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Tan Z, Feng M, Liu H, Luo Y, Li W, Song D, Tan Q, Ma X, Lu K, Zhang Y. Atmospheric Oxidation Capacity Elevated during 2020 Spring Lockdown in Chengdu, China: Lessons for Future Secondary Pollution Control. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8815-8824. [PMID: 38733566 DOI: 10.1021/acs.est.3c08761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
This study presents the measurement of photochemical precursors during the lockdown period from January 23, 2020, to March 14, 2020, in Chengdu in response to the coronavirus (COVID-19) pandemic. To derive the lockdown impact on air quality, the observations are compared to the equivalent periods in the last 2 years. An observation-based model is used to investigate the atmospheric oxidation capacity change during lockdown. OH, HO2, and RO2 concentrations are simulated, which are elevated by 42, 220, and 277%, respectively, during the lockdown period, mainly due to the reduction in nitrogen oxides (NOx). However, the radical turnover rates, i.e., OH oxidation rate L(OH) and local ozone production rate P(O3), which determine the secondary intermediates formation and O3 formation, only increase by 24 and 48%, respectively. Therefore, the oxidation capacity increases slightly during lockdown, which is partly attributed to unchanged alkene concentrations. During the lockdown, alkene ozonolysis seems to be a significant radical primary source due to the elevated O3 concentrations. This unique data set during the lockdown period highlights the importance of controlling alkene emission to mitigate secondary pollution formation in Chengdu and may also be applicable in other regions of China given an expected NOx reduction due to the rapid transformation to electrified fleets in the future.
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Affiliation(s)
- Zhaofeng Tan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control (Peking University), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Miao Feng
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Hefan Liu
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Yina Luo
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Wei Li
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Danlin Song
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Qinwen Tan
- Chengdu Academy of Environmental Sciences, Chengdu 610072, China
| | - Xuefei Ma
- State Key Joint Laboratory of Environmental Simulation and Pollution Control (Peking University), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control (Peking University), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control (Peking University), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Li R, Gao Y, Han Y, Zhang Y, Zhang B, Fu H, Wang G. Elucidating the mechanisms of rapid O 3 increase in North China Plain during COVID-19 lockdown period. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167622. [PMID: 37806584 DOI: 10.1016/j.scitotenv.2023.167622] [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: 06/20/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/10/2023]
Abstract
Ozone (O3) levels in North China Plain (NCP) suffered from rapid increases during the COVID-19 period. Many previous studies have confirmed more rapid NOx reduction compared with VOCs might be responsible for the O3 increase during this period, while the comprehensive impacts of each VOC species and NOx on ambient O3 and their interactions with meteorology were not revealed clearly. To clarify the detailed reasons for the O3 increase, a continuous campaign was performed in a typical industrial city of NCP. Meanwhile, the machine-learning technique and the box model were employed to reveal the mechanisms of O3 increase from the perspective of meteorology and photochemical process, respectively. The result suggested that the ambient O3 level in Tangshan increased from 18.7 ± 4.63 to 45.6 ± 8.52 μg/m3 (143%) during COVID-19 lockdown, and the emission reduction and meteorology contributed to 54 % and 46 % of this increment, respectively. The lower wind speed (WS) coupled with regional transport played a significant role on O3 increase (30.8 kg/s). The O3 sensitivity verified that O3 production was highly volatile organic compounds (VOC)-sensitive (Relative incremental reactivity (RIR): 0.75), while the NOx showed the negative impact on O3 production in Tangshan (RIR: -0.59). It suggested that the control of VOCs rather than NOx might be more effective in reducing O3 level in Tangshan because it was located on the VOC-limited regime. Besides, both of ozone formation potential (OFP) analysis and observation-based model (OBM) demonstrated that the alkenes (36.3 ppb) and anthropogenic oxygenated volatile organic compounds (OVOCs) (15.2 ppb) showed the higher OFP compared with other species, and their reactions released a large number of HO2 and RO2 radicals. Moreover, the concentrations of these species did not experience marked decreases during COVID-19 lockdown, which were major contributors to O3 increase during this period. This study also underlined the necessity of priority controlling alkenes and OVOCs across the NCP.
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Affiliation(s)
- Rui Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, PR China.
| | - Yining Gao
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, PR China
| | - Yu Han
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200433, PR China
| | - Yi Zhang
- Tangshan Ecological Environment Publicity and Education Center, Tangshan 063000, Hebei, PR China
| | - Baojun Zhang
- Tangshan Ecological Environment Publicity and Education Center, Tangshan 063000, Hebei, PR China
| | - Hongbo Fu
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200433, PR China
| | - Gehui Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, PR China.
