For the first time in several years, Tooele County’s air quality rating has seen slight improvement, according to a report from the American Lung Association.
Tooele County received a “B” grade for fine-particle pollution, after several years of straight “Cs” in the same category. The county’s grade for ozone pollution remained constant at a “C” rating.
Fine-particulate pollution, officially known as PM 2.5, is a category comprised of tiny solids that tend to accumulate in Utah’s valleys during the winter. Ozone, a chemical that forms when sunlight reacts in the atmosphere with vehicle emissions, is associated with the summertime haze that occasionally blankets the Wasatch Front.
The air quality grades issued by the American Lung Association are based on the number of days that the concentration of pollution in a given area exceeded levels considered by the Environmental Protection Agency to be unhealthy for sensitive populations.
These levels are sorted into color-coded categories and reported to the public as orange, red, and purple air quality days.
According to the 2014 State of the Air report, Tooele County experienced an average of 1.9 fewer days of unhealthy particulate levels in 2012 than in 2000. Ozone, likewise, has seen a downward trend in the valley, with five fewer unhealthy days in 2012 than in 2005.
However, because the valley continues to experience an average of 1.3 days where ozone exceeds healthy levels, the county’s grade for ozone did not change.
Tooele County compares favorably to other counties in the state, and was the only county in the Wasatch region to receive a B grade for particulate pollution. Box Elder and Davis counties received D grades for particulates, and Salt Lake, Utah and Weber counties received F grades.
For ozone, Tooele County’s C grade was on par with Box Elder, Davis and Utah counties. Weber received a D and Salt Lake County received an F.
According to the report, the Salt Lake-Provo-Orem metropolitan area, which in the report includes Box Elder and Tooele counties, ranked within the top 10 most polluted areas for short-term particulate episodes. Fresno, California, came in as No. 1. New York City, for comparison, came in at No. 16.
Even though the Salt Lake area reported worse particulate pollution than New York City, the American Lung Association praised the metropolitan area for reporting its fewest unhealthy air days in the history of the 15-year-old report card.
However, the most recent data included in the 2014 State of the Air report came from 2012 and did not include measurements from the 2012-13 winter, which according to the Utah Division of Air Quality was one of the worst winters on record for air quality.