SALT LAKE COUNTY, Utah -- Exhaust for tailpipes and triple-digit temperatures are creating the perfect storm for bad air during Utah's ozone season.
"It's a chemical reaction -- it's admitted by pollutants by vehicle exhaust it gets cooked up by sunlight and heat and forms this chemical reaction, which typically is high levels during the hottest part of the day," said Donna Kemp Spangler, Communications Director for the Department of Environmental Quality.
In Salt Lake County, 19 days in June were marked voluntary or mandatory no drive, bad air days by the Department of Environmental Quality.
"We've been really hit it hard this month we've had a lot of challenging days," Spangler said.
The ozone season typically starts in July and spans through August. In 2014 only one day in Salt Lake County was marked mandatory action. Already this summer they've had 13.
"I hope it doesn't get any worse if I had a crystal ball I would hope it doesn't get any worse and it would temper down a little bit," Spangler said.
To help create a culture of clean air, Salt Lake City is reminding residents that idle-free has been the law since 2011.
"The ordinance, which is in place to indicate how serious we are that this," said Salt Lake City Mayor Ralph Becker.
To remind residents to turn their key, 500 idle-free signs will be all around the city at parks businesses and schools.
"It is our small steps that will make the biggest difference in improving our air quality and getting in the habit changing our behavior," Becker said.
Cars are the culprit with ozone but with fireworks starting Wednesday, DEQ officials say the state will not only see high levels of ozone but particulate matter as well.
"Which kind of creates a double whammy -- we're getting both kinds of pollutants," Spangler said.
Air experts say travel wise, take transit if you can. And those with breathing problems should stay inside during peak hours.