Utah’s ozone problem could lead to higher disability rates in children, according to a recently published study.
Ozone’s negative effect on lung function and other health outcomes is well documented, but a new study examined the impact of exposure during the second trimester of pregnancy.
There is a “sea of papers” showing how air pollution harms health. Research leader Sara Grineski said the study, published in November in the Journal of Exposure Science & Environmental Epidemiology, shows a “troubling association” between pregnant mothers’ ozone exposures and the increased chances the baby develops an intellectual disability.
Unlike the ozone layer in the upper atmosphere, ground-level ozone is created by chemical reactions between sunlight and pollutants emitted by cars, power plants, refineries and other sources.
The invisible but highly reactive oxygen molecule can inflame and damage airways and otherwise harm the lungs.
It is a growing summer-time pollution hazard in Utah, particularly as the climate warms, and in the winter in the Uinta Basin. Most of the state’s oil and gas production is in the basin 100 miles east of Salt Lake City, and emissions contribute to the region’s unique winter ozone issues.
The federal health standard for ambient ozone concentrations is 70 parts per billion (ppb), a threshold frequently breached on summer afternoons on the Wasatch Front and in the winter in the Uinta Basin.
In its 2024 “State of the Air” report, the American Lung Association gave Davis, Salt Lake, Tooele, Uintah, Utah and Weber counties an “F” grade for high ozone days. Duchesne County received a “D.”
Grineski, who is a professor of sociology at the University of Utah, and a team of researchers focused on ozone exposure during pregnancy, using exposure data linked to children with intellectual disabilities born from 2003 to 2014, their siblings and population controls.
They found ozone exposure at all stages of pregnancy correlated with a higher risk of the baby developing an intellectual disability.
The second trimester of pregnancy is the most critical period for ozone exposure, according to the study. For every increase of 10 parts per billion in ozone levels, children were 55.3% more likely than their siblings to develop an intellectual disability and 22.8% more likely than other children in Utah.
Kids included in the study were born throughout Utah, Grineski said, but researchers did not separate results for children born in the Uinta Basin because of small counts.
Though the study found an association between ozone exposure and intellectual disability, Grineski said researchers cannot explain why this is happening.
Some research shows that oxidative stress — an imbalance of free radicals and antioxidants in the body — that can come from ozone exposure can interfere with regular neurological development, the study says, and other studies have identified ozone as harmful to placenta health.
But it now is up to other scientists to “dig in with a different set of research skills” to understand the relationship between ozone and intellectual disability, Grineski said.
Amanda Bakian, a research associate professor of psychiatry and a co-author of the study, said there are other big questions, like whether certain demographics are more vulnerable. She added there is a need for population-based studies in different groups to get a better understanding.
“We’re still working on that foundation of research,” Bakian said.
Previous research found a connection between particulate matter measuring 2.5 microns or less — small enough to easily wiggle its way into our lungs and then into our bloodstreams — and intellectual disability.
Pregnant women should be most worried about wildfire smoke, dust and other particulate matter before conception and about ozone in the second trimester, Grineski said, which can make it hard to determine when it is safe.
“I think it’s really tricky here, given the seasonality of the pollution,” she said.
She recommended reducing exposure and using air purifiers inside but added it’s harder to remove ozone from indoor air.
It also is hard to tell when ozone is building up, Bakian said, because we can’t see or taste it.
People can visit air.utah.gov to check for ozone and particulate matter levels in 14 counties.
Megan Banta is The Salt Lake Tribune’s data enterprise reporter, a philanthropically supported position. The Tribune retains control over all editorial decisions.
