Northern Utah’s ozone problem isn’t getting any better

EPA likely will drop Utah from “moderate” non-attainment to “serious”

Al Hartmann | The Salt Lake Tribune View of the white hot haze in the valley looking west from the Utah Capitol on July 1, 2015. Despite years of effort, northern Utah's summer ozone problem hasn't gotten any better than it was then.

Northern Utah’s ozone pollution problem is not getting better.

Two years after the U.S. Environmental Protection Agency moved the northern Wasatch Front from “marginal” to “moderate” status for missing the federal limits on ozone pollution, it now appears inevitable that it will move from “moderate” to “serious.”

The consequences of that are still to be seen, but it could include more stringent controls on Utah industries, tighter emissions standards on cars and further limits on gas-powered yard equipment and chemical solvents.

While the state has had some success in reducing wintertime particulate pollution, summer ozone levels have stayed stubbornly high. Ozone — a molecule made of three oxygen atoms — plays a key role in the upper atmosphere, shielding the earth from intense solar radiation. Ozone is less visible than the winter particulate pollution that often blankets the metro area, but it still can produce a haze. And when it is produced at ground level from a combination of pollutants and sunlight, it sears human lungs and is linked to several respiratory illnesses.

That is why EPA has set a limit for ozone at 70 parts per billion, a level the Wasatch Front exceeds multiple times every summer. More than 80% of the ozone comes from natural or foreign sources, so state regulators can only try to address the small fraction that comes from human activity in the state, mainly vehicles and industry.

“We’re having a really difficult time attaining the standard,” said Becky Close, air quality policy section manager at Utah Division of Air Quality. “It’s become extremely challenging to find more reductions.”

Plans on top of plans

The state’s failing to meet the federal standard of 70 ppb for several years has created a cascading set of requirements. The state just this month submitted its final “state implementation plan” (SIP) for addressing its “moderate” non-attainment status for ozone, but it already has started on the plan for “serious” non-attainment.

EPA will make a final determination around 2025, “but we already know based on data that we will be reclassified,” Close said.

The state definitely has more levers it could pull to address ozone, said David Garbett, executive director of O2, a clean-air advocacy group. “We see this a little differently than the division of Air Quality,” adding that he’s “not disputing that we have a tricky problem here.”

“The really hard part for Utah is climate,” said Ashley Miller, executive director for BreatheUtah, another nonprofit that advocates for cleaner air. “It’s just so hot and dry in our summers, and getting increasingly hotter and earlier in the season. It’s not the months of July and August anymore.”

The northern Utah valleys now see levels over 70 ppb from April through September. “It’s just a recipe for ozone disaster,” Miller said.

Blaming foreigners

For years, Utah’s industrial pollution generators have argued that Utah shouldn’t be held to the ozone standard because so much of ozone’s precursors — volatile organic compounds and nitrogen oxides — come from uncontrollable sources like wildfires and foreign countries.

In fact, the EPA has what’s called a 179B exemption from standards if the state can show foreign sources are responsible, but Utah came up short in an earlier attempt at that exemption.

Close said Utah applied for a “retrospective” 179B exemption in 2021, but EPA rejected it because the state couldn’t prove that international emissions were greater on the days Utah exceeded the standard than on the days when it didn’t.

So the state has now applied for a “prospective” 179B exemption based on what foreign ozone it expects to see in the future. Close was not optimistic about its success. “They will likely come back with the same response,” she said. “However, we’re trying to get the point across to EPA that these high-elevation western states are facing a problem that others don’t have.”

She said background levels of ozone average around 50 ppb in western states, while eastern states hover around 20 to 25 ppb.

Miller won’t be surprised if the application is rejected. “It’s tricky. Even in a more conservative EPA, it would be hard.” Still, she thinks a successful 179B could be a good thing because it allows the state to consider solutions that don’t fit EPA’s requirements for a state implementation plan.

Only two companies

In its filing last month to address its moderate non-attainment status, the state is requiring two companies to upgrade their pollution controls. Moderate status means the state must require companies releasing more than 100 tons of pollutants annually to use “reasonably available control technology” to limit emissions.

There are only about a dozen Utah businesses that are above that 100-ton threshold, and of those only Marathon Oil’s Salt Lake City refinery and U.S. Magnesium’s Tooele County operations were required to add new equipment. The rest were found by DAQ to have already exhausted all reasonably available options. The state at one point was also requiring Chevron’s refinery to make improvements, but the company challenged that and the state removed it.

“It’s disappointing that of the very limited menu they had, they only took a couple of appetizers from it,” Miller said.

When the state hits serious non-attainment status, it can then require reasonably available controls on any business that generates over 50 tons instead of 100 tons. That will cover another 53 large businesses in the state, Close said.

Garbett said the state is focused on the big polluters that EPA requires it to regulate, and that’s worthwhile, but it isn’t looking hard enough at the larger but more dispersed sources like vehicles and buildings.

Leah Hogsten | The Salt Lake Tribune Clean air advocates say ozone levels could improve greatly if more people drove vehicles manufactured after 2017. Newer cars and trucks can use Tier 3 gasoline, and produce 80% less pollutants than comparable older cars, such as these on Interstate 15 on Thursday, July 12, 2018.

One example he gave is old cars. State legislators have been loathe to regulate or incentivize the retirement of older cars, which contribute the overwhelming majority of the ozone-causing precursors that come from vehicles. Cars made after 2017, when fueled with widely available Tier 3 gasoline, produce 80% less pollutants than comparable older cars, but they are only about a quarter of the cars on the road.

He also said the state sets its vehicle taxes and fees with no regard to how much the vehicle pollutes. “We don’t do much to connect people with the level of pollution their vehicles generate. There’s nothing in state policy that makes a dirty car more expensive.”