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Chen P, Kang S, Hu Y, Pu T, Liu Y, Wang S, Rai M, Wang K, Tripathee L, Li C. South and Southeast Asia controls black carbon characteristics of Meili Snow Mountains in southeast Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172262. [PMID: 38583605 DOI: 10.1016/j.scitotenv.2024.172262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024]
Abstract
South and Southeast Asia (SSA) emitted black carbon (BC) exerts potential effects on glacier and snow melting and regional climate change in the Tibetan Plateau. In this study, online BC measurements were conducted for 1 year at a remote village located at the terminus of the Mingyong Glacier below the Meili Snow Mountains. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to investigate the contribution and potential effect of SSA-emitted BC. In addition, variations in the light absorption characteristics of BC and brown carbon (BrC) were examined. The results indicated that the annual mean concentration of BC was 415 ± 372 ngm-3, with the highest concentration observed in April (monthly mean: 930 ± 484 ngm-3). BC exhibited a similar diurnal variation throughout the year, with two peaks observed in the morning (from 8:00 to 9:00 AM) and in the afternoon (from 4:00 to 5:00 PM), with even lower values at nighttime. At a short wavelength of 370 nm, the absorption coefficient (babs) reached its maximum value, and the majority of babs values were < 20 Mm-1, indicating that the atmosphere was not overloaded with BC. At the same wavelength, BrC substantially contributed to babs, with an annual mean of 25.2 % ± 12.8 %. SSA was the largest contributor of BC (annual mean: 51.1 %) in the study area, particularly in spring (65.6 %). However, its contributions reached 20.2 % in summer, indicating non-negligible emissions from activities in other regions. In the atmosphere, the SSA BC-induced radiative forcing (RF) over the study region was positive. While at the near surface, the RF exhibited a significant seasonal variation, with the larger RF values occurring in winter and spring. Overall, our findings highlight the importance of controlling BC emissions from SSA to protect the Tibetan Plateau against pollution-related glacier and snow cover melting.
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Affiliation(s)
- Pengfei Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yuling Hu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Tao Pu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Yajun Liu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shijin Wang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Yulong Snow Mountain National Field Observation and Research Station for Cryosphere and Sustainable Development, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Mukesh Rai
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ke Wang
- Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
| | - Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Chaoliu Li
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Pei C, Wu Y, Tao J, Zhang L, Zhang T, Zhang R, Li S. Seasonal variations of mass absorption efficiency of elemental carbon in PM 2.5 in urban Guangzhou of South China. J Environ Sci (China) 2023; 133:83-92. [PMID: 37451792 DOI: 10.1016/j.jes.2022.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/13/2022] [Accepted: 04/13/2022] [Indexed: 07/18/2023]
Abstract
This study investigates seasonal variations of mass absorption efficiency of elemental carbon (MAEEC) and possible influencing factors in urban Guangzhou of South China. Mass concentrations of elemental carbon (EC) and organic carbon (OC) in PM2.5 and aerosol absorption coefficient (bap) at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer. Seasonal average mass concentrations of EC were in the range of 1.36-1.70 µgC/m3 with a lower value in summer than in the other seasons, while those of OC were in the range of 4.70-6.49 µgC/m3 with the lowest value in summer and the highest in autumn. Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols. The average aerosol absorption Ångström exponents (AAE) were lower than 1.2 in four seasons, indicating EC and bap were closely related with vehicle exhaust. Seasonal MAEEC at 550 nm was 11.0, 8.5, 10.4 and 11.3 m2/g in spring, summer, autumn, and winter, respectively. High MAEEC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.
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Affiliation(s)
- Chenglei Pei
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China; Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou 518049, China
| | - Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Jun Tao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China.
