Seasonal changes in the recent decline of combined high PM2.5 and O3 pollution and associated chemical and meteorological drivers in the Beijing-Tianjin-Hebei region, China

Yuehan Luo; Tianliang Zhao; Yuanjian Yang; Lian Zong; Kanike Raghavendra Kumar; Hong Wang; Kai Meng; Lei Zhang; Shuo Lu; Yushan Xin

doi:10.1016/j.scitotenv.2022.156312

Seasonal changes in the recent decline of combined high PM_2.5 and O₃ pollution and associated chemical and meteorological drivers in the Beijing-Tianjin-Hebei region, China

Sci Total Environ. 2022 Sep 10;838(Pt 3):156312. doi: 10.1016/j.scitotenv.2022.156312. Epub 2022 May 27.

Authors

Yuehan Luo¹, Tianliang Zhao², Yuanjian Yang¹, Lian Zong¹, Kanike Raghavendra Kumar³, Hong Wang⁴, Kai Meng⁵, Lei Zhang⁴, Shuo Lu¹, Yushan Xin¹

Affiliations

¹ Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory of Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, China.
² Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory of Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing, China. Electronic address: tlzhao@nuist.edu.cn.
³ Department of Engineering Physics, College of Engineering, Koneru Lakshmaiah Education Foundation (KLEF), Vaddeswaram 522302, Guntur, Andhra Pradesh, India.
⁴ State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
⁵ Key Laboratory of Meteorology and Ecological Environment of Hebei Province, Hebei Provincial Institute of Meteorological Sciences, Shijiazhuang 050021, China.

PMID: 35636546
DOI: 10.1016/j.scitotenv.2022.156312

Abstract

China suffers from combined air pollution (CAP) comprising dual high O₃ and PM_2.5, particularly in the Beijing-Tianjin-Hebei (BTH) region, which is an urban agglomeration in the North China Plain. To characterize the seasonal changes in regional CAP, 82 CAP days were identified during the study period from 2015 to 2019 with the co-occurring pollution of O₃ and PM_2.5 in the BTH. It is found that CAP seasonality has undergone distinct changes with a declining trend in the interannual variations in CAP over recent years. It is also revealed that the monthly CAP peaks have recently shifted from summer to early spring (March and April), indicating seasonal changes in CAP in the BTH. Furthermore, the of chemical and meteorological roles in CAP changes was investigated using environmental and meteorological observation data. The recent reduction in PM_2.5 and O₃ concentrations had enhanced O₃ production and atmospheric oxidizability, thereby causing increments in secondary PM_2.5 proportion. The interaction between O₃ and PM_2.5 was responsible for changing the CAP of dual high O₃ and PM_2.5 to the transition/spring season in the context of mitigation of air pollutant emissions. Furthermore, principal component analysis in the T-mode (T-PCA) was applied to identify four synoptic circulation patterns that regulate CAP occurrence. The results show that the CAP occurrence was regulated by the dominant patterns of synoptic circulation in the BTH. Warm temperature and strong downward ultraviolet radiation anomalies were observed in the BTH, indicating the importance of meteorological drivers in O₃ photochemical production on the CAP. The frequency of key synoptic circulation patterns during the spring season increased annually, thereby inducing seasonal changes in the atmospheric environment with CAP in the BTH in recent years.

Keywords: Combined air pollution; Interaction of O(3) and PM(2.5); Meteorological factor; Seasonal change; Secondary aerosols; Synoptic circulation.

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Beijing
China
Environmental Monitoring / methods
Particulate Matter / analysis
Seasons
Ultraviolet Rays

Substances

Air Pollutants
Particulate Matter