An examination of peer-reviewed studies published over 6 years on hazardous air pollutants associated with the extraction of oil and natural gas finds that measurements of hazardous air pollutant concentrations near operational sites have generally failed to capture levels above standard health benchmarks; yet, the majority of studies continue to find poor health outcomes increasing as distance from these operations decreases.
While it is unclear why there is a gap in the evidence between environmental sampling and health-based studies, the current review provides insights into methodological shortcomings that may help explain this discrepancy. The authors state that current health benchmarks may not provide accurate risk estimates from the broad range of pollutants associated with oil and natural gas development and fail to adequately address potential risks associated with long-term, chronic, lower levels of exposure or from a mixture of chemicals. Further, a failure of sampling methods to properly account for degradation and dispersion of pollutants, or inappropriate sampling timeframes that may not capture peak emission periods that are characteristic of oil and natural gas extraction, may also contribute to the current gap in the literature.
The authors call for additional investigations of emissions using measurements and research that incorporate appropriate timeframes and proximity to oil and gas extraction on health effects from chronic, low-level ambient hazardous air pollutant exposures, among others.
The researchers reviewed 37 peer-reviewed journal articles published between 1 January 2012 and 28 February 2018.