Objective To assess the relationship between air pollution and risk of death from circulatory diseases among residents in Harbin City in Heilongjiang Province.
Methods Air pollutant concentrations (PM2.5, SO2, NO2, CO, and O3), meteorological data (average temperature and relative humidity), and death data of residents due to circulatory diseases in Harbin were collected in 2016. The relationship between levels of selected air pollutants and the risk of death caused by circulatory diseases was evaluated by time-series analyses with generalized additive models of single pollutant and multiple pollutants.
Results In 2016, the annual average concentrations of PM2.5 and NO2 exceeded the limits of corresponding pollutant concentrations, according to the Ambient Air Quality Standard (GB 3095-2012). A total of 33 694 deaths were registered with the primary cause as circulatory diseases in the city, of which 71.2% were over 65 years old. The results of single-pollutant model showed that the risk of death from circulatory diseases increased in the total population and those aged ≥ 65 years by 0.37% (95% CI:0.06%-0.68%) and 0.44% (95% CI:0.09%-0.78%) after 3 days of PM2.5 exposure, respectively, for each 10 μg/m3 increase of PM2.5 concentration. In the multi-pollutant models of PM2.5+SO2 and PM2.5+O3, the risks in the residents aged ≥ 65 years were basically the same as that of the PM2.5 single-pollutant model; in the multi-pollutant models of PM2.5+SO2+O3, PM2.5+SO2+CO, PM2.5+SO2+NO2+O3, or PM2.5+SO2+NO2+O3+CO, the risks in the residents aged < 65 years were significantly higher than that in the PM2.5 single-pollutant model, which increased 3.70% (95% CI:0.69%-6.79%), 3.86% (95% CI:0.75%-7.07%), 5.32% (95% CI:1.75%-9.01%) and 5.30% (95% CI:1.73%-9.01%), respectively. The negative health effects of PM2.5 on the daily mortality risk due to circulatory diseases increased in heating period in total population and those aged ≥ 65 years, which increased 0.48% (95% CI:0.16%-0.81%) and 0.56% (95% CI:0.21%-0.92%), respectively; in non-heating period, enhanced negative effects of PM2.5 (0.23%-0.26% and 0.29%-0.31%) on the daily death risk of circulatory diseases in total population and those ≥ 65 years were observed when CO, NO2+SO2+CO, NO2+O3+CO, and SO2+O3+CO were additionally fitted in the PM2.5 single-factor model.
Conclusion PM2.5 exposure may increase the risk of death from circulatory diseases. There are synergistic effects of PM2.5 on the circulatory diseases' death risk with SO2, NO2, O3, and CO.
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