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Canada
| | - Tao Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China; Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510308, China
| | - Runqi Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sheng Li
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Lei S, Ge B, Liu H, Quan J, Xu D, Zhang Y, Yao W, Lei L, Tian Y, Liao Q, Liu X, Li J, Xin J, Sun Y, Fu P, Cao J, Wang Z, Pan X. Refractory black carbon aerosols in rainwater in the summer of 2019 in Beijing: Mass concentration, size distribution and wet scavenging ratio. J Environ Sci (China) 2023; 132:31-42. [PMID: 37336608 DOI: 10.1016/j.jes.2022.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 05/21/2022] [Accepted: 07/22/2022] [Indexed: 06/21/2023]
Abstract
Black carbon (BC) aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation. The lifetime of BC depends on atmospheric transport, aging and consequently on wet scavenging processes (in-cloud and below-cloud scavenging). In this study, sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer (SP2) and a nebulizer. The results showed that the volume-weighted average (VWA) mass concentrations of refractory black carbon (rBC) in each rainfall event varied, ranging from 10.8 to 78.9 µg/L. The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events. The geometric mean median mass-equivalent diameter (MMD) decreased under precipitation, indicating that rBC with larger sizes was relatively aged and preferentially removed by wet scavenging. A positive correlation (R2 = 0.73) between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process. Additionally, the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74% and 26% to wet scavenging, respectively. The scavenging ratio of rBC particles was estimated to be 0.06 on average. This study provides helpful information for better understanding the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.
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Affiliation(s)
- Shandong Lei
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baozhu Ge
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Hang Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Jiannong Quan
- Institute of Urban Meteorology, China Meteorological Administration, Beijing 100089, China
| | - Danhui Xu
- National Center for Climate Change Strategy and International Cooperation, Ministry of Ecology and Environment, Beijing 100035, China
| | - Yuting Zhang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weijie Yao
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lu Lei
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Tian
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Qi Liao
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyong Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Jie Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Jinyuan Xin
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Junji Cao
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zifa Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiaole Pan
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
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Chen P, Kang S, Gan Q, Yu Y, Yuan X, Liu Y, Tripathee L, Wang X, Li C. Concentrations and light absorption properties of PM 2.5 organic and black carbon based on online measurements in Lanzhou, China. J Environ Sci (China) 2023; 131:84-95. [PMID: 37225383 DOI: 10.1016/j.jes.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 04/21/2022] [Accepted: 08/02/2022] [Indexed: 05/26/2023]
Abstract
To elucidate the variations in mass concentrations of organic carbon (OC) and black carbon (BC) in PM2.5 and their light absorption characteristics in Lanzhou, we conducted one-year online measurements by using a newly developed total carbon analyzer (TCA08) coupled with an aethalometer (AE33) from July 2018 to July 2019. The mean OC and BC concentrations were 6.4 ± 4.4 and 2.0 ± 1.3 µg/m3, respectively. Clear seasonal variations were observed for both components, with winter having the highest concentrations, followed by autumn, spring, and summer. The diurnal variations of OC and BC concentrations were similar throughout the year, with daily two peaks occurring in the morning and evening, respectively. A relatively low OC/BC ratio (3.3 ± 1.2, n = 345) were observed, indicating that fossil fuel combustion was the primary source of the carbonaceous components. This is further substantiated by relatively low biomass burning contribution (fbiomass: 27.1% ± 11.3%) to BC using aethalometer based measurement though fbiomass value which increased significantly in winter (41.6% ± 5.7%). We estimated a considerable brown carbon (BrC) contribution to the total absorption coefficient (babs) at 370 nm (yearly average of 30.8% ± 11.1%), with a winter maximum of 44.2% ± 4.1% and a summer minimum of 19.2% ± 4.2%. Calculation of the wavelength dependence of total babs revealed an annual mean AAE370-520 value of 4.2 ± 0.5, with slightly higher values in spring and winter. The mass absorption cross-section of BrC also exhibited higher values in winter, with an annual mean of 5.4 ± 1.9 m2/g, reflecting the impact of emissions from increased biomass burning on BrC concentrations.
