Downwind of the Bus Lane: Transit Pollution and Academic Performance
With Diego Martin and Dario Salcedo
Abstract
We estimate the effect of air pollution from Bogotá’s Bus Rapid Transit system on high school test scores. Using wind direction interacted with bus route intensity as an instrument, we find that schools more frequently downwind of BRT corridors score significantly lower in math and global exams. The instrumental variable estimates imply that an additional μg/m³ of PM2.5 reduces math scores by 0.10 standard deviations and global scores by 0.09 standard deviations, with no effect on language. NOx and PM10 show similar negative effects. Girls and students from higher-income households experience larger declines. A georeferenced household survey provides suggestive evidence that respiratory disease mediates the pollution-achievement relationship. These results reveal a human capital cost of diesel-powered transit and underscore the importance of cleaner fuel technologies in urban transportation policy.