The Utah Division of Air Quality put Salt Lake, Davis, Utah, Weber, Box Elder, Cache and Tooele counties under "mandatory air quality action" restrictions.
Those regions earned "unhealthy for everyone" grades. In addition to bans on wood-burning stove or other "solid fuel" use and open burning, DAQ urged motorists to avoid driving when possible, and to use mass transit or car-pooling if they must go out.
Pollution-plagued northern Utah was due a little breather on Thursday as a weak storm system, bearing gusty winds, was expected to reach the region.
Emphasis on "little," though. The air inversions trapping urban valleys in the sooty hydrocarbon soup were to re-establish themselves in time for a gray weekend.
"We've really been wrestling through today with what impact this little wriggle in the atmosphere we're expecting [late Wednesday and through Thursday] will have on the inversions," DAQ environmental scientist Kent Bott said Tuesday. "But it does look like it will be just enough to at least thin out the smog."
The EPA's predictions come from the AirNow website (http://www.airnow.gov) and are based on 24-hour forecasts provided daily by air monitoring agencies across the nation not actual, real-time results.
Rated "unhealthy for sensitive groups" the elderly, young children and those with heart or lung ailments were Duchesne and Uintah counties.
While Wednesday's forecast called for smoggy skies and high temperatures in the upper-30s along the Wasatch Front, the National Weather Service predicted Thursday would see modest clearing as winds of 15-25 mph, and gusts topping 40 mph, kicked up. Highs again were to be in the upper-30s with overnight lows in the low-20s.
Southern Utahns were to bask in the upper-50s under partly cloudy skies on Thursday, mirroring Wednesday's forecast. Lows were to be in the upper-20s.
The Utah Avalanche Center put the mountains of Logan and the Uintas under "considerable" risk for potentially deadly snowslides, while the rest of the state's slopes with the exception of Moab, which was "low" were graded at "moderate" risk.
For more extensive forecast information, visit the Tribune's weather page at http://www.sltrib.com/weather.