Unconventional Natural Gas Development And Self-Reported Health Symptoms: A Two-Year Survey In Washington County, Pennsylvania

Abstract Introduction: Natural gas is a cleaner and more efficient energy type compared to coal and oil and could be vital to tackle the global energy crisis. The technical advance of unconventional natural gas development (UNGD) has permitted us to extract natural gas from shale formations, which were previously inaccessible for natural gas drilling. However, the new technology has concerns about its environmental safety and impacts on human health. So far, no definitive conclusion about this issues is reached. Methods: In this cohort study in Washington County, Pennsylvania, we used an innovative exposure assessment model, integrating local wind flow directions and gas well production days, to assess residential exposure to gas well released air pollutants. We recorded the residents’ respiratory and dermal symptoms in 2012 and 2014 and then used multi-level logistic regressions to estimate the risk of exposure to the pollutants and health outcomes. Results: We found significantly elevated risk of having dermal symptoms in 2012 among people who were exposed to high level of pollutants at that time compared to those who were exposed to low level of pollutants in 2012 [odds ratio (OR) = 4.27; 95% confidence interval (CI): 1.06, 17.14]. There is no significant association detected of increase of exposure level over the year and new health symptom occurrence in 2014. Conclusions: Estimated exposure to high level of air pollutants released by unconventional gas wells could lead to significantly elevated risk of having dermal symptoms. However, we do not find that experiencing a rapid increase of exposures over the years could substantially increase the risk of having any dermal or respiratory symptoms. Future studies on this very topic are necessary to further investigate the association