Canada’s controversial oil-producing tar sands generate a substantial amount of unaccounted-for carbon-based emissions that can affect air quality, according to measurements taken by aircraft. The sands release more of these pollution-causing gases than megacities such as Los Angeles, California, and about the same as the rest of Canada’s human-generated sources combined—including emissions from motor traffic and all other industries.
“No rules have been broken, or guidelines exceeded here,” said Janetta McKenzie, an oil and gas analyst for the Pembina Institute, a think tank in Calgary, Canada. “But that speaks to some issues in our rules and our guidelines.”
The team that conducted the study—led by environmental engineer Drew Gentner at Yale University in New Haven, Connecticut, and chemist John Liggio at the federal agency Environment and Climate Change Canada (ECCC) in Toronto—used an innovative approach to measure all the carbon-based molecules in the air over oil sands in the province of Alberta. The researchers factored out greenhouse gases such as carbon dioxide and instead tracked only molecules important to air quality, many of which haven’t been monitored at the oil sands before. These carbon-based gases can seed particulate pollution in the air and react with other chemicals to form ground-level ozone.
The results, reported in Science on 25 January, show that these pollution-causing gases from the oil sands are 20 to 64 times what has been detailed in industry reports based on standard monitoring techniques.
“I’m concerned by how big this number is,” said Nadine Borduas-Dedekind, an atmospheric chemist at the University of British Columbia in Vancouver who has worked with Liggio but was not involved with this project. “You want to be measuring all this carbon. For air quality, for health, but also for climate,” she said. Some of the carbon molecules, she notes, will eventually be oxidized to CO2 and, therefore, also affect climate change.
Liggio says that the ECCC is already working with partners to determine how the paper’s results can improve reporting methods used at the oil sands.
Mark Cameron, a spokesperson for the Pathways Alliance, a Calgary-based coalition of Canada’s largest oil-sands companies, told Nature: “The oil sands industry measures emissions using standards set by ECCC, and we look forward to working together to explore opportunities to further enhance our measurement practices.”