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Affiliation(s)
- Pengfei Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qinyi Gan
- College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ye Yu
- Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, Northwest Institute of Eco-Environment and Resources, CAS, Lanzhou 730000, China
| | - Xianlei Yuan
- Xinjiang Bayingolin Mongolian Autonomous Prefecture Meteorological Bureau, Korla 841000, China
| | - Yajun Liu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Lekhendra Tripathee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Xiaoxiang Wang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China
| | - Chaoliu Li
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences (CAS), Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Xu M, Qin Z. How does vehicle emission control policy affect air pollution emissions? Evidence from Hainan Province, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 866:161244. [PMID: 36586700 DOI: 10.1016/j.scitotenv.2022.161244] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/06/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
Vehicular emissions have become important sources of air pollution in China. Regarding the environmental impacts of vehicle emission control policies (VECPs), changes in air pollutants and CO2 emissions have attracted more attention. Hainan is the first province in China declared to ban the sale of fuel-powered cars by 2030, aiming to accelerate cutting down the local air pollution emissions. However, there is no previous study examining how these VECPs would affect air pollutants in Hainan. Further, research on whether the controls would lead to a real carbon reduction is limited. Therefore, this paper quantitatively assesses the emission changes of primary air pollutants (including NOx, CO, VOCs, PM2.5, PM10, and PMTSP) and greenhouse gases (CO2, CH4, and N2O) in the transportation sector with regard to different VECPs in Hainan. The results reveal that (1) VECPs would lead to significant increases in vehicular population by 21 %-65 % in 2025-2050. Specifically, light-duty cars and buses with 4-stroke engines (LD4Cs) is the largest contributor and banning sales of fuel-powered vehicles would lead to a larger increase of 1914.6 thousand (64 %) in 2030; (2) for air pollutant emissions, the policy scenario would bring notable reduction effects, decreasing by 1.0 %-16.0 % and 16.7 %-38.7 % in 2030 and 2050 (PM excluding), respectively, suggesting VECPs play important roles in alleviating environmental pollution; (3) conversely, for CO2 emissions, the policy scenario would cause increases of 0.8 Mt. (17.8 %) and 0.3 Mt. (6.1 %) in 2035 and 2050, respectively, indicating promoting new energy vehicles (NEVs) would increase carbon emissions. Meanwhile, it suggests that CO2 emission in the transportation sector of Hainan peaked in 2020. This research highlights that VECPs would be a double-edged sword, leading to air pollutants reductions but not necessarily decline CO2 emissions. This fact would further accelerate mechanism and technological innovation in transport to alleviate air pollution and carbon emissions simultaneously.
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Affiliation(s)
- Meng Xu
- School of Management, Wuhan Institute of Technology, Wuhan 430205, China
| | - Zhongfeng Qin
- School of Economics and Management, Beihang University, Beijing 100191, China; Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operation, China.
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Tao J, Zhang Z, Zhang L, Li J, Wu Y, Pei C, Nie F. Quantifying the relative contributions of aqueous phase and photochemical processes to water-soluble organic carbon formation in winter in a megacity of South China. CHEMOSPHERE 2022; 300:134598. [PMID: 35430199 DOI: 10.1016/j.chemosphere.2022.134598] [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: 01/20/2022] [Revised: 04/04/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
To identify potential formation mechanisms of water-soluble organic carbon (WSOC) and quantify their contributions to WSOC in urban Guangzhou of south China, a comprehensive campaign was carried out in winter of 2019-2020. During the campaign, WSOC, total carbon (TC), black carbon (BC), water-soluble inorganic ions (WSIIs) and fourteen elements in PM2.5 were collected using inline instruments. Bulk PM2.5 and size-segregated particle samples were also synchronously collected using offline instruments for analyzing the dominant chemical components including WSOC, organic carbon (OC), elemental carbon (EC) and WSIIs. In addition, gaseous pollutants (e.g., NH3, SO2, HNO3, NO2, O3) and meteorological parameters were also measured during the same period. PM2.5 pollution episodes during the campaign period were mainly driven by increased nitrate concentrations. The mass concentration of WSOC increased from 3.9 ± 1.1 μg m-3 on non-episode days to 6.8 ± 0.6 μg m-3 on episode days, although the mass ratio of WSOC to OC in PM2.5 changed little (<4%). Photochemical processes dominated WSOC formation in the afternoon and aqueous phase chemical processes played the dominant role in the night, from which newly formed WSOC distributed in the condensation mode and the droplet mode, respectively. Source apportionment analysis using positive matrix factorization (PMF) model suggested that on average 35% and 65% of WSOC mass in PM2.5 were related with the photochemical processes and aqueous phase chemical processes, respectively. Aqueous phase chemical processes were highly affected by nitrate pollution, which was closely related with O3 pollution.
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Affiliation(s)
- Jun Tao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China.
| | - Zhisheng Zhang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China.
