Comparative analysis of the impact of rising temperatures on ozone levels in China and the United States
Jiemeng Bao, Xin Li, Liuwei Kong, Jie Li, Qi Chen, Yuanhang Zhang
Abstract
Abstract As global warming accelerates, surface ozone (O₃) pollution under high-temperature conditions poses growing environmental and health risks. This study analyzes observational data from China and the United States to assess how rising temperatures impact ozone formation. Results show a stronger ozone–temperature sensitivity in China, with climate penalty factors of 2.9 μg·m −3 °C −1 vs 2.1 μg·m −3 °C −1 in the U.S. Structural equation modeling reveals that direct temperature effects dominate, while photochemical modeling attributes China’s heightened response to elevated NO ₓ and VOC emissions. Under prolonged heat events, ozone increases plateau or decline in the U.S., but remain pronounced in China. During COVID-19 lockdowns, emission reductions curbed ozone levels in China but not in the U.S., where meteorological factors prevailed. These findings highlight the urgent need for region-specific emission control, improved heat-adaptive air quality management, and alignment with climate goals to mitigate ozone pollution in a warming world.