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Hwang SH, Won JU, Park WM. Changes in total volatile organic compound concentration in Seoul subway stations before (2019) and after (2021) the COVID-19 outbreak. Sci Rep 2023; 13:20328. [PMID: 37990122 PMCID: PMC10663549 DOI: 10.1038/s41598-023-46519-9] [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: 07/18/2023] [Accepted: 11/02/2023] [Indexed: 11/23/2023] Open
Abstract
Volatile organic compounds (VOCs) are major air pollutants often designated as specific hazardous or toxic. This study analyzed the trends in concentration changes and influencing factors of VOCs in underground subway stations in the Seoul Metro before (2019) and after (2021) the COVID-19 pandemic. A total of 506 samples were collected from 253 stations on lines 1-8 between May 2019 and September 2021. Total VOC concentrations in Seoul Metro increased after the COVID-19 pandemic 3.8 times over. The deeper the underground station platform, the greater the difference in the VOC concentrations between 2019 and 2021, which was positively related. Average VOC concentration was the highest (52.8 µg/m3) at a depth of 25-30 m and the lowest (23.9 µg/m3) at a depth of < 10 m in 2019. In conclusion, excessive disinfection during the COVID-19 pandemic resulted in increased VOC concentrations in the Seoul Metro, especially in the deeper underground stations. Less frequent quarantine disinfection is recommended to improve air quality.
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Affiliation(s)
- Sung Ho Hwang
- Institute of Health & Environment, Seoul National University, Seoul, South Korea
| | - Jong-Uk Won
- Institute for Occupational Health, College of Medicine, Yonsei University, Seoul, South Korea
- Graduate School of Public Health, Yonsei University, Seoul, South Korea
- Department of Occupational and Environmental Medicine, Severance Hospital, Yonsei University Health System, Seoul, South Korea
| | - Wha Me Park
- Institute for Occupational Health, College of Medicine, Yonsei University, Seoul, South Korea.
- Graduate School of Public Health, Yonsei University, Seoul, South Korea.
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Li B, Ho SSH, Li X, Guo L, Feng R, Fang X. Pioneering observation of atmospheric volatile organic compounds in Hangzhou in eastern China and implications for upcoming 2022 Asian Games. J Environ Sci (China) 2023; 124:723-734. [PMID: 36182177 DOI: 10.1016/j.jes.2021.12.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/16/2021] [Accepted: 12/19/2021] [Indexed: 06/16/2023]
Abstract
Understanding the emission sources of volatile organic compounds (VOCs) is critical for air pollution mitigation. Continuous measurements of atmospheric VOCs were conducted from January to February in Hangzhou in 2021. The average measured concentration of total VOCs (TVOCs) was 38.2 ± 20.9 ppb, > 42% lower than that reported by previous studies at the urban center in Hangzhou. The VOC concentrations and proportions were similar between weekdays and weekends. During the long holidays of the Spring Festival in China, the concentrations of TVOCs were ∼50% lower than those during the regular days, but their profiles showed no significant difference (p > 0.05). Further, we deduced that aromatics and alkenes were the most crucial chemicals promoting the formation of O3 and secondary organic aerosol (SOA) in Hangzhou. According to interspecies correlations, combustion processes and solvent use were inferred as major VOC emission sources. This study provides implications for air quality improvements before and during the upcoming Asian Games that will be hosted in Hangzhou in 2022.
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Affiliation(s)
- Bowei Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, 89512, USA
| | - Xinhe Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Liya Guo
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Rui Feng
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xuekun Fang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, China; Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Zhou X, Zhou X, Wang C, Zhou H. Environmental and human health impacts of volatile organic compounds: A perspective review. CHEMOSPHERE 2023; 313:137489. [PMID: 36513206 DOI: 10.1016/j.chemosphere.2022.137489] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Volatile organic compounds (VOCs) are synthetic chemicals that are broadly used in the production of numerous day-to-day products for residential and commercial-based applications. VOCs are naturally occurring in the environment; however, average annual emissions of man-made volatile organic compounds may have increased dramatically in recent decades. Although many factors were attributed to influencing volatile compounds' emission, only mankind's activities are mainly proclaimed. Since vehicle and industrial pollution are mounting for years and years, urban areas are highly prone to the impacts of VOCs. Generally, volatile compounds are highly spontaneous and readily react with the particles of ambiance and produce a polluted atmosphere through several physical and chemical reactions. Though the volatile compounds play an indispensable role in the manufacture and maintaining the stability of many products, the health impacts associated with their prolonged exposure are gaining attention as recent research reports underline the influence of a wide range of diseases and disorders. Likewise, since the modern way of life applies a lot of day-to-day chemicals, it is imperative to spread a wide knowledge and safety aspects about these chemicals so that people of a wide category can implement preventive measures according to their exposure and living style. In this context, the review article attempts to shed light on past and current updates concerning the relationship between VOCs exposure and environmental and human health impacts.
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Affiliation(s)
- Xihe Zhou
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China
| | - Xiang Zhou
- Sinomaple Furnishing (Jiangsu) Co., Ltd., 99 Fen an Dong Lu, Wujiang District, Suzhou, Jiangsu, 215200, China
| | - Chengming Wang
- Holtrop & Jansma (Qingdao) Environmental Protection Equipment Co., Ltd., 8 Tongshun Road, High-tech District, Qingdao, Shandong, 266114, China
| | - Handong Zhou
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, International Innovation Center for Forest Chemicals and Materials, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China.
