Understanding the Joint Impacts of Fine Particulate Matter Concentration and Composition on the Incidence and Mortality of Cardiovascular Disease: A Component-Adjusted Approach

摘要

Past health impact assessments of ambient fine particulate matter (particles with an aerodynamic diameter ≤2.5 μm; PM_(2.5)) have generally considered mass concentration only, despite PM_(2.5) being a heterogeneous mixture. Given constant changes in the concentration and the composition of atmospheric aerosol, uncertainty exists as to whether the current focus on PM_(2.5) mass or individual components may fully characterize the health burden of PM_(2.5). We proposed a component-adjusted method that Jointly estimates the health impacts of PM_(2.5) and its major components while allowing for a potential nonlinear PM_(2.5)-outcome relationship. Using this method, we quantified the effects of PM_(2.5) on the risks of developing acute myocardial infarction (AMI) and dying from cardiovascular causes in comparison to three traditional approaches in the entire adult population across Ontario, Canada. We observed that PM_(2.5) was positively associated with AMI incidence and cardiovascular mortality with all four methods. Compared to the traditional approaches, however, the new component-adjusted approach demonstrated a significant improvement in explaining the health impacts of PM_(2.5), especially in the presence of a nonlinear PM_(2.5)-outcome relationship. Using the new approach, we found that the effects of PM_(2.5) on AMI incidence and cardiovascular mortality may be 10% to 27% higher than what would be estimated from the conventional approaches examining PM_(2.5) alone.