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Liu G, Ma X, Li W, Chen J, Ji Y, An T. Pollution characteristics, source appointment and environmental effect of oxygenated volatile organic compounds in Guangdong-Hong Kong-Macao Greater Bay Area: Implication for air quality management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170836. [PMID: 38346658 DOI: 10.1016/j.scitotenv.2024.170836] [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: 11/22/2023] [Revised: 01/24/2024] [Accepted: 02/07/2024] [Indexed: 02/17/2024]
Abstract
Same as other bay areas, the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is also suffering atmospheric composite pollution. Even a series of atmospheric environment management policies have been conducted to win the "blue sky defense battle", the atmospheric secondary pollutants (e.g., O3) originated from oxygenated volatile organic compounds (OVOCs) still threaten the air quality in GBA. However, there lacks a systematic summary on the emission, formation, pollution and environmental effects of OVOCs in this region for further air quality management. This review focused on the researches related to OVOCs in GBA, including their pollution characteristics, detection methods, source distributions, secondary formations, and impacts on the atmosphere. Pollution profile of OVOCs in GBA revealed that the concentration percentage among total VOCs from Guangzhou and Dongguan cities exceeded 50 %, while methanol, formaldehyde, acetone, and acetaldehyde were the top four highest concentrated OVOCs. The detection technique on regional atmospheric OVOCs (e.g., oxygenated organic molecules (OOMs)) underwent an evolution of off-line derivatization method, on-line spectroscopic method and on-line mass spectrometry method. The OVOCs in GBA were mainly from primary emissions (up to 80 %), including vehicle emissions and biomass combustion. The anthropogenic alkenes and aromatics in urban area, and natural isoprene in rural area also made a significant contribution to the secondary emission (e.g., photochemical formation) of OVOCs. About 20 % in average of ROx radicals was produced from photolysis of formaldehyde in comparison with O3, nitrous acid and rest OVOCs, while the reaction between OVOCs and free radical accelerated the NOx-O3 cycle, contributing to 15 %-60 % cumulative formation of O3 in GBA. Besides, the heterogeneous reactions of dicarbonyls generated 21 %-53 % of SOA. This review also provided suggestions for future research on OVOCs in terms of regional observation, analytical method and mechanistic study to support the development of a control and management strategy on OVOCs in GBA and China.
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Affiliation(s)
- Guanyong Liu
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaoyao Ma
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Wanying Li
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Jiangyao Chen
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
| | - Yuemeng Ji
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Taicheng An
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
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Yuan Q, Zhang Z, Wang M, Ho KF, Wang T, Lee S. Characterization of a smog chamber for studying formation of gas-phase products and secondary organic aerosol. J Environ Sci (China) 2024; 136:570-582. [PMID: 37923466 DOI: 10.1016/j.jes.2022.12.027] [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: 08/25/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 11/07/2023]
Abstract
Smog chambers provide a potent approach to explore the secondary organic aerosol formation under varied conditions. This study describes the construction and characterization of a new smog chamber facility for studying the formation mechanisms of gas-phase products and secondary organic aerosol from the photooxidation of volatile organic compounds. The chamber is a 5.4 m3 Fluorinated Ethylene Propylene (FEP) Teflon reactor with the potential to perform photooxidation experiments at controlled temperature and relative humidity. Detailed characterizations were conducted for evaluation of stability of environmental parameters, mixing time, background contamination, light intensity, and wall losses of gases and particles. The photolysis rate of NO2 (JNO2) ranged from (1.02-3.32) ×10-3 sec-1, comparable to the average JNO2 in ambient environment. The wall loss rates for NO, NO2, and O3 were 0.47 × 10-4, 0.37 × 10-4, and 1.17 × 10-4 min-1, while wall loss of toluene was obsoletely found in a 6 hr test. The particle number wall loss rates are (0.01-2.46) ×10-3 min-1 for 40-350 nm with an average lifetime of more than one day. A series of toluene photooxidation experiments were carried out in absence of NOx under dry conditions. The results of the simulation experiments demonstrated that the chamber is well designed to simulate photolysis progress in the atmosphere.
