I would like to respond to the letter to the editor by the Energy Council (Herald, May 18) regarding the April 24 Herald story, “La Plata County receives an ‘F’ for ozone levels.”
The Energy Council stated that methane is not an ozone precursor; therefore oil and gas activity is not the significant source of ozone precursors in Durango. They are correct that methane only reacts to form ozone on longer time scales and thus is not a precursor at the regional scale. However, methane from oil and gas activities is co-emitted with more reactive non-methane hydrocarbon ozone precursor volatile organic compounds (VOC).
In other words, methane is not the only concern: oil and gas activities emit numerous VOC that are ozone precursors. In the northern Front Range of Colorado, an area with diverse VOC and NOx sources including vehicles, oil and gas activities, power plants, and biogenic sources, oil and gas has been proven by multiple studies to be the primary source of VOC reactivity in the region.
While the original article published on April 24 focused on methane rather than VOC emissions, VOC emissions from the oil and gas industry are significant and potentially contribute to the high ozone levels in Durango. Although oil and gas activities may not be the only source of ozone precursors in Durango, it is important to understand that the industry does emit significant ozone precursor VOC in addition to methane.
Lucy Cheadle, M.S. Environmental Engineering/B.S. Chemical Engineering
Boulder
