Study: Oil, gas big sources of ozone ingredients
Oil and gas operations in the Uinta Basin are the prime source there of volatile organic compounds and nitrogen oxide, two factors in ozone pollution, according to an inventory developed for a new study of the problem of winter ozone in the basin.
The study also suggests that reductions in certain kinds of volatile organic compounds, including benzene and toluene, “could be particularly effective since they are not only a direct health concern but are more active in ozone production than many other” VOCs.
The Utah Department of Environmental Quality has released a final report on a multi-agency 2011-12 ozone study for the basin, centered in northeastern Utah. Recently identified winter ozone problems there have extended to Rangely and western Rio Blanco County, which is on the basin’s eastern edge.
Ironically, ozone levels during the study season of winter 2011-12 were well below acceptable Environmental Protection Agency standards, unlike the prior two winters. The basin had little snow cover and no persistent temperature inversions that trap colder air in valleys, both of which are linked to high ozone levels. The study notes that snow cover reflects sunlight, limiting daytime heating and further adding to inversions, and it estimates that the reflected sunlight nearly doubles ozone-creating chemical reactions involving VOCs and nitrogen oxide.
It said historical weather data suggests a severe ozone season in the basin will occur about once every four winters, with conditions conducive to ozone formation occurring on at least some days during about half of winters.
The study said the oil and gas industry is responsible for 98 to 99 percent of VOCs and 57 to 61 of nitrogen oxide, for sources within the basin considered in an emissions inventory. The Bonanza Power Plant near Vernal emitted an estimated 33 to 36 percent of nitrogen oxide originating within the basin during the study.
While not specifically seeking to quantify the possible role of pollutants coming in from outside the basin, the study said they aren’t likely a major contributor, for reasons such as higher concentrations of VOCs and nitrogen oxide inside the basin than outside.
Further study is occurring this winter, when weather conditions conducive to ozone formation have occurred.
The Department of Environmental Quality organized the study, with involvement from entities such as the Bureau of Land Management, Environmental Protection Agency and several universities. The Western Energy Alliance contributed more than $2 million, collected from several member energy companies.