气候变化领域集成服务门户(CCPortal): Sulfate formation during heavy winter haze events and the potential contribution from heterogeneous SO2 + NO2 reactions in the Yangtze River Delta region; China

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DOI	10.5194/acp-19-14311-2019
	Sulfate formation during heavy winter haze events and the potential contribution from heterogeneous SO2 + NO2 reactions in the Yangtze River Delta region; China
	Huang L.; An J.; Koo B.; Yarwood G.; Yan R.; Wang Y.; Huang C.; Li L.
发表日期	2019
ISSN	16807316
起始页码	14311
结束页码	14328
卷号	19 期号:22
英文摘要	Rapid sulfate formation is recognized as a key characteristic of severe winter haze in China. However, air quality models tend to underestimate sulfate formation during heavy haze periods, and heterogeneous formation pathways have been proposed as promising mechanisms to reduce gaps between observation and model simulation. In this study, we implemented a reactive SO2 uptake mechanism through the SO2+NO2 heterogeneous reactions in the Comprehensive Air Quality Model with Extensions (CAMx) to improve simulation of sulfate formation in the Yangtze River Delta (YRD) region. Parameterization of the SO2+NO2 heterogeneous reactions is based on observations in Beijing and considered both the impact of relative humidity and aerosol pH on sulfate formation. Ammonia is reported to be critical for the formation of secondary inorganic aerosols. Estimation of ammonia emissions is usually associated with large uncertainties and models tend to underestimate ammonia concentrations substantially. Sensitivity tests were conducted to evaluate the influence of the SO2+NO2 heterogeneous reactions as well as ammonia emissions on modeled sulfate concentrations during a period with several heavy haze episodes in the YRD region. Base case model results show large underestimation of sulfate concentrations by 36 % under polluted conditions in the YRD region. Adding the SO2+NO2 heterogeneous reactions or doubling ammonia emissions alone leads to slight model improvement (ĝ1/46 %) on simulated sulfate concentrations in the YRD region. However, model performance significantly improved when both the SO2+NO2 heterogeneous reactions and doubled ammonia emissions were included in the simulation: predicted sulfate concentrations during polluted periods increased from 23.1 μg m-3 in the base scenario to 29.1 μg m-3 (representing an increase of 26 %). Aerosol pH is crucial for the SO2+NO2 heterogeneous reactions, and our calculated aerosol pH is always acidic and increased by 0.7 with doubled ammonia emissions. Modeling results also show that this reactive SO2 uptake mechanism enhanced sulfate simulations by 1 to 5 μg m-3 for the majority of the eastern and central parts of China, with more than 20 μg m-3 increase in sulfate concentrations over the northeastern plain. These findings suggest that the SO2+NO2 heterogeneous reactions could be potentially important for sulfate formation in the YRD region as well as other parts of China. Further studies are needed to constrain the uncertainties associated with the parameterization of the SO2+NO2 heterogeneous reactions based on local data as well as to evaluate this mechanism in other regions. In addition, ammonia emissions were found to be a key driving variable of the spatial patterns of sulfate enhancement due to the new pathway. Substantial efforts are needed to improve the accuracy of the ammonia emission inventory. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	aerosol; air quality; concentration (composition); haze; heterogeneity; nitrogen dioxide; numerical model; seasonal variation; sulfate; sulfur dioxide; China; Yangtze River
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/144016
作者单位	School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China; State Environ. Protection Key Laboratory of the Cause and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai, 200233, China; Bay Area Air Quality Management, San Francisco, CA 94105, United States; Ramboll, Novato, CA 95995, United States
推荐引用方式 GB/T 7714	Huang L.,An J.,Koo B.,et al. Sulfate formation during heavy winter haze events and the potential contribution from heterogeneous SO2 + NO2 reactions in the Yangtze River Delta region; China[J],2019,19(22).
APA	Huang L..,An J..,Koo B..,Yarwood G..,Yan R..,...&Li L..(2019).Sulfate formation during heavy winter haze events and the potential contribution from heterogeneous SO2 + NO2 reactions in the Yangtze River Delta region; China.Atmospheric Chemistry and Physics,19(22).
MLA	Huang L.,et al."Sulfate formation during heavy winter haze events and the potential contribution from heterogeneous SO2 + NO2 reactions in the Yangtze River Delta region; China".Atmospheric Chemistry and Physics 19.22(2019).