If you’ve been following the discussion of pollution risks around the unconventional oil and gas development that has been enabled by hydraulic fracturing and other technologies, then you’ve probably heard a lot about water contamination risks. These risks are certainly worth discussing, but discussion of air pollution risks also deserves some attention. We want to take the time to talk about air quality concerns—not just because this is where Gretchen’s past interests lie—but also because current research suggests there may be real risks from air pollution near oil and gas activities.
One of a series of posts discussing critical questions highlighted in the Fracking Informational Toolkit, a resource for active citizens in communities facing decisions on fracking.
The UCS Center for Science and Democracy’s Branscomb Forum, Science, Democracy, and Community Decisions on Fracking, brought together experts to participate in discussions of these risks. One thing that struck us was just how multi-faceted the answer to a simple question was:
How does unconventional oil and gas development affect air quality?
The answer required participants to consider multiple pollutants—ozone, particulate matter, and hazardous air pollutants—being emitted from multiple places—well sites, compressor stations, roadways, and pipelines. Developing a simple answer quickly became challenging. One thing was clear: the question was most meaningful when all of the stages of oil and gas development, not simply the well completion step of hydraulic fracturing, were considered. Here’s what the research tells us and what we still need to know.
Risks to water quality may receive more attention but unconventional oil and gas development also raises concerns about air quality. Air pollution can be emitted at the well site and from truck traffic to and from the site. These risks vary widely by location. Credit: NIEHS/NIH
At the well site: measuring and modeling exposures
We know that exposure to elevated levels of the air pollutants mentioned above, from any activity, can lead to adverse health outcomes, including respiratory symptoms, cardiovascular disease, and cancer. And one recent study found that residents living less than half a mile from unconventional gas well sites were at greater risk of health effects from air pollution from natural gas development than those living farther from the well sites. Although the study relied on older data and used questionable exposure calculations, it does still imply that further study is needed on this subject to understand the level at which workers and nearby residents may be exposed to harmful air pollutants.
Air pollution from oil and gas development may be of greatest concern during the well completion phase, when most of the water and chemicals flow back from a well to the surface, and there is significant venting and flaring of gases. But because the venting and flaring occur at specific stages of the process and are not continuously emitting, their impact will vary depending on such factors as the number of oil and gas operations concentrated in a particular area and the existing air quality in a region. In addition, different regions of the country have different requirements for air pollution controls on oil and gas facilities, further adding to the variability of this concern. Southern California, for example, has much tighter air quality requirements for oil and gas operations than other areas.
Any onsite processing to separate gases from oil or other substances may also contribute air pollutants, especially ozone precursors. Residents of the town of Dish, Texas, for example, believe the health effects they have experienced—including nosebleeds, pain, and cancer—are the result of natural gas compressor stations that were installed in the town starting in 2005. To date, the residents have not been successful in proving the link. Some studies have found elevated concentrations of a number of carcinogenic and otherwise hazardous compounds in and around residential areas in Dish, but scientists have yet to find an association between the residents’ health concerns and the local gas facilities.
On the roads: the effect of truck traffic
While air pollution emitted from well sites may be of more interest, the bigger air quality change some communities experience may be from traffic. This is especially true in more rural areas, where the increase in truck traffic will be more significant. All kinds of truck traffic, including that for transporting water and materials to and from the well site, produce diesel emissions. Diesel emissions include particulate matter, which has been linked to decreased lung function, asthma, and respiratory symptoms such as coughing and difficulty breathing.
Air pollution from traffic may be worsened in North Dakota by the use of unpaved roads that incorporate gravel containing a fibrous mineral called erionite, which has properties similar to asbestos. Trucks driving over such gravel roads can release harmful dust plumes into the air, which could present health risks for workers and area residents
For some communities, the most significant air quality change from oil and gas operations may be from truck traffic carrying materials and waste to and from the well site. Credit: US Geological Survey
What about climate change?
While the potential health effects related to toxic air contaminants discussed above may be the immediate concern for most communities, the burning of any carbon-based fuel including natural gas contributes to global warming pollution. From a climate standpoint, use of natural gas is less attractive than lower- and zero-carbon alternatives, such as energy efficiency and renewable energy. On the other hand, the availability of relatively inexpensive and abundant supplies of natural gas has contributed to a reduction in coal generation and power sector carbon emissions in the United States.
However, several studies are underway that evaluate the leakage of methane during the life cycle of natural gas production, transport, and use. Methane is a potent heat-trapping gas, and the leakage studies suggest that the benefits of switching from coal to natural gas may be less than initially predicted. Last week UCS released a report on the climate risks of an increased reliance on natural gas for electricity. The report shows that transitioning from a coal- to a natural-gas- dominated electricity system would not be sufficient to meet U.S. climate goals.
Why don’t we know more? Restrictions on research and lacking laws
Research on air pollution from unconventional oil and gas development has been limited by a lack of information on and access to well sites and other facilities. Without access to such locations to carry out measurements and obtain information on the timing of different stages of extraction, it can be difficult to determine the source and extent of emissions and how and when people may be exposed to health risks.
The federal Clean Air Act regulates the release of pollutants into the air from stationary and mobile sources and authorizes the EPA to set national ambient air quality standards, but the law included an exemption for certain groups of oil and gas wells. Pollution from such wells cannot be aggregated for the purpose of determining regulatory standards.
At the state level, few states require air quality monitoring near wells. Though some states do regulate venting or flaring at well sites, most do not have any comprehensive monitoring program. Such monitoring is needed for two important reasons: First, to detect any changes in air quality from oil and gas activities and potential for health risks for workers and nearby residents; and second, so that we know when and how to regulate air pollution from such activities to protect people.
Clearing the air: what can be done
Under new federal regulations, green completion technologies will have to be installed on most new gas wells by January 2015. The technologies capture air emissions from flowback water and fractured wells, capture a large percentage of volatile organic compounds (VOCs) and methane. Additional air emission restrictions will apply to certain wellhead compressors, storage vessels, pneumatic controllers, and other equipment.
Still, there have been remarkably few studies assessing health risks from air pollution near wells that employ hydraulic fracturing. To fully know the risks and to fully address them, researchers need access to well sites, stronger monitoring programs need to be in place, and companies need to provide information to researchers and regulators. We’ve got a ways to go before we can clear the air on air pollution from unconventional oil and gas development, but hopefully, these new regulations are a good start.