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Wang J, Yue H, Cui S, Zhang Y, Li H, Wang J, Ge X. Chemical Characteristics and Source-Specific Health Risks of the Volatile Organic Compounds in Urban Nanjing, China. TOXICS 2022; 10:722. [PMID: 36548555 PMCID: PMC9783090 DOI: 10.3390/toxics10120722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/16/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
This work comprehensively investigated the constituents, sources, and associated health risks of ambient volatile organic compounds (VOCs) sampled during the autumn of 2020 in urban Nanjing, a megacity in the densely populated Yangtze River Delta region in China. The total VOC (TVOC, sum of 108 species) concentration was determined to be 29.04 ± 14.89 ppb, and it was consisted of alkanes (36.9%), oxygenated VOCs (19.9%), halogens (19.1%), aromatics (9.9%), alkenes (8.9%), alkynes (4.9%), and others (0.4%). The mean TVOC/NOx (ppbC/ppbv) ratio was only 3.32, indicating the ozone control is overall VOC-limited. In terms of the ozone formation potential (OFP), however, the largest contributor became aromatics (41.9%), followed by alkenes (27.6%), and alkanes (16.9%); aromatics were also the dominant species in secondary organic aerosol (SOA) formation, indicative of the critical importance of aromatics reduction to the coordinated control of ozone and fine particulate matter (PM2.5). Mass ratios of ethylbenzene/xylene (E/X), isopentane/n--pentane (I/N), and toluene/benzene (T/B) ratios all pointed to the significant influence of traffic on VOCs. Positive matrix factorization (PMF) revealed five sources showing that traffic was the largest contributor (29.2%), particularly in the morning. A biogenic source, however, became the most important source in the afternoon (31.3%). The calculated noncarcinogenic risk (NCR) and lifetime carcinogenic risk (LCR) of the VOCs were low, but four species, acrolein, benzene, 1,2-dichloroethane, and 1,2-dibromoethane, were found to possess risks exceeding the thresholds. Furthermore, we conducted a multilinear regression to apportion the health risks to the PMF-resolved sources. Results show that the biogenic source instead of traffic became the most prominent contributor to the TVOC NCR and its contribution in the afternoon even outpaced the sum of all other sources. In summary, our analysis reveals the priority of controls of aromatics and traffic/industrial emissions to the efficient coreduction of O3 and PM2.5; our analysis also underscores that biogenic emissions should be paid special attention if considering the direct health risks of VOCs.
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Li X, Li B, Guo L, Feng R, Fang X. Research progresses on VOCs emission investigations via surface and satellite observations in China. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1968-1981. [PMID: 36000414 DOI: 10.1039/d2em00175f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Volatile organic compounds (VOCs) are important precursors of severe pollution of ozone (O3) and secondary organic aerosols in China. Fully understanding the VOCs emission is crucial for making regulations to improve air quality. This study reviews the published studies on atmospheric VOCs concentration observations in China and observation-based estimation of China's VOCs emission strengths and emission source structures. The results reveal that direct sampling and stainless-steel-tank sampling are the most commonly used methods for online and offline observations in China, respectively. The GC-MS/FID is the most commonly used VOCs measuring instrument in China (in 60.8% of the studies we summarized). Numerous studies conducted observation campaigns in urban areas (76.2%) than in suburban (17.1%), rural (18.1%), and background areas (14.3%) in China. Moreover, observation sites are largely set in eastern China (83.8%). Though there are published studies reporting observation-based China's VOCs emission investigation, these kinds of studies are still limited, and gaps are found between the results of top-down investigation and bottom-up inventories of VOCs emissions in China. In order to enhance the observation-based VOCs emission investigations in China, this study suggests future improvements including: (1) development of VOCs detection techniques, (2) strengthening of atmospheric VOCs observations, (3) improvement of the accuracy of observation-based VOCs emission estimations, and (4) facilitation of better VOCs emission inventories in China.
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Affiliation(s)
- Xinhe Li
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China.
| | - Bowei Li
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China.
| | - Liya Guo
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China.
| | - Rui Feng
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China.
| | - Xuekun Fang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, P. R. China.
