Wang Jun, Zhang Yanli, Wu Zhenfeng, Luo Shilu, Song Wei, Wang Xinming
State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2022 Apr;114:322-333. doi: 10.1016/j.jes.2021.09.009. Epub 2022 Feb 21.
The impact of reducing industrial emissions of volatile organic compounds (VOCs) on ozone (O) pollution is of wide concern particularly in highly industrialized megacities. In this study, O, nitrogen oxides (NOx) and VOCs were measured at an urban site in the Pearl River Delta region during the 2018 Chinese National Day Holidays and two after-holiday periods (one with ozone pollution and another without). O pollution occurred throughout the 7-day holidays even industrial emissions of VOCs were passively reduced due to temporary factory shutdowns, and the toluene to benzene ratios dropped from ∼10 during non-holidays to ∼5 during the holidays. Box model (AtChem2-MCM) simulations with the input of observation data revealed that O formation was all VOC-limited, and alkenes had the highest relative incremental reactivity (RIR) during the holiday and non-holiday O episodes while aromatics had the highest RIR during the non-pollution period. Box model also demonstrated that even aromatics decreased proportionally to levels with near-zero contributions of industrial aromatic solvents, O concentrations would only decrease by less than 20% during the holiday and non-holiday O episodes and ozone pollution in the periods could not be eliminated. The results imply that controlling emissions of industrial aromatic solvents might be not enough to eliminate O pollution in the region, and more attention should be paid to anthropogenic reactive alkenes. Isoprene and formaldehyde were among the top 3 species by RIRs in all the three pollution and non-pollution periods, suggesting substantial contribution to O formation from biogenic VOCs.
减少挥发性有机化合物（VOCs）的工业排放对臭氧（O₃）污染的影响备受广泛关注，尤其是在高度工业化的大城市。在本研究中，于2018年中国国庆假期及两个节后时期（一个有臭氧污染，另一个无臭氧污染），在珠江三角洲地区的一个城市站点对O₃、氮氧化物（NOₓ）和VOCs进行了测量。尽管由于工厂临时停产，VOCs的工业排放被动减少，但在整个7天假期中仍出现了O₃污染，且甲苯与苯的比例从非假期期间的约10降至假期期间的约5。利用观测数据输入进行的箱式模型（AtChem2-MCM）模拟显示，O₃形成均受VOCs限制，在假期和非假期的O₃污染事件中烯烃具有最高的相对增量反应活性（RIR），而在无污染时期芳烃具有最高的RIR。箱式模型还表明，即使芳烃按比例减少至工业芳烃溶剂贡献近乎为零的水平，在假期和非假期的O₃污染事件中O₃浓度仅会降低不到20%，且这些时期的臭氧污染无法消除。结果表明，控制工业芳烃溶剂的排放可能不足以消除该地区的O₃污染，应更多关注人为排放的活性烯烃。在所有三个污染和无污染时期，异戊二烯和甲醛的RIR均位列前三位，这表明生物源VOCs对O₃形成有显著贡献。
