The impact of the aerosol reduction on the worsening ozone pollution over the Beijing-Tianjin-Hebei region via influencing photolysis rates

Jinhui Gao; Ying Li; Zhouqing Xie; Bo Hu; Lili Wang; Fangwen Bao; Shidong Fan

doi:10.1016/j.scitotenv.2022.153197

The impact of the aerosol reduction on the worsening ozone pollution over the Beijing-Tianjin-Hebei region via influencing photolysis rates

Sci Total Environ. 2022 May 15:821:153197. doi: 10.1016/j.scitotenv.2022.153197. Epub 2022 Jan 19.

Authors

Jinhui Gao¹, Ying Li², Zhouqing Xie³, Bo Hu⁴, Lili Wang⁴, Fangwen Bao⁵, Shidong Fan⁵

Affiliations

¹ Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, China; Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Center for the Oceanic and Atmospheric Science at SUSTech (COAST), Southern University of Science and Technology, Shenzhen, China.
² Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Center for the Oceanic and Atmospheric Science at SUSTech (COAST), Southern University of Science and Technology, Shenzhen, China. Electronic address: liy66@sustech.edu.cn.
³ Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.
⁴ State Key Laboratory of Atmosphere Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
⁵ Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China; Center for the Oceanic and Atmospheric Science at SUSTech (COAST), Southern University of Science and Technology, Shenzhen, China.

PMID: 35063532
DOI: 10.1016/j.scitotenv.2022.153197

Abstract

Due to the implementation of the toughest-ever emission control actions across China from 2013 to present, the aerosols are decreasing annually but ozone is simultaneously increasing, especially over the Beijing-Tianjin-Hebei (BTH) region, where ozone pollution can even spread into winter. Quantifying each impact of aerosols on ozone in all seasons is urgent for the worsening ozone pollution in the improved aerosol air quality. In this study, we focused on the impact of aerosols on ozone via influencing photolysis rates. The air pollutants were simulated over the Central East China (CEC) in 2018 by using the Weather Research and Forecasting with Chemistry (WRF-Chem) model. By implementing emissions with base years of 2014 and 2018, we quantified the increase in ozone (ΔOzone_photolysis) caused by the decreasing aerosol concentrations (ΔPM_2.5) by influencing photolysis rates over the BTH region in all seasons. Furthermore, combined with the ozone observations, the contribution of ΔOzone_photolysis to the total changes in ozone (ΔOzone_total) in all seasons was quantitatively discussed. Our results showed that ΔPM_2.5 showed obvious seasonal variations, which PM_2.5 decreased more significantly in winter and autumn than in spring and summer, although significant reductions in anthropogenic emissions were observed in all seasons. Consistent seasonal variations were also observed in ΔOzone_photolysis, and the mean increases reached 5.5 μg m^-3, 2.6 μg m^-3, 1.2 μg m^-3, and 1.4 μg m^-3 in winter, autumn, spring, spring, and summer, respectively. Compared with ΔOzone_total, ΔOzone_photolysis accounted for 36.3%, 17.2%, 3.5% and 10.6% of ΔOzone_total in winter, autumn, spring, and summer, respectively, suggesting that ΔOzone_photolysis was not the primary contributor to the current changes in ozone over the BTH region. However, the 36.3% contribution to ΔOzone_total in winter suggested that ΔOzone_photolysis is still an important contributor and should not be ignored when discussing the formation of high ozone episodes occurring in winter.

Keywords: Aerosol reductions; Ozone pollution; Photolysis rates; WRF-Chem.

MeSH terms

Aerosols / analysis
Air Pollutants* / analysis
Air Pollution* / analysis
Beijing
China
Environmental Monitoring
Ozone*
Particulate Matter / analysis
Photolysis
Seasons

Substances

Aerosols
Air Pollutants
Particulate Matter
Ozone