COVID-19 societal slow-down to characterize the aerosol masking effect over South Asia. During this period, the aerosol loading decreased substantially and our observations reveal that the magnitude of this aerosol demasking corresponds to nearly three-fourths of the CO2-induced radiative forcing over South Asia. Concurrent measurements over the northern Indian Ocean unveiled a ~7% increase in the earth's surface-reaching solar radiation (surface brightening). Aerosol-induced atmospheric solar heating decreased by ~0.4 K d-1. Our results reveal that under clear sky conditions, anthropogenic emissions over South Asia lead to nearly 1.4 W m-2 heating at the top of the atmosphere during the period March-May. A complete phase-out of today's fossil fuel combustion to zero-emission renewables would result in rapid aerosol demasking, while the GHGs linger on.
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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
- Divecha Centre for Climate Change, Indian Institute of Science, Bangalore, India
| | - August Andersson
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - 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
| | - V. Ramanathan
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA USA
| | - Örjan Gustafsson
- Department of Environmental Science and the Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
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Siddiqui A, Chauhan P, Halder S, Devadas V, Kumar P. Effect of COVID-19-induced lockdown on NO 2 pollution using TROPOMI and ground-based CPCB observations in Delhi NCR, India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:714. [PMID: 36044095 PMCID: PMC9428889 DOI: 10.1007/s10661-022-10362-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/11/2022] [Indexed: 05/21/2023]
Abstract
The present study investigates the reduction in nitrogen dioxide (NO2) levels using satellite-based (Sentinel-5P TROPOMI) and ground-based (Central Pollution Control Board) observations of 2020. The lockdown duration, monthly, seasonal and annual changes in NO2 were assessed comparing the similar time period in 2019. The study also examines the role of atmospheric parameters like wind speed, air temperature, relative humidity, solar radiation and atmospheric pressure in altering the monthly and annual values of the pollutant. It was ascertained that there was a mean reduction of ~ 61% (~ 66.5%), ~ 58% (~ 51%) in daily mean NO2 pollution during lockdown phase 1 when compared with similar period of 2019 and pre-lockdown phase in 2020 from ground-based (satellite-based) measurements. April month with ~ 57% (~ 57%), summer season with ~ 48% (~ 32%) decline and an annual reduction of ~ 20% (~ 18%) in tropospheric NO2 values were observed (p < 0.001) compared to similar time periods of 2019. It was assessed that the meteorological parameters remained almost similar during various parts of the year in 2019 and 2020, indicating a negligent role in reducing the values of atmospheric pollution, particularly NO2 in the study area. It was concluded that the halt in anthropogenic activities and associated factors was mainly responsible for the reduced values in the Delhi conglomerate. Similar work can be proposed for other pollutants to holistically describe the pollution scenario as an aftermath of COVID-19-induced lockdown.
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Affiliation(s)
- Asfa Siddiqui
- Indian Institute of Remote Sensing, Indian Space Research Organisation, Dehradun, Uttarakhand, India, 248001.
