Elsevier

The Lancet

Volume 360, Issue 9341, 19 October 2002, Pages 1210-1214
The Lancet

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

https://doi.org/10.1016/S0140-6736(02)11281-5Get rights and content

Summary

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 μg/m3 (70%) after the ban on coal sales. Adjusted non-trauma death rates decreased by 5·7% (95% Cl 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.

Introduction

Results of many epidemiological studies have suggested an association between particulate air pollution and daily deaths.1, 2, 3 Despite these findings, it does not follow that a reduction in particulate air pollution would diminish daily deaths or increase life-expectancy.4 Great improvements in air quality in Dublin after the introduction of domestic coal-burning regulations offered an opportunity to assess the effects of reduced particulate air pollution on death rates in the general population.

Dublin's air quality deteriorated in the 1980s after a switch from oil to cheaper and more readily available solid fuels, mainly bituminous coal for domestic space and water heating.5 Periods of high air pollution were associated with increased in-hospital respiratory deaths.6

On Sept 1, 1990, the Irish Government banned the marketing, sale, and distribution of bituminous coals within the city of Dublin.7 The effect of this intervention was an immediate and permanent reduction in average monthly particulate concentrations.8 We assessed the effect of the ban of coal on death in Dublin.

Section snippets

Procedures

We compared air pollution, weather, and deaths for 72 months before (Sept 1, 1984, to Aug 31, 1990) and after (Sept 1, 1990, to Aug 31, 1996) the ban, by seasons. We defined spring as March-May, summer as June–August, autumn as September–November, and winter as December–February. We calculated mean daily air pollution (black smoke and sulphur dioxide) concentrations with measurements from six residential monitoring stations in the city of Dublin (Dublin County Borough).8 We obtained mean daily

Results

Mean black smoke concentrations were highest in winter (table 1). A substantial reduction in black smoke concentrations was seen after the ban on sale of coal on Sept 1, 1990 (figure 1). Overall, mean black smoke concentration fell by about two-thirds after introduction of the ban on coal sales (table 1). This concentration declined in all months, but the largest fall was noted in winter. Sulphur dioxide concentrations were also higher in winter than in other seasons (table 1) and gradually

Discussion

We have shown that the 1990 ban on sale of coal in Dublin led to a reduction in average black smoke concentrations by 35·6 (μg/m3 and average sulphur dioxide concentrations by 11·1 (μ/m3. Non-trauma age-standardised death rates in Dublin decreased by about 5·7% in the 72 months after the ban compared with the same period before, after adjustment for population changes, weather, respiratory epidemics, and secular changes in death rates in the rest of Ireland. The largest decrease was seen in

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