Chemistry Seminar Series: Sumi Wren, Environment and Climate Change Canada
To view the full listing of the Chemistry Seminar Series, including the location and time, please visit: https://www.yorku.ca/science/chemistry/news/seminar-series/.
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Towards an improved understanding of air pollutant mixtures and greenhouse gas emissions from oil sands operations using ground-based monitoring, aircraft observations, and satellites
Dr. Sumi Wren
Air Quality Research Division
Environment and Climate Change Canada
Date: November 10, 2022
Time: 1:30 pm - 2:30 pm
Location: PSE 317
Emissions of greenhouse gases (GHGs) and air pollutants from oil sands (OS) operations in Alberta, Canada have both air quality and climate impacts. The first part of this talk will focus on air pollutants measured at an intensive ground-based monitoring station, Oski-ôtin, in Fort McKay. An ‘event-based’ approach to characterizing the complex air pollutant mixtures was applied to better-inform source characterization and attribution of the air pollution in the community, within the context of the lived experience of residents. A chemical mass balance model was used for the source apportionment of industry-specific volatile organic compounds (VOCs) to nearby oil sands facilities. Analysis of the frequency distribution of air pollution ‘events’ indicate that Fort McKay is regularly impacted by multiple mixtures simultaneously, underscoring the limitations of an exceedance-based approach relying on a small number of air quality standards as the only tool to assess risk.
The latter part of the talk will focus on estimates of CO2 emissions from oil sands operations. Measurement-based estimates of greenhouse gas (GHG) emissions from complex industrial operations are challenging to obtain, but serve as an important, independent check on inventory-reported emissions. A multifaceted top-down approach for estimating CO2 emissions that combines measured CO2/NOx emission ratios (ERs) with inventory and satellite-derived NOx emissions from OMI and TROPOMI was applied to the Athabasca Oil Sands Region (AOSR). Historical CO2 emissions were reconstructed for the surface mining region and average top-down estimates were found to be >65% higher than facility-reported, bottom-up estimates from 2005 – 2020. Higher top-down vs. bottom-up emissions estimates were also consistently obtained for individual surface mining and in situ extraction facilities, which represent a growing category of energy-intensive OS operations. Although the magnitudes of the measured discrepancies vary between facilities, they combine such that the observed reporting gap for total AOSR emissions is ≥ (31 ± 8) Mt for each of the last three years (2018 – 2020). This potential underestimation is large and broadly highlights the importance of continued review and refinement of bottom-up estimation methodologies and inventories. The ER method herein offers a powerful approach for upscaling measured facility-level or regional fossil-fuel CO2 emissions by taking advantage of satellite remote sensing observations.