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Canada
| | - Jiawei Li
- RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Chenglei Pei
- Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou, China
| | - Fuli Nie
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China
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Huang J, Zhang Z, Tao J, Zhang L, Nie F, Fei L. Source apportionment of carbonaceous aerosols using hourly data and implications for reducing PM 2.5 in the Pearl River Delta region of South China. ENVIRONMENTAL RESEARCH 2022; 210:112960. [PMID: 35189099 DOI: 10.1016/j.envres.2022.112960] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 05/28/2023]
Abstract
Ambient fine particulate matter (PM2.5) levels in South China have been decreasing in the past decade, but the decreasing rates differed between its major chemical components, e.g., with much small rates for carbonaceous aerosols than for secondary inorganic aerosols. To investigate the sources of carbonaceous aerosols in this region, a comprehensive campaign was carried out in urban Guangzhou in the winter of 2019-2020 using a combination of various instruments. Data generated from this campaign include hourly total carbon (TC), black carbon (BC), criteria air pollutants and meteorological parameters, 4-hourly particle-bound elements, and chemically-resolved daily PM2.5. Similar diurnal patterns were observed for TC, CO and NO2, suggesting TC was very likely related to vehicle exhaust emission. Secondary organic carbon (SOC) estimated using the Minimum R squared (MRS) method accounted for 35 ± 17% of OC, indicating strong atmospheric oxidation capacity. Four major source factors for carbonaceous aerosols were identified by positive matrix factorization (PMF) model, including coal combustion, traffic emissions, soil dust and ship emissions, which accounted for 37 ± 23%, 39 ± 23%, 14 ± 10% and 10 ± 13%, respectively, of TC mass concentration, 38 ± 24%, 38 ± 23%, 14 ± 10% and 10 ± 12%, respectively, of OC mass concentration, and 29 ± 21%, 43 ± 22%, 14 ± 11% and 14 ± 15%, respectively, of EC mass concentration. Among these sources, traffic emission was the most important one, suggesting the necessity for promoting clean energy vehicles and relieving urban traffic congestion.
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Affiliation(s)
- Junjun Huang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Zhisheng Zhang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China.
| | - Jun Tao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China; South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China.
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Canada
| | - Fuli Nie
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China
| | - Leilei Fei
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou, China
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Ma Q, Wang W, Liu D, Zhao R, Zhao J, Li W, Pan Y, Zhang D. Haze Occurrence Caused by High Gas-to-Particle Conversion in Moisture Air under Low Pollutant Emission in a Megacity of China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19116405. [PMID: 35681990 PMCID: PMC9179953 DOI: 10.3390/ijerph19116405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 12/10/2022]
Abstract
Haze occurred in Zhengzhou, a megacity in the northern China, with the PM2.5 as high as 254 μg m−3 on 25 December 2019, despite the emergency response measure of restriction on the emission of anthropogenic pollutants which was implemented on December 19 for suppressing local air pollution. Air pollutant concentrations, chemical compositions, and the origins of particulate matter with aerodynamic diameter smaller than 2.5 µm (PM2.5) between 5–26 December were investigated to explore the reasons for the haze occurrence. Results show that the haze was caused by efficient SO2-to-suflate and NOx-to-nitrate conversions under high relative humidity (RH) condition. In comparison with the period before the restriction (5–18 December) when the PM2.5 was low, the concentration of PM2.5 during the haze (19–26 December) was 173 µg m−3 on average with 51% contributed by sulfate (31 µg m−3) and nitrate (57 µg m−3). The conversions of SO2-to-sulfate and NOx-to-nitrate efficiently produced sulfate and nitrate although the concentration of the two precursor gases SO2 and NOx was low. The high RH, which was more than 70% and the consequence of artificial water-vapor spreading in the urban air for reducing air pollutants, was the key factor causing the conversion rates to be enlarged in the constriction period. In addition, the last 48 h movement of the air parcels on 19–26 December was stagnant, and the air mass was from surrounding areas within 200 km, indicating weather conditions favoring the accumulation of locally-originated pollutants. Although emergency response measures were implemented, high gas-to-particle conversions in stagnant and moisture circumstances can still cause severe haze in urban air. Since the artificial water-vapor spreading in the urban air was one of the reasons for the high RH, it is likely that the spreading had unexpected side effects in some certain circumstances and needs to be taken into consideration in future studies.
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Affiliation(s)
- Qingxia Ma
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; (Q.M.); (D.L.); (J.Z.); (W.L.)
- Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security, Kaifeng 475004, China
| | - Weisi Wang
- Henan Ecological and Environmental Monitoring Center, Zhengzhou 450007, China;
| | - Dexin Liu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; (Q.M.); (D.L.); (J.Z.); (W.L.)
| | - Rongke Zhao
- Henan Kaifeng College of Science Technology and Communication, Kaifeng 475004, China;
| | - Jingqi Zhao
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; (Q.M.); (D.L.); (J.Z.); (W.L.)
| | - Wanlong Li
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; (Q.M.); (D.L.); (J.Z.); (W.L.)
| | - Yanfang Pan
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; (Q.M.); (D.L.); (J.Z.); (W.L.)
- Correspondence: (Y.P.); (D.Z.)
| | - Daizhou Zhang
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto 862-8502, Japan
- Correspondence: (Y.P.); (D.Z.)
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9
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Jiang F, Liu J, Cheng Z, Ding P, Xu Y, Zong Z, Zhu S, Zhou S, Yan C, Zhang Z, Zheng J, Tian C, Li J, Zhang G. Dual-carbon isotope constraints on source apportionment of black carbon in the megacity Guangzhou of the Pearl River Delta region, China for 2018 autumn season. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 294:118638. [PMID: 34890747 DOI: 10.1016/j.envpol.2021.118638] [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: 09/07/2021] [Revised: 11/21/2021] [Accepted: 12/03/2021] [Indexed: 06/13/2023]
Abstract
Black carbon (BC) aerosol negatively affects air quality and contributes to climate warming globally. However, little is known about the relative contributions of different source control measures to BC reduction owing to the lack of powerful source-diagnostic tools. We combine the fingerprints of dual-carbon isotope using an optimized Bayesian Markov chain Monte Carlo (MCMC) scheme and for the first time to study the key sources of BC in megacity Guangzhou of the Pearl River Delta (PRD) region, China in 2018 autumn season. The MCMC model-derived source apportionment of BC shows that the dominant contributor is petroleum combustion (39%), followed by coal combustion (34%) and biomass burning (27%). It should be noted that the BC source pattern is highly sensitive to the variations of air masses transported with an enhanced contribution of fossil source from the eastern area, suggesting the important impact of regional atmospheric transportation on the BC source profile in the PRD region. Also, we further found that fossil fuel combustion BC contributed 84% to the total BC reduction during 2013-2018. The response of PM2.5 concentration to the 14C-derived BC source apportionment is successfully fitted (r = 0.90) and the results predicted that it would take ∼6 years to reach the WHO PM2.5 guideline value (10 μg m-3) for the PRD region if the emission control measures keep same as they are at present. Taken together, our findings suggest that dual-carbon isotope is a powerful tool in constraining the source apportionment of BC for the evaluations of air pollution control and carbon emission measures.
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Affiliation(s)
- Fan Jiang
- Institute of Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Junwen Liu
- Institute of Environmental and Climate Research, Jinan University, Guangzhou, China.
| | - Zhineng Cheng
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, China
| | - Ping Ding
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Yuanqian Xu
- Institute of Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Zheng Zong
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Sanyuan Zhu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, China
| | - Shengzhen Zhou
- School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, China
| | - Caiqing Yan
- Environment Research Institute, Shandong University, Qingdao, China
| | - Zhisheng Zhang
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China
| | - Junyu Zheng
- Institute of Environmental and Climate Research, Jinan University, Guangzhou, China
| | - Chongguo Tian
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Jun Li
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, China
| | - Gan Zhang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China; CAS Center for Excellence in Deep Earth Science, Guangzhou, China
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10
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Li J, Zhang Z, Wu Y, Tao J, Xia Y, Wang C, Zhang R. Effects of chemical compositions in fine particles and their identified sources on hygroscopic growth factor during dry season in urban Guangzhou of South China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 801:149749. [PMID: 34428665 DOI: 10.1016/j.scitotenv.2021.149749] [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: 06/30/2021] [Revised: 08/12/2021] [Accepted: 08/14/2021] [Indexed: 06/13/2023]
Abstract
Knowledge of aerosol hygroscopicity is essential to assess visibility improvement and aerosol radiative forcing. Aerosol hygroscopicity is highly dependent on emission sources, while the hygroscopicity of different sources remains largely unexplored. In the current study, the hygroscopic growth factor (i.e., f(RH)) and relevant chemical compositions (e.g., water-soluble inorganic ions, carbonaceous fractions and elements) in fine particles were synchronously measured for nearly 3 months within 2019-2020 in an urban site of Guangzhou. The mean value (± standard deviation) of f(RH) at 70% RH was 1.50 (± 0.11). The diurnal cycle in aerosol hygroscopic growth strongly depended on the mass fraction of hydrophilic chemical compositions (e.g., SO42-, NO3- and NH4+) in fine particles and variation in contributions of aerosol sources. A Positive Matrix Factorization model was applied to distinguish the different hygroscopicity of specific source factors in a mixed aerosol. Secondary nitrate and secondary sulfate were more hydrophilic, whereas emissions from primary combustion processes (i.e., ship emission, coal combustion and road traffic) were less hygroscopic. Soil dust was almost insoluble. The hygroscopic growth of each source was parameterized that quantified the emission sources and f(RH) relationship for use of air quality and radiative transfer models either as input or as validation.
