Source apportionment of airborne particulate matters over the Athabasca oil sands region: Inter-comparison between PMF modeling and ground-based remote sensing

Abstract

The airborne particulate matters (PM) emissions associated with oil sands mining and processing operations in Athabasca oil sands regions (AOSR) could impact ambient air quality. But to what scales the effects could geographically reach remains unclear. The study was conducted to investigate the geographical influence of PM emissions within the AOSR at three sampling sites. The first site is sandwiched by oil sands mining and processing facilities. The second site is an urban site and close to the oil sands mining and processing areas. The third site is a remote rural site. Over the 2-year period (2015 and 2016), the observed geometric mean PM2.5 concentrations at Fort McKay (in AOSR), Fort McMurray (near AOSR), and Anzac (far away from AOSR) were 4.81, 5.89, and 3.30 μg/m3, respectively. The temporal variations of PM2.5 showed more elevated concentrations in spring and summer than winter and fall, which was consistent with the aerosol optical depth (AOD) observation. The Positive Matrix Factorization (PMF) modeling results at the above three sites suggest that anthropogenic sources were the dominant contributors of ambient aerosol concentrations within AOSR. According to the depleted vanadium (V) content in the surface dust factor from near AOSR site to remote site, the influence of petroleum coke dust as the primary source on aerosol emissions is geographically limited. The result also revealed the considerably long lasting influence of bitumen spill on the local aerosol source contributions. From the ground-based remote sensing observations of aerosol optical properties, petroleum coke could influence the atmospheric aerosol levels over AOSR with highly light-absorbing coarse-mode aerosols under warm and dry weather conditions.