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
- Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Tong L, Liu Y, Meng Y, Dai X, Huang L, Luo W, Yang M, Pan Y, Zheng J, Xiao H. Surface ozone changes during the COVID-19 outbreak in China: An insight into the pollution characteristics and formation regimes of ozone in the cold season. JOURNAL OF ATMOSPHERIC CHEMISTRY 2022; 80:103-120. [PMID: 36248311 PMCID: PMC9540070 DOI: 10.1007/s10874-022-09443-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
The countrywide lockdown in China during the COVID-19 pandemic provided a natural experiment to study the characteristics of surface ozone (O3). Based on statistical analysis of air quality across China before and during the lockdown, the tempo-spatial variations and site-specific formation regimes of wintertime O3 were analyzed. The results showed that the O3 pollution with concentrations higher than air quality standards could occur widely in winter, which had been aggravated by the emission reduction during the lockdown. On the national scale of China, with the significant decrease (54.03%) in NO2 level from pre-lockdown to COVID-19 lockdown, the maximum daily 8-h average concentration of O3 (MDA8h O3) increased by 39.43% from 49.05 to 64.22 μg/m3. This increase was comprehensively contributed by attenuated NOx suppression and favorable meteorological changes on O3 formation during the lockdown. As to the pollution states of different monitoring stations, surface O3 responded oppositely to the consistent decreased NO2 across China. The O3 levels were found to increase in the northern and central regions, but decrease in the southern region, where the changes in both meteorology (e.g. temperature drops) and precursors (reduced emissions) during the lockdown had diminished local O3 production. The spatial differences in NOx levels generally dictate the site-specific O3 formation regimes in winter, with NOx-titration/VOCs-sensitive regimes being dominant in northern and central China, while VOCs-sensitive/transition regimes being dominant in southern China. These findings highlight the influence of NOx saturation levels on winter O3 formation and the necessity of VOCs emission reductions on O3 pollution controls.
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Affiliation(s)
- Lei Tong
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
| | - Yu Liu
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yang Meng
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
| | - Xiaorong Dai
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100 China
| | - Leijun Huang
- College of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou, 311300 China
| | - Wenxian Luo
- College of Mathematics and Computer Science, Zhejiang A & F University, Hangzhou, 311300 China
| | - Mengrong Yang
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yong Pan
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jie Zheng
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
| | - Hang Xiao
- Center for Excellence in Regional Atmospheric Environment & Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 China
- Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo (Beilun) Zhongke Haixi Industrial Technology Innovation Center, Ningbo, 315800 China
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Hawari NSSL, Latif MT, Hamid HHA, Leng TH, Othman M, Mohtar AAA, Azhari A, Dominick D. The concentration of BTEX in selected urban areas of Malaysia during the COVID-19 pandemic lockdown. URBAN CLIMATE 2022; 45:101238. [PMID: 35855931 PMCID: PMC9276713 DOI: 10.1016/j.uclim.2022.101238] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 06/23/2022] [Accepted: 07/09/2022] [Indexed: 05/29/2023]
Abstract
Volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene and xylene (BTEX) are air pollutants that harm human health. This study aims to identify BTEX concentrations before the lockdown known as the Movement Control Order was imposed (BMCO), during the implementation of the Movement Control Order (MCO), and then during the Conditional Movement Control Order (CMCO). These orders were introduced during the COVID-19 pandemic in Malaysia. The study utilised data measured by the continuous monitoring of BTEX using online gas chromatography instruments located at three urban area stations. The results showed that the BTEX concentrations reduced by between -38% and -46% during the MCO compared to the BMCO period. The reduction of human mobility during the MCO and CMCO influenced the lower BTEX concentrations recorded at a station within the Kuala Lumpur area. The results of the BTEX diagnostic ratios and principal component analysis showed that the major source of BTEX, especially during the BMCO and CMCO periods, was motor vehicle emissions. Further investigation, using correlation analysis and polar plots, showed that the BTEX concentrations were also influenced by meteorological variables such as wind speed, air temperature and relative humidity.
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Affiliation(s)
- Nor Syamimi Sufiera Limi Hawari
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
| | - Mohd Talib Latif
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
- Department of Environmental Health, Faculty of Public Health, Universitas Airlangga, 60115 Surabaya, Indonesia
| | - Haris Hafizal Abd Hamid
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
| | - Teoh Hwai Leng
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
| | - Murnira Othman
- Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Anis Asma Ahmad Mohtar
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
| | - Azliyana Azhari
- Monash Climate Change Communication Research Node, School of Arts and Social Sciences, Monash University Malaysia, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia
- Center for Research in Development, Social and Environment, Faculty of Social Science and Humanities, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia
| | - Doreena Dominick
- Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
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Singh BP, Kumari S, Nair A, Kumari S, Wabaidur SM, Avtar R, Rahman S. Temporary reduction in VOCs associated with health risk during and after COVID-19 in Maharashtra, India. JOURNAL OF ATMOSPHERIC CHEMISTRY 2022; 80:53-76. [PMID: 35992767 PMCID: PMC9382016 DOI: 10.1007/s10874-022-09440-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED A novel coronavirus has affected almost all countries and impacted the economy, environment, and social life. The short-term impact on the environment and human health needs attention to correlate the Volatile organic compounds (VOCs) and health assessment for pre-, during, and post lockdowns. Therefore, the current study demonstrates VOC changes and their effect on air quality during the lockdown. The findings of result, the levels of the mean for total VOC concentrations were found to be 15.45 ± 21.07, 2.48 ± 1.61, 19.25 ± 28.91 µg/m3 for all monitoring stations for pre-, during, and post lockdown periods. The highest value of TVOCs was observed at Thane, considered an industrial region (petroleum refinery), and the lowest at Bandra, which was considered a residential region, respectively. The VOC levels drastically decreased by 52%, 89%, 80%, and 97% for benzene, toluene, ethylbenzene, and m-xylene, respectively, during the lockdown period compared to the previous year. In the present study, the T/B ratio was found lower in the lockdown period as compared to the pre-lockdown period. This can be attributed to the complete closure of non-traffic sources such as industries and factories during the lockdown. The Lifetime Cancer Risk values for all monitoring stations for benzene for pre-and-post lockdown periods were higher than the prescribed value, except during the lockdown period. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10874-022-09440-5.
