Ambient Air Pollution Associated With Cardiovascular Mortality In Ningbo City,2011-2014:A Time-series Analysis

Objective:To explore the short-term association between ambient air pollutants and daily population mortality of cardio-cerebrovascular diseases in Ningbo, which will provide population-based evidence for ambient air pollution control.Methods:The data of daily cardiovascular mortality, corresponding meteorological factors( temperature, relative humidity, air pressure, windspeed) and ambient air pollution( particulate matter with an aerodynamic diameter less than 2.5μm [PM2.5], particulate matter with an aerodynamic diameter less than 10μm [PM10], sulfur dioxide [SO2], nitrogen dioxide[NO2], carbon monoxide[CO] and ozone[O3]) from 1 January 2011 to 31 December 2014 in Ningbo city were collected. Time series study using generalized additive models and distributed lag non-linear models were employed to evaluate the relationship between the mortality of cardiovascular disease and ambient air pollution. The statistical analyses were finished in R software.Results :1、The concentrations of ambient air pollutants were associated with an increased risk of daily cardiovascular mortality in Ningbo city with lag-effect from 2011 to 2014. In single-day lag pollutant models, no significant difference was observed for the associations of increasing concentrations of pollutants in day 0( lag0) with an increased risk of cardiovascular mortality. the short-term effects of pollutants on cardiovascular mortality was strongest in day 2( lag2) in Ningbo city, and an increase of 10μg/m3 of PM2.5, PM10, SO2, NO2 and O3 have increased the cardiovascular mortality by 0.50%( 95%CI:0.22-0.78%), 0.43%( 95%CI:0.23-0.63%), 2.90%( 95%CI:2.08-3.73%), 1.33%( 95%CI:0.71-1.95%) and 0.45%( 95%CI:0.12-0.78%), respectively, except CO, that an increase of 10mg/m3 has increased the cardiovascular mortality by 0.52%( 95%CI:0.25-0.80%) in day 3( lag3). The lag-effect have decreased with the time after reaching the peak. In multi-pollutant models, the pollutants did remain robust after being adjusted for other co-pollutants except PM2.5 and O3. Compared to generalized additive models, slight changes have been observed with an increase of 10μg/m3 of PM2.5、PM10 and SO2 using distributed lag non-linear models, corresponded to 0.55%( 95%CI:0.06-1.05%), 0.45%( 95%CI:0.18-0.73%) and 3.23%( 95%CI:1.53-4.96%), While NO2 and CO have reduced apparently, corresponded to 0.39%( 95%CI:0.06-0.71%) and 0.26%( 95%CI:0.08-0.43%) increase in daily cardiovascular mortality, respectively. About one day late can been observed by distributed lag non-linear models compared to generalized additive models while considering the strongest lag-effect in time.2、The effect estimates of air pollutants have shown obvious seasonlity, which in cool period( November to April) were much higher than in warm period( May to October) on cardiovascular mortality. Significant associations were consistent with the effects in the whole period in lag-effect time and estimate in cool period. There were no statistical significance in warm period except SO2, an increase of 10μg/m3 corresponded to 3.18%( 95%CI:0.42-6.01%) increase in daily cardiovascular mortality in day 2( lag2).3、The curves for ambient air pollutions appeared to be linearly positive without any thresholds in Ningbo city during 2011 to 2014.Conclusion: The concentrations of ambient air pollutants were associated with an increased risk of daily cardiovascular mortality in Ningbo city and obvious lag-effect and seasonlity have been observed. Although the acute effect of ambient air pollutants on cardiovascular mortality were relatively weak, the researches of which remain have an important significance in public health since China suffering from serious air pollution problem, as well as elevated prevalence of cardiovascular disease and being the leading cause of death. Particulate matters and gaseous pollutants in the air are the risk factors for cardio-cerebrovascular diseases mortality in Ningbo.