OTTAWA—A new study in the journal Nature finds that Alberta’s oilsands are one of the largest sources of organic aerosol air pollution in North America.
Data from airborne measurements over the bitumen-producing region in August 2013 found that oilsands production generates at least 45 to 84 tonnes per day of the tiny particulate matter—comparable to mega-cities such as Paris and Mexico City.
The study, whose lead authors are Environment Canada scientists, says secondary organic aerosol production should be taken into consideration when assessing the environmental impact of current and planned oilsands development.
And it suggests heavy-oil extraction projects around the globe are likely large sources of this type of air pollution.
“The oilsands on its own as a global source is probably not very significant,” research scientist John Liggio of Environment Canada said in an interview Wednesday.
“But you have to keep in mind that extraction of viscous, heavy oil is happening all over the world. That’s the globalness of it. This type of process is expected to occur in multiple places, wherever you extract bitumen, heavy oil, and so on.”
Secondary organic aerosols are produced when volatile organic compounds interact with sunlight and other airborne chemicals to create tiny particles, which have been found to cause lung and heart problems and other health effects.
The Nature study found that low-volatility organic vapours from mined oilsands material is “directly responsible” for the majority of the observed secondary organic aerosols downwind from oilsands mining projects.
Multiple flights over the course of a month aboard a National Research Council aircraft and using mass spectrometers found differing plumes up to 100 kilometres downwind of oilsands projects.
And while other pollutants such as black carbon and sulphate aerosols dissipated as the plumes spread in width from 39 kilometres to 79 kilometres, the secondary organic aerosols, or SOAs, remained relatively steady, “indicating a significant SOA formation rate within these plumes, overriding the effect of dilution,” says the Nature article.
Shao-Meng Li, who co-authored the study with Liggio, said the study of SOAs has been done mostly in cities. This is the first time that the contribution from a specific industrial sector has been able to be measured, in significant part due to northern Alberta’s lack of other heavy industry or emission sources.
“Because of the uniqueness in that area (of Alberta), because of the non-source, if you will, we are able to thoroughly study and specifically say this is from that industrial source sector,” Li said in an interview. “In a big urban area, it’s a lot more difficult to isolate different sources.”
Air pollution rather than climate impact was the focus of the study, said the government research scientist, although particulate matter in the atmosphere is known to absorb solar radiation.
The researchers said they haven’t pinpointed the exact emission sources within oilsands projects, whether it be tailings ponds, the mines themselves or processing. They also don’t know what effect in situ oilsands extraction—which uses steam to melt bitumen deep underground and then pumps it to the surface—has on the formation of secondary organic aerosols.
And they’d like to test those oilsands plumes at a different time of year to see how seasonal changes impact the formation of SOAs.
“We’re hoping in the next couple of years we’ll have another study, in another season, looking at different sources, including in situ, and different parts of the facilities as well,” said Liggio.