Utah's sickening smog dissipates, for now

Regulators called for at least two days of clean air and lifted a ban on wood-burning starting Monday for the urban corridor anchored by Salt Lake City. The relief came courtesy of a storm that brought heavy snow to northern Utah.

Winds finally loosened an icy fog that was trapping tailpipe and other emissions in mountain valleys.

Doctors had declared a health emergency, but Gov. Gary Herbert refused to follow suit with a decree of his own. The doctors called for lower highway speed limits, curbs on industrial activity and free mass transit.

Soot along the greater Salt Lake region topped out at up to 130 micrograms per cubic meter last week. That was more than three times the clean-air limit set by the U.S. Environmental Protection Agency. But on Sunday, the count of extremely fine particulates was down to 10 micrograms per cubic meter in Salt Lake and Davis counties.

Later Sunday, regulators issued an all-clear for the greater Salt Lake region as the winter storm scoured out mountain valleys. Only two counties in eastern Utah — Duchesne and Uintah — remained under an advisory for people sensitive to air pollution.