Sources of particulate matter components in the Athabasca oil sands region: investigation through a comparison of trace element measurement methodologies

摘要

The province of Alberta, Canada, is home to three oil sands regions which, combined, contain the third largest deposit of oil in the world. Of these, the Athabasca oil sands region is the largest. As part of Environment and Climate Change Canada's program in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring program, concentrations of trace elements in PMsub2.?5/sub (particulate matter smaller than 2.5?μm in diameter) were measured through two campaigns that involved different methodologies: a long-term filter campaign and a short-term intensive campaign. In the long-term campaign, 24?h filter samples were collected once every 6?days over a 2-year period (December?2010–November?2012) at three air monitoring stations in the regional municipality of Wood Buffalo. For the intensive campaign (August?2013), hourly measurements were made with an online instrument at one air monitoring station; daily filter samples were also collected. The hourly and 24?h filter data were analyzed individually using positive matrix factorization. Seven emission sources of PMsub2.?5/sub trace elements were thereby identified: two types of upgrader emissions, soil, haul road dust, biomass burning, and two sources of mixed origin. The upgrader emissions, soil, and haul road dust sources were identified through both the methodologies and both methodologies identified a mixed source, but these exhibited more differences than similarities. The second upgrader emissions and biomass burning sources were only resolved by the hourly and filter methodologies, respectively. The similarity of the receptor modeling results from the two methodologies provided reassurance as to the identity of the sources. Overall, much of the PMsub2.?5/sub-related trace elements were found to be anthropogenic, or at least to be aerosolized through anthropogenic activities. These emissions may in part explain the previously reported higher levels of trace elements in snow, water, and biota samples collected near the oil sands operations.