气候变化领域集成服务门户(CCPortal): Decoupling impacts of weather conditions on interannual variations in concentrations of criteria air pollutants in South China - constraining analysis uncertainties by using multiple analysis tools

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DOI	10.5194/acp-22-16073-2022
	Decoupling impacts of weather conditions on interannual variations in concentrations of criteria air pollutants in South China - constraining analysis uncertainties by using multiple analysis tools
	Lin, Yu; Zhang, Leiming; Fan, Qinchu; Meng, He; Gao, Yang; Gao, Huiwang; Yao, Xiaohong
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	16073
结束页码	16090
卷号	22 期号:24 页码:18
英文摘要	In this study, three methods, i.e., the random forest (RF) algorithm, boosted regression trees (BRTs) and the improved complete ensemble empirical-mode decomposition with adaptive noise (ICEEMDAN), were adopted for investigating emission-driven interannual variations in concentrations of air pollutants including PM2.5, PM10, O-3, NO2, CO, SO2 and NO2 + O-3 monitored in six cities in South China from May 2014 to April 2021. The first two methods were used to calculate the deweathered hourly concentrations, and the third one was used to calculate decomposed hourly residuals. To constrain the uncertainties in the calculated deweathered or decomposed hourly values, a self-developed method was applied to calculate the range of the deweathered percentage changes (DePCs) of air pollutant concentrations on an annual scale (each year covers May to the next April). These four methods were combined together to generate emission-driven trends and percentage changes (PCs) during the 7-year period. Consistent trends between the RF-deweathered and BRT-deweathered concentrations and the ICEEMDAN-decomposed residuals of an air pollutant in a city were obtained in approximately 70 % of a total of 42 cases (for seven pollutants in six cities), but consistent PCs calculated from the three methods, defined as the standard deviation being smaller than 10 % of the corresponding mean absolute value, were obtained in only approximately 30 % of all the cases. The remaining cases with inconsistent trends and/or PCs indicated large uncertainties produced by one or more of the three methods. The calculated PCs from the deweathered concentrations and decomposed residuals were thus combined with the corresponding range of DePCs calculated from the self-developed method to gain the robust range of DePCs where applicable. Based on the robust range of DePCs, we identified significant decreasing trends in PM2.5 concentration from 2014 to 2020 in Guangzhou and Shenzhen, which were mainly caused by the reduced air pollutant emissions and to a much lesser extent by weather perturbations. A decreasing or probably decreasing emission-driven trend was identified in Haikou and Sanya with inconsistent PCs, and a stable or no trend was identified in Zhanjiang with positive PCs. For O-3, a significant increasing trend from 2014 to 2020 was identified in Zhanjiang, Shenzhen, Guangzhou and Haikou. An increasing trend in NO2 + O-3 was also identified in Zhanjiang and Guangzhou and an increasing or probably increasing trend in Haikou, suggesting the contributions from enhanced formation of O-3. The calculated PCs from using different methods implied that the emission changes in O-3 precursors and the associated atmospheric chemistry likely played a dominant role than did the perturbations from varying weather conditions. Results from this study also demonstrated the necessity of combining multiple decoupling methods in generating emission-driven trends in atmospheric pollutants.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000900228000001
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/273284
作者单位	Ocean University of China; Environment & Climate Change Canada; Ocean University of China; Laoshan Laboratory
推荐引用方式 GB/T 7714	Lin, Yu,Zhang, Leiming,Fan, Qinchu,et al. Decoupling impacts of weather conditions on interannual variations in concentrations of criteria air pollutants in South China - constraining analysis uncertainties by using multiple analysis tools[J],2022,22(24):18.
APA	Lin, Yu.,Zhang, Leiming.,Fan, Qinchu.,Meng, He.,Gao, Yang.,...&Yao, Xiaohong.(2022).Decoupling impacts of weather conditions on interannual variations in concentrations of criteria air pollutants in South China - constraining analysis uncertainties by using multiple analysis tools.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(24),18.
MLA	Lin, Yu,et al."Decoupling impacts of weather conditions on interannual variations in concentrations of criteria air pollutants in South China - constraining analysis uncertainties by using multiple analysis tools".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.24(2022):18.