Ambient Air Pollution and Non-Communicable Diseases Among Older Adults in China: The Mediating Role of Social Participation

Amid rapid industrialization and urbanization, air pollution has emerged as a major public health concern linked to non-communicable diseases (NCDs), with older adults particularly vulnerable. Beyond its direct physiological effects, social participation could buffer environmental health risks by enhancing resilience, encouraging healthy behaviors, and reducing stress. Using data from the 2020 China Longitudinal Aging Social Survey (CLASS; 11,398 respondents aged 60 and above), linked with county-level air pollution indicators (PM 2.5 , O 3 , SO 2 , NO 2 , and CO), this study applied multilevel models to examine the association between air pollution and NCD prevalence among older adults, as well as the mediating role of social participation. Results show that higher NO 2 concentrations significantly increased NCD risk (OR = 1.27, 95% CI: 0.87–1.73), whereas higher SO 2 concentrations (mean = 9.96 µg/m 3 , ranged from 5.69 to 19.99 µg/m 3 ) were unexpectedly associated with reduced risk (OR = 0.68, 95% CI: 0.58–0.8). This finding should be interpreted with caution and warrants further investigation; notably, the observed SO 2 levels were well below the World Health Organization air quality guideline values. CO exhibited an inverted U-shaped relationship with disease prevalence. Social participation functioned as a protective factor, lowering NCD risk (OR = 0.75, 95% CI: 0.66–0.84) and may partly explain the association between NO 2 exposure and NCDs. These findings highlight the complex and sometimes counterintuitive pathways through which air pollution and social participation jointly shape NCDs in later life. Policy interventions should integrate air quality improvements with initiatives that promote social participation to enhance resilience, reduce disparities, and foster healthy aging in polluted urban environments. For example, establishing well-ventilated indoor community centers equipped with air filtration systems in high-pollution areas could provide safer spaces for older adults to participate in social activities while minimizing exposure to harmful pollutants. Such interventions could simultaneously reduce environmental health risks and strengthen social participation, thereby offering a practical pathway for promoting healthy aging.