Air pollution in Utah conjures images of wildfire smoke blocking views of the Wasatch Front and thick, soupy air settling into the Salt Lake Valley during winter inversions.
That’s been true this month, as wildfire smoke settles into the valley. Air quality was moderate in Salt Lake County as of Thursday morning, and forecasts showed conditions worsening, with three days in a row expected to reach unhealthy levels for sensitive groups, such as people with asthma and the elderly.
But last year, eastern Utah had worse air quality overall than the Salt Lake Valley, something one state official credited to a combination of strong inversions and snowy weather.
Uintah and Duchesne counties had some of the worst air quality last year, based on a Healthnews ranking of hundreds of counties based on the number of days where the air was at least “unhealthy for sensitive groups.”
The two counties ranked in the worst 10 for air quality, and Salt Lake County was the only other county in the Beehive State in the top 100.
Air quality in Utah has worsened even though emissions across the state are down, said Bryce Bird, who directs the Utah Department of Environmental Quality’s air quality division.
That’s true across the West, especially as wildfires increase and more people move to Western states, leading to more cars on the road, said Nick Torres, director of advocacy for the American Lung Association in Colorado, Utah and Wyoming.
Utah is working on long-term planning to address poor air quality, Bird said, but the “vast majority” of emissions now come from individual Utahns.
He recommended people learn ways they can lower their own emissions – including driving less and not using two-stroke lawn and garden equipment during high-pollution times – and take precautions to protect their health.
Two air pollution seasons
(Francisco Kjolseth | The Salt Lake Tribune) The Kennecott Garfield Smelter Stack is pictured during inversion conditions on the south side of the Great Salt Lake on Friday, December 29, 2023.
Utah has two air pollution seasons, Bird said – summer and winter.
In winter, the Wasatch Front and Uintah Basin experience inversions, where cold air at the surface gets trapped under a layer of warmer air and makes pollutants build up to unhealthy levels.
That means emissions from vehicles and consumer products build up in the Salt Lake Valley, and oil and gas industry emissions build up in the Uintah Basin, especially when there is snow on the ground.
Inversions in the Wasatch Front typically lead to particulate matter that exceeds federal standards, Bird said, but that typically doesn’t happen in the Uintah Basin unless it’s a snowy winter.
Summer presents different challenges, as wildfire smoke filters into the state’s valleys and basins, and hot, dry conditions make ground-level ozone a problem.
Unlike the ozone layer in the upper atmosphere, ground-level ozone is created by chemical reactions when pollutants emitted by cars, power plants, refineries and other sources react in sunlight.
It also inflames and damages airways and has other negative health effects, including an increase in hospitalizations for asthma and a higher chance of fatal heart attacks.
Bird compared ozone in our lungs to hydrogen peroxide bubbling on surfaces.
Ozone also forms in the Uintah Basin when there is a strong inversion and snow on the ground, he said.
Some of the worst air quality nationally
Healthnews looked at data from the U.S. Environmental Protection Agency and applied a scoring system to poor air quality days to rank counties:
One point for days categorized as unhealthy for sensitive groups.
Two points for days categorized as unhealthy.
Three points for days categorized as very unhealthy.
Four points for for days categorized as hazardous.
That resulted in three Utah counties making the top 100 of 950 across the country:
Uintah County ranked fourth worst with a score of 61. The county experienced 16 days that were unhealthy for sensitive groups, 18 unhealthy days and three very unhealthy days.
Duchesne County ranked sixth worst with a score of 47. The county experienced 22 days that were unhealthy for sensitive groups, 11 unhealthy days and one very unhealthy day.
Salt Lake County tied with several other counties for 59th with a score of 17. The county experienced 15 days that were unhealthy for sensitive groups and one unhealthy day.
None of those three counties had any days that reached an air quality level that was hazardous.
About a dozen other counties in Utah with air monitoring scored between 0 and 14 using the Healthnews calculations.