| | - Prakash Chauhan
- Indian Institute of Remote Sensing, Indian Space Research Organisation, Dehradun, Uttarakhand, India, 248001
- National Remote Sensing Centre, Indian Space Research Organisation, Hyderabad, Telangana, India, 500037
| | - Suvankar Halder
- Indian Institute of Remote Sensing, Indian Space Research Organisation, Dehradun, Uttarakhand, India, 248001
| | - V Devadas
- Indian Institute of Technology, Roorkee, Uttarakhand, India, 247667
| | - Pramod Kumar
- Indian Institute of Remote Sensing, Indian Space Research Organisation, Dehradun, Uttarakhand, India, 248001
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6
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Bhat MA, Romshoo SA, Beig G. Characteristics, source apportionment and long-range transport of black carbon at a high-altitude urban centre in the Kashmir valley, North-western Himalaya. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 305:119295. [PMID: 35439603 DOI: 10.1016/j.envpol.2022.119295] [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: 01/21/2022] [Revised: 03/22/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
Six years of data (2012-2017) at an urban site-Srinagar in the Northwest Himalaya were used to investigate temporal variability, meteorological influences, source apportionment and potential source regions of BC. The daily BC concentration varies from 0.56 to 40.16 μg/m3 with an inter-annual variation of 4.20-7.04 μg/m3 and is higher than majority of the Himalayan urban locations. High mean annual BC concentration (6.06 μg/m3) is attributed to the high BC observations during winter (8.60 μg/m3) and autumn (8.31 μg/m3) with a major contribution from Nov (13.88 μg/m3) to Dec (13.4 μg/m3). A considerable inter-month and inter-seasonal BC variability was observed owing to the large changes in synoptic meteorology. Low BC concentrations were observed in spring and summer (3.14 μg/m3 and 3.21 μg/m3), corresponding to high minimum temperatures (6.6 °C and 15.7 °C), wind speed (2.4 and 1.6 m/s), ventilation coefficient (2262 and 2616 m2/s), precipitation (316.7 mm and 173.3 mm) and low relative humidity (68% and 62%). However, during late autumn and winter, frequent temperature inversions, shallow PBL (173-1042 m), stagnant and dry weather conditions cause BC to accumulate in the valley. Through the observation period, two predominant diurnal BC peaks were observed at ⁓9:00 h (7.75 μg/m3) and ⁓21:00 h (6.67 μg/m3). Morning peak concentration in autumn (11.28 μg/m3) is ⁓2-2.5 times greater than spring (4.32 μg/m3) and summer (5.23 μg/m3), owing to the emission source peaks and diurnal boundary layer height. Diurnal BC concentration during autumn and winter is 65% and 60% higher than spring and summer respectively. During autumn and winter, biomass burning contributes approximately 50% of the BC concentration compared to only 10% during the summer. Air masses transport considerable BC from the Middle East and northern portions of South Asia, especially the Indo-Gangetic Plains, to Srinagar, with serious consequences for climate, human health, and the environment.
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Affiliation(s)
| | - Shakil Ahmad Romshoo
- Department of Geoinformatics, University of Kashmir, Srinagar, India; Islamic University of Science and Technology (IUST), Awantipora, Kashmir, India.
| | - Gufran Beig
- Indian Institute of Tropical Meteorology (IITM), Pune, India; National Institute of Advanced Studies (NIAS), Indian Institute of Science (IISc) Campus, Bengaluru, India
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7
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Wei L, Lu Z, Wang Y, Liu X, Wang W, Wu C, Zhao X, Rahimi S, Xia W, Jiang Y. Black carbon-climate interactions regulate dust burdens over India revealed during COVID-19. Nat Commun 2022; 13:1839. [PMID: 35383203 PMCID: PMC8983761 DOI: 10.1038/s41467-022-29468-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 03/14/2022] [Indexed: 11/30/2022] Open
Abstract
India as a hotspot for air pollution has heavy black carbon (BC) and dust (DU) loadings. BC has been identified to significantly impact the Indian climate. However, whether BC-climate interactions regulate Indian DU during the premonsoon season is unclear. Here, using long-term Reanalysis data, we show that Indian DU is positively correlated to northern Indian BC while negatively correlated to southern Indian BC. We further identify the mechanism of BC-dust-climate interactions revealed during COVID-19. BC reduction in northern India due to lockdown decreases solar heating in the atmosphere and increases surface albedo of the Tibetan Plateau (TP), inducing a descending atmospheric motion. Colder air from the TP together with warmer southern Indian air heated by biomass burning BC results in easterly wind anomalies, which reduces dust transport from the Middle East and Sahara and local dust emissions. The premonsoon aerosol-climate interactions delay the outbreak of the subsequent Indian summer monsoon. Black carbon produced by human activities impacts climate. Here, the authors find that black carbon-climate interactions regulate Indian dust during the premonsoon season and further affect the outbreak of the subsequent Indian summer monsoon.
