FOCUS Environmental Computational Engineering Biology AIRBORNE MYSTERIES Challenging Air Pollution Estimates Across Canada’s Oil Sands By abigail jolteus Art by Kara Tao 16 Yale Scientific Magazine March 2024 www.yalescientific.org
Environmental Engineering FOCUS Oil production is estimated to be responsible for around fifteen percent of total global energy- related emissions. From extraction to refining to consumption, various stages of oil production are heavily associated with air pollution. But our ability to estimate organic carbon emissions from these processes may be threatened by the emergence of more unconventional oil sources in recent decades. Two of these sources, heavy oil and bitumen deposits, are projected to account for about forty percent of oil production by the year 2040. In a recent paper published in Science, a team of researchers from Yale and Environment and Climate Change Canada, a department of the Canadian government, examined the magnitude and impact of traditionally unmonitored gases on total organic carbon emissions. Addressing Overlooked Air Pollutants Organic carbon emissions, or gaseous organic compounds, refer to substances containing carbon and hydrogen that are released into the atmosphere. Historically, studies on carbon emissions have focused on volatile organic compounds (VOCs), a subset of organic carbon emissions that have short- and long-term adverse effects on human health and the environment. “These compounds pose both environmental and human health risks,” said Lexie Gardner (YC ’23), a co-author of the study and environmental engineer at CDM Smith. Short-term health effects include respiratory irritation, headaches, dizziness, and fatigue, while more long-term effects include cancer, organ damage, and neurological effects. While certain subsets are typically the focus of monitoring and industry reporting, many types of emissions go unmonitored— including emissions that still contribute greatly to air pollution. These compounds include intermediate-volatility organic compounds (IVOCs) and semivolatile organic compounds (SVOCs). Their volatility, or tendency to evaporate at a given temperature, influences their emissions and abundance in the atmosphere, though they all undergo chemical reactions in the atmosphere that affect air quality. Up until now, they have largely gone unmonitored compared to VOCs. “There are opportunities for improvement in emissions reporting,” said Drew Gentner, an associate professor of chemical and environmental engineering at www.yalescientific.org Yale and senior author of the study. Studying unmonitored gases is particularly important because the reported concentration of emissions helps dictate policy on environmental regulations. Air pollution contributes to the worsening effects of climate change, which has direct ramifications on legislation. “Organic carbon emissions encompass a wide range of species with a diverse range of sizes and functionalities,” said Megan He (YC '22), the lead author of the study and a current graduate student at Harvard University. “For typical research and reporting purposes, it is hard to measure all of these individual species together,” He said. Underreporting by Canadian Oil Sands Operations Oil sands are a critical contributor to the majority of Canadian oil production, particularly in the Athabasca oil sands regions in northern Alberta, which make up about two-thirds of Canadian oil production. Oil sands provide a substantial source of unconventional petroleum, which refers to compounds of hydrogens and carbons (hydrocarbons) extracted from unconventional sources, such as tight reservoirs and oil sands themselves. Special extraction and processing techniques are used to extract these compounds from unconventional sources compared to conventional ones. Oil sands, often incorrectly known as tar sands, are composed of bitumen—a heavier version of crude oil— sand, and clay. The bitumen is separated from the sand and the clay and is then refined into various petroleum products. However, the extraction and processing techniques pose several environmental challenges, one of which is their impact on air quality. The researchers were interested in using new measurements to quantify the total carbon emissions and compare those values to estimates reported by the industry on the Athabasca oil sands. They performed both airborne measurements and supplementary laboratory experiments. The first experiment they did was to collect air samples and later analyze their contents. The researchers used an aircraft to measure the total carbon emissions in the Athabasca oil sands. A total of thirty flights were conducted flying both upwind and downwind near five different facilities, some of which were for surface mining and others for in situ mining. Surface mining consists of the removal of overlying rock or soil to access the valuable minerals underneath and is ideal when the minerals are located close to the surface. In situ mining consists of extracting minerals directly from their location without the removal of overlying rock or soil. The five facilities were Syncrude Mildred Lake, Suncor, Canadian Natural Resources, Imperial Kearl Lake, and MJP Petroleum Corporation. “The aircrafts were equipped with instruments capable of analyzing gas-phase organic pollutants and were supplemented by samples taken in the field,” Gardner said. After the samples were analyzed, the researchers found that the total reported annual carbon emissions were underestimated by about 1,900 percent to over 6,300 percent, depending on the respective facility. The researchers focused on the three facilities that had the highest carbon emissions, which were Syncrude Mildred Lake, Suncor, and Canadian Natural Resources. Of the three facilities, Syncrude Mildred Lake was found to have the highest IMAGE COURTESY OF FLICKR Various stages of oil production contribute to global emissions. Offshore oil rigs, constructed for the extraction, storage, and processing of oil, release vast amounts of greenhouse gases into the atmosphere. March 2024 Yale Scientific Magazine 17
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