Effects of particulate and gaseous air pollution on cardiorespiratory hospitalizations

We obtained data on daily numbers of admissions to hospital in Toronto, Can ada, from 1980 to 1994 for respiratory, cardiac, cerebral vascular, and per ipheral vascular diseases. We then linked the data to daily measures of par ticulate mass less than 10 microns in aerodynamic diameter (PM10,), particu late mass less than 2.5 microns in aerodynamic diameter (PM2.5), and partic ulate mass between 2.5 and 10 microns in aerodynamic diameter (PM10-2.5), o zone, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Air pollution was only associated weakly with hospitalization for cerebral vascular and p eripheral vascular diseases. We controlled for temporal trends and climatic factors, and we found that increases of 10 mu g/m(3) in PM10, PM2.5, and P M10-2.5 were associated with 1.9%, 3.3%, and 2.9% respective increase in re spiratory and cardiac hospital admissions. We further controlled for gaseou s pollutants, and the percentages were reduced to 0.50%, 0.75%, and 0.77%, respectively. Of the 7.72 excess daily hospital admissions in Toronto attri butable to the atmospheric pollution mix,11.8% resulted from PM2.5, 8.2% to PM10-2.5, 17% to carbon monoxide, 40.4% to nitrogen dioxide, 2.8% to sulfu r dioxide, and 19.8% to ozone.