PNNL

Abstract

Ozone (O3) has become one of the most concerning air pollutants in China in recent decades. In this study, based on surface observations, reanalysis data and global atmospheric chemistry model simulations, meteorological characteristics conducive to severe O3 pollution in various regions of China are investigated, and their historical changes and future trends are analyzed. During the most severe O3 pollution months over the North China Plain (NCP) and Yangtze River Delta (YRD), the chemical production of O3 is enhanced under the hot and dry conditions, while the regional transport is the main reason causing the severe O3 pollution over Sichuan Basin (SCB) and Pearl River Delta (PRD) during the severe polluted months. Over the last four decades, the frequencies of high temperature and low relative humidity conditions increased in 2000-2019 relative to 1980-1999, indicating that O3 pollution in both NCP and YRD became more frequent under the historical climate change. In SCB and PRD, the occurrence of atmospheric circulation patterns similar to those during the polluted months increased, together with the more frequent hot and dry conditions, contributing to the increases in severe O3 pollution in SCB and PRD during 1980–2019. In the future (by 2100), the frequencies of months with anomalous high temperature show stronger increasing trends in the high forcing scenario (SSP5-8.5) compared to the sustainable scenario (SSP1-2.6) in China. It suggests that high anthropogenic forcing will not only lead to slow economic growth and climate warming, but also likely result in environmental pollution issues.