That's the question I raised a month ago when writing about the need for health impact studies. Anecdotal evidence in one Barnett Shale community found an increase in the rate of heart attacks and exposure to drilling emissions.
People living near wells are exposed to a whole host of potential pollutants, many airborne. For example, they breathe in volatile organic chemicals much higher than what's considered "potentially harmful" to public health. And drilling sites aren't the only problem: airborne toxins from compressor stations are finding their way into people's lungs and bloodstream. They also breathe in more particulates.
But one of the real killers hiding in the emissions may be ozone - not an emission itself, but something created when nitrogen oxides combine with volatile organic compounds in the sunlight. It's such a concern that NY's Department of Environmental Conservation (and PA's Department of Environmental Protection) issues "ozone alerts" on very hot days, warning people to stay inside.
Now new research shows that high levels of ozone can increase the risk for heart attacks and stroke. EPA toxicologist Robert Devlin exposed healthy young volunteers to high levels of ozone - levels that reflect the same cumulative dose they would receive had they been working outside for eight hours in a place like Los Angeles. Or the Upper Green River Basin of Wyoming, where ozone levels can get as high as 124 parts per billion (ppb) - that's way over the US federal limit of 75 ppm and higher than Los Angeles on its smoggiest day.
The problem boils down to inflammation. Ozone exposure triggers high blood levels of inflammatory agents that stick around in the blood for a long time. In turn, the body could perceive the inflammation as a wound and turn on a clotting response, potentially blocking blood flow. Ozone also changed the levels of some proteins involved in blood clotting and affected the heart rate.