Differences between measured and reported volatile organic compound emissions from oil sands facilities in Alberta, Canada

Abstract

Large-scale oil production from oil sands deposits in Alberta, Canada has raised concerns about environmental impacts, such as the magnitude of air pollution emissions. This paper reports compound emission rates (E) for 69-89 nonbiogenic volatile organic compounds (VOCs) for each of four surface mining facilities, determined with a top-down approach using aircraft measurements in the summer of 2013. The aggregate emission rate (aE) of the nonbiogenic VOCs ranged from 50 ± 14 to 70 ± 22 t/d depending on the facility. In comparison, equivalent VOC emission rates reported to the Canadian National Pollutant Release Inventory (NPRI) using accepted estimation methods were lower than the aE values by factors of 2.0 ± 0.6, 3.1 ± 1.1, 4.5 ± 1.5, and 4.1 ± 1.6 for the four facilities, indicating underestimation in the reported VOC emissions. For 11 of the combined 93 VOC species reported by all four facilities, the reported emission rate and E were similar; but for the other 82 species, the reported emission rate was lower than E. The median ratio of E to that reported for all species by a facility ranged from 4.5 to 375 depending on the facility. Moreover, between 9 and 53 VOCs, for which there are existing reporting requirements to the NPRI, were not included in the facility emission reports. The comparisons between the emission reports and measurementbased emission rates indicate that improvements to VOC emission estimation methods would enhance the accuracy and completeness of emission estimates and their applicability to environmental impact assessments of oil sands developments.volatile organic compounds | emissions | emission inventory validation | oil sands | aircraft measurements

Contributions of natural and anthropogenic sources to ambient ammonia in the Athabasca Oil Sands and north-western Canada

“…These measurements are described in detail in ; Gordon et al (2015); Liggio et al (2016);and Li et al (2017), and are summarized here. Aircraft NH 3 measurements were conducted with a dual quantum cascade laser (QCL) trace gas monitor (Aerodyne Inc., Billerica, MA, USA; McManus et al, 2008), collecting data every 1 s. Outside air was sampled through a heated Teflon inlet tube shared with a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS); the flow rate through the QCL was 10.8 L min −1 .…”

“…The Athabasca Oil Sands region (AOSR), located in the north-eastern part of the province of Alberta, Canada, is a large source of pollution to air Liggio et al, 2016;Li et al, 2017) and ecosystems (Kelly et al, 2009;Kirk et al, 2014;Hsu et al, 2016), as well as a source of greenhouse gases (Charpentier et al, 2009) due to mining and processing by the oil industry. While NH 3 volume mixing ratios (VMRs) surrounding the AOSR in northern Alberta and Saskatchewan remain relatively low -around 0.6 to 1.2 ppbv background (this study -due to low population and lack of agriculture, the northern Alberta and Saskatchewan ecosystems are sensitive to nitrogen deposition (Clair and Percy, 2015;Wieder et al, 2016a, b;Vitt, 2016;Makar et al, 2018), and the modelled background NH 3 must be correct in order to understand the relative impacts of the oil sand operations.…”

Understanding the primary emissions and secondary formation of gaseous organic acids in the oil sands region of Alberta, Canada

“…This includes species such as unsaturated hydrocarbons, aromatics, and various oxygenated compounds. Details of the PTR-TOF-MS technique and application have been described previously (Graus et al, 2010;De Gouw and Warneke, 2007;Li et al, 2017). The deployment of the PTR-ToF-MS on the aircraft during this study, its calibration, and data processing have been described elsewhere .…”

“…Primary emissions of various pollutants from specific surface-mining oil sands facilities were estimated by flying virtual boxes around operations followed by subsequent analysis using TERRA Liggio et al, 2016;Li et al, 2017). The specific oil sands facilities that were evaluated are shown in Table S1 in the Supplement with corresponding flight numbers and include Syncrude, Suncor, Canadian Natural Resources Limited (CNRL), Shell, and Imperial Oil.…”

A chemical transport model study of plume-rise and particle size distribution for the Athabasca oil sands

“…These flights included flight paths designed for emission estimation for the study of downwind transport and chemical transformation and for satellite validation. Emission estimation flights took place around individual facilities at multiple altitudes, with the concentration and meteorological information gathered subsequently used to estimate fluxes entering and leaving the facility and hence estimate emissions directly from aircraft observations Li et al, 2017). Transformation flights were designed to follow plumes downwind, with observations taken in cross sections at set distances downwind perpendicular to the plume direction in order to study chemical transformations between point of emission and downwind receptors (see Liggio et al, 2016).…”