Wyoming – Over the last two weeks, state regulators have issued numerous ozone advisories for western Wyoming's Upper Green River Basin. These are the first advisories issued in the area in more than two years. And in fact ozone levels have spiked, well above federal limits. Local natural gas development is responsible for most of the emissions that contribute to ozone formation, including volatile organic compounds, or VOCs, and oxides of nitrogen, also called NOX. I spoke to the Department of Environmental Quality's Air Quality Administrator, Steven Dietrich. We began by talking about why western Wyoming is seeing high levels now, after a two-year break.