2013–2019 increases of surface ozone pollution in China: anthropogenic and meteorological influences
Ke Li, Daniel J. Jacob, Lu Shen, Xiao Lu, Isabelle De Smedt, Hong Liao
Abstract
Abstract. Surface ozone data from the Chinese Ministry of Ecology and Environment (MEE) network show sustained increases across the country over the 2013–2019 period. Despite Phase 2 of Clean Air Action targeting ozone pollution, ozone was higher in 2018–2019 than in previous years. The mean summer 2013–2019 trend of maximum 8-h average (MDA8) ozone was 1.9 ppb a−1 across China and 3.3 ppb a−1 in the North China Plain (NCP). Fitting ozone to meteorological variables with a multiple linear regression model shows that meteorology played a significant but not dominant role in the 2013–2019 ozone trend, contributing 0.70 ppb a−1 across China and 1.4 ppb a−1 in the NCP. Higher June–July temperatures over the NCP were the main meteorological driver, particularly in recent years (2017–2019), and were associated with increased foehn winds. NCP data for 2017–2019 show a 15 % continuing decrease in fine particulate matter (PM2.5) and flat emissions of volatile organic compounds (VOCs), which would explain the continued anthropogenic increase in ozone. VOC emission controls, as targeted by Phase 2 of the Chinese Clean Air Action, are needed to reverse the increase of ozone.