Northern Utah’s ozone pollution problem isn’t getting any better.
Two years after the U.S. Environmental Protection Agency downgraded the northern Wasatch Front from “marginal” to “moderate” due to failure to meet federal ozone pollution limits, it now seems inevitable that it will be downgraded from “moderate” to “severe.”
The consequences remain to be seen, but could include stricter controls on Utah’s industry, stricter emissions standards for cars and further restrictions on gas-powered garden tools and chemical solvents.
While the state has had some success in reducing particulate matter pollution in the winter, ozone levels remained stubbornly high in the summer. Ozone – a molecule made up of three oxygen atoms – plays a key role in the upper atmosphere, protecting the Earth from intense solar radiation. Ozone is less visible than the winter particulate matter pollution that often covers urban areas, but it can still create haze. And when formed near the ground from a combination of pollutants and sunlight, it burns human lungs and is linked to several respiratory diseases.
For this reason, the EPA has set a safe limit for ozone at 70 parts per billion, a level that is exceeded many times over on the Wasatch Front every summer. More than 80% of ozone comes from natural or foreign sources, so state regulators can only try to combat the small portion created by human activity in the state, primarily vehicles and industry.
“We’re having a really hard time meeting the standard,” said Becky Close, air quality policy division manager for the Utah Division of Air Quality. “It has become extremely difficult to find further reductions.”
Plans upon plans
The state’s failure to meet the federal standard of 70 ppb for several years has led to a series of cascading requirements. Just this month, the state submitted its final State Implementation Plan (SIP) to resolve its “moderate” nonattainment status for ozone, but it has already begun developing the plan for “severe” nonattainment.
The EPA will make a final decision around 2025, “but we already know from the data that we will be reclassified,” Close said.
The state definitely has more options to address ozone, said David Garbett, executive director of O2, a clean air advocacy group. “We see this a little differently than the Department of Air Quality,” adding that he “doesn’t deny that we have a thorny issue here.”
“The really difficult part for Utah is the climate,” said Ashley Miller, executive director of BreatheUtah, another nonprofit that advocates for cleaner air. “Our summers are just so hot and dry, and the season gets hotter and earlier. It’s no longer the months of July and August.”
In Utah’s northern valleys, levels now exceed 70 ppb from April to September. “It’s just a recipe for an ozone catastrophe,” Miller said.
Blame the foreigners
For years, Utah’s industrial polluters have argued that Utah should not meet the ozone standard because much of the ozone precursors – volatile organic compounds and nitrogen oxides – come from uncontrollable sources such as wildfires and foreign countries.
In fact, the EPA has a so-called 179B exemption to the standards if the state can show that foreign sources are responsible, but Utah failed in a previous attempt at this exemption.
Close said Utah applied for a “retroactive” 179B exemption in 2021, but the EPA rejected it because the state could not prove that international emissions were higher on the days Utah exceeded the standard than on the days when this was not the case.
Therefore, the state has now applied for a “future” 179B exemption based on expected foreign ozone in the future. Close was not optimistic about his success. “They’ll probably come back with the same answer,” she said. “But we are trying to make it clear to the EPA that these high-altitude western states are facing a problem that others are not.”
She said the ozone background averages about 50 ppb in western states, while the level in eastern states is about 20 to 25 ppb.
Miller won’t be surprised if the application is rejected. “It’s difficult. Even in a more conservative EPA it would be difficult.” Still, she believes a successful 179B could be a good thing because it allows the state to consider solutions that don’t meet the EPA’s requirements for a state correspond to the implementation plan.
Just two companies
In its application filed last month to resolve moderate nonattainment status, the state is requiring two companies to improve their pollution controls. Moderate status means the state must require companies that release more than 100 tons of pollutants annually to use “reasonably available control technology” to limit emissions.
There are only about a dozen Utah companies above that 100-ton threshold, and of those, only Marathon Oil’s Salt Lake City refinery and US Magnesium’s Tooele County operations have had to add new equipment. For the remaining companies, DAQ found that all reasonably available options had already been exhausted. The state also once required the Chevron refinery to make improvements, but the company objected and the state removed them.
“It’s disappointing that they only included a few entrees from the very limited menu,” Miller said.
If the state reaches serious noncompliance status, it may require appropriately available controls for any company that produces more than 50 tons instead of 100 tons. This will cover an additional 53 large companies in the state, Close said.
Garbett said the state is focusing on the big polluters that the EPA requires it to regulate, and that’s worthwhile, but it’s not looking hard enough at the larger but more dispersed sources like vehicles and buildings.
He gave old cars as an example. State lawmakers are reluctant to regulate or incentivize the retirement of older cars because they make up the vast majority of ozone-causing precursors from vehicles. Cars manufactured after 2017 that run on widely available Tier 3 gasoline produce 80% fewer emissions than comparable older cars, but only account for about a quarter of all cars on the road.
He also said the state sets its vehicle taxes and fees regardless of how much of a burden the vehicle has on the environment. “We don’t do much to inform people about the level of pollution their vehicles produce. There is nothing in state politics that makes a dirty car more expensive.”