Cumulative effect of PM 2.5 components is larger than the effect of PM 2.5 mass on child health in India.

While studies on ambient fine particulate matter (PM 2.5 ) exposure effect on child health are available, the differential effects, if any, of exposure to PM 2.5 species are unexplored in lower and middle-income countries. Using multiple logistic regression, we showed that for every 10 μg m -3 increase in PM 2.5 exposure, anaemia, acute respiratory infection, and low birth weight prevalence increase by 10% (95% uncertainty interval, UI: 9-11), 11% (8-13), and 5% (4-6), respectively, among children in India. NO 3 - , elemental carbon, and NH 4 + were more associated with the three health outcomes than other PM 2.5 species. We found that the total PM 2.5 mass as a surrogate marker for air pollution exposure could substantially underestimate the true composite impact of different components of PM 2.5 . Our findings provide key indigenous evidence to prioritize control strategies for reducing exposure to more toxic species for greater child health benefits in India.