Until now, the vast majority of our oil supply has come from easy-to-exploit deposits, although these are being depleted even as our need for oil continues to grow. This growing demand helps keep the price of oil up, which has spurred technology advances that now make possible exploiting oil reserves such as the Canadian oil sands. Extracting useable oil from the mix of sand, clay, water, and bitumen is an energy-intensive process, and many are worried about its environmental impact. A new study from researchers in Canada, the Netherlands, and the US has assessed air quality over the region using satellite remote sensing to give us a better idea of exactly what that impact looks like.

In 2010, we reported on a paper in PNAS that directly contradicted official claims that neither humans nor the environment were at risk from the oil extraction. That study determined levels of pollutants by analyzing snow samples from around 30 sites, finding significant levels of heavy metal contamination. This new study, by contrast, has used satellites to obtain high resolution measures of NO 2 and SO 2 over North America between 2005-2010.

The data shows an increase in NO 2 levels in the air over the Syncrude Canada's Mildred Lake and Suncor Energy's Millenium surface mining operations. The authors state that the output of SO 2 over the oil sands appears to be at least as great as any other source in Canada, and comparable to sulfur emissions from a large powerplant (around 100 kt/year) but the data is noisy and not statistically significant. The NO 2 emissions from the oil sands are also comparable to those emitted by a large powerplant, but unlike SO 2 levels, they're dwarfed by those coming from Edmonton to the south.

Comparing data from 2005-2007 with data from 2008-2010, the authors find NO 2 levels increasing at a rate of just over 10 percent a year, roughly in line with the rate of increased oil production from the oil sands (around seven percent annually).

Geophysical Research Letters, 2012. DOI: 10.1029/2011GL050273 (About DOIs).