The impact of exposure to air pollution on cognitive performance

Abstract

This paper examines the effect of both cumulative and transitory exposures to air pollution for the same individuals over time on cognitive performance by matching a nationally representative longitudinal survey and air quality data in China according to the exact time and geographic locations of the cognitive tests. We find that long-term exposure to air pollution impedes cognitive performance in verbal and math tests. We provide evidence that the effect of air pollution on verbal tests becomes more pronounced as people age, especially for men and the less educated. The damage on the aging brain by air pollution likely imposes substantial health and economic costs, considering that cognitive functioning is critical for the elderly for both running daily errands and making high-stake decisions.

Keywords: China; aging; air pollution; cognitive decline; gender difference.

Fig. 1.

The figures plot the estimated coefficients on air pollution for the male and female subsamples with 95% and 99% confidence intervals based on the estimates in SI Appendix, Tables S2a and S2b. A and B refer to verbal and math test scores, respectively. Air pollution data are matched between each CFPS county centroid and its nearest API reporting city boundary within a radius of 40 km (i.e., 25 miles). The asterisks in the figure indicate the significance of the male–female difference denoting the results of Wald tests: *10% significance level; **5% significance level; ***1% significance level.

Fig. 2.

The age cohort effects of air pollution on cognitive test scores include interaction terms between 3-y-mean API and age cohort dummies 25–34, 35–44, 45–54, 55–64, and 65+ in 2014. The age band 10–24 is the reference category. The figures plot the estimated coefficients on the interaction terms for the male and female subsamples with 95% and 99% confidence intervals based on the estimates in SI Appendix, Table S3. A and B refer to verbal and math test scores, respectively. Air pollution data are matched between each CFPS county centroid and its nearest API reporting city boundary within a radius of 40 km (i.e., 25 miles). The asterisks in the figure indicate the significance of the male–female difference denoting the results of Wald tests: *10% significance level; **5% significance level; ***1% significance level.

Fig. 3.

The age cohort effects of air pollution on verbal test scores by educational attainment include interaction terms between 3-y-mean API and age cohort dummies 25–34, 35–44, 45–54, 55–64, and 65+ in 2014. The age band 10–24 is the reference category. The figures plot the estimated coefficients on the interaction terms for the male and female subsamples with 95% and 99% confidence intervals based on the estimates in SI Appendix, Table S4a. A refers to the subsample with education level at the primary school or below, while B includes the subsample with middle school education or above. Air pollution data are matched between each CFPS county centroid and its nearest API reporting city boundary within a radius of 40 km (i.e., 25 miles). The asterisks in the figure indicate the significance of the male–female difference denoting the results of Wald tests: *10% significance level; **5% significance level; ***1% significance level.