This paper by Dean and Sangita (co-authored with Sagnik Dey, Sourangshu Choundary, Noah Scovronick and Joshua Apte) is the first study to directly estimate the impact of early-life exposure to ambient fine particulate matter (PM2.5) on child height-for-age at the range of exposures found in India. It is well known that children in India are exposed to high levels of ambient PM2.5, yet population-level evidence of associations with adverse health outcomes from within the country is limited.
The study finds that children in the sample were exposed to an average of 55 μ3 of PM2.5in their birth month. After controlling for potential confounders, a 100 μg/m3 increase in PM2.5 in the month of birth was associated with a 0.05 [0.01–0.09] standard deviation reduction in child height. For an average 5-year-old girl, this represents a height deficit of 0.24 [0.05–0.43] cm. It also found that exposure to PM2.5 in the last trimester in utero and in the first few months of life are significantly (p < 0.05) associated with child height deficits.
Because average exposure to ambient PM2.5 is high in India, where child height-for-age is a critical challenge in human development, the results highlight ambient air pollution as a public health policy priority. Ambient PM2.5 exposure is likely to increase in India in the near future. therefore, the health burden that the paper quantifies here could potentially increase unless appropriate policy action is taken to reduce air pollution throughout India. In particular, although policy conversations often focus on Delhi (and, to a lesser extent, other big cities), we find effects throughout India, and on both rural and urban children, suggesting that the policy challenges are broader than is commonly understood. Because child height has lasting consequences for human capital, this is a problem with potential ramifications throughout Indian society and the economy.