Objective To evaluate the effect of PM2.5 exposure on daily resident mortality risk in the urban area of Changsha.
Methods Daily meteorological data (temperature and relative humidity), air pollutant data (PM2.5, PM10, NO2, SO2, and CO), and daily resident mortality data in urban area of Changsha were collect from January 1, 2014 to December 31, 2016. Distributed lag non-linear model was used to evaluate the association between PM2.5 exposure and co-exposure with PM10, NO2, SO2, and CO and daily all-cause mortality, cardiovascular disease mortality, and respiratory disease mortality from current day of exposure to lag 14 days, with adjustment for confounding factors such as long-term trend, meteorological factors, day of the week, and holiday effect.
Results The annual mean concentration of PM2.5 in urban area of Changsha was 63 μg/m3. In the single-pollutant models, an increase of 10μg/m3 in PM2.5 was associated with increased risks (RR, 95% CI) of daily all-cause mortality (lag10) (1.0518, 1.0065-1.0994) and daily cardiovascular disease mortality (lag1) (1.086 1, 1.005 6-1.173 0), but no significant result was found on daily respiratory disease mortality. In the two-pollutant models, after adjusted for NO2 and SO2, the relative risks (RR, 95% CI) of daily all-cause mortality were 1.084 3 (1.027 8-1.143 9) and 1.067 9 (1.015 5-1.123 0), respectively, while the relative risks of daily cardiovascular disease mortality and daily respiratory disease mortality were decreased. After adjusted for CO, the relative risks of daily all-cause mortality and daily cardiovascular disease mortality were increased, while the relative risk of respiratory disease mortality was decreased.
Conclusion Increasing PM2.5 concentrations may be associated with a higher risk of daily all-cause resident mortality in Changsha urban area.
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