Air pollution, deaths, and the weather were compared for 72 months before and 72 months after the ban on coal sales in the city of Dublin on 1 September 1990. This led to a fall in black smoke of 35.6 μg/m³ (70%) and a fall in sulphur dioxide levels of 33%. Age standardised death rates were adjusted to the 1991 Irish census population. Cardiovascular deaths accounted for 45% and respiratory deaths for 15% of non-trauma deaths. Total non-trauma deaths fell by 5.7%, cardiovascular deaths by 10.3%, and respiratory deaths by 15.5% (p<0.001 in all cases). This amounted to 243 fewer cardiovascular deaths and 116 fewer respiratory deaths per year after the ban.

This study shows substantially larger effect estimates compared with the effect sizes from daily time series mortality studies, strongly suggesting a long term cumulative effect of air pollution exposure.