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Affiliation(s)
- Bhupendra Pratap Singh
- Delhi School of Climate Change and Sustainability (Institute of Eminence) & Department of Environmental Studies, Deshbadhu College, University of Delhi, New Delhi, India
| | - Saumya Kumari
- Delhi School of Climate Change and Sustainability (Institute of Eminence) & Department of Environmental Studies, Deshbadhu College, University of Delhi, New Delhi, India
| | - Arathi Nair
- Delhi School of Climate Change and Sustainability (Institute of Eminence) & Department of Environmental Studies, Deshbadhu College, University of Delhi, New Delhi, India
| | - Sweety Kumari
- Delhi School of Climate Change and Sustainability (Institute of Eminence) & Department of Environmental Studies, Deshbadhu College, University of Delhi, New Delhi, India
| | | | - Ram Avtar
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Shakilur Rahman
- Department of Medical Elementology and Toxicology, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
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11
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Yang Y, Liu B, Hua J, Yang T, Dai Q, Wu J, Feng Y, Hopke PK. Global review of source apportionment of volatile organic compounds based on highly time-resolved data from 2015 to 2021. ENVIRONMENT INTERNATIONAL 2022; 165:107330. [PMID: 35671590 DOI: 10.1016/j.envint.2022.107330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/27/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Highly time-resolved data for volatile organic compounds (VOCs) can now be monitored. Source analyses of such high time-resolved concentrations provides key information for controlling VOC emissions. This work reviewed the literature on VOCs source analyses published from 2015 to 2021, and assesses the state-of-the-art and the existing issues with these studies. Gas chromatography system and direct-inlet mass spectrometry are the main monitoring tools. Quality control (QC) of the monitoring process is critical prior to analysis. QC includes inspection and replacement of instrument consumables, calibration curve corrections, and reviewing the data. Approximately 54% published papers lacked details on the quantitative evaluation of the effectiveness of QC measures. Among the reviewed works, the number of monitored species varied from 5 to 119, and fraction of papers with more than 90 monitored species increased yearly. US EPA PMF v5.0 was the most commonly used (∼86%) for VOC source analyses. However, conventional source apportionment directly uses the measured VOCs and may be problematic given the impacts of dispersion and photochemical losses, uncertainty setting of VOCs data, factor resolution, and factor identification. Excluding species with high-reactivity or estimation of corrected concentrations were often applied to reduce the influence of photochemical reactions on the results. However, most reports did not specify the selection criteria or the specific error fraction values in the uncertainty estimation. Model diagnostic indexes were used in 99% of the reports for PMF analysis to determine the factor resolution. Due to lack of known local source profiles, factor identification was mainly achieved using marker species and characteristic species ratios. However, multiple sources had high-collinearity and the same species were often used to identify different sources. Vehicle emissions and fuel evaporation were the primary contributors to VOCs around the world. Contribution of coal combustion in China was substantially higher than in other countries.
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Affiliation(s)
- Yang Yang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China
| | - Baoshuang Liu
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China.
| | - Jing Hua
- Tianjin Ecology and Environment Bureau, Tianjin 300191, China
| | - Tao Yang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China
| | - Qili Dai
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China
| | - Jianhui Wu
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China
| | - Yinchang Feng
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control & Tianjin Key Laboratory of Urban Transport Emission Research, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; CMA-NKU Cooperative Laboratory for Atmospheric Environment-Health Research, Tianjin 300350, China
| | - Philip K Hopke
- Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA; Institute for a Sustainable Environment, Clarkson University, Potsdam, NY 13699, USA
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12
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Pei C, Yang W, Zhang Y, Song W, Xiao S, Wang J, Zhang J, Zhang T, Chen D, Wang Y, Chen Y, Wang X. Decrease in ambient volatile organic compounds during the COVID-19 lockdown period in the Pearl River Delta region, south China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153720. [PMID: 35149077 PMCID: PMC8821021 DOI: 10.1016/j.scitotenv.2022.153720] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/30/2022] [Accepted: 02/03/2022] [Indexed: 05/22/2023]
Abstract
During the COVID-19 lockdown, ambient ozone levels are widely reported to show much smaller decreases or even dramatical increases under substantially reduced precursor NOx levels, yet changes in ambient precursor volatile organic compounds (VOCs) have been scarcely reported during the COVID-19 lockdown, which is an opportunity to examine the impacts of dramatically changing anthropogenic emissions on ambient VOC levels in megacities where ozone formation is largely VOC-limited. In this study, ambient VOCs were monitored online at an urban site in Guangzhou in the Pearl River Delta region before, during, and after the COVID-19 lockdown. The average total mixing ratios of VOCs became 19.1% lower during the lockdown than before, and those of alkanes, alkenes and aromatics decreased by 19.0%, 24.8% and 38.2%, respectively. The levels of light alkanes (C < 6) decreased by only 13.0%, while those of higher alkanes (C ≥ 6) decreased by 67.8% during the lockdown. Disappeared peak VOC levels in morning rush hours and the drop in toluene to benzene ratios during the lockdown suggested significant reductions in vehicle exhaust and industrial solvent emissions. Source apportioning by positive matrix factorization model revealed that reductions in industrial emissions, diesel exhaust (on-road diesel vehicles and off-road diesel engines) and gasoline-related emissions could account for 48.9%, 42.2% and 8.8%, respectively, of the decreased VOC levels during the lockdown. Moreover, the reduction in industrial emissions could explain 56.0% and 70.0% of the reductions in ambient levels of reactive alkenes and aromatics, respectively. An average increase in O3-1 h by 17% and a decrease in the daily maximum 8-h average ozone by 11% under an average decrease in NOx by 57.0% and a decrease in VOCs by 19.1% during the lockdown demonstrated that controlling emissions of precursors VOCs and NOx to prevent ambient O3 pollution in megacities such as Guangzhou remains a highly challenging task.