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Affiliation(s)
- Linyi Wei
- Department of Earth System Science, Ministry of Education Key Laboratory for Earth System Modeling, Institute for Global Change Studies, Tsinghua University, Beijing, 100084, China
| | - Zheng Lu
- Department of Atmospheric Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Yong Wang
- Department of Earth System Science, Ministry of Education Key Laboratory for Earth System Modeling, Institute for Global Change Studies, Tsinghua University, Beijing, 100084, China.
| | - Xiaohong Liu
- Department of Atmospheric Sciences, Texas A&M University, College Station, TX, 77843, USA.
| | - Weiyi Wang
- International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chenglai Wu
- International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Xi Zhao
- Department of Atmospheric Sciences, Texas A&M University, College Station, TX, 77843, USA
| | - Stefan Rahimi
- Institute of the Environment and Sustainability, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Wenwen Xia
- Department of Earth System Science, Ministry of Education Key Laboratory for Earth System Modeling, Institute for Global Change Studies, Tsinghua University, Beijing, 100084, China
| | - Yiquan Jiang
- CMA-NJU Joint Laboratory for Climate Prediction Studies, Institute for Climate and Global Change Research, School of Atmospheric Sciences, Nanjing University, Nanjing, 210023, China
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8
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Rajesh TA, Ramachandran S. Assessment of the coronavirus disease 2019 (COVID-19) pandemic imposed lockdown and unlock effects on black carbon aerosol, its source apportionment, and aerosol radiative forcing over an urban city in India. ATMOSPHERIC RESEARCH 2022; 267:105924. [PMID: 34803200 PMCID: PMC8594172 DOI: 10.1016/j.atmosres.2021.105924] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/08/2021] [Accepted: 11/10/2021] [Indexed: 05/30/2023]
Abstract
A nationwide lockdown was imposed in India due to the Coronavirus Disease 2019 (COVID-19) pandemic which significantly reduced the anthropogenic emissions. We examined the characteristics of equivalent black carbon (eBC) mass concentration and its source apportionment using a multiwavelength aethalometer over an urban site (Ahmedabad) in India during the pandemic induced lockdown period of year 2020. For the first time, we estimate the changes in BC, its contribution from fossil (eBC ff ) and wood (eBC wf ) fuels during lockdown (LD) and unlock (UL) periods in 2020 with respect to 2017 to 2019 (normal period). The eBC mass concentration continuously decreased throughout lockdown periods (LD1 to LD4) due to enforced and stringent restrictions which substantially reduced the anthropogenic emissions. The eBC mass concentration increased gradually during unlock phases (UL1 to UL7) due to the phase wise relaxations after lockdown. During lockdown period eBC mass concentration decreased by 35%, whereas during the unlock period eBC decreased by 30% as compared to normal period. The eBC wf concentrations were higher by 40% during lockdown period than normal period due to significant increase in the biomass burning emissions from the several community kitchens which were operational in the city during the lockdown period. The average contributions of eBC ff and eBC wf to total eBC mass concentrations were 70% and 30% respectively during lockdown (LD1 to LD4) period, whereas these values were 87% and 13% respectively during the normal period. The reductions in BC concentrations were commensurate with the reductions in emissions from transportation and industrial activities. The aerosol radiative forcing reduced significantly due to the reduction in anthropogenic emissions associated with COVID-19 pandemic induced lockdown leading to a cooling of the atmosphere. The findings in the present study on eBC obtained during the unprecedented COVID-19 induced lockdown can provide a comprehensive understanding of the BC sources and current emission control strategies, and thus can serve as baseline anthropogenic emissions scenario for future emission control strategies aimed to improve air quality and climate.
