Despite significant air quality improvements from China's two-stage Clean Air Actions, demographic disparities in pollution exposure persist. Evaluating disparities in air pollution exposure among distinct age groups is crucial for advancing environmental justice and promoting health equity in China. This study employed population-weighted PM_2.5 concentration exposure (PM_2.5 PWE) and the coefficient of variation (COV) to quantify and assess inter-group exposure disparities at three geographical scales (county, prefectural, and provincial levels) for the years 2010 and 2020. Although air quality in China improved significantly, the benefits were unevenly distributed among age groups, leading to heightened disparities. Specifically, the elderly consistently experienced the highest PM_2.5 PWE_, whereas children exhibited lower PWE in 2010 but higher PWE in 2020. The working-age group demonstrated the biggest drop in exposure over time. Children transitioned from the lowest-exposed group to surpassing working-age adults. Inter-group exposure disparities (COV) nearly surged from 0.012 to 0.023 at the county level, with larger spatial scales exhibiting greater inequalities. The geographical detector analysis identified key factors contributing to these disparities, including permanent population, industrial structure, demographic composition, and industrial sulfur dioxide emissions. This study provides novel perspectives on age-related disparities in air pollution exposure in China, underscoring the importance of addressing inequities to inform targeted air quality interventions and policies.
 

Multi-spatial scales; Air pollution exposure; Age-related disparities; PM2.5 PWE; Geographical detector.