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Affiliation(s)
- Jiwei Li
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhisheng Zhang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environmental, Guangzhou 510655, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou 510275, China
| | - Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Jun Tao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China; South China Institute of Environmental Sciences, Ministry of Ecology and Environmental, Guangzhou 510655, China; Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Guangzhou 510275, China.
| | - Yunjie Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoying Wang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Renjian Zhang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
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11
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Jia H, Pan J, Huo J, Fu Q, Duan Y, Lin Y, Hu X, Cheng J. Atmospheric black carbon in urban and traffic areas in Shanghai: Temporal variations, source characteristics, and population exposure. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 289:117868. [PMID: 34364117 DOI: 10.1016/j.envpol.2021.117868] [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: 11/25/2020] [Revised: 07/25/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Black carbon (BC) measurements were performed at Pudong (PD) urban supersite and Gonghexin (GH) roadside station from December 1, 2017 to August 10, 2020 to investigate the variations, source characteristics, and population exposure levels of BC in traffic and urban areas in Shanghai, China. The BC median concentration at GH was more than two-fold that at PD. Absorption Ångström exponent (AAE) values were 1.27 ± 0.17 and 1.31 ± 0.17 at PD and GH, respectively, suggesting the dominance of liquid fossil fuel combustion sources (i.e., traffic exhaust) at these stations. The higher BC and AAE values in winter at PD indicated the relatively increasing contribution of solid fuels (i.e., biomass burning) to BC concentration in urban Shanghai. The diurnal variation in BC showed similar twin-peak patterns at PD and GH, implying that traffic emission mainly contributed to ambient BC concentration in urban Shanghai. The estimated daily intakes (EDIs) of BC were generally higher in males than in females at both PD and GH. The highest BC EDIs at PD were found in age subgroups 1-<2 and 2-<3 years. In contrast, the BC EDIs at GH were observed in age subgroups 6-<9, 12-<15, and 15-<18 years, which were higher than those determined at PD, indicating that more attention must be paid to BC exposure of the population in these age subgroups. These results provide scientific insights into variations, source characteristics, and population exposure levels of BC in urban and traffic areas and could help in the development of BC control strategies in Shanghai.
