Atmospheric concentration of fine particulate matter and its impact on daily hospital admissions for respiratory disease in the prairies of Canada

Numerous studies have demonstrated a fairly consistent association between fine particulate matter (PM2.5) and respiratory disease hospital admissions (respiratory hospitalization) in Canada. Most recently, there has been increased concern about the impacts of PM2.5 in the Canadian prairies, mainly caused by activities such as agriculture, mining, forest fires, and oil and gas production. In this study, we characterize the trend of PM2.5 concentrations in the Canadian prairies. Our trend analysis estimates the time point at which PM2.5 took an upturn from a non-increasing trend. We then quantify the association between PM2.5 and respiratory hospitalizations before and after this time point. Our analyses revealed that: (a) on average, the atmospheric concentration of PM2.5 went through a transition between 28 September 2009 and 25 February 2010 in the Canadian prairies; (b) an increasing concentration of PM2.5 was observed after completing the transition, (c) there was a significant positive association between PM2.5 and respiratory hospitalization after the time point at which PM2.5 took an upturn; and (d) the relative risk estimates for PM2.5 on respiratory hospitalization were generally higher after the time point at which PM2.5 took an upturn than before this time point. © 2015 Taylor & Francis.