The Impact of Sustained Exposure to Air Pollutant on the Mental Health: Evidence from China

Emerging evidence suggests that poor mental health is particularly pronounced among Chinese residents, who are exposed to nearly the worst air pollution worldwide. However, the correlations between air pollutant concentration and mental health have not been consistently reported in previous studies. Methodologically speaking, a sufficiently rigorous design is required to demonstrate the causal relationship between the two factors. In this study, we aimed to infer the causal relationship between air pollutant concentration and mental health. In this panel research, the data were compiled through a combination of statistics from the China Family Panel Study, China Environmental Statistics Yearbook, World Meteorological Association, and China National Bureau of Statistics. Ultimately, this study enrolled 65,326 individuals whose mental health, air pollutant concentration, and other demographic information was available and robust. The RD design of this study utilizes the discontinuous variation in air pollutant concentrations and mental health as one crosses the Huai River boundary, which is an arbitrary heating policy that caused the difference in air pollutant concentrations between the north and south of China. In this study, we found that a 10 µg/m³ increase in air pollutant concentrations (air particulate matter smaller than 10 µm (PM₁₀)) leads to a 4.9-unit decrease in the mental health of the Chinese residents(coeff = 0.49, SD = 0.07, p < 0.05), equivalent to 36% of the average of Chinese residents. In the heterogeneity model, the impairment of mental health by air pollutant concentrations was more pronounced in male residents (coeff = 1.37, SD = 0.10, p < 0.05) compared to female residents (coeff = 0.42, SD = 0.04, p < 0.05) and smokers (compared to non-smokers). The robustness of the results is ensured by changing the RD bandwidth and polynomial order, and by two unique sensitivity analyses. The results indicate that air pollutant concentrations significantly impair the mental health of Chinese residents, which provides empirical evidence supporting the Chinese government’s decision to invest more in combating air pollution and ensuring the mental health of Chinese residents.