The devil in the air: Air pollution and dementia

We study the causal relationship between air pollution and dementia prevalence. Leveraging the strict air pollution regulations implemented during the 2008 Beijing Olympics and employing a Synthetic Difference-in-Differences (SDID) approach, we find that a 1 $\mu {\mathrm{g/m}}^3$ decrease in annual PM₁₀ levels corresponds to a 0.82 percentage point reduction in dementia prevalence (equivalent to 2.39% of the mean). Analyses across demographics show a more pronounced impact on vulnerable groups. Moreover, an economic assessment suggests that a 10 $\mu {\mathrm{g/m}}^3$ reduction in China’s air pollution in 2010 could generate up to 2.36 billion US dollars in benefits due to a lower dementia prevalence. These results highlight the potential public health gains achievable through air pollution regulations.