Whilst public perception on the environmental risks of unconventional shale gas extraction has focused upon the negative impacts on water quality, less attention is paid to the risks of air pollution.
Rural Wyoming, is known for its idyllic countryside. Yet, with the arrival of unconventional shale gas extraction, came a reduction in local air quality that to a state that exceeds that of the U.S. national average, and sometimes, the city of Los Angeles on its worst days.
U.S. National Ambient Air Quality Standards (NAAQS), introduced as a result of the Clean Air Act, dictate legal limits of pollutants deemed harmful to public health. Limits for ground level ozone are set at 75 parts per billion (ppb).
However in 2011, preliminary tests undertaken in Wyoming found levels of ozone reaching 124 ppb, two thirds above the NAAQS legal limit.