Effect of air-pollution control on death rates in Dublin, Ireland: an intervention study

Abstract

Background: Particulate air pollution episodes have been associated with increased daily death. However, there is little direct evidence that diminished particulate air pollution concentrations would lead to reductions in death rates. We assessed the effect of air pollution controls--ie, the ban on coal sales--on particulate air pollution and death rates in Dublin.

Methods: Concentrations of air pollution and directly-standardised non-trauma, respiratory, and cardiovascular death rates were compared for 72 months before and after the ban of coal sales in Dublin. The effect of the ban on age-standardised death rates was estimated with an interrupted time-series analysis, adjusting for weather, respiratory epidemics, and death rates in the rest of Ireland.

Findings: Average black smoke concentrations in Dublin declined by 35.6 mg/m(3) (70%) after the ban on coal sales. Adjusted non-trauma death rates decreased by 5.7% (95% CI 4-7, p<0.0001), respiratory deaths by 15.5% (12-19, p<0.0001), and cardiovascular deaths by 10.3% (8-13, p<0.0001). Respiratory and cardiovascular standardised death rates fell coincident with the ban on coal sales. About 116 fewer respiratory deaths and 243 fewer cardiovascular deaths were seen per year in Dublin after the ban.

Interpretation: Reductions in respiratory and cardiovascular death rates in Dublin suggest that control of particulate air pollution could substantially diminish daily death. The net benefit of the reduced death rate was greater than predicted from results of previous time-series studies.