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Lim S, Lee M, Yoo HJ. Size distributions, mixing state, and morphology of refractory black carbon in an urban atmosphere of northeast Asia during summer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158436. [PMID: 36108842 DOI: 10.1016/j.scitotenv.2022.158436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/21/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Black carbon (BC) exerts profound impacts on air quality, human health, and climate. Here, we investigated concentrations and size distributions of refractory BC (rBC) and mixing state and morphology of rBC-containing particles in urban Seoul for 2019 summer. Mass concentrations of rBC ranged from 0.02 μgm-3 to 2.89 μgm-3, and daily maximums of rBC mass, daily minimums of rBC mass median diameter (MMD) (110-130 nm), and shell-to-core ratio (Rshell/core) occurred with NO2 maximums during morning rush hour. As the first report of ground observations on rBC mixing state, these results indicate that vehicle emission is a major local source of rBC in Seoul. MMDs of 127-146 nm and the greatest mass loadings of ≥1 μg m-3 were accompanied by high O3 and PM2.5 concentrations, in contrast to the largest MMDs (135-165 nm) associated with transport from upstream regions. The average Rshell/core was 1.25 for the rBC mass-equivalent diameter (DrBC) of 140-220 nm. Rshell/core increased gradually through the day and was positively correlated with Ox concentration, indicating photochemical aging of rBC particles. Co-emissions of rBC and volatile organic compounds from vehicles facilitated internal mixing during the daytime. However, Rshell/core tended to be low at temperature >∼30 °C, while 58 % of rBC particles with Rshell/core exceeding 1.25 were found at nighttime under relative humidity >75 %. These results demonstrate that the mixing state of freshly-emitted rBC particles was altered through coating by photochemically oxidized vapors during the day and hygroscopic growth at night. Additionally, the delay-time approach revealed rBC morphological characteristics, the most common being the bare type (74 %), and the attached type (6 %) was relatively large in numbers during morning rush hour. Therefore, it is suggested that during summer, rBC particles from traffic emissions should be considered in parallel to winter pollution mitigation strategies in urban atmosphere of northeast Asia.
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Affiliation(s)
- Saehee Lim
- Dept. of Earth and Environmental Sciences, Korea University, Seoul 02841, Republic of Korea; Dept. of Environmental Engineering, Chungnam National University, Deajeon 34134, Republic of Korea
| | - Meehye Lee
- Dept. of Earth and Environmental Sciences, Korea University, Seoul 02841, Republic of Korea.
| | - Hee-Jung Yoo
- Climate Research Department, National Institute of Meteorological Sciences, Jeju 63568, Republic of Korea
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Song X, Hu Y, Ma Y, Jiang L, Wang X, Shi A, Zhao J, Liu Y, Liu Y, Tang J, Li X, Zhang X, Guo Y, Wang S. Is short-term and long-term exposure to black carbon associated with cardiovascular and respiratory diseases? A systematic review and meta-analysis based on evidence reliability. BMJ Open 2022; 12:e049516. [PMID: 35504636 PMCID: PMC9066484 DOI: 10.1136/bmjopen-2021-049516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE Adverse health effects of fine particles (particulate matter2.5) have been well documented by a series of studies. However, evidences on the impacts of black carbon (BC) or elemental carbon (EC) on health are limited. The objectives were (1) to explored the effects of BC and EC on cardiovascular and respiratory morbidity and mortality, and (2) to verified the reliability of the meta-analysis by drawing p value plots. DESIGN The systematic review and meta-analysis using adapted Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and p value plots approach. DATA SOURCES PubMed, Embase and Web of Science were searched from inception to 19 July 2021. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Time series, case cross-over and cohort studies that evaluated the associations between BC/EC on cardiovascular or respiratory morbidity or mortality were included. DATA EXTRACTION AND SYNTHESIS Two reviewers independently selected studies, extracted data and assessed risk of bias. Outcomes were analysed via a random effects model and reported as relative risk (RR) with 95% CI. The certainty of evidences was assessed by adapted GRADE. The reliabilities of meta-analyses were analysed by p value plots. RESULTS Seventy studies met our inclusion criteria. (1) Short-term exposure to BC/EC was associated with 1.6% (95% CI 0.4% to 2.8%) increase in cardiovascular diseases per 1 µg/m3 in the elderly; (2) Long-term exposure to BC/EC was associated with 6.8% (95% CI 0.4% to 13.5%) increase in cardiovascular diseases and (3) The p value plot indicated that the association between BC/EC and respiratory diseases was consistent with randomness. CONCLUSIONS Both short-term and long-term exposures to BC/EC were related with cardiovascular diseases. However, the impact of BC/EC on respiratory diseases did not present consistent evidence and further investigations are required. PROSPERO REGISTRATION NUMBER CRD42020186244.
