Unveiling the potential gain in life expectancy by improving air quality for ambient ozone in eastern China

Abstract

Short-term ambient ozone (O₃) exposure is widely linked to heightened mortality risk, while its effects on life expectancy remain largely unstudied. This multi-city time-series study aims to assess the potential gain in life expectancy (PGLE) from reduced O₃ concentrations in eastern China. Generalized additive model was applied to quantify city-specific effects of short-term O₃ exposure on years of life lost (YLL), and associations at the provincial level were pooled through random-effects meta-analysis. By assuming that daily O₃ level met the World Health Organization air quality guideline 2021 (WHO AQG 2021) and interim target 2 (IT-2), we estimated PGLE and attributable fraction (AF) of YLL on the basis of counterfactual analysis. Approximately 1.9 million nonaccidental deaths were included in the analysis. We observed a pooled estimate of 0.44% (95% confidence interval: 0.36%, 0.52%) in excess risk and 0.56 (0.39, 0.72) years increase in YLL (per million population) for each 10-μg/m³ rise in 2-day moving average O₃. By reducing daily O₃ concentrations to WHO IT-2 and WHO AQG 2021, we estimated that 0.13 million (AF = 0.56%) and 0.22 million (AF = 0.97%) years of YLL could be avoided per million population, equivalent to the PGLE of 0.054 (0.038, 0.070) years and 0.094 (0.066, 0.121) years for each death, respectively. This study provided province-wide evidence for prolonged population life expectancy by achieving cleaner air quality for ambient O₃ in eastern China, underscoring the great public health significance through implementing more stringent standards.