Air Pollution, Cognitive Performance, and the Role of Task Proficiency

We estimate the acute effect of air pollution on cognitive performance and how the effect varies with task proficiency using data from over 25,000 individuals and 925,000 plays of a popular online arithmetic training game. To isolate exogenous pollution fluctuation, we interact spatial variation in NOx emissions with thermal inversion episodes. This exogenous variation negatively affects the cognitive performance of proficient players but not of beginners. Instrumenting NO2 pollution with the emissions x inversion interaction, we find that a 1 part per billion concentration increase lowers the number of correct answers of proficient individuals by 0.5% and by 0.3% overall.