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Affiliation(s)
- Qi Yuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Zhuozhi Zhang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Meng Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Kin Fai Ho
- School of Public Health and Primary Care, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Shuncheng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
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Li Q, Gong D, Wang H, Deng S, Zhang C, Mo X, Chen J, Wang B. Tibetan Plateau is vulnerable to aromatic-related photochemical pollution and health threats: A case study in Lhasa. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166494. [PMID: 37659561 DOI: 10.1016/j.scitotenv.2023.166494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/20/2023] [Accepted: 08/20/2023] [Indexed: 09/04/2023]
Abstract
Anthropogenic aromatics play a key role in photochemical pollution and pose a serious threat to human health. Current knowledge on source characteristics of aromatics in the urban region of the Tibetan Plateau (TP), the "Third Pole" and ecologically sensitive area, remains limited. In this study, an intensive observation of 17 aromatic hydrocarbons was conducted in Lhasa, the cultural and economic center of TP, during the second Tibetan Plateau Scientific Expedition and Research in summer 2020. The results showed that the average concentration of aromatics in Lhasa (7.6 ± 7.4 ppbv) was unexpectedly higher than those in megacities such as Beijing, Shanghai, and Guangzhou. Tripled concentrations and corresponding ozone formation potential during pollution episodes were recorded. Further source apportionment using positive matrix factorization revealed that solvent usage (60.0 %) was the dominant source, which may be due to the extremely low atmospheric pressure. Vehicle exhaust (15.4 %), industrial emissions (12.8 %), fuel evaporation (6.2 %), and burning emissions (5.7 %) were also important sources. The concentration weighted trajectory analysis revealed that the observed high levels of aromatics were mainly driven by local anthropogenic emissions, rather than the regional transport by the Indian summer monsoon. Long-term exposure to aromatics in Lhasa was assessed to pose carcinogenic risks to the population, with the risks of benzene and ethylbenzene 5 times the criteria. Our results suggest that, given the magnified emissions of aromatics in this extreme environment (low atmospheric pressure and strong solar radiation), the implementation of targeted pollution controls is urgently needed to mitigate the aromatic-related photochemical pollution and health threats in TP.
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Affiliation(s)
- Qinqin Li
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Daocheng Gong
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China
| | - Hao Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China.
| | - Shuo Deng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Chengliang Zhang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China
| | - Xujun Mo
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Jun Chen
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Boguang Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China.
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Yu Z, Wei Z, Zhang Z, Li Z, Zhang P, Yang B, Shu J, Wang H, Yan Z. Insight into the crucial reason causing the difference in secondary organic aerosol yields of monocyclic aromatic hydrocarbons with different methyl substituent numbers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:166353. [PMID: 37597565 DOI: 10.1016/j.scitotenv.2023.166353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/13/2023] [Accepted: 08/15/2023] [Indexed: 08/21/2023]
Abstract
The secondary organic aerosol (SOA) yield of toluene photooxidation was reported to substantially higher than that of trimethylbenzene due to the effect of the number of methyl substituents. However, the intrinsic mechanism for this disparity is not clear enough. In this study, a highly-sensitive thermal-desorption photoinduced associative ionization mass spectrometer (TD-PAI-MS) was used to real-time characterize the molecular composition and its evolution of the SOA generated from the photooxidation of toluene and 1,2,3-trimethylbenzene (1,2,3-TMB) in a smog chamber. In the new particle formation (NPF) stage, toluene generated more variety of nucleation precursors, such as benzaldehyde (MW 106) and benzoic acid (MW 122), resulting in a much higher nucleation rate and SOA number concentration. In the SOA growth/aging stage, the key SOA components of toluene were mainly dialdehydes, e.g., 2-oxopropanedial (MW 86) and 4-oxopent-2-enedial (MW 112), which played an important role in the formation of highly oxidized species (HOS) through oligomerization or cyclization reactions. In contrast, due to the presence of more methyl groups, 1,2,3-TMB was inclined to produce ketones, e.g., 2,3-butanedione (MW 86) and 3-methyl-4-oxopent-2-enal (MW 112), which would be cleaved into high-volatility low molecular compounds, e.g., acetic acid, through fragmentation. Taken together, relative to 1,2,3-TMB, the higher nucleation rate during NPF and the significant oligomerization/functionalization process during SOA growth are thought to be the major reasons resulting in the higher SOA yield of toluene. This work provides a reference for the insight into the different SOA yields of monocyclic aromatic hydrocarbons (MAHs) through further revealing the SOA formation mechanism during toluene and 1,2,3-TMB photooxidation.