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Affiliation(s)
- Haohao Jia
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jun Pan
- State Ecologic Environmental Scientific Observation and Research Station at Dianshan Lake (SEED), Shanghai Environmental Monitor Center, Shanghai, 200235, China
| | - Juntao Huo
- State Ecologic Environmental Scientific Observation and Research Station at Dianshan Lake (SEED), Shanghai Environmental Monitor Center, Shanghai, 200235, China
| | - Qingyan Fu
- State Ecologic Environmental Scientific Observation and Research Station at Dianshan Lake (SEED), Shanghai Environmental Monitor Center, Shanghai, 200235, China
| | - Yusen Duan
- State Ecologic Environmental Scientific Observation and Research Station at Dianshan Lake (SEED), Shanghai Environmental Monitor Center, Shanghai, 200235, China
| | - Yanfen Lin
- State Ecologic Environmental Scientific Observation and Research Station at Dianshan Lake (SEED), Shanghai Environmental Monitor Center, Shanghai, 200235, China
| | - Xue Hu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jinping Cheng
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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12
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Black Carbon over Wuhan, China: Seasonal Variations in Its Optical Properties, Radiative Forcing and Contribution to Atmospheric Aerosols. REMOTE SENSING 2021. [DOI: 10.3390/rs13183620] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
As an important fraction of light-absorbing particles, black carbon (BC) has a significant warming effect, despite accounting for a small proportion of total aerosols. A comprehensive investigation was conducted on the characteristics of atmospheric aerosols and BC particles over Wuhan, China. Mass concentration, optical properties, and radiative forcing of total aerosols and BC were estimated using multi-source observation data. Results showed that the BC concentration monthly mean varied from 2.19 to 5.33 μg m−3. The BC aerosol optical depth (AOD) maximum monthly mean (0.026) occurred in winter, whereas the maximum total AOD (1.75) occurred in summer. Under polluted-air conditions, both aerosol radiative forcing (ARF) and BC radiative forcing (BCRF) at the bottom of the atmosphere (BOA) were strongest in summer, with values of −83.01 and −11.22 W m−2, respectively. In summer, ARF at BOA on polluted-air days was more than two-fold that on clean-air days. In addition, compared with clean-air days, BCRF at BOA on polluted-air days was increased by 76% and 73% in summer and winter, respectively. The results indicate an important influence of particulate air pollution on ARF and BCRF. Furthermore, the average contribution of BCRF to ARF was 13.8%, even though the proportion of BC in PM2.5 was only 5.1%.
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13
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One-Year Real-Time Measurement of Black Carbon in the Rural Area of Qingdao, Northeastern China: Seasonal Variations, Meteorological Effects, and the COVID-19 Case Analysis. ATMOSPHERE 2021. [DOI: 10.3390/atmos12030394] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper, we report the results obtained from one year of real-time measurement (i.e., from December 2019 to November 2020) of atmospheric black carbon (BC) under a rural environment in Qingdao of Northeastern China. The annual average concentration of BC was 1.92 ± 1.89 μg m−3. The highest average concentration of BC was observed in winter (3.65 ± 2.66 μg m−3), followed by fall (1.73 ± 1.33 μg m−3), spring (1.53 ± 1.33 μg m−3), and summer (0.83 ± 0.56 μg m−3). A clear weekend effect was observed in winter, which was characterized by higher BC concentration (4.60 ± 2.86 μg m−3) during the weekend rather than that (3.22 ± 2.45 μg m−3) during weekdays. The influence of meteorological parameters, including surface horizontal wind speed, boundary layer height (BLH), and precipitation, on BC, was investigated. In particular, such BLH influence presented evidently seasonal dependence, while there was no significant seasonality for horizontal wind speed. These may reflect different roles of atmospheric vertical dilution on affecting BC in different seasons. The △BC/△CO ratio decreased with the increase of precipitation, indicative of the influence of below-cloud wet removal of BC, especially during summertime where rainfall events more frequently occurred than any of other seasons. The bivariate-polar-plot analysis showed that the high BC concentrations were mainly associated with low wind speed in all seasons, highlighting an important BC source originated from local emissions. By using concentration-weighted trajectory analysis, it was found that regional transports, especially from northeastern in winter, could not be negligible for contributing to BC pollution in rural Qingdao. In the coronavirus disease 2019 (COVID−19) case analysis, we observed an obvious increase in the BC/NO2 ratio during the COVID-19 lockdown, supporting the significant non-traffic source sector (such as residential coal combustion) for BC in rural Qingdao.
