Air quality in the Tooele Valley has been better this winter than last winter, and remains drastically better than along the Wasatch Front, according to data from the Utah Department of Environmental Quality.

The state DEQ hasn?t instituted the color-coded air pollution warnings of green, yellow or red days for Tooele County, but based on those standards, the county would have qualified for one red day and no yellow days so far this winter, according to Jeff Coombs, environmental health director for the Tooele County Health Department.

In contrast, Salt Lake and Davis counties have received 20 yellow days and nine red days; Utah County has received seven yellow and six red days; Weber County has received 16 yellow and six red days; and Cache County has received 10 yellow days and five red days.

?It?s been a good year because of the number of storms we?ve had,? Coombs said. ?Whenever a storm comes through, it clears the air out.?

Bucky Whitehouse, public information officer for the Tooele County Health Department, said the county isn?t classified as a non-attainment zone ? an area that does not meet air quality standards set by the Environmental Protection Agency ? and therefore color-coded restrictions put in place for counties along the Wasatch Front are not enforced here. Also, the DEQ air monitoring station in Tooele has only been operating for two years and is still collecting baseline data.

Despite the thick inversion that settled into the Wasatch Front last week, a winter-long pattern of wet, fast-moving storms has made air quality better across the state this winter than it was last winter.

Last winter, Tooele would have qualified for two yellow days and one red day. For Salt Lake and Davis counties, this winter?s air has been substantially more healthy than last winter, when the two counties combined received nine yellow days and 28 red days.

On yellow and red days, people are encouraged to drive less, and if possible, avoid using wood- and coal-burning stoves.

The Salt Lake Valley?s air tends to be of poorer quality than Tooele Valley?s because of its larger population, which in turn means more cars on the roads.

In the winter, the pollutant of concern is PM 2.5, which is particulate matter made up of small pieces of dust and soot. According to the DEQ, part of PM 2.5?s danger comes from being so small it can become entrenched in lung tissue, which can in turn cause respiratory problems.

An inversion occurs when colder air and pollution become trapped beneath warmer air. As pollutants rise, they also become trapped, causing the brown air often seen during the winter months.

Coombs said individuals most susceptible to health issues associated with poor air quality and inversions are young children and the elderly, as well as anyone with a compromised immune system or respiratory problems. This includes people with asthma, and even those suffering from a cold or bronchitis. He said the health department encourages these people to be careful during inversion days and limit outside activity.

Whitehouse said the department also encourages Tooele County residents to carpool and refrain from using wood-burning stoves on inversion days.

Sarah Miley: swest@tooeletranscript.com