Does Bad Air Quality Contribute to Obesity? Evidence from Chinas Central Heating System

This study finds that individuals exposed to an additional 1 μg/m3 airborne particulate matter smaller than 2.5 lead to a statistically significant 0.121 kg/m2 rising of body mass index. This positive relationship is identified by two-stage least square regression using a regression discontinuity estimator of air pollution generated by China’s coal-burning winter heating policy, which only heats for northerners but not for southerners, as the instrument variable. This identification utilizing the quasi-experimental method of regression discontinuity design based on the difference of county’s latitude from both parametric and nonparametric approaches, using different kernel types and bandwidth sizes, with 6000 observations in 2008. Further, the result shows that heating policy caused airborne particulate matter smaller than 2.5 and body mass index significantly increasing in the north and south divided line. These findings not only contribute to the identification of causality between air pollution and obesity but help guide social and environmental policy as well.