This is an archived article that was published on sltrib.com in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
Northern Utah's air quality took a foul-smelling nose dive on Saturday as the region's winter inversion returned to trap valley pollution.
The Division of Environmental Quality issued "red" air quality alerts for Weber, Salt Lake and Davis counties, banning coal and wood burning and strongly urging motorists to avoid travel. Red alerts also include strong recommendations for the elderly, young children and those with compromised breathing to remain indoors.
Box Elder, Cache and Utah counties had "yellow" or moderate air quality advisories, urging avoidance of burning and voluntary reduction of driving in favor of mass transit.
Only western Utah's Tooele County was rated as "green," or having healthy air quality on Saturday.