Wyoming Smog

The wintertime smog problem in the Upper Green River Basin is surprising, but it's real. It's aggravated by UV light reflecting off of snow, very low inversions, and high hydrocarbon levels from drilling operations.

I remember seeing what I thought were high ozone levels in Flagstaff, AZ in the winter of 1985-6 (70 ppb), which I attributed to transport from LA (the winds were from that general direction). But maybe the west is just vulnerable to this problem, whenever you have high UV levels, high hydrocarbon levels (whether anthropogenic, or from vegetation), snowpack, and inversions:

Folks who live near the gas fields in the western part of this outdoorsy state are complaining of watery eyes, shortness of breath and bloody noses because of ozone levels that have exceeded what people in L.A. and other major cities wheeze through on their worst pollution days.

...In many ways, it's a haze of prosperity: Gas drilling is going strong again, and as a result, so is the Cowboy State's economy.

...Preliminary data show ozone levels last Wednesday got as high as 124 parts per billion. That's two-thirds higher than the Environmental Protection Agency's maximum healthy limit of 75 parts per billion and above the worst day in Los Angeles all last year, 114 parts per billion, according to EPA records. Ozone levels in the basin reached 116 on March 1 and 104 on Saturday.

The Wyoming Department of Environmental Quality urged the elderly, children and people with respiratory conditions to avoid strenuous or extended activity outdoors.

...High levels of ozone happen in the Upper Green River Basin only during the winter. They result from a combination of gas industry emissions, snow on the ground, bright sunshine and temperature inversions, in which cool air near the ground is covered by a layer of warmer air. Pollution builds up during the day and becomes visible along the horizon as a thin layer of brown smudge -- smog -- by midafternoon.