Daily mortality in Santiago and its relationship with air pollution

Background: Santiago de Chile, due to meteorological and topographic factor s, is one of the most polluted cities in the world. The adverse effects of contamination on health are relatively well known, but they may be overvalu ed. Aim: To evaluate the short term effects of exposure to air pollution on mortality of people over 65 years old. Material and methods: Daily mortali ty data in Santiago, from 1988 to 1993, was obtained from the National Stat istics Institute. Daily concentrations of contaminants in Santiago and mete orological variables, were obtained from SESMA the Metropolitan Environment al Health Services. An association between contamination and mortality due to respiratory or cardiovascular diseases in subjects over 65 years old was searched, using temporal series analysis. Results: There was a significant association between air pollution, meteorological values on the same and p revious days and mortality. PM10 had the strongest association with mortali ty. The relative risk of a 100 mu g/m(3) increment in PM10 was 1.052 for th e elderly, 1.025 for cardiovascular and 1.061 for respiratory mortality. Th e relative risk of SO2 was 1.006 for all deaths and 1.017 for respiratory d eaths. The figures for O-3 were 1.015 for all deaths and 1.008 for cardiova scular deaths. Conclusions: This work confirms a consistent association bet ween air pollution and daily mortality, specially for particulate matter, e ven for levels below Chilean norms.