Importance of regional PM2.5 transport and precipitation washout in heavy air pollution in the Twain-Hu Basin over Central China: Observational analysis and WRF-Chem simulation

Weiyang Hu; Tianliang Zhao; Yongqing Bai; Shaofei Kong; Jie Xiong; Xiaoyun Sun; Qingjian Yang; Yao Gu; Huicheng Lu

doi:10.1016/j.scitotenv.2020.143710

Importance of regional PM_2.5 transport and precipitation washout in heavy air pollution in the Twain-Hu Basin over Central China: Observational analysis and WRF-Chem simulation

Sci Total Environ. 2021 Mar 1:758:143710. doi: 10.1016/j.scitotenv.2020.143710. Epub 2020 Nov 14.

Authors

Weiyang Hu¹, Tianliang Zhao², Yongqing Bai³, Shaofei Kong⁴, Jie Xiong⁵, Xiaoyun Sun¹, Qingjian Yang⁶, Yao Gu¹, Huicheng Lu¹

Affiliations

¹ Climate and Weather Disasters Collaborative Innovation Center, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science &Technology, Nanjing 210044, China.
² Climate and Weather Disasters Collaborative Innovation Center, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science &Technology, Nanjing 210044, China. Electronic address: tlzhao@nuist.edu.cn.
³ Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205, China. Electronic address: 2007byq@163.com.
⁴ Department of Atmospheric Sciences, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China.
⁵ Institute of Heavy Rain, China Meteorological Administration, Wuhan 430205, China.
⁶ Climate and Weather Disasters Collaborative Innovation Center, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, PREMIC, Nanjing University of Information Science &Technology, Nanjing 210044, China; Henan Meteorological Observatory, Zhengzhou 450003, China.

PMID: 33223179
DOI: 10.1016/j.scitotenv.2020.143710

Abstract

With observational analysis and WRF-Chem simulation on a heavy air pollution event in January 2019 over the Twain-Hu Basin (THB) in Central China, this study characterized the regional transport of PM_2.5 emitted from the North China Plain (NCP) to the THB region in Central China and quantitatively assessed the influence of the regional PM_2.5 transport and precipitation washout on PM_2.5 change in the wintertime heavy air pollution over the THB. It was found that the THB's heavy air pollution event was exacerbated by the strong northeasterly winds driving a quasi 2-day time lag of regional PM_2.5 transport from the NCP to the THB. The multi-scale atmospheric circulations of cold air invasion influenced by East Asian winter monsoon and the terrain block of THB altered the structures of regional PM_2.5 transport in deteriorating air quality to the THB. It was assessed for the THB region that the enhancing contribution of regional PM_2.5 transport to the high air pollution level reached up to 70.5% in the heavy air pollution, and the precipitation washout could contribute the 55.3% PM_2.5 removal to dissipating the PM_2.5 pollution over the THB with frequent precipitation and wet environment, distinguishing from the dominance of wind-cleaning air pollution in the other regions in China.

Keywords: PM(2.5) pollution; Precipitation washout; Regional transport; Twain-Hu Basin; WRF-Chem.