The impact of the 2016 Fort McMurray Horse River Wildfire on ambient air pollution levels in the Athabasca Oil Sands Region, Alberta, Canada

摘要

AbstractAn unprecedented wildfire impacted the northern Alberta city of Fort McMurray in May 2016 causing a mandatory city wide evacuation and the loss of 2,400 homes and commercial structures. A two-hectare wildfire was discovered on May 1, grew to ~157,000ha by May 5, and continued to burn an estimated ~590,000ha by June 13. A comprehensive air monitoring network operated by the Wood Buffalo Environmental Association (WBEA) in and around Fort McMurray provided essential health-related real-time air quality data to firefighters during the emergency, and provided a rare opportunity to elucidate the impact of gaseous and particulate matter emissions on near-field communities and regional air pollution concentrations. The WBEA network recorded 188 fire-related exceedances of 1-hr and 24-hr Alberta Ambient Air Quality Objectives. Two air monitoring sites within Fort McMurray recorded mean/maximum 1-hr PM2.5concentrations of 291/5229μgm−3(AMS-6) and 293/3259μgm−3(AMS-7) during fire impact periods. High correlations (r2=0.83–0.97) between biomass combustion related gases (carbon monoxide (CO), non-methane hydrocarbons (NMHC), total hydrocarbons (THC), total reduced sulfur (TRS), ammonia) and PM2.5were observed at the sites. Filter-based 24-hr integrated PM2.5samples collected every 6 days showed maximum concentrations of 267μgm−3(AMS-6) and 394μgm−3(AMS-7). Normalized excess emission ratios relative to CO were 149.87±3.37μgm−3ppm−1(PM2.5), 0.274±0.002ppmppm−1(THC), 0.169±0.001ppmppm−1(NMHC), 0.104±0.001ppmppm−1(CH4), 0.694±0.007ppbppm−1(TRS), 0.519±0.040ppbppm−1(SO2), 0.412±0.045ppbppm−1(NO), 1.968±0.053ppbppm−1(NO2), and 2.337±0.077ppbppm−1(NOX). A subset of PM2.5filter samples was analyzed for trace elements, major ions, organic carbon, elemental carbon, and carbohydrates. Sample mass reconstruction and fire specific emission profiles are presented and discussed. Potential fire-related photometric ozone instrument positive interferences were observed and were positively correlated with NO and NMHC.Graphical abstractDisplay OmittedHighlights•Horse River Fire had a major air quality impact on the city of Fort McMurray.•PM2.5enhancements at the community monitoring sites ranged from a factor of 19–54.•Significant enhancements of NMHC, NH3, BC, DC, TRS, NOx, and H2S were observed.•First observations of reduced sulfur compounds (TRS/H2S) emissions from a wildfire•Fire PM2.5profiles were uniform across the network, can be used as a fingerprint.