This is an archived article that was published on sltrib.com in 2010, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
Salt Lake Valley began Saturday with a dirty, smelly, gray shroud of aerial gunk air deemed bad enough for a "red" air quality alert. More of the same is expected Sunday.
Blame it on northern Utah's dreaded winter air inversion and the automobile and industrial emissions it is trapping over the region's valleys. Until possibly early Monday, when the National Weather Service predicts a low pressure front from the Pacific via California and Nevada may bring rain and snow, Utahns will just have to scowl and live with it.
In addition to Salt Lake County, the Utah Division of Environmental Quality issued red or "unhealthy" air warnings Saturday through Sunday for Davis, Weber, and Cache counties.
DEQ officials cautioned people with heart or lung disease, older adults and children to shun prolonged or heavy outdoors exertion. In fact, those with breathing ailments should stay indoors, and motorists were urged to avoid adding to the pollution woes by putting off unnecessary travel altogether.
Only Utah County, which had a "green" or moderate rating for Saturday and Sunday, seemed to be escaping the worst of the health-comprising effects of the inversion.
Salt Lake Valley, in particular, is geologically made for winter air inversions. Indeed, in colder weather the usual conditions of cool air at higher elevations and warmer air below is reversed, or "inverted," DEQ air quality experts explain.
Northern Utah's winter inversions thus trap thick layers of cold air under the warmer air, confining pollution near the valley floors. The longer the inversions last, undisturbed by incoming storms or winds, the worse the pollution levels and their subsequent health impact will become.