Ground-Based Measurements of NO2 and SO2 in the Alberta Oil Sands using MAX-DOAS

Speaker: Zoey Davis, Graduate Student

Discussion:  Our understanding of the levels of gas pollutants emitted by Alberta oil sands industry is essential to making quality environmental management decisions but is currently limited due to a lack of peer reviewed studies that quantify these gases. In August 2013 a mini-Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was used to measure Slant Column Densities of NO₂ and SO₂ at a ground site operated by Environment Canada north of Fort McMurray, Alberta in order to quantify tropospheric trace gas levels. Research objectives of this study include the determination of tropospheric vertical column densities (VCDs) of NO₂ and SO₂ in the oil sands region, validation of the accuracy of equivalent satellite retrievals of VCDs, and independent estimations of NO_x and SO₂ emissions from oil sands facilities to compare with industry reported emission rates. Preliminary analyses indicate maximum NO₂ VCDs of 4.3x10¹⁶ molec cm^-2, three times the maximum measured by MAX-DOAS in southern Ontario and four times the mean VCDs measured by the OMI satellite over major US cities, and maximum SO₂ VCDs of 8x10¹⁶ molec cm^-2, four times the mean VCDs measured by the OMI satellite over Central China. Preliminary findings and proposed methodology to compute emission rates of NO₂ and SO₂ will be discussed.