Association of aerosols, trace gases and black carbon with mortality in an urban pollution hotspot over central Indo-Gangetic Plain

摘要

The short-term effect of multiple air pollutants, for example, aerosols (black carbon, BC; PM_(2.5) and PM_(10)) and trace gases (NO_2, SO_2, and O_3), on all-cause mortality was systematically investigated in a typical urban pollution hotspot over central Indo-Gangetic Plain (IGP). This was the first report of mortality estimates for exposure to BC aerosols and multiple trace gases over South Asia. Daily all-cause mortality and ambient air quality were analysed following a semiparametric quasi-Poisson regression model adjusting mean temperature, relative humidity, and long-term time trend as potential confounders. The inclusion of co-pollutants in the multi-pollutant model increased the individual mortality risks for BC aerosols (7.3%). Mortality estimates were further stratified considering different effect modifiers, namely, sex, age, place of death, and season. Almost in all the cases statistically insignificant differences in effect modification were noted for all the pollutants except PM_(10). The authors explored a distributed lag nonlinear model to estimate the lag effect and all the pollutants showed significant lag up to 3 days while BC showed lag effect up to 5 days. The exposure-response curves for individual air pollutants were mostly linear, while a considerable increase in mortality was noted for an exposure >15 μg/m~3 for BC aerosols and >60 μg/m~3 for PM_(2.5). The effect estimates of air pollutants during haze and no-haze days were also defined.