Mortality Effects of PM10 and O-3 in Chilean Cities: Results from the ESCALA Project
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Date
2009
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Oxford University Press
Abstract
ESCALA (Estudio de Salud y Contaminación del Aire en Latinoamérica) is a study that examines the association between outdoor air pollution (PM10 and O3) and health effects in Brazil, Mexico and Chile, in all causes, all ages mortality and in subgroups defined by cause, age and gender. We report the results for Santiago, a 5 M people city, Concepcion, a 600,000 people industrial city, and Temuco, a city of 360,000 people dominated by wood-burning pollution in winter. Poisson regression was used to fit a model to the time-series data (1997–2005), adjusting for seasonality and meteorology. Distributed lag models were fitted considering a 2nd degree polynomial with exposure lagged up to 5 days. In Santiago, in most of the age groups and causes studied, PM10 had a signficant impact on daily mortality. The risk percentage change (RPC) for 10 μg/m3 PM10 ranged from 0.12% (cardiopulmonary, all ages) to 0.46% (respiratory, all ages). Ozone also had significant impacts for all causes, cardiopulmonary causes. The biggests effects were found for cerebrovascular/stroke (CEV) deaths (RPC 0.56 to 0.66 for all ages and elder). The only significant effects in Concepcion were found for the elder population for respiratory causes (RPC 1.65%) and COPD (RPC 2.6 to 2.9%). In Temuco, COPD had the higher risk for the whole population (RPC 2.7 to 4%) and CEV also had a high risk (RPC 1.2 for all ages, 1.1 to 1.5 for elder). These results provide further evidence of the adverse health effects of PM10 and O3 in cities of the developing world. The higher effects were found for two relatively small cities, with different mixtures of air pollution. Possible differential effects by socioeconomic characteristics of the exposed populations may explain much of the differences and are being currently investigated.