Air quality in Utah is often some of the worst in the United States. Poor air quality in Utah is due to the mountainous topography which can cause pollutants to build up near the surface (especially during inversions) combined with the prevalence of emissions from gasoline- and diesel-powered vehicles, especially older models. Burning wood fuel for home heating can also contribute significantly to poor air quality. Homes heated with wood contribute about 3000 times the amount of pollution as homes heated with natural gas. About 50% of air pollution in Salt Lake County is from vehicles.
In 2017 the American Lung Association (ALA) ranked Salt Lake City-Provo-Orem area as the 14th worst city for ozone air quality in the U.S. and 8th for worst short-term particle pollution, just after Los Angeles. Logan was ranked the 11th worst city for short-term particle pollution. Of the 12 counties with ozone data from 2014 to 2016, 7 received an “F” grade by the ALA, and 6 of 9 counties monitored received an “F” for particulate pollution. An MIT study estimated that over 450 deaths annually in Utah are due to poor air quality.
Utah has had mixed responses to poor air quality. For example, from 2015 to 2016 the state offered up to a $1500 credit for clean fuel vehicles However, in 2019 Utah began imposing an additional registration fee on clean fuel vehicles that will increase to $120 annually by 2021.
Due to the mountainous terrain, and cold winters inversions frequently occur in Utah and throughout the Intermountain West. While inversions are a natural phenomenon, when coupled with community emissions from gasoline and diesel vehicles, wood fires, industry, and agriculture they can cause unnatural accumulations of hazardous pollutants (especially PM2.5). A typical winter in Salt Lake City has about 6 multi-day inversions that lead to about 18 days of pollution above National Ambient Air Quality Standards. Pollution for inversions can begin to build-up even when the air is clear.
To improve air quality, especially during inversions, there are restrictions on burning wood fires with fines starting at $150 for first-time offenses in Salt Lake County. Emissions can be reduced by using gasoline and diesel vehicles less by more carpooling and taking public transit, less idling, use of newer vehicles (especially clean fuel vehicles), and combining trips. Less use of gas-powered snow blowers, fireworks, gas-powered lawnmowers, and materials with high volatile organic compound emissions such as certain paints can help keep air clean throughout the year.