Model based exposure to ambient fine particulate matter is associated with infant mortality and child health outcomes among over 200,000 children in India

Air pollution is a major risk factor for mortality and adverse health outcomes globally, but particularly in South Asia, which currently experiences the highest air pollution levels. Nevertheless, there is comparatively little epidemiological evidence from this region to quantify the potential health impact.

We combined geocoded data from the Indian nationally representative Demographic and Health Survey Phase 7 (DHS-7) with remote sensed- and model-based exposure estimates for ambient fine particulate matters (PM_2.5) at a 10km resolution from 2010 - 2016. The DHS-7 dataset includes over 200,000 children under 5 years of age born from 2010 - 2016. The PM_2.5 exposure data provides estimates for both 9 month in-utero before birth and over the year following birth for each child. We used multi-level mixed-effect logistic modeling to estimate the association between PM_2.5 exposure and mortality and adverse health outcomes including acute respiratory infection (ARI), diarrhea and stunting (height-age score less than -2). We controlled for household electricity, wealth index, bed nets, birth weight, birth order, birth month, mothers' education, exposure to cigarette smoke, self-reported use of biomass for cooking percentage of households with access to improved drinking water source, sanitation facilities, and hand-washing facilities in our model.

A 10 μg/m³ increase of long-term exposure to PM_2.5 one year after birth is associated with a 6% (95% confidence interval: 5% - 8%) increase of infant mortality and a 3% (95% CI: 1% - 5%) increase in child stunting. A 10 μg/m³ increase of monthly exposure to PM_2.5 during at the time the DHS survey is associated with a 10% (95% CI: 6% - 12%) increase in risk of ARI and a 1.8% (95% CI: 0.7% - 3% ) increase in diarrhea, in each case for the two weeks preceding the survey.

This is the first study assessing association between ambient PM_2.5 and child health outcomes in India using national representative population. The analysis also demonstrates the potential for assessing the association between air pollution and health in settings with limited air quality monitoring and health outcome data.