The association of ozone and fine particulate matter with mortality and hospital admissions in 12 Canadian cities

Abstract

Many recent epidemiological studies have linked health effects with short-term exposure to air pollution levels commonly found in North America. The association of ozone and fine particulate matter with mortality and hospital admissions in 12 Canadian cities was explored in a time-series study. City-specific estimates were obtained by Poisson regression models adjusting for the confounding effects of seasonality and temperature. Estimates were then pooled across cities using the inverse variance method. Results suggest significant associations across all outcomes except cardiovascular hospital admissions. Generally, stronger associations were found among the elderly. Effect estimates were robust to adjustment for seasonality confounding but were sensitive to lag structures. Considering the large population exposed to air pollution, reductions in ozone and particulate matter would lead to considerable health benefits.