Evaluating the contributions of changed meteorological conditions and emission to substantial reductions of PM2.5 concentration from winter 2016 to 2017 in Central and Eastern China

Wenjie Zhang; Hong Wang; Xiaoye Zhang; Yue Peng; Junting Zhong; Yaqiang Wang; Yifan Zhao

doi:10.1016/j.scitotenv.2020.136892

Evaluating the contributions of changed meteorological conditions and emission to substantial reductions of PM_2.5 concentration from winter 2016 to 2017 in Central and Eastern China

Sci Total Environ. 2020 May 10:716:136892. doi: 10.1016/j.scitotenv.2020.136892. Epub 2020 Jan 23.

Authors

Wenjie Zhang¹, Hong Wang², Xiaoye Zhang³, Yue Peng¹, Junting Zhong¹, Yaqiang Wang¹, Yifan Zhao¹

Affiliations

¹ State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing, China.
² State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing, China; Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044, China. Electronic address: [email protected].
³ State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of CMA, Chinese Academy of Meteorological Sciences, Beijing, China; Center for Excellence in Regional Atmospheric Environment, IUE, Chinese Academy of Sciences, Xiamen, China.

PMID: 32036150
DOI: 10.1016/j.scitotenv.2020.136892

Abstract

The monthly average PM_2.5 concentration decreased from 127.15 μg m^-³ in December 2016 to 85.54 μg m^-³ in December 2017 (approximately 33%) in Central and Eastern China (33°N-41°N, 113°E-118°E). This decrease is attributed to the combined impacts of meteorology and emission sources changes, though the question of which is more important has raised great concerns. Four sensitivity experiments based on the Global-Regional Assimilation and Prediction System coupled with the Chinese Unified Atmospheric Chemistry Environment (GRAPES-CUACE) model, together with comparative analysis of the observed meteorological conditions and emission inventory between 2016 and 2017, are used to evaluate the relative contributions of meteorology and emission to the substantial reductions of PM_2.5 concentration from December 2016 to December 2017. The results show that the meteorological conditions and emission in December 2017 were both beneficial to the PM_2.5 decrease in Central and Eastern China. Regarding the entire region, 21.9% of the PM_2.5 decrease was a result of the favorable meteorological conditions, and 78.1% of the decrease was a result of emission reductions, showing the distinct contributions of emission reductions on the air quality. The relative contributions of meteorology varied from 12.2% to 50.9% to the PM_2.5 decrease from December 2016 to December 2017, while the emission contributed 49.1% to 87.8%, in different cities depending on geographical location and topography. Meteorology showed the largest contributions to the PM_2.5 decrease from 2016 to 2017 in Beijing (BJ), which caused the greatest total decrease of PM_2.5 compared to that of other cities. In addition, in Central and Eastern China, the dominant factors of the decrease of PM_2.5 were favorable meteorological conditions (accounting for 98.2%) during clear periods and emission reductions (accounting for 72.5-81.2%) during pollution periods.

Keywords: Central and Eastern China; Emission; GRAPES-CUACE model; Meteorological conditions; PM(2.5) concentration.