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Affiliation(s)
- T A Rajesh
- Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad 380009, India
| | - S Ramachandran
- Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad 380009, India
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Singh S, Gokhale S. Effect of COVID-19 epidemic-led lockdowns on aerosol black carbon concentration, sources and its radiation effect in northeast India. JOURNAL OF EARTH SYSTEM SCIENCE 2022; 131:139. [PMCID: PMC9166673 DOI: 10.1007/s12040-022-01883-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 06/02/2023]
Abstract
Abstract The COVID-19 epidemic-led lockdown (LD) from March 25 to May 31, 2020, had a different level of impact on air quality in the ecologically sensitive region of northeast India, even though the restriction on main anthropogenic activities was expected to reduce particulate matter concentration. The daily average black carbon concentration measured at 880 nm (BC880) was 1.5–15.6 μg m−3 (mean: 5.75±4.24 μg m−3) during the measurement period. It was 9.29±4.11 μg m−3 during pre-LD (February 12–March 21), 4.70±0.95 μg m−3 during LD1 (March 25–April 14), 3.41±0.56 μg m−3 during LD2 (April 15–May 3), 3.69±1.50 μg m−3 during LD3 (May 4–17), 2.94±0.93 μg m−3 during LD4 (May 18–31), and 6.56±5.35 μg m−3 during the Post-LD (June 6–July 3) of 2020. It decreased up to 68% during the lockdowns. The source apportionment based on an improved method showed a significant improvement in the contribution of BC880 sources. The radiation effect determined by Angstrom Absorption Exponent showed that brown carbon accounted for 25% of the aerosol light absorption at 370 nm during the lockdown period. Relative humidity correlates substantially with BC880, while rainfall, temperature, and solar radiation were negatively correlated. The bivariate analysis showed the dominance of local emissions in the BC880 concentrations. Research highlights Black carbon concentration decreased up to 68% during the different phases of lockdown. BC associated with fossil fuel was 51–78%, and biomass burning was 22–49%. The fraction of fossil fuel and biomass burning in whole BC fallen to 0.73 and 0.65 during the lockdowns. Air quality improved by about 47–58% on the 4th and 7th day of lockdown. Brown carbon and meteorological parameters significantly impacted aerosol light absorption in this region.
Supplementary Information The online version contains supplementary material available at 10.1007/s12040-022-01883-4.
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Affiliation(s)
- Sameer Singh
- Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781 039 India
| | - Sharad Gokhale
- Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781 039 India
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10
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Adhikari A, Sengupta J, Hussain CM. Declining carbon emission/concentration during COVID-19: A critical review on temporary relief. CARBON TRENDS 2021; 5:100131. [PMID: 38620883 PMCID: PMC8590614 DOI: 10.1016/j.cartre.2021.100131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/22/2021] [Accepted: 11/10/2021] [Indexed: 06/19/2023]
Abstract
In December 2019 the deadly pandemic COVID-19 traumatized mankind through its lethal impact. To seize the outbreak, nationwide/region-based lockdown strategies were adopted by most of the COVID-19 affected countries. This in turn resulted in restricted transportation via surface, water, and air, as well as significantly reduced working hours of the industry sectors, so on and so forth. The obvious outcome was a sudden discernible decline in atmospheric adulteration. Accordingly, the anthropogenic emissions at the global and regional/local scales were examined during the lockdown period by several researchers using both or either satellite-based and ground-based monitoring. Among several other air-contaminants, carbon has a dominant toxicological profile causing adverse health effects and thereby attracting researches interest in carbon-release probing during the systematic confinement period imposed by the ruling authorities across the globe. The results of those studies indicated a confirmed decline in carbon emission/concentration making the air more breathable for the period. In this review, the studies related to anthropogenic emissions of carbon during the lockdown period are accounted for by compiling the recently reported data from published articles.
