Effects of air pollution on daily mortality in Zaragoza, Spain, 1991-1995.

Objective. To analyze the short-term impact of air pollution on daily mortality in the City of Zaragoza (Spain). Material and methods. This ecologic study was conducted in Zaragoza, Spain, from 1991 to 1993. Poisson autoregressive models were constructed to assess the association between air particulate matter and sulphur dioxide SO2 and daily deaths. Four outcome variables were studied: overall mortality (excluding external deaths), mortality in subjects over 69 years of age, mortality due to respiratory disease, and mortality due to cardiovascular disease. A sample size was not obtained. Data analysis was conducted using the statistical software EGRET and SPSS. Results. SO2 levels were significantly associated with cardiovascular deaths (RR= 1.018 IC 95%:1.001-1.036) and particulate matter levels with respiratory deaths (RR= 1.028 IC 95%: 1.006-1.051). During the warm season,a significant relationship was found between particulate mater and cardiovascular deaths (RR= 1.020 IC 95%:1.001-1.040). Conclusions. Low levels of air pollution were found in Zaragoza, with considerable variation in the concentration of air pollutant concentrations and daily respiratory and cardiovascular deaths, particularly during the warm season. The English version of this paper is available at: http://www.insp.mx/salud/index.html.