Burden of mortality due to ambient fine particulate air pollution (PM2.5) in interior and Northern BC.

Objectives: Our objective was to estimate the burden of mortality attributable to long-term exposure to ambient fine particulate matter (PM 2.5 ) among adults in two rural regions of British Columbia, the Interior and the North, in order to provide information for public health professionals setting health priorities. Methods: We used the standard method to calculate the fraction of all-cause mortality among adults (≥30 years old) attributable to long-term exposure to ambient PM 2.5 as described in the World Health Organization global burden of disease study. PM 2.5 concentration was either locally measured using tapered element oscillating microbalance (TEOM) continuous monitors or estimated for unmonitored cities. For the base case, we used a conservative PM 2.5 threshold (5.0 ug/m3); for sensitivity analysis, we set the threshold to estimate all mortality attributable to anthropogenic PM 2.5 (3.1 ug/m 3 ). We conducted sensitivity analysis for PM 2.5 concentrations estimated in unmonitored cities. Results and Conclusions: Mean annual PM 2.5 concentration ranged from 3.1 to 7.4 ug/m 3 across local health areas in Northern and Interior BC. Sixty percent of the adult population lived in monitored regions. PM 2.5 was estimated to cause 0.20% of all-cause mortality among adults (16 deaths/year). Anthropogenic PM 2.5 was estimated to cause 0.93% of all-cause mortality among adults (74 deaths/year). Estimates were sensitive to both PM 2.5 threshold and estimated PM2.5 in unmonitored communities. This demonstrates that ambient PM 2.5 air pollution does have an important mortality burden, even in a region with relatively low PM 2.5 concentrations. Key words: Air pollution; particulate matter; public health; British Columbia; Canada; mortality