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Affiliation(s)
- Xuping Song
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Yue Hu
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Yan Ma
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Liangzhen Jiang
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Xinyi Wang
- Second Clinical College, Lanzhou University, Lanzhou, Gansu, China
| | - Anchen Shi
- Department of General Surgery, Xi'an Jiaotong University Medical College First Affiliated Hospital, Xi'an, Shaanxi, China
| | - Junxian Zhao
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Yunxu Liu
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Yafei Liu
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Jing Tang
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Xiayang Li
- School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Xiaoling Zhang
- College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, Sichuan, China
| | - Yong Guo
- Department of Civil Affairs in Guizhou Province, Guizhou Province People's Government, Guiyang, Guizhou, China
| | - Shigong Wang
- College of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, Sichuan, China
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Columnar Aerosol Optical Property Characterization and Aerosol Typing Based on Ground-Based Observations in a Rural Site in the Central Yangtze River Delta Region. REMOTE SENSING 2022. [DOI: 10.3390/rs14020406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Accurate and updated aerosol optical properties (AOPs) are of vital importance to climatology and environment-related studies for assessing the radiative impact of natural and anthropogenic aerosols. We comprehensively studied the columnar AOP observations between January 2019 and July 2020 from a ground-based remote sensing instrument located at a rural site operated by Central China Comprehensive Experimental Sites in the center of the Yangtze River Delta (YRD) region. In order to further study the aerosol type, two threshold-based aerosol classification methods were used to investigate the potential categories of aerosol particles under different aerosol loadings. Based on AOP observation and classification results, the potential relationships between the above-mentioned results and meteorological factors (i.e., humidity) and long-range transportation processes were analyzed. According to the results, obvious variation in aerosol optical depth (AOD) during the daytime, as well as throughout the year, was revealed. Investigation into AOD, single-scattering albedo (SSA), and absorption aerosol optical depth (AAOD) revealed the dominance of fine-mode aerosols with low absorptivity. According to the results of the two aerosol classification methods, the dominant aerosol types were continental (accounting for 43.9%, method A) and non-absorbing aerosols (62.5%, method B). Longer term columnar AOP observations using remote sensing alongside other techniques in the rural areas in East China are still needed for accurate parameterization in the future.
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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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Tan Y, Wang H, Shi S, Shen L, Zhang C, Zhu B, Guo S, Wu Z, Song Z, Yin Y, Liu A. Annual variations of black carbon over the Yangtze River Delta from 2015 to 2018. J Environ Sci (China) 2020; 96:72-84. [PMID: 32819701 DOI: 10.1016/j.jes.2020.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
In this study, the black carbon (BC) measurements in the atmosphere of Nanjing, China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer. By combining dataset of PM2.5, PM10, CO, NO2, SO2, O3 and meteorological parameters, the temporal variations and the source apportionment of BC were given in this study. The results showed that the PM2.5 mass concentrations decreased in Nanjing, with an average annual rate of variation of 6.50 μg/(m3⋅year). Differently, the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m3⋅year). The seasonal variations showed the pattern of BC mass concentrations in winter > autumn > spring > summer. The diurnal variations of BC mass concentrations showed a double-peak in all four seasons. The first peak occurred at approximately 7:00 in spring, summer and autumn and around 8:00 in winter. The second peak took place after 18:00. The average AAE (absorption Ångström exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest (1.12) during summertime. In addition, the AAE was smaller in the daytime than that at night, with a minimum occurring between 13:00 and 14:00. BC and visibility show a good power-function relationship at different humidity levels. The average values of the visibility thresholds of the BC mass concentrations in spring, summer, autumn and winter were 1.326, 5.522, 1.340 and 0.708 μg/m3, respectively. The greater the relative humidity, the smaller the visibility threshold for the BC mass concentrations was.
