SALT LAKE CITY -- Utah doctors warned people Monday of the dangers of summer ozone - an invisible gas produced by smog that can tax the lungs of even healthy people.
As a pollutant, ozone often goes overlooked, but it acts on lung tissue like sandpaper, said doctors who joined state officials at a news conference.
"I didn't even realize ozone was an issue" until recently, said Brent Muhlestein, a cardiologist who paid more attention to Utah's wintertime inversions, which can trap soot close to the ground.
Ozone is Utah's twin pollution problem. It most often occurs in summer, when sunshine and hot weather cook ozone from tailpipe and other emissions.
"Ozone is harmful. It damages cells and triggers inflammation inside our lungs," said Bob Rolfs, Utah's state epidemiologist.
Ozone has yet to hit dangerous levels this summer - for weeks, readings around Salt Lake City have hovered just inside the safe zone.
Utah Division of Air Quality Director Bryce Bird was surprised by the tardy appearance of higher levels of ozone, but said it can spike quickly if wildfire smoke and stagnant conditions settle over the urban areas.
Ozone readings can fluctuate rapidly - cloud cover can chase it away.
Ozone readings along the Wasatch Front reached nearly 75 parts per billion Monday, a level rated as unhealthy for sensitive groups.
Ozone above 95 parts per billion is considered a problem for anybody.
Muhlestein said he plans to take a closer look at health risks by matching data on hospital admissions against bad ozone days.
Medical studies have shown that air pollution inflames blood vessels and major arteries, which for people with heart disease can be deadly, he said.
Doctors urged people to stay indoors during the highest ozone levels. People can still exercise outdoors in morning and evening when the levels drop, they said.
To get active, "You don't have to go to the gym and wear stretchy pants," said Dr. Terri Flint of an employee and patient wellness program sponsored by Intermountain Healthcare, Utah's largest medical provider.
Grabbing short periods of exercise throughout the week does the trick - walking 6,000 steps a day is considered a minimum, she said.