Agency to issue smog alerts so public can take precautions.

Byline: SCOTT MABEN The Register-Guard

The Eugene-Springfield area is socked with fog far more often than smog, but summer is the time when ground-level ozone can build to unhealthy levels.

In an effort to give residents advance notice of days when dirty air is expected to be its worst, the Lane Regional Air Pollution Authority is once again issuing smog alerts for the metro area.

The warnings are meant to give people time to arrange to stay indoors as much as possible and encourage them to curtail activities that further diminish air quality.

"We do this to let people know what they can do to protect themselves and also do their little part to cut down on pollution," LRAPA Director Brian Jennison said.

The alerts, which will be sent to local news media, are important particularly for children, the elderly and people with bronchitis, asthma or other respiratory problems.

"But even healthy people, especially people who go out jogging and biking, can be susceptible to high ozone levels," Jennison said.

Ground-level or "bad" ozone builds up on hot days and poses a greater health risk in the afternoon and evening. At those times, it's best to stay indoors, he said.

"If we get into a period of long, hot, stagnant days, we may see on our monitoring equipment that the ozone goes up to unhealthful levels," Jennison said. "So perhaps plan to exercise early in the day rather than wait until the afternoon. People don't have to miss their workout, but they might want to modify their schedule."

Not to be confused with the Earth's protective ozone layer 10 to 30 miles in the atmosphere, ground-level ozone forms when nitrogen oxides, or NOx, react with volatile organic compounds, or VOCs, in the presence of sunlight and heat.

NOx, a byproduct of combustion, comes from power plants, industrial boilers, motor vehicles, lawn care equipment and other sources that burn fuel. VOCs, or hydrocarbons, come from cars, service stations, dry cleaners and factories, as well as natural sources such as trees and other vegetation.

A community is in violation of the federal clean air standard for ozone if it exceeds healthy levels four times in one year. The Eugene-Springfield area came close in 1998, when ozone levels twice exceeded the federal standard.

It hasn't happened more often, Jennison said, in part because cleaner-burning cars have replaced older models.

"Our fear is eventually this welcome trend may be reversed by population increase," he said. "Our hope is to keep the trend going in the right direction with new technology."

Tougher federal air quality rules are expected to lead to cleaner diesel engines, big equipment and off-road vehicles.

Residents also can keep high ozone days from getting worse, Jennison said. Activities that help include:

Driving less, riding bikes, walking and taking the bus.

Turning off the car engine while waiting for construction or a train.

Avoiding topping off the gas tank; fumes and spills are especially bad for the air.

Avoiding drive-up windows.

Keeping vehicles tuned up and changing oil and gas filters regularly.

Using electric or push mowers or avoiding use of gas mowers and other gas-powered lawn equipment on hot days.

Using gas barbecues.