People display their signs during a public hearing to let federal regulators know what they think about a proposal to require more pollution controls at two of the state's oldest coal-fired power plants. Hundreds of people supporting the coal industry who oppose the plan were in attendance. (AP Photo/Rick Bowmer)
Utah's pollution is at its highest levels since 2013 thanks to an inversion that is trapping murky air above Salt Lake and Utah valleys.
Salt Lake City registered a red-air day on Wednesday, with the Utah Division of Air Quality reporting PM 2.5 concentrations as high as 70 micrograms of particles per cubic meter, well above the Environmental Protection Agency's acceptable level of 35 micrograms per cubic meter, The Salt Lake Tribune reported.
DAQ Air-Quality Monitoring Manager Bo Call said the high pollution levels can be blamed on a prolonged temperature inversion that started earlier this week. The inversion moves warm air over Utah's valleys, acting as a lid to keep cold air — and pollution — beneath it.
Call says a prolonged period of low air quality hasn't occurred since January 2013 when a similar inversion moved over the city.
'There's been the odd day that's a high value, but not nearly as much,' Call said.
The current inversion is expected to stick around for a while. Salt Lake, Utah, Davis, Weber, Cache, Box Elder and Tooele counties have instituted mandatory solid-fuel burning bans.
Call said a weak storm system expected this weekend may break the inversion or at least weaken it, but otherwise a storm isn't on the forecast until Feb. 18.
The Utah Climate Center expects the current inversion to continue for about a week.