The implementation of the "Three-Year Action Plan for Winning the Blue Sky Defense Battle" has significantly reduced surface ozone pollution and its impacts on crop yields in China

Jiayan Wang; Zhuzi Zhao; Mohan Cai; Youfei Zheng; Hui Zhao

doi:10.1016/j.envres.2025.122333

The implementation of the "Three-Year Action Plan for Winning the Blue Sky Defense Battle" has significantly reduced surface ozone pollution and its impacts on crop yields in China

Environ Res. 2025 Jul 10;285(Pt 1):122333. doi: 10.1016/j.envres.2025.122333. Online ahead of print.

Authors

Jiayan Wang¹, Zhuzi Zhao¹, Mohan Cai¹, Youfei Zheng², Hui Zhao³

Affiliations

¹ School of Resources and Environmental Engineering, Jiangsu University of Technology, Changzhou, 213001, China.
² School of Ecology and Applied Meteorology, Nanjing University of Information Science&Technology, Nanjing, 210044, China.
³ School of Resources and Environmental Engineering, Jiangsu University of Technology, Changzhou, 213001, China; Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China. Electronic address: zhaohui_nuist@163.com.

PMID: 40651756
DOI: 10.1016/j.envres.2025.122333

Abstract

China has experienced a substantial reduction in PM_2.5 concentrations since the enforcement of the "Air Pollution Prevention and Control Action Plan (APPCAP)". However, surafce ozone (O₃) levels and the resulting threats to agriculture have intensified. To further mitigate PM_2.5 pollution, the government promulgated the "Three-Year (2018-2020) Action Plan for Winning the Blue Sky Defense Battle" (the Blue Sky Defense Battle). Throughout its implementation, research has consistently shown a steady decrease in PM_2.5 levels. Yet, it is still uncertain whether this reduction in PM_2.5 would lead to a rise in O₃ pollution and its associated effects on agriculture, similar to the patterns observed during the APPCAP period. This study utilized nationwide O₃ monitoring data to systematically evaluate O₃ concentrations and agricultural risks during the Blue Sky Defense Battle period. Results indicated that from 2018 to 2020, the maximum daily 8-h running average O₃ concentration (MDA8 O₃) in China decreased by 3.8 %. Spatially, regions such as Beijing-Tianjin-Hebei, the Yangtze River Delta, and the Fen-Wei Plain exhibited notably high MDA8 O₃ concentrations. By 2020, the Accumulated O₃ exposure over a Threshold of 40 ppb (AOT40) values had declined by 16.2 % and 8.1 % in regions cultivating winter wheat and single rice, respectively, compared to 2018. During 2018-2020, the average relative yield losses due to O₃ were 22.1-27.2 % for winter wheat and 7.5-9.2 % for single rice. Additionally, in 2020, O₃-related crop production losses (CPL) reached 6.35 × 10⁷ tons for winter wheat and 1.07 × 10⁷ tons for single rice, representing reductions of 21.0 % and 12.3 %, respectively, compared to 2018. Spatially, higher CPL of winter wheat were mainly observed in Henan, Hebei, and Shandong, while higher CPL of single rice were distributed in Jiangsu, Hubei, and Anhui. In summary, this study revealed the effectiveness of the Blue Sky Defense Battle in mitigating O₃ pollution and emphasized the necessity of regional O₃ control targeting major crop production areas to reduce agricultural risks.

Keywords: Crops; O(3) indicators; Risk assessment; Surface O(3).