Uintah and Duchesne counties both had a spike in unhealthy air quality days compared to previous years, something Bird credited to a snowier winter.
Oil and gas extraction are the main source of pollution in both counties, and though emissions are down there was “a very strong inversion” in January and February in the Uintah Basin, Bird said.
Healthnews also points to natural dust events and wildfire smoke as reasons for elevated air pollution in 2023 in Uintah and Duchesne counties.
Emissions down, state is working on other solutions
(Trent Nelson | The Salt Lake Tribune) Oil and gas extraction, including oil fields of the Uintah Basin southeast of Vernal pictured here in 2012, is the largest source of air pollution in Uintah and Duchesne counties. Those counties saw a spike in poor air quality in 2023.
Utah state officials have been working to reduce emissions for years, Bird said, and they are down 60% or so from where they were 15 years ago.
In Uintah County specifically, natural gas from local wells helps power public transportation, Healthnews pointed out.
The oil and gas industry also has been working to install collection and control systems, Bird said, including flares that release carbon dioxide into the air instead of methane, a gas that is the primary contributor to the formation of ground-level ozone.
But other things work against those efforts, leading to higher concentrations of ozone despite reduced emissions, Bird said.
More wildfires means more wildfire smoke – a precursor for ground-level ozone production, he said.
There also is a trend of warmer, drier, sunnier summers, he said, leading to a higher possibility of elevated ground-ozone levels.
Summer monsoons help by bringing clouds to block the sun and rain to clear the air, he said. But forecasts from the National Oceanic and Atmospheric Administration call for less rain than usual and an underperforming monsoon season.
The state already has one plan to reduce ozone levels, Bird said, and it is planning for work on another because regions still are not meeting Clean Air Act standards.
How people can help, protect themselves
(Rick Egan | The Salt Lake Tribune) Traffic on 5600 West, on Tuesday, December 26, 2023.
Utahns can provide input on that plan and help identify other potential emissions reductions, Bird said.
They also can be aware of their own contribution, he said.
Bird pointed to the Salt Lake area, where petroleum refineries that used to be the largest source of emissions are now 3% of the total.
“The vast majority of the emissions are coming from us as individuals,” he said, including driving 55 million vehicle miles a day in Salt Lake County.
Cars manufactured after 2017 have fewer emissions, he said, and hybrid and electric vehicles also can help reduce mobile emissions.
Zero-emission vehicles are not an instant fix, Torres said, but they will help – there just needs to be a faster transition.
Some states are taking steps to speed up the transition, he said, and the American Lung Association hopes Utah also goes in that direction.
In addition to mobile emissions, Bird said, there are area emissions from such consumer products as hairspray or insecticides. Each individual item doesn’t do much, he said, but with 2 million people in the valley using products, it adds up.
Small, two-stroke lawn and garden equipment such as leaf blowers also are an issue, he said. Running a gas-powered leaf blower for one hour is the same as driving to Disneyland, Bird said.
The state has an incentive program to help people change leaf blowers, edgers and similar tools out to electric models, Bird said. People who still have gas-powered ones, he said, can avoid using them during high-pollution times.
It’s easy to check air pollution levels, he added, by using the Utah air app on iPhone or Android, or going to air.utah.gov.
The state also maintains a three-day forecast for counties with air monitoring, so people can take action to reduce their individual emissions and take precautions as needed, Bird said. The federal government has similar resources at airnow.gov.
Taking precautions can mean staying indoors, switching their air conditioning to circulate instead of pull air from outside and talking to health care providers to make sure they can access medication, inhalers and other needs, Torres said.
People should not assume they don’t need to worry as much about air quality just because they don’t have asthma or other respiratory issues, he said.
“Every family has someone who’s at heightened risk,” Torres said, adding that ozone and poor air quality can affect even people who don’t have heightened risk.
Megan Banta is The Salt Lake Tribune’s data enterprise reporter, a philanthropically supported position. The Tribune retains control over all editorial decisions.