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DOI	10.5194/acp-19-11267-2019
	Ozone enhancement due to the photodissociation of nitrous acid in eastern China
	Tie X.; Long X.; Li G.; Zhao S.; Cao J.; Xu J.
发表日期	2019
ISSN	16807316
起始页码	11267
结束页码	11278
卷号	19 期号:17
英文摘要	PM2:5, particulate matter with a diameter of 2.5 μm or less, is one of the major components of air pollution in eastern China. In the past few years, China's government has made strong efforts to reduce PM2:5 pollution. However, another important pollutant (ozone) is becoming a problem in eastern China. Ozone (O3) is produced by photochemistry, which requires solar radiation for the formation of O3. Under heavy PM2:5 pollution, solar radiation is often depressed, and the photochemical production of O3 is prohibited. This study shows that during late spring and early fall in eastern China, under heavy PM2:5 pollution, there was often strong O3 photochemical production, causing a co-occurrence of high PM2:5 and O3 concentrations. This co-occurrence of high PM2:5 and O3 is unusual and is the main focus of this study. Recent measurements show that there were often high HONO surface concentrations in major Chinese megacities, especially during daytime, with maximum concentrations ranging from 0.5 to 2 ppbv. It is also interesting to note that high HONO concentrations occurred during high aerosol concentration periods, suggesting that there were additional HONO surface sources in eastern China. Under high daytime HONO concentrations, HONO can be photodissociated to OH radicals, which enhance the photochemical production of O3. In order to study the above scientific issues, a radiative transfer model (TUV; tropospheric ultraviolet-visible) is used in this study, and a chemical steady-state model is established to calculate OH radical concentrations. The calculations show that by including the OH production of photodissociated HONO, the calculated OH concentrations are significantly higher than the values without including this production. For example, by including HONO production, the maximum OH concentration under high aerosol conditions (AODD2.5) is similar to the value under low aerosol conditions (AODD0.25) in the no-HONO case. This result suggests that even under high aerosol conditions, the chemical oxidizing process for O3 production can occur, which explains the co-occurrence of high PM2:5 and high O3 in late spring and early fall in eastern China. However, the O3 concentrations were not significantly affected by the appearance of HONO in winter. This study shows that the seasonal variation of solar radiation plays important roles for controlling the OH production in winter. Because solar radiation is at a very low level in winter, adding the photolysis of HONO has a smaller effect in winter than in other seasons, and OH remains at low values by including the HONO production term. This study provides some important scientific insight to better understand O3 pollution in eastern China. © Author(s) 2019.
语种	英语
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144168
作者单位	KLACP, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Shanghai Typhoon Institute, Shanghai Meteorological Service, Shanghai, 200135, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; Shanghai Key Laboratory of Meteorology and Health, Shanghai, 200030, China; School of Environment Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
推荐引用方式 GB/T 7714	Tie X.,Long X.,Li G.,et al. Ozone enhancement due to the photodissociation of nitrous acid in eastern China[J],2019,19(17).
APA	Tie X.,Long X.,Li G.,Zhao S.,Cao J.,&Xu J..(2019).Ozone enhancement due to the photodissociation of nitrous acid in eastern China.Atmospheric Chemistry and Physics,19(17).
MLA	Tie X.,et al."Ozone enhancement due to the photodissociation of nitrous acid in eastern China".Atmospheric Chemistry and Physics 19.17(2019).