Air pollution in China and the undesired effects of mitigation strategies: Understanding why ozone is increasing in response to air pollution mitigation strategies

• Applicants: Professor Dr. Guy Brasseur; Professorin Dr. Maria Kanakidou, Ph.D.; Professor Dr. Mihalis Vrekoussis, Ph.D.
• Subject Area: Atmospheric Science
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448720203

After having observed a substantial increase for more than two decades, anthropogenic emissions of air pollutants in China peaked during the 2010s and have since declined as a result of the “Action Plan on the Prevention and Control of Air Pollution” imposed by Chinese authorities. However, in spite of general expectations, concentrations of tropospheric ozone did not drop as a result of these measures but rather increased.In this project, our established Sino-German collaboration of atmospheric scientists proposes to analyze the key factors that have driven surface ozone concentrations in response to the imposed emission control measures. Hereto, we will combine state-of-the-art numerical simulations by a small ensemble of regional and global atmospheric chemistry models with past and present in-situ and space observations of atmospheric composition. State-of-the-art in situ and satellite observations of atmospheric composition will be performed and analyzed in order to characterize the chemical regimes prevalent in China’s urban agglomerations. Simulation results from our model ensemble will be confronted with these observations to test our understanding of the processes leading to the observed, increased ozone concentrations.We will project future ozone trends in response to different emission scenarios, additional mitigation measures, and change in climate forcing. Effective strategies informed by scientific results will be proposed to limit ozone increases in the short-time (years) and long-time (decades). Lessons learned from the actions taken in Europe and the US to reduce air pollution will be taken into account. The drastic economic slowdown resulting from the 2020 coronavirus disease (COVID-19) epidemics where emissions of primary pollutants have been drastically reduced, but ozone levels remained high will be analyzed as a test case. This situation mimics, to a large extent, the conditions that should result from future air pollution mitigation actions.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partners: Professor Dr. Yele Sun, Ph.D.; Privatdozent Dr. Hongli Wang, Ph.D.; Professor Dr. Hongliang Zhang, Ph.D.