In one small sign that the state’s air-quality cleanup plan is working, the Cache Valley has attained national clean-air standards for winter smog for three years in a row.
The U.S. Environmental Protection Agency’s determination, announced last month in the Federal Register, marks the first time in more than a decade that one of Utah’s pollution hotspots has met EPA health-based limits for winter smog episodes.
The EPA signed off last month on reports from the Utah Division of Air Quality showing that Logan and the Cache Valley area met standards between 2015 and 2017 for fine-particulate pollution known as called PM2.5,
The national standards were tightened in 2006. Ever since then, three Utah valleys — Salt Lake, Utah and Cache — have failed to meet the federal standard. That prompted EPA to order the state Division of Air Quality to develop and implement plans to reduce emissions that make the air unhealthy for weeks at a time.
An entire decade of meeting clean-air standards is required before EPA would remove Utah counties from its “nonattainment” list, said Randy Martin, a pollution researcher and member of the state Air Quality Board.
“Things are moving in the right direction,” Martin said. “If we have a couple of bad winters in a row, we could be right back in that bad situation.”
Martin credits the progress in cleaning up Utah’s winter smog hotspots on emissions-reducing measures like tailpipe testing, wood-burning restrictions and anti-idling campaigns. Regulations that reduce emissions from vehicles, homes, business and industrial polluters are also gradually lowering pollution levels.
Utah County also had a string of lower pollution years and is applying for official recognition from EPA. In addition, plans for reducing emissions in the Salt Lake County airshed are weeks away from being sent to EPA, according to Bryce Bird, director of the state Division of Air Quality. The EPA has designated PM2.5 a “serious” problem in the Salt Lake airshed, which includes Salt Lake, Davis, Weber, Tooele, Box Elder counties.
But weather and geography also play a role in northern Utah’s pollution problems. During periods of high pressure, thermal inversions form in the valleys and trap pollution. Over time, the pollution that would normally be blown away builds up instead. That’s when the PM2.5 reaches unhealthy levels.
For many people, these episodes simply mean burning eyes, nostrils and lungs. But winter smog can also increase the likelihood of heart attacks, asthma, preterm birth and even premature death.