In the context of population aging, the establishment and improvement of the basic elderly care service system must be oriented toward precisely addressing the actual health needs of middle-aged and elderly individuals. Based on data from the China Health and Retirement Longitudinal Study (CHARLS), this paper employs a two-stage least squares (2SLS) approach to analyze the effects of air pollution on the self-care ability of China's middle-aged and elderly population. The results show that a 1 μg/m³ increase in PM_2.5 concentration during the exposure window raises the impairment levels of Activities of Daily Living (ADL), Basic Activities of Daily Living (BADL), and Instrumental Activities of Daily Living (IADL) by 8.40%, 7.93%, and 8.90% relative to their sample means, respectively. Heterogeneity analyses indicate that air pollution has the most significant effects on four specific activities—bathing, toileting, shopping, and finance management—and inflicts greater damage on women, the less educated, individuals exposed to poor indoor air quality, and residents of highly polluted areas. Mechanism analysis shows that air pollution indirectly affects the self-care ability of middle-aged and elderly people by increasing the incidence of cardiovascular diseases and impairing cognitive ability. Further analysis finds that financial support and companionship provided by children can effectively buffer the above negative ability shocks.