Utah's gunky air prompts yellow alert

For the first time since February, an air inversion has settled over northern Utah that is severe enough to trigger a yellow alert.

The wintertime inversion prompted state officials to issue a yellow alert for Salt Lake, Davis, Utah and Weber counties. Although this is considered a moderate level of air pollution, residents were asked to voluntarily curtail activities that could add to the pollution.

Among several airsheds monitored by the Utah Department of Environmental Quality in the northern Wasatch Front, only Cache County was reported to have air clean enough for a green classification. During a green day, "Wood and coal burning stoves and fireplaces may be used but please use them in a proper manner to reduce smoke emissions," says a Web site maintained by the Utah Division of Air Quality.

Whenever the index reaches yellow, air quality has deteriorated to the extent that the division asks residents to refrain voluntarily from using wood-burning stoves and fireplaces and reduce vehicle trips.

Wood burning releases a great deal of smoke pollution, while vehicle tailpipes are another big source of particulates and gases.

During yellow alerts, "Industry should optimize operations to minimize air pollution emissions," the site adds.

When red conditions are designated, air quality is so poor that it poses a danger to some residents. Some voluntary restraints become mandatory, with a ban on wood burning.

Before now, Utah had a relatively warm fall, with a lot of wind that swept away airborne gunk. "But the winds are gone, the temperature is cold and the inversion has set up," said Bob Dalley, who manages the state's Air Monitoring Center.

Weather forecasters say the inversion may weaken Friday, when some winds kick up. But they are not certain how strong the winds will be or whether they will thoroughly scrub the atmosphere.

Soon afterward a series of storms is expected, which should sweep out the pollution.

---

E-mail: bau@desnews.com