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Affiliation(s)
- Arpita Adhikari
- Department of Electronics and Communication Engineering, Techno Main Salt Lake, Kolkata 700091, India
| | - Joydip Sengupta
- Department of Electronic Science, Jogesh Chandra Chaudhuri College, Kolkata 700033, India
| | - Chaudhery Mustansar Hussain
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, 07102, NJ, USA
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11
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Girach IA, Ojha N, Babu SS. Ozone chemistry and dynamics at a tropical coastal site impacted by the COVID-19 lockdown. JOURNAL OF EARTH SYSTEM SCIENCE 2021; 130:158. [PMCID: PMC8351570 DOI: 10.1007/s12040-021-01666-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/17/2021] [Accepted: 04/24/2021] [Indexed: 05/25/2023]
Abstract
The nationwide lockdown in India to curb the spread of Coronavirus disease 2019 (COVID-19) led to colossal reduction in anthropogenic emissions. Here, we investigated the impact of lockdown on surface ozone (O3) and nitrogen dioxide (NO2) over a tropical coastal station – Thumba, Thiruvananthapuram (8.5°N, 76.9°E). Daytime as well as night-time NO2 showed reduction by 0.8 (40%) and 2.3 (35%) ppbv, respectively during the lockdown period of 25–30 March 2020 as compared with the same period of previous 3 years. Unlike many urban locations, daytime surface O3 is found to be dramatically reduced by 15 ppbv (36%) with O3 production rate being lower by a factor of 3 during the lockdown. Interestingly, a feature of O3-hump during the onset of land breeze typically observed during 1997–1998 has reappeared with magnitude of 5–10 ppbv. A photochemical box model, capturing this feature, revealed that significant O3 sustained till onset of land breeze over the land due to weaker titration with NOx during lockdown. It is suggested that the transport of this O3 rich air with onset of land breeze led to the observed hump. Our measurements unravel a remarkable impact of the COVID-19 lockdown on the chemistry and dynamics of O3 over this tropical coastal environment.
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Affiliation(s)
- Imran A Girach
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, 695 022 India
| | - Narendra Ojha
- Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad, 380 009 India
| | - S Suresh Babu
- Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram, 695 022 India
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Pratap V, Tiwari S, Kumar A, Singh AK. COVID-19 lockdown induced air pollution reduction over India: A lesson for future air pollution mitigation strategies. JOURNAL OF EARTH SYSTEM SCIENCE 2021. [PMCID: PMC8577420 DOI: 10.1007/s12040-021-01722-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Air pollution is one of the biggest problems worldwide and needs to be addressed potentially with the implementation of updated stringent policies and legislative laws. The nationwide lockdown imposed to prevent the COVID-19 outbreak, has given us a unique opportunity to understand the contribution of anthropogenic emissions to the total atmospheric pollutant burden on a global as well as regional scale. Thus, in the present study, we try to investigate the impact of COVID-19 induced lockdown on common ambient air pollutants (i.e., PM2.5, NO2, and SO2) concentration over 22 cities in India using in-situ measurement under a network of Centre Pollution and Control Board (CPCB). A significant reduction in the mean mass concentration of all the studied air pollutants (i.e., PM2.5, NO2, and SO2) (nearly 10–70%) is found during different phases of lockdown which reached within the National Ambient Air Quality Standard (i.e., NAAQS). The reduction in studied air pollutants is more prominent during the first phase of lockdown (mainly NO2) which could be due to the complete shutdown of industrial activities. The outcome of the present study will be helpful for policymakers to design cost-effective and accurate air pollution mitigation strategies for the development of a sustainable environment. The study also suggests that well-planned short-term and periodical lockdown could be an alternative effective tool of air pollution mitigation.
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Affiliation(s)
- Vineet Pratap
- Atmospheric Research Laboratory, Department of Physics, Banaras Hindu University, Varanasi, 221 005 India
| | - Shani Tiwari
- CSIR - National Institute of Oceanography, Dona Paula, Goa, 403 004 India
| | - Akhilesh Kumar
- Atmospheric Research Laboratory, Department of Physics, Banaras Hindu University, Varanasi, 221 005 India
| | - Abhay Kumar Singh
- Atmospheric Research Laboratory, Department of Physics, Banaras Hindu University, Varanasi, 221 005 India
- DST - Mahamana Centre of Excellence in Climate Change Research, Banaras Hindu University, Varanasi, 221 005 India
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