It didn't take long for Utah to rack up its first high-smog days of the summer.

Only a couple days after a June storm-athon ended, state air officials declared Monday a "red" day for increasing ozone in Salt Lake and Davis counties.

The trend is expected to continue through Tuesday, when the chance of thunderstorms goes up again. In addition, pollution levels are expected to build in Weber County on Tuesday to "red" levels.

This week's warnings indicate outdoor air has unhealthy levels of ozone pollution. People in sensitive groups -- the very young, the very old and people with heart and lung problems -- are most at risk.

But people who exert themselves working or playing outdoors during the afternoon also are exposed to the health damage caused by ozone. Exercising before noon or after 6 p.m. can minimize ozone exposure.

"Some people are more sensitive than others to ozone," said Michelle Hofmann, a Salt Lake City pediatrician.

Hofmann was a member of a yearlong ozone review team that looked at the hazards of ozone and helping Utahns deal with those threats. The advisory group has posted some of its findings, including a symptom-tracking chart, on the Utah Asthma Center Web page.

Neither Washington County nor Cache County is expected to see high ozone levels this week.

Utah County has an "action alert" in place through Wednesday. That means that drivers are urged to carpool, link trips together and otherwise minimize emissions as much as possible.

People who mow their lawns can help by mowing in the morning. Even gassing up vehicles in the morning helps reduce the amount of ozone-building chemicals that go into the air .

fahys@sltrib.com