The Aggravation of Summertime Nocturnal Ozone Pollution in China and Its Potential Impact on the Trend of Nitrate Aerosols
Xue Li, Jingye Ren, Ru‐Jin Huang, Lu Chen, Yan Li, Xinrui Qiao, Yiling J. Cheng, Bin Zhao, Dejia Yin, Da Gao, Yele Sun, Fang Zhang
Abstract
Abstract Tropospheric ozone (O 3 ) concentration continued to increase over past years, thereby becoming a growing environmental concern in China. Most studies have focused on the analysis of daily maximum 8‐hr O 3 concentration, while there is still a dearth of investigations of nocturnal O 3 . Here, by analyzing the data of 1,313 sites from the China National Environmental Monitoring Center, we show a remarkable increase in the nocturnal O 3 concentration during summertime of 2015–2019 in most regions of China, revealing an aggravation of nocturnal O 3 pollution. Combining with a GeoDetector model and statistical analysis, we clarify that the aggravation of nocturnal O 3 pollution is mainly caused by reduction in both ambient nitrogen dioxide (NO 2 ) concentration and wet scavenging in recent years. We further reveal that the increasing O 3 may have enhanced the nocturnal particulate nitrate () formation through N 2 O 5 heterogeneous hydrolysis, and thereby driving the variation and long‐term trend of nocturnal .