In the first three posts (parts one, two and three) in our series on the risks of hydraulic fracturing, we have focused on the potential issues that hydraulic fracturing poses to water. We now turn our attention to the risks hydraulic fracturing can pose to air quality.

Similar to many other industrial processes, hydraulic fracturing releases pollutants into the air. One of the largest sources of emissions from hydraulic fracturing is the use of diesel generators. The extraction process can also bring a variety of chemicals to the surface, which if not trapped and safely handled could be released into the atmosphere.

In a recent study conducted at the behest of the B.C. Ministry of Health, Intrinsik Environmental Sciences conducted a human health risk assessment of the potential impacts of oil and gas activities in northeastern British Columbia. In assessing the human health impacts from emissions, the study primarily focused on Chemicals of Potential Concern (COPC), which include NO2, SO2 PM2.5, formaldehyde, etc. Intrinsik’s review concluded that:

“[o]n a short-term basis, the predicted air concentrations of the COPC generally were less than their health based exposure limits. The potential combined effects of these COPC were also not predicted to result in adverse health effects in people living or visiting the study area… Long-term inhalation exposures to the COPC were generally predicted to be associated with a low potential for adverse health effects… In the assessment of potential exposures to the COPC that people in the area might receive over the long term through the consumption of local foods, drinking water, contact with soils and water, it was determined that the potential for adverse human health effects is low.” (p. 8)

These results are similar to those from the Quebec government’s assessment of danger posed by air emissions related to hydraulic fracturing, concluding that the risk of widespread pollution is small and can be mitigated through the use of existing technologies.

Hydraulic fracturing and the natural gas it produces also lead to reductions in greenhouse gas emissions through its displacement of coal. The Joint Institute for Strategic Energy Analysis estimated that “low-priced natural gas has led to more than 300 terawatt-hours of fuel switching from coal to gas in the U.S. power sector between 2008 and 2012.”

This can have considerable benefits since high efficiency natural gas plants can reduce CO2 emissions by 63 per cent when replacing a typical 33 per cent efficient (in terms of the energy available in coal that is converted to electricity) U.S., United Kingdom or European coal plant for the same electric power.

One point of contention regarding hydraulic fracturing and emissions has been concerns over leaked methane emissions. This is concerning, in part, because methane has a higher global warming potential than does CO2.

These concerns though appear to be overblown. One recent estimate calculated that 12 per cent of produced natural gas would have to leak in order to cancel out the benefits of replacing a coal power plant with natural gas.

Best estimates of fugitive methane emissions are that leakages across the whole supply chain are below three per cent.

When it comes to the risks that hydraulic fracturing poses to air, the conclusions are similar to those for the risks to water. While there are indeed risks, they appear to be modest and manageable with current technologies.