Association between Acute Exposure to PM(2.5 )Chemical Species andMortality in Megacity Delhi, India br

The association between daily all-cause mortality andshort-termfine particulate matter (PM2.5) exposure is well established inthe literature. However, association between acute exposure to PM2.5chemical species and mortality is not well known, especially indeveloping countries like India. Here we examined associations betweenmortality and acute exposure to PM2.5mass concentration and their 15chemical components using data from 2013 to 2016 in megacity Delhiusing a semiparametric quasi-Poisson regression model, adjusting formean temperature, relative humidity, and long-term time trend as themajor potential confounders. Mortality estimates were further checkedfor effect modification by sex, age group, and season. The subspecies ofNO3-,NH4NO3, Cr, NH4+, EC, and OC showed a higher mortalityimpact than the total PM2.5mass. Males were at higher risk from NO3-,SO42-, and their NH4+compounds along with carcinogen Cr, whereasfemale group was at higher risk from EC and OC. Among all age groups, the elderly above 65 years were the most vulnerable groupprone to mortality effects from maximum species. The major mortality risk from all hazardous species arose from their winterexposures. Our study provides thefirst evidence of association between acute exposure to PM2.5chemical species and mortalityanywhere in India and recommends similar studies in other regions so that sectoral mitigation emitting the most toxic species can beprioritized to maximize the health benefits