Total organic carbon measurements reveal major gaps in petrochemical emissions reporting.

Anthropogenic organic carbon emissions reporting has been largely limited to subsets of chemically speciated volatile organic compounds. However, new aircraft-based measurements revealed total gas-phase organic carbon emissions that exceed oil sands industry-reported values by 1900% to over 6300%, the bulk of which was due to unaccounted-for intermediate-volatility and semivolatile organic compounds. Measured facility-wide emissions represented approximately 1% of extracted petroleum, resulting in total organic carbon emissions equivalent to that from all other sources across Canada combined.

Evolution of Atmospheric Total Organic Carbon from Petrochemical Mixtures.

Reactive organic compounds play a central role in the formation of ozone and secondary organic aerosols. The ability to accurately predict their fate, in part, relies upon quantitative knowledge of the chemical and physical parameters associated with the total organic carbon (TOC), which includes both precursors and oxidation products that evolve in the atmosphere over short to long time scales. However, such knowledge, obtained via limited carbon closure experiments, has not been attained for complex anthropogenic emissions.

Fugitive Emissions of Volatile Organic Compounds from a Tailings Pond in the Oil Sands Region of Alberta.

Tailings ponds in the oil sands (OS) region in Alberta, Canada, have been associated with fugitive emissions of volatile organic compounds (VOCs) and other pollutants to the atmosphere. However, the contribution of tailings ponds to the total fugitive emissions of VOCs from OS operations remains uncertain. To address this knowledge gap, a field study was conducted in the summer of 2017 at Suncor's Pond 2/3 to estimate emissions of a suite of pollutants including 68 VOCs using a combination of micrometeorological methods and measurements from a flux tower.

Fugitive emissions of polycyclic aromatic compounds from an oil sands tailings pond based on fugacity and inverse dispersion flux calculations.

Alberta's oil sands tailings ponds are suspected to be a source of fugitive emissions of polycyclic aromatic compounds (PACs) to the atmosphere. Here we report, for the first time, fluxes of 6 parent and 21 alkylated PACs based on the measured co-located air and water concentrations using a two-film fugacity-based model (FUG), an inverse dispersion model (DISP) and a simple box model (BOX). Air samples were collected at the Suncor Tailings Pond 2/3 using a high volume air sampler from the "pond" and towards the pond ("non-pond") directions separately.

Understanding the Impact of High-NO Conditions on the Formation of Secondary Organic Aerosol in the Photooxidation of Oil Sand-Related Precursors.

Oil sands (OS) are an important type of heavy oil deposit, for which operations in Alberta, Canada, were recently found to be a large source of secondary organic aerosol (SOA). However, SOA formation from the OS mining, processing, and subsequent tailings, especially in the presence of NO, remains unclear. Here, photooxidation experiments for OS-related precursors under high-NO conditions were performed using an oxidation flow reactor, in which ∼95% of peroxy radicals (RO) react with NO.

Quantifying the Primary Emissions and Photochemical Formation of Isocyanic Acid Downwind of Oil Sands Operations.

Isocyanic acid (HNCO) is a known toxic species and yet the relative importance of primary and secondary sources to regional HNCO and population exposure remains unclear. Off-road diesel fuel combustion has previously been suggested to be an important regional source of HNCO, which implies that major industrial facilities such as the oil sands (OS), which consume large quantities of diesel fuel, can be sources of HNCO. The OS emissions of nontraditional toxic species such as HNCO have not been assessed.

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

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 () 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 () of the nonbiogenic VOCs ranged from 50 ± 14 to 70 ± 22 t/d depending on the facility.

Oil sands operations as a large source of secondary organic aerosols.

Worldwide heavy oil and bitumen deposits amount to 9 trillion barrels of oil distributed in over 280 basins around the world, with Canada home to oil sands deposits of 1.7 trillion barrels. The global development of this resource and the increase in oil production from oil sands has caused environmental concerns over the presence of toxic compounds in nearby ecosystems and acid deposition.

Nitric acid-induced surface disordering on ice.

We examined the interaction of HNO3 with water ice for partial pressures 2 × 10(-8) Torr to 1 × 10(-5) Torr and at temperatures from 216 to 256 K using (i) the surface-specific technique ellipsometry and (ii) a coated wall flow tube reactor, both coupled with chemical ionization mass spectrometry detection of HNO3 in the gas phase. Our ellipsometry results show that exposure to HNO3 induces surface disordering on ice at a range of environmentally relevant temperatures and HNO3 partial pressures, particularly in the vicinity of the boundary between the ice and the HNO3·3H2O phases. The coated wall flow tube studies indicate that the nature of HNO3 uptake changes from reversible adsorption to a continuous flux of HNO3 into the bulk in the presence of a disordered interfacial layer.

Photochemical aging of light-absorbing secondary organic aerosol material.

Dark reactions of methylglyoxal with NH4(+) in aqueous aerosols yield light-absorbing and surface-active products that can influence the physical properties of the particles. Little is known about how the product mixture and its optical properties will change due to photolysis as well as oxidative aging by O3 and OH in the atmosphere. Here, we report the results of kinetics and product studies of the photochemical aging of aerosols formed by atomizing aqueous solutions of methylglyoxal and ammonium sulfate.

Reaction of gas phase OH with unsaturated self-assembled monolayers and relevance to atmospheric organic oxidations.

The kinetics and mechanisms of the reaction of gas phase OH radicals with organics on surfaces are of fundamental chemical interest, as well as relevant to understanding the degradation of organics on tropospheric surfaces or when they are components of airborne particles. We report here studies of the oxidation of a terminal alkene self-assembled monolayer (7-octenyltrichlorosilane, C8= SAM) on a germanium attenuated total reflectance crystal by OH radicals at a concentration of 2.1 x 10(5) cm(-3) at 1 atm total pressure and 298 K in air.

Experimental and theoretical characterization of adsorbed water on self-assembled monolayers: understanding the interaction of water with atmospherically relevant surfaces.

A combination of experiments and molecular dynamic (MD) simulations has been applied to elucidate the nature of water on organic self-assembled monolayers (SAMs) before and after oxidation. SAMs mimic organics adsorbed on environmental urban surfaces. Water on clean or SAM-coated borosilicate glass surfaces was measured at equilibrium as a function of relative humidity (RH), using transmission Fourier transform infrared (FTIR) spectroscopy at 1 atm and 22 +/- 1 degrees C.