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Affiliation(s)
- Zhangqi Yu
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Zhiyang Wei
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Zhongshen Zhang
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Zhen Li
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Peng Zhang
- State Key Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China.
| | - Bo Yang
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China.
| | - Jinian Shu
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Haijie Wang
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
| | - Zitao Yan
- National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, People's Republic of China
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Wang F, Liu X, Lv S, Zhang S, Wu C, Liu S, Lei Y, Chen Y, Li R, Wang G. Increasing role of phenolic oxidative branch in daytime oxidation process of aromatics in Chinese haze period. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159578. [PMID: 36270370 DOI: 10.1016/j.scitotenv.2022.159578] [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: 09/05/2022] [Revised: 10/15/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
To understand the photooxidation mechanisms of aromatic compounds in the NOx-rich atmosphere, gaseous aromatics and their oxidization products (i.e., methyl glyoxal (MGLY), and nitrated phenols (NPs) including nitrophenols (NPhs) and methylnitrophenols (MNPs)) were measured with a 1-h time resolution on Chongming Island, a downwind region of the Yangtze River Delta (YRD) metropolitans of China in winter 2019 by using a proton-transfer-reaction mass spectrometer (PTR-MS). During the entire observation period, concentrations of the measured VOCs were 9.6 ± 7.1 ppbv for aromatics, 118 ± 59 pptv for MGLY, 36 ± 10 pptv for NPhs, and 9.3 ± 2.8 pptv for MNPs, respectively. Secondary NPs (SNPs) accounted for only 19-24 % of the total nitrated phenols during the clean and transition periods but increased to 44 % of the total on the hazy days. Moreover, the daytime mixing ratios of SNPs increased along with an increasing NO2 concentration during the clean and transition periods, but in the haze period the daytime SNPs first increased along with the increasing NO2 levels and then increased much more sharply when NO2 was >25 ppbv. Such highly proportional and sharply increased daytime SNPs in the haze period indicated an enhanced phenolic oxidation under the high NOx conditions. In addition, the lack of correlations between aromatics and MGLY, increased MGLYaro (MGLY produced by aromatics), and sharply increased ΔSNPs / Δ(benzene + toluene) further suggested that such an increasing role of the phenolic oxidative branch in the daytime oxidation process of aromatics during the YRD haze period was caused by the strong atmospheric oxidation capacity and the high level of NOx.
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Affiliation(s)
- Fanglin Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Xiaodi Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shaojun Lv
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Si Zhang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Can Wu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shijie Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Yali Lei
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Yubao Chen
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Rui Li
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming, Chenjia Zhen, Chongming, Shanghai 202150, China.
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Zhou J, Chen H, Chen J, Wan D, Zhang H, Wang R, Xie D, Mao C. Mechanisms and Kinetics Studies of Butylated Hydroxytoluene Degradation to Isobutene. J Phys Chem A 2022; 126:3210-3218. [PMID: 35549278 DOI: 10.1021/acs.jpca.2c01961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2,6-Di-tert-butyl-hydroxytotulene (BHT) is a widely used antioxidant in various fields. In this study, we explored comprehensively the mechanisms and kinetics of BHT degradation to produce isobutene using the density functional theory method. Furthermore, the intrinsic chemical reactivity of BHT was investigated using the electrostatic potential, average local ionization energy, and Fukui function, and the most likely reaction site with OH radical was predicted. Two initiation pathways of BHT with OH radicals were reported. The OH addition pathways at the C2 site of BHT was found more likely to occur than the pathways of H abstracts from the t-butyl group due to the lower energy barrier. Rate constants of two initiation pathways were calculated by transition state theory, and they were promoted by the temperature rise. Mayer bond order and localized molecular orbitals analysis were conducted to reveal the variation of the chemical bonds in the reaction process. The tertiary butyl radical that had been generated in the OH-addition reaction was more likely to generate isobutene with the participation of oxygen. Overall, this research could help to reveal the transformation mechanism of isobutene produced by BHT degradation.
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Affiliation(s)
- Junwei Zhou
- Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210023, China
| | - Hongrui Chen
- Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210023, China
| | - Jianfa Chen
- Shanghai Space Propulsion Technology Research Institute, Shanghai 201100, China
| | - Daihong Wan
- Shanghai Space Propulsion Technology Research Institute, Shanghai 201100, China
| | - Huikun Zhang
- Shanghai Space Propulsion Technology Research Institute, Shanghai 201100, China
| | - Rong Wang
- Key Laboratory of High Performance Polymer Materials and Technology of Ministry of Education, Department of Polymer Science and Engineering, State Key Laboratory of Coordination Chemistry and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210023, China
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Chengli Mao
- Shanghai Space Propulsion Technology Research Institute, Shanghai 201100, China
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