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Affiliation(s)
- Yue Tan
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Honglei Wang
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (Peking University) College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Shuangshuang Shi
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Lijuan Shen
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Chen Zhang
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Bin Zhu
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Song Guo
- State Key Joint Laboratory of Environment Simulation and Pollution Control (Peking University) College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control (Peking University) College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ziyi Song
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Yan Yin
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
| | - Ankang Liu
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing 210044, China
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Gao L, Cao L, Zhang Y, Yan P, Jing J, Zhou Q, Wang Y, Lv S, Jin J, Li Y, Chi W. Re-evaluating the distribution and variation characteristics of haze in China using different distinguishing methods during recent years. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:138905. [PMID: 32438159 DOI: 10.1016/j.scitotenv.2020.138905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
Haze is identified via different methods using hourly visibility, relative humidity (RH) and PM2.5 mass concentration observations collected from 2013 to 2018 at 502 stations in China. An inter-comparison of a new haze identification method (MGB) and other currently used methods (M80 and M90) is performed in this research. Compared with other methods, the MGB method has an advantage in the expression of fine particle pollution characteristics, especially in high humidity areas. The mean value of the correlation coefficient of the daily mean PM2.5 and daily haze hour obtained by MGB in China is 0.69 which is higher than the correlation coefficients of the daily mean PM2.5 and haze hour identified by the other two methods. Compared with M80, the haze identified by MGB and M90 is less influenced by daily or monthly variations of RH. Approximately 75% of haze occurs when the RH is exceeds 60% or the PM2.5 mass concentration is below 105 μg/m3 over China, no matter which haze identification method is used. Haze has obvious regional distribution characteristics and is relatively higher in Beijing-Tianjin-Hebei and its surrounding areas, and the middle and lower reaches of the Yangtze River. The 6-year mean annual total haze identified by the MGB method is 1167 h for mainland China. Compared with MGB, M80 underestimates the haze hour by -34%, and M90 produces a smaller positive overestimation by 18%. The annual total haze hour of China and its three major economic regions shows significant decreasing trends regardless of the identification method used. Daily variation of haze is obtained in this research via automatic visibility measurement. The daily cycles of haze hour identified by MGB and M90 are similar, whereas that identified by M80 behaves differently affected by daily variation of RH. Haze hour is high in winter and low in summer.
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Affiliation(s)
- Lina Gao
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Lijuan Cao
- National Meteorological Information Center, China Meteorological Administration, Beijing 100081, China.
| | - Yong Zhang
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China.
| | - Peng Yan
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Junshan Jing
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Qing Zhou
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Yimeng Wang
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Shanshan Lv
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Junli Jin
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Yanan Li
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
| | - Wenxue Chi
- Meteorological Observation Center, China Meteorological Administration, Beijing 100081, China
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Contrasting Aerosol Optical Characteristics and Source Regions During Summer and Winter Pollution Episodes in Nanjing, China. REMOTE SENSING 2019. [DOI: 10.3390/rs11141696] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Two episodes with heavy air pollution in Nanjing, China, one in the summer and another one in the winter of 2017, were selected to study aerosol properties using sun photometer and ground-based measurements, together with source region analysis. The aerosol properties, the meteorological conditions, and the source regions during these two episodes were very different. The episodes were selected based on the air quality index (AQI), which reached a maximum value of 193 during the summer episode (26 May–3 June) and 304 during the winter episode (21–31 December). The particulate matter (PM) concentrations during the winter episode reached maximum values for PM2.5/10 of 254 g m−3 and 345 g m−3, much higher than those during the summer (73 and 185 g m−3). In contrast, the value of aerosol optical depth (AOD) at 500 nm was higher during the summer episode (2.52 0.19) than during that in the winter (1.38 0.18). A high AOD value does not necessarily correspond to a high PM concentration but is also affected by factors, such as wind, Planetary Boundary Layer Height (PBLH), and relative humidity. The mean value of the Ångström Exponent (AE) varied from 0.91–1.42, suggesting that the aerosol is a mixture of invaded dust and black carbon. The absorption was stronger during the summer than during the winter, with a minimum value of the single scattering albedo (SSA) at 440 nm of 0.86 on 28 May. Low values of asymmetry factor (ASY) (0.65 at 440 nm and 0.58 at 1020 nm) suggest a large number of anthropogenic aerosols, which are absorbing fine-mode particles. The Imaginary part of the Refractive Index (IRI) was higher during the summer than during the winter, indicating there was absorbing aerosol during the summer. These differences in aerosol properties during the summer and winter episodes are discussed in terms of meteorological conditions and transport. The extreme values of PM and AOD were reached during both episodes in conditions with stable atmospheric stratification and low surface wind speed, which are conducive for the accumulation of pollutants. Potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analysis show that fine mode absorbing aerosols dominate during the summer season, mainly due to emissions of local and near-by sources. In the winter, part of the air masses was arriving from arid/semi-arid regions (Shaanxi, Ningxia, Gansu, and Inner Mongolia provinces) covering long distances and transporting coarse particles to the study area, which increased the scattering characteristics of aerosols.
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