Wyoming air quality today

Ozone here is a cold-weather pollutant. In the Upper Green River Basin, natural gas production releases precursor emissions into a basin that holds multi-day inversions through the winter; snow cover reflects sunlight back up into that shallow trapped layer, and the reaction runs. EPA designated all of Sublette County and parts of Lincoln and Sweetwater counties nonattainment for the 2008 ozone standard in July 2012, found the area attaining in 2016, and the Department of Environmental Quality has worked toward redesignation since. Snow is a required ingredient rather than an incidental one: the division lists it alongside inversion, light winds, sunlight and precursor chemicals as a condition the basin needs before any of this happens.

The Air Quality Division forecasts for this rather than only measuring it. Its meteorologists run the winter season from January through March, issuing an Ozone Outlook about forty-eight hours ahead when conditions look conducive over several days and an Ozone Action Day notice one day out. That is a seasonal product aimed at a few thousand square miles of basin, not a statewide daily index.

The rest of the state’s air is mostly a wind story. For the Powder River Basin coal mines in Campbell and Converse counties the division runs a high-wind PM10 plan, approved by EPA in 2007, that works from National Weather Service forecasts of the wind that lifts the dust — coarse particulate and a wind advisory arriving in the same notice. Little of that shows up here. Wyoming’s metros are few and small, so most of the state has no page, and the places where its air gets complicated are not metros at all.