AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Profiling of Polycyclic Aromatic Compounds in Ambient Air Samples Collected in the Athabasca Oil Sands Region (Canada) from 2011 to 2015
ANDRZEJ WNOROWSKI, Jasmin Schuster, Tom Harner, Yayne Aklilu, Jean-Pierre Charland, Environment and Climate Change Canada
Abstract Number: 407 Working Group: Aerosol Chemistry
Abstract We report on a study of the temporal and spatial distributions of 110 polycyclic aromatic compounds (PACs) monitored in ambient air in proximity of oil sands exploitation and bitumen processing. Composite gas- (GP) and particle-phase (PM) samples were collected for 24 hours every six days between December 2010 and December 2015 from three monitoring sites. PACs in these samples were characterized as a function of distance to oil sands exploration, concentration levels, ratio of PAC subclasses (parent polycyclic aromatic hydrocarbons (PAHs), alkylated-PAHs (alk-PAHs) and dibenzothiophenes (DBTs)) and seasonal variations. The results indicated that alk-PAHs represent the majority of the PACs determined and their correlation with parent PAHs confirmed common emission sources. Individual PACs exhibited variations in their spatial and seasonal profiles. Their concentrations declined over distance from a Reference Point at the arbitrary geographic centre of the Athabasca Oil Sands Region. The rate of concentration decay changed with the volatility of the PACs studied, affecting the shape of the PAC fingerprint with distance from the Reference Point. The median air concentration levels for alk-PAHs were highest in the summer (100 ng/m3) and lowest in the winter (86 ng/m3), while parent PAHs exhibited opposite trend with highest median concentrations in the winter (12 ng/m3) and lowest in the summer (7 ng/m3). Correlations of PAC levels with production factors (bitumen extraction, crude oil production, diluent naphtha, sulphur, petcoke) provided indications on the contributions of oil sands exploration processes to the PAC profiles. Annual PAC concentration levels did not correlate with increasing bitumen processing in the Athabasca Region. In comparison, results from the farthest monitoring site located 15 km from the Reference Point indicated that PAC levels were in general lower than at the nearest urban site. This comprehensive study provides first insights on multiyear active air sampling for PACs in the oil sands region.