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Affiliation(s)
- Chenglei Pei
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510060, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiqiang Yang
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong Provincial Academy of Environmental Sciences, Guangzhou 510045, China
| | - Yanli Zhang
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
| | - Wei Song
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Shaoxuan Xiao
- State Key Laboratory of Organic Geochemistry, 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
| | - Jun Wang
- State Key Laboratory of Organic Geochemistry, 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
| | - Jinpu Zhang
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510060, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Zhang
- State Environmental Protection Key Laboratory of Regional Air Quality Monitoring, Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510308, China
| | - Duohong Chen
- State Environmental Protection Key Laboratory of Regional Air Quality Monitoring, Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510308, China
| | - Yujun Wang
- Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510060, China
| | - Yanning Chen
- Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center, Guangzhou 510060, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, 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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13
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Abstract
In order to investigate the seasonal variation in chemical characteristics of VOCs in the urban and suburban areas of southwest China, we used SUMMA canister sampling in Jinghong city from October 2016 to June 2017. Forty-eight VOC species concentrations were analyzed using atmospheric preconcentration gas chromatography–mass spectrometry (GC–MS), Then, regional VOC pollution characteristics, ozone formation potentials (OFP), source identity, and health risk assessments were studied. The results showed that the average concentration of total mass was 144.34 μg·m−3 in the urban area and 47.81 μg·m−3 in the suburban area. Alkanes accounted for the highest proportion of VOC groups at 38.11%, followed by olefins (36.60%) and aromatic hydrocarbons (25.28%). Propane and isoprene were the species with the highest mass concentrations in urban and suburban sampling sites. The calculation of OFP showed that the contributions of olefins and aromatic hydrocarbons were higher than those of alkanes. Through the ratio of specific species, the VOCs were mainly affected by motor vehicle exhaust emissions, fuel volatilization, vegetation emissions, and biomass combustion. Combined with the analysis of the backward trajectory model, biomass burning activities in Myanmar influenced the concentration of VOCs in Jinghong. Health risk assessments have shown that the noncarcinogenic risk and hazard index of atmospheric VOCs in Jinghong were low (less than 1). However, the value of the benzene cancer risk to the human body was higher than the safety threshold of 1 × 10−6, showing that benzene has carcinogenic risk. This study provides effective support for local governments formulating air pollution control policies.
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14
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Insights on In-Situ Photochemistry Associated with Ozone Reduction in Guangzhou during the COVID-19 Lockdown. ATMOSPHERE 2022. [DOI: 10.3390/atmos13020212] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Increases in ground-level ozone (O3) have been observed during the COVID-19 lockdown in many places around the world, primarily due to the uncoordinated emission reductions of O3 precursors. In Guangzhou, the capital of Guangdong province in South China, O3 distinctively decreased during the lockdown. Such a phenomenon was attributed to meteorological variations and weakening of local O3 formation, as indicated by chemical transport models. However, the emission-based modellings were not fully validated by observations, especially for volatile organic compounds (VOCs). In this study, we analyzed the changes of O3 and its precursors, including VOCs, from the pre-lockdown (Pre-LD) to lockdown period (LD) spanning 1 week in Guangzhou. An observation-based box model was applied to understand the evolution of in-situ photochemistry. Indeed, the ambient concentrations of O3 precursors decreased significantly in the LD. A reduction of 20.7% was identified for the total mixing ratios of VOCs, and the transportation-related species experienced the biggest declines. However, the reduction of O3 precursors would not lead to a decrease of in-situ O3 production if the meteorology did not change between the Pre-LD and LD periods. Sensitivity tests indicated that O3 formation was limited by VOCs in both periods. The lower temperature and photolysis frequencies in the LD reversed the increase of O3 that would be caused by the emission reductions otherwise. This study reiterates the fact that O3 abatement requires coordinated control strategies, even if the emissions of O3 precursors can be significantly reduced in the short term.
