Projecting Future Ozone Episodes in China by 2060 Under Diverse Emission and Climate Pathways: Insights From Extreme Value Theory

Abstract

Ozone concentrations in China have been rising since 2013 despite emission reductions, yet future episode frequencies remain poorly investigated. In this study, we employ extreme value theory (EVT) to project ozone episode frequency in China by 2060, integrating six emission pathways and four climate scenarios. Under the baseline (most polluted) scenario, annual population‐weighted ozone exceedances (>82 ppb, national standard) reach 65 days nationally and 112 days in northern China by 2060, with climate change driving >50% of the increases. In the 1.5°C (cleanest) scenario, reduced emissions considerably lower ozone levels nationally, yet northern China still experiences 56 annual exceedances of the WHO Interim Target 2 (>61 ppb). Across all scenarios, ozone episode frequency and its temperature sensitivity continuously decline with anthropogenic NOx emissions reduction, highlighting the critical role of NOx mitigation in curbing ozone episodes.