Surface ozone pollution in China: Trends, exposure risks, and drivers.

Area of Science:

• Environmental Science
• Public Health
• Atmospheric Chemistry

Background:

• Particulate matter (PM) pollution has seen yearly improvements in Chinese cities.
• Surface ozone (O3) concentrations are increasing, becoming the second-most significant air pollutant after PM.
• Long-term O3 exposure adversely affects human health, necessitating investigation into its patterns and drivers.

Purpose of the Study:

• To investigate the spatiotemporal patterns of O3 pollution in China.
• To assess population exposure risks associated with O3.
• To identify the dominant drivers of O3 pollution for informed policy-making.

Main Methods:

• Utilized high-resolution O3 concentration reanalysis data from 2013 to 2018.
• Employed trend analysis, spatial clustering, exposure-response functions, and multi-scale geographically weighted regression models (MGWR).
• Analyzed spatial and temporal variations, population exposure, and key influencing factors.

Main Results:

• Annual average O3 concentration increased significantly (1.84 μg/m³/year) from 2013-2018.
• O3 pollution exposure affected 28.9% of the population by 2018, causing over 20,000 premature deaths annually.
• Population, industrial activity, NOx emissions, temperature, wind speed, and humidity were identified as key drivers of O3 variations.

Conclusions:

• Sustained O3 increase poses a growing threat to human health in China.
• Spatial heterogeneity in drivers leads to varied O3 concentrations and exposure risks across regions.
• Region-specific O3 control policies are crucial for future air pollution regulation.