Surface ozone in global cities: A synthesis of basic features, exposure risk, and leading meteorological driving factors

Abstract

Long-term exposure to high surface ozone (O3) concentrations, a complex oxidative atmospheric pollutant, can adversely impact human health. Based on O3 monitoring data from 261 cities worldwide in 2020, generalized additive model (GAM) and spatial data analysis (SDA) methods were applied in this study to quantitatively evaluate the spatiotemporal distribution of O3 concentration, exposure risk, and dominant meteorological factors. Results indicated that over 40% of the cities worldwide were exposed to harmful O3 concentration ranges (40–60 µg/m3), with most cities distributed in China and India. Moreover, significant seasonal variations in global O3 concentrations were observed, presenting as summer (45.6 µg/m3) > spring (47.3 µg/m3) > autumn (38.0 µg/m3) > winter (33.6 µg/m3). Exposure analysis revealed that approximately 12.2% of the population in 261 cities were exposed to an environment with high O3 concentrations (80–160 µg/m3), with about 36.32 million people in major countries. Thus, the persistent increase in high O3 levels worldwide is a critical factor contributing to threats to human health. Furthermore, GAM results indicated temperature, relative humidity, and wind speed as primary determinants of O3 variability. The synergy of meteorological factors is critical for understanding O3 changes. Our findings are important for enforcing robust air quality policies and mitigating public risk.

Keywords

• Ozone pollution
• Spatiotemporal variation
• Exposure risk
• GAM
• Meteorological factors