In the context of global aging, the decline in cognitive abilities among individuals, which can potentially worsen into dementia, poses a significant health challenge. China is a country with a high degree of population aging and severe air pollution. By applying regression analysis methods, this paper has analyzed the influence of air pollution on the cognitive decline of Chinese adults. The research results based on the China Family Panel Studies 2018 data and the China Statistical Yearbook reveal that: (1) There is a significant negative correlation between air pollution and cognitive abilities. (2) Mechanism analysis shows that air pollution indirectly affects cognitive abilities through its impact on individual depression levels, but the mediating effect of exercise on the relationship between pollution and cognitive abilities is not significant. (3) Heterogeneity analysis indicates that pollution has a greater negative impact on cognitive abilities in the younger population compared to middle-aged and elderly individuals, and it has a significant negative impact on females, urban residents, and those with healthcare. (4) The main pollutants in exhaust gases all have significant cognitive ability depreciation effects, with SO2 being more harmful. The research results shall provide a realistic basis and a policy reference for the systematic promotion of environmental health work related to cognitive abilities.