Seasonal Transition in PM₁₀ Exposure and Associated All-Cause Mortality Risks in India

Lack of a consistent PM₁₀ (particulate matter smaller than 10 μm) database at high spatial resolution hinders in assessing the environmental impact of PM₁₀ in India. Here we propose an alternate approach to estimate the PM₁₀ database. Aerosol extinction coefficients at the surface are calculated from midvisible aerosol optical depth from MERRA-2 reanalysis data using characteristics vertical profiles from CALIOP and then are converted to PM₁₀ mass using aerosol property information and microphysical data. The retrieved PM₁₀ are bias-corrected and evaluated ( R² = 0.85) against coincident ground-based data maintained under the Central Pollution Control Board network. PM₁₀ exposure exceeds Indian annual air quality standard in 72.3% districts. Transition in PM₁₀ exposure from the monsoon (Jun-Sep) to postmonsoon season (Oct-Nov) translates to 1-2% higher all-cause mortality risk over the polluted Indo-Gangetic Basin (IGB). Mortality risk increases in the central to eastern IGB and central India and reduces in Delhi national capital region in the winter (Dec-Feb) relative to the postmonsoon season. Mortality risk decreases by 0.5-1.8% in most parts of India in the premonsoon season (Mar-May). Our results quantify the vulnerability in terms of seasonal transition in all-cause mortality risks due to PM₁₀ exposure at district level for the first time in India.