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14
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Wu Y, Li J, Jiang C, Xia Y, Tao J, Tian P, Zhou C, Wang C, Xia X, Huang RJ, Zhang R. Spectral absorption properties of organic carbon aerosol during a polluted winter in Beijing, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142600. [PMID: 33045607 DOI: 10.1016/j.scitotenv.2020.142600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/09/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
A fraction of organic carbon (OC) is found to exhibit the capability to absorb solar radiation. However, the absorption properties of OC remain poorly characterized partly due to uncertainties in determination methods. In this study, the absorption coefficient (bap) of OC (bap,OC) in Beijing during a polluted winter was estimated on the basis of the combined measurements of black carbon (BC) size distribution and total aerosol bap (bap,meas). The bare BC bap (bap,bareBC) calculated using Mie theory on the basis of measured size distribution exhibited weak wavelength dependence, with a mean absorption Ångström exponent (AAE) of 0.56 ± 0.04 within the 470-660 nm wavelength range, which was lower than the value of 1 commonly used for freshly emitted BC. The calculated bap,bareBC was compared with bap,meas at 950 nm to derive the coating thickness of BC, from which the calculation of coated BC bap (bap,coatBC) within 370-660 nm was based using the core-shell Mie model. Given the thick coatings, the AAE of coated BC, with a mean of 0.53 ± 0.12, was slightly lower than that of bare BC. Subsequently, bap,OC was obtained by subtracting bap,coatBC from bap,meas, accounting for 59.57 ± 4.82% of bap,meas at 370 nm on average. The average mass absorption efficiency of OC was estimated to be 1.48 ± 0.36 m2 g-1 at 370 nm. bap,OC significantly decreased as wavelength increased, deriving an AAE of OC with a mean of 2.72 ± 0.32 within the 370-660 nm range. The level of bap,OC estimated on the basis of a widely used attribution method assuming a constant BC AAE of 1 was ~60% lower than the currently presented value, probably underestimating OC radiative effect by a factor of >3. More accurate estimations of bap,OC based on more advanced measurements and suitable theory calculations are recommended to provide more reliable assessments of OC radiative effects.
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Affiliation(s)
- Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Jiwei Li
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Jiang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunjie Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Tao
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, China
| | - Ping Tian
- Beijing Weather Modification Office, Beijing 100089, China
| | - Chang Zhou
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoying Wang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangao Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
| | - Ru-Jin Huang
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Renjian Zhang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
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15
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Wu Y, Xia Y, Zhou C, Tian P, Tao J, Huang RJ, Liu D, Wang X, Xia X, Han Z, Zhang R. Effect of source variation on the size and mixing state of black carbon aerosol in urban Beijing from 2013 to 2019: Implication on light absorption. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 270:116089. [PMID: 33246761 DOI: 10.1016/j.envpol.2020.116089] [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: 08/06/2020] [Revised: 11/10/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Black carbon (BC) is the most important aerosol light-absorbing component, and its effect on radiation forcing is determined by its microphysical properties. In this study, two microphysical parameters of refractory BC (rBC), namely, size distribution and mixing state, in urban Beijing from 2013 to 2019 were investigated to understand the effects of source changes over the past years. The mass equivalent diameter of rBC (Dc) exhibited bimodal lognormal distributions in all seasons, with the major modes accounting for most (>85%) of the rBC masses. The mass median diameter (MMD) was obviously larger in winter (209 nm) than in summer (167 nm) likely due to the contribution of more rBC with larger Dc from solid fuel combustion and enhanced coagulation of rBC in polluted winter. More rBC particles were thickly coated in winter, with the number fraction of thickly coated rBC (fcoatBC) ranging within 29%-48% compared with that of 12%-14% in summer. However, no evidential increase in BC light-absorption capability was observed in winter. This finding was likely related to the lower absorption efficiency of larger rBC in winter, which partly offset the coating-induced light enhancement. Two stage of decreases in MMD and fcoatBC were observed, accompanied with a persistent decrease in rBC loading, thereby reflecting the discrepant effects of source control measures on rBC loading and physical properties. The control measures in the earlier stage before 2016 was more efficient to reduce the rBC loading but slightly influenced the microphysical properties of rBC. As of 2016, the reduction in rBC concentration slowed down because of its low atmospheric loading. However, rBC showed a more obvious decrease in its core size and became less coated. The decrease in fcoatBC may have weakened the BC absorption and accelerated the decrease in light absorption resulting from the reduction in rBC loading.
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Affiliation(s)
- Yunfei Wu
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Yunjie Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang Zhou
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Tian
- Beijing Weather Modification Office, Beijing 100089, China
| | - Jun Tao
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510530, China
| | - Ru-Jin Huang
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Dantong Liu
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Xin Wang
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, Lanzhou University, Lanzhou 730000, China
| | - Xiangao Xia
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
| | - Zhiwei Han
- Key Laboratory of Regional Climate-Environment for Temperate East Asia (RCE-TEA), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Renjian Zhang
- Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Xianghe Observatory of Whole Atmosphere, Institute of Atmospheric Physics, Chinese Academy of Sciences, Xianghe 065400, China
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