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15
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Assessment of COVID-19 Lockdown Impact on the Air Quality in Eastern Spain: PM and BTX in Urban, Suburban and Rural Sites Exposed to Different Emissions. ATMOSPHERE 2022. [DOI: 10.3390/atmos13010097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In early 2020, the COVID-19 pandemic spread globally, and severe measures to control it were implemented. This study investigates the impact of the lockdown on the air quality of three provinces in the Valencia region, eastern Spain, in the years 2015–2020, focusing on particulate matter (PM). A thorough statistical analysis using different approaches is conducted. Hourly patterns are also assessed. In addition, the role of meteorological parameters on PM is explored. The results indicate an overall PM10 reduction of 16.5% when comparing the lockdown in 2020 and the 2015–2019 period, while PM2.5 increased by 3.1%. As expected, urban zones experienced higher reductions than suburban zones, which experienced a PM concentration increase. The impact of the drastic drops of benzene, toluene and xylene (77.4%, 58.0% and 61.8%, respectively) on the PM values observed in urban sites is discussed. Our study provides insights on the effect of activity changes over a wide region covering a variety of air quality stations, urban, suburban and rural, and different emission types. The results of this work are a valuable reference and suggest the need for considering different factors when establishing scientific air pollution control strategies.
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16
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Zhang J, Li H, Chen L, Huang X, Zhang W, Zhao R. Particle composition, sources and evolution during the COVID-19 lockdown period in Chengdu, southwest China: Insights from single particle aerosol mass spectrometer data. ATMOSPHERIC ENVIRONMENT (OXFORD, ENGLAND : 1994) 2022; 268:118844. [PMID: 34776748 PMCID: PMC8575539 DOI: 10.1016/j.atmosenv.2021.118844] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
In order to investigate the effects of the Coronavirus Disease 2019 (COVID-19) lockdown on air quality in cities in southwest China, a single particle aerosol mass spectrometer (SPAMS) and other online equipments were used to measure the air pollution in Chengdu, one of the megacities in this area, before and during the lockdown period. It was found that the concentrations of fine particulate matter (PM2.5), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO) decreased by 38.6%, 77.5%, 47.0%, 35.1% and 14.1%, respectively, while the concentration of ozone (O3) increased by 57.5% from the time before to the time during lockdown. All particles collected during the study period could be divided into eight categories: biomass burning (BB), coal combustion (CC), vehicle emissions (VE), cooking emissions (CE), Dust, K-nitrate (K-NO3), K-sulfate (K-SO4) and K-sulfate-nitrate (K-SN) particles, and their contributions changed significantly after the beginning of lockdown. Compared to before lockdown, the contribution of VE particles experienced the largest reduction (by 14.9%), whereas the contributions of BB and CE particles increased by 7.0% and 7.3%, respectively, during the lockdown period. Regional transmission was critical for pollution formation before lockdown, whereas the pollution that occurred during the lockdown period was caused mainly by locally emitted particles (such as VE, CE and BB particles). Weighted potential source contribution function (WPSCF) analysis further verified and emphasized the difference in the contribution of regional transmission for pollution formation before and during lockdown. In addition, the potential source area and intensity of the particles emitted from different sources or formation mechanisms were quite different.
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Affiliation(s)
- Junke Zhang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Huan Li
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Luyao Chen
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
| | - Xiaojuan Huang
- Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610225, China
| | - Wei Zhang
- Sichuan Environmental Monitoring Center, Chengdu, 610074, China
| | - Rui Zhao
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China
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17
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Li B, Ho SSH, Li X, Guo L, Chen A, Hu L, Yang Y, Chen D, Lin A, Fang X. A comprehensive review on anthropogenic volatile organic compounds (VOCs) emission estimates in China: Comparison and outlook. ENVIRONMENT INTERNATIONAL 2021; 156:106710. [PMID: 34144364 DOI: 10.1016/j.envint.2021.106710] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/31/2021] [Accepted: 06/08/2021] [Indexed: 06/12/2023]
Abstract
Accurate measurement and estimation on the trends and spatial distributions of VOCs emissions in China are critical to establishing efficient local or regional pollution control measures, while less is known about the discrepancies on VOCs emissions estimated by previous studies. In this study, two of the estimation approaches including the bottom-up and top-down methods have been reviewed with the data collected from many studies. The approaches demonstrated that the total anthropogenic VOCs emissions in China have been increasing since 1949. The contributions of industrial and solvent use to total VOCs emissions have been increasing since 2000, whereas the contributions of transportation sector have shown a decreasing trend since 2000. The contributions of fuel combustion have also been decreasing since 1950. The gaps of emission estimates for the industry and solvent use were 99.3 ± 22.7% and 81.5 ± 41.8%, respectively, which distributed in much wider ranges than other sources (e.g. 28.9 ± 16.7% for fuel combustion). In comparison to the top-down method, larger variations on the annual VOCs emission estimates were seen using the bottom-up method that comprised different data sources. For the view of spatial pattern, most hot emission estimate spots were concentrated in the eastern China, consistent to their relatively stronger strengths in the industrialization and urbanization. Although the total VOCs emission in China has been continuously increasing during 2008-2016, the VOCs emissions per gross domestic production (GDP) showed a decreasing trend. As for individual compounds, large discrepancy was seen on formaldehyde, with the coefficient of variation (CV) ranged from 37% to 128% over the years. In overall of view, the importance of industrial process and solvent use is increasing. More focuses must be made to these two sources. Emissions of individual compound, particularly those of oxygenated VOCs, were not completely determined and should be better quantified.
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Affiliation(s)
- Bowei Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA
| | - Xinhe Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Liya Guo
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ao Chen
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Liting Hu
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yang Yang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Di Chen
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Anan Lin
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xuekun Fang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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18
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Alam MD, Lu J, Ni L, Hu S, Xu Y. Psychological Outcomes and Associated Factors Among the International Students Living in China During the COVID-19 Pandemic. Front Psychiatry 2021; 12:707342. [PMID: 34483997 PMCID: PMC8414650 DOI: 10.3389/fpsyt.2021.707342] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 07/16/2021] [Indexed: 12/22/2022] Open
Abstract
Background: The emergence of coronavirus disease 2019 (COVID-19) has created a severe mental health problem for international students living in China. Despite the little information on the psychological impact on international students, we aimed to assess the psychological outcomes and associated factors among international students currently living in China during the COVID-19 pandemic. Methods: An online cross-sectional survey was conducted from May 28, 2020 to June 12, 2020 on 402 full-time international students across 26 provinces in China. The frequency of symptoms of depression, anxiety, stress, insomnia, psychological distress, loneliness, and fear was assessed with the English versions of the Depression Anxiety Stress Scale (DASS-21), Insomnia Severity Index (ISI), Kessler Psychological Distress Scale (K6), University of California, Los Angeles, Loneliness Scale (UCLA-LS), and Fear of COVID-19 scale (FCV-19S) scales, respectively. Results: The prevalence of symptoms of depression (73.4%), anxiety (76.6%), stress (58.5%), insomnia (77.6%), psychological distress (71.4%), loneliness (62.4%), and fear (73.1%) among international students during the COVID-19 pandemic was shown. The prevalence of moderate to extremely severe symptoms of all psychological outcomes was significantly associated with 26-30-year-old students, students who lived with roommates, and students who stayed in China shorter than 2 years. Participants in the central region reported significantly moderate to extremely severe symptom levels of all the psychological outcomes except fear symptoms. Univariate analysis indicated that a significant association of all psychological outcomes was found among 26-30-year-old students and students who stayed in China shorter than 2 years. Multivariate analysis showed that Engineering, Business, Social Sciences and Law, and Language students were significantly associated with the symptoms of depression, anxiety, insomnia, and fear. Participants staying in China for shorter than 2 years were associated with a higher risk of all psychological outcomes except psychological distress and loneliness symptoms. Conclusions: We found a higher prevalence of psychological outcomes and risk factors among international students during the COVID-19 pandemic. We immediately appealed to university authorities, mental health professionals, and government officials to provide mental health interventions and strategies for their international students, particularly young, central region students, living with roommates, different study backgrounds, and short time staying during the pandemic.
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Affiliation(s)
- Md. Dhedharul Alam
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Hangzhou, China
| | - Jing Lu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Hangzhou, China
| | - Li Ni
- Department of Psychiatry, Fuyang Third Peoples Hospital, Hangzhou, China
| | - Shaohua Hu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Hangzhou, China
| | - Yi Xu
- Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- The Key Laboratory of Mental Disorder Management in Zhejiang Province, Hangzhou, China
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19
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Li Y, Qin L, Shi Y, Han J. The Psychological Symptoms of College Student in China during the Lockdown of COVID-19 Epidemic. Healthcare (Basel) 2021; 9:healthcare9040447. [PMID: 33920411 PMCID: PMC8070548 DOI: 10.3390/healthcare9040447] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 12/23/2022] Open
Abstract
The COVID-19 epidemic has had a huge impact on the mental state of human beings due to its high infection and fatality rates in early 2020. In this paper, a cross-sectional online survey was designed to understand the mental state of college students in a university located in Wuhan city during the lockdown. Out of 1168 respondents, above 50% participants had obvious fear and anxiety symptoms; anxiety and fear were 61.64% and 58.39%, respectively. Conformity (49.49%), invulnerability (26.11%), insensitivity (21.49%) and rebelliousness (12.41%) symptoms also appeared. Meanwhile, it was revealed that the senior students experienced more anxiety than the freshmen. Moreover, it was found that the psychological symptoms (except for the insensitivity symptom) had no significant difference in gender, residence and annual household income after the one-way analysis of variance.
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Affiliation(s)
| | | | | | - Jun Han
- Correspondence: ; Tel.:+86-27-6886-2880
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