By GRETCHEN WILSO
Opening a window won’t make the air along the Wasatch Front seem less stuffy until high temperature inversion levels release their firm grasp on the area.
Air pollution levels are rising daily and carbon-monoxide levels in the Provo area exceeded the federal health standard on Feb. 9.
According to the federal health standard, only one day per calendar year can exceed the set carbon-monoxide levels. One more day of excessive levels will be a violation and could cause rigid measures to be instituted to control the pollution levels.
Inversion occurs when cold air puddles at the bottom of the valley and is then trapped under warm air. Usually, cold air is at a higher elevation than warmer air. Hence the term “inversion” is used: it is an inversion of a normal situation.
Robert Dalley, manager of the Utah Division of Air Quality’s air-monitoring center, said that during winter monthsthe sun has a hard time warming the ground.
“There are only two ways to get rid of inversion: either a storm front has to come in and blow out the cold air, or the sun has to heat the cold air,” he said.
Dalley said high pressure systems and a valley setting in this area contribute to high levels of inversion.
“Denver has a similar setting to Salt Lake, but has plains to the east,” he said. “Their inversion periods usually last two or three days, while Salt Lake can experience an inversion period of 14-20 days.”
Dalley said carbon monoxide and particulate matter (PM10) are the major factors measured when evaluating air quality.
PM10 is always in the air but is particularly high during inversion periods. PM10 is any form of liquid, solid or waxy materials in the air. PM10 comes from combustion, soot, fly ash, dirt or other chemicals.
During inversion periods, pollution such as carbon monoxide and PM10 becomes trapped in air levels 1,000-3,000 feet thick.
Dalley said if temperatures at ski resorts are warmer than temperatures in the valley, inversion is likely.
The Utah Department of Environmental Quality recommends driving less and car pooling more during peak inversion periods because car emissions contribute to increased levels of PM10 and carbon monoxide.
Air quality updates are available by calling 1-800-228-5434.