Heat means high ozone level

With temperatures expected to be in the 90s at least through Friday, the Spokane County Air Pollution Control Authority wants to inform people about a fairly new pollution problem – ozone, the main ingredient in smog.

Levels for the gas are “good” to “moderate” in Spokane and Coeur d’Alene, but the summer swelter has air quality officials advising people to avoid filling up their gas tanks or mowing their lawns during the heat of the day.

Ozone is formed on the Earth’s surface when heat and sunlight hit areas with populations of about a half-million people or more, said Ron Edgar, chief of technical services for SCAPCA. Nitrogen and volatile organic compounds – industrial, automobile and lawn-equipment emissions – from everyday use, combined with hot weather, create ozone-rich smog that can irritate the lungs of those who inhale it.

It takes an extended period of hot weather for ozone levels to become uncomfortable, Edgar said. He expects moderate levels of ozone this week – between .06 and .07 parts per million – with higher levels still to come.

“We usually see our higher numbers in late July and August,” Edgar said.

Spokane County has never exceeded the .08 ppm threshold in 35 years of monitoring, Edgar said, but last year it came close.

During the summer, levels rose to .081, but that number dropped after it was averaged over an eight-hour span. Should such a breach happen four times in three years, sweeping environmental changes would need to go into effect.

Aside from population, factors such as wind and elevation can affect the amount of ozone in the air. Edgar said the highest levels of ozone in Spokane County are typically found at Green Bluff.

Ozone is “good” at heights of 10 to 30 miles above the Earth, but at ground level it is deemed “bad,” especially upon extended exposure. In the past, area residents’ biggest pollution worry came during the winter in the form of carbon monoxide.

Adults