气候变化领域集成服务门户(CCPortal): Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area

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DOI	10.1016/j.atmosenv.2020.117747
	Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area
	Zavala M.; Brune W.H.; Velasco E.; Retama A.; Cruz-Alavez L.A.; Molina L.T.
发表日期	2020
ISSN	1352-2310
卷号	238
英文摘要	The introduction of aggressive emission control policies propelled three decades ago has led to significant reductions of ozone (O3) levels in the Mexico City Metropolitan Area (MCMA). However, in recent years the levels have stalled, and there is evidence that the production of secondary pollutants may have started to rebound. Similar responses to changes in O3 precursors observed in other urban areas suggest major changes in atmospheric reactivity and O3 production P(O3), prompting the introduction of new emission control policies. In this study, we evaluate the changes in VOC-OH reactivity and P(O3) using data of O3, volatile organic compounds (VOCs), carbon monoxide (CO), and nitrogen oxides (NOx) collected from the 1990s to 2019 by the local air quality monitoring network and during two dedicated 6-week field measurement campaigns in the MCMA. The results show a reduction of VOC-OH reactivity from 38 s−1 in 2003–2006 to about 19 s−1 in 2018 within the urban core, a slight increase from around 8 s−1 to 9 s−1 for the northern peripheral urban sites in the same period, and a small decrease from about 18 s−1 to 15 s−1 during 2014–2016 in the south of the city. Alkanes are still key contributors to VOC-OH reactivity, whereas the contribution from aromatic and alkene species has decreased, in agreement with reductions of VOC emissions from mobile sources. Changes in P(O3) suggest that increases in the relative contributions from highly oxygenated volatile chemical products from solvents consumption, personal care and other products are responsible for sustained high O3 levels in recent years. We also found that there is a marked spatial dependency of P(O3) in the northern, central, and southern areas of the city, suggesting spatially different VOC and NOx sensitivity regimes. Finally, significant increases in NO2/NO ratios suggest changes in the pathways for the nighttime accumulation of HOx radicals and NOy species that could impact the morning photochemistry and radical budgets for secondary aerosol formation. These results strongly suggest a need for new measurements of radical budgets in the MCMA, the expansion of a continuous measurement network of VOCs with the addition of oxygenated species, and the use of these data to support comprehensive modeling studies for the design of effective emission control strategies. © 2020 Elsevier Ltd
关键词	Emission controls Mexico City air quality Oxygenated VOCs Ozone production Urban air pollution VOC-OH reactivity
语种	英语
scopus关键词	Air quality; Budget control; Carbon monoxide; Emission control; Hydrocarbons; Nitrogen oxides; Ozone; Urban growth; Volatile organic compounds; Air quality monitoring networks; Comprehensive model; Continuous measurements; Mexico City metropolitan areas; Oxygenated species; Relative contribution; Secondary aerosols; Spatial dependencies; Quality control; carbon monoxide; nitrogen oxide; ozone; volatile organic compound; air quality; alkene; atmospheric pollution; carbon monoxide; emission control; metropolitan area; nitrogen oxides; ozone; photochemistry; urban atmosphere; volatile organic compound; air pollution control; air quality; Article; atmosphere; chemical composition; chemoluminescence; controlled study; environmental monitoring; greenhouse gas; limit of detection; mathematical model; Mexico City; photochemistry; photolysis; priority journal; secondary organic aerosol; temperature dependence; urban area; Federal District [Mexico]; Mexico City; Mexico [North America]
来源期刊	ATMOSPHERIC ENVIRONMENT
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/249037
作者单位	Molina Center for Energy and the Environment, La Jolla, CA 92037, United States; Department of Meteorology and Atmospheric Science, Pennsylvania State University, University ParkPA 16802, United States; Independent Research Scientist118719, Singapore; Independent Research Scientist, Mexico City, 11800, Mexico; Secretaría del Medio Ambiente de la Ciudad de México, Mexico City, 06068, Mexico
推荐引用方式 GB/T 7714	Zavala M.,Brune W.H.,Velasco E.,et al. Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area[J],2020,238.
APA	Zavala M.,Brune W.H.,Velasco E.,Retama A.,Cruz-Alavez L.A.,&Molina L.T..(2020).Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area.ATMOSPHERIC ENVIRONMENT,238.
MLA	Zavala M.,et al."Changes in ozone production and VOC reactivity in the atmosphere of the Mexico City Metropolitan Area".ATMOSPHERIC ENVIRONMENT 238(2020).