EPA rejects Utah’s claim that its ozone pollution comes from Asia

Despite gains in reducing winter particulate pollution, summer ozone remains a stubborn presence for Salt Lake

Francisco Kjolseth | The Salt Lake Tribune Utah is currently experiencing the worst summer air quality in nearly ten years, largely due to a persistent high pressure system that has parked over the Wasatch Front. The summer equivalent of an inversion is not as obvious to spot but the high ozone levels are there none the less as seen near the Salt Lake Valley on Tuesday, Aug. 1, 2017.

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The Environmental Protection Agency is turning up the pressure on Utah to reduce ozone pollution along the northern half of the Wasatch Front.

On Tuesday, the agency rejected state regulators’ efforts to attribute Salt Lake City’s elevated ozone levels to Asia and natural emissions and proposed increasing the region’s nonattainment status from “marginal” to “moderate” for federal air quality standards.

Utah has made progress reducing wintertime particulate pollution, known as PM2.5, but solutions to high ozone have proven elusive.

“This has been perplexing and disappointing,” said Becky Close, policy section manager for the Utah Division of Air Quality. “We have reduced a lot of NOx [nitrogen oxide] and VOCs [volatile organic compounds] over the years with our PM2.5 work and you would expect to see a decrease in ozone. The chemistry is complicated and the weather is complicated, and now we have many summers with wildfire issues. We suspect that the increase in ozone over the most recent years are impacts from wildfires.”

The proposed reclassification, if finalized, would obligate the state to adopt additional measures to reduce emissions to protect human health and submit new plans for getting the impacted airshed into attainment with federal standards.

The FDA based the decision on monitoring data gathered in Salt Lake, Davis and Weber counties from 2018 through 2020.

The northern Wasatch Front is one of 24 areas across the country that the EPA determined have failed to meet deadlines for reducing ozone to within federal standards, according to a recent posting on the Federal Register.

Federal regulators are accepting public comment on the proposed reclassifications through June 13.

Ozone, a highly reactive three-atom oxygen molecule that damages lung tissues, is formed in the atmosphere when various pollutants undergo chemical transformation in the presence of sunlight. The federal standard is currently set at 70 parts per billion (ppb), a level that is sometimes exceeded in the urban Wasatch Front and rural Uinta Basin.

Last year, Salt Lake City experienced a near-record 39 days where the ozone threshold was breached, or nearly double the 20-year average, according to the EPA.

DAQ would have until Jan. 1 to submit a plan for reducing emissions to get the Wasatch Front in compliance, according to Close. The agency currently is developing an emissions inventory to determine where reductions can best be achieved.

One strategy could seek to reduce residents’ reliance on equipment powered with high-polluting two-stroke engines, such as lawnmowers, chainsaws and snowblowers.

The Uinta Basin’s ozone problem is largely a result of emissions from oil and gas operations, with episodes of high ozone occurring in the winter. In 2018, the basin was classified as “marginal” for ozone nonattainment, establishing a 3-year deadline for the state to get the airshed into compliance. On Tuesday, the EPA granted the state’s request to push back the Uinta Basin’s deadline by a year to Aug. 3.

Should the basin fail to get into compliance, the EPA could wind up imposing limits on oil and gas development or require costly upgrades to reduce emissions from wells, pipelines, compressors, separators, storage tanks and other oil field equipment.

The EPA did have some good news for some of Utah’s air quality. Also on Tuesday, the EPA proposed reclassifying the southern Wasatch Front’s ozone status to attainment for the ozone standard.