Regional Distributions of Atmospheric Emission, Concentration, and Deposition of Particulate Elements in the Canadian Athabasca Oil Sands Region

LEIMING ZHANG, Abdulla Al Mamun, Irene Cheng, Fuquan Yang, Xin Qiu, Environment and Climate Change Canada

     Abstract Number: 88
     Working Group: Remote and Regional Atmospheric Aerosol

Abstract
To assess potential impacts of particulate elements associated with mining activities in Athabasca oil sands region (AOSR) in northern Alberta, Canada on human and ecosystem health, regional scale distributions of atmospheric emission, concentration, and deposition of major and trace elements need to be quantified. An emission inventory for 29 elements was first developed based on PM2.5 and PM2.5-10 emissions distributions in AOSR and USEPA SPECIATE database, which was then used as input in the CALPUFF dispersion modeling to simulate ambient concentration distributions, covering an area of approximately 300 by 420 km2 in AOSR. Modeled concentrations were evaluated using field measurements collected at three monitoring sites to ensure the reasonable accuracy of the developed emission inventory. The model simulated ambient concentrations were further bias-corrected against measured concentrations and then combined with separately modeled dry deposition velocities, forecasted precipitation rates, and literature values of element-specific fine mode fractions and scavenging ratios by rain and snow to generate regional scale atmospheric dry and wet deposition amounts. The emission database was further split into three sub-categories for fine elements and two sub-categories for coarse elements to assess the direct impact of oil sands emissions on the ambient levels and atmospheric deposition of particulate elements through model sensitivity tests. Annual mean total deposition (mg/m2/year) of all elements was 717 in Zone 1 (within 30 km from the reference point, representing the center of the industrial facilities), 115 in Zone 2 (30-100 km from the reference point), and 35.4 in Zone 3 (beyond 100 km from the reference point). Emissions related to oil sands mining activities were responsible for 78% and 68% of the sum of the mean ambient concentrations of all elements in PM2.5 and PM2.5-10, respectively, and for ~74% of the total atmospheric deposition of all elements.