RT Journal Article SR Electronic T1 Air Filters, Pollution, and Student Achievement JF Journal of Human Resources JO J Hum Resour FD University of Wisconsin Press SP 0421-11642R2 DO 10.3368/jhr.0421-11642R2 A1 Gilraine, Michael YR 2023 UL http://jhr.uwpress.org/content/early/2023/02/01/jhr.0421-11642R2.abstract AB This paper identifies the impact of installing air filters in classrooms for the first time. To do so, I leverage a unique setting arising from the largest gas leak in U.S. history, whereby the offending gas company installed air filters in every classroom within five miles of the leak (but not beyond). Using a spatial regression discontinuity design, I find substantial improvements in student performance: air filters raised test scores by 0.1-0.2σ. Natural gas was not detected inside schools, implying that the filters improved air quality by removing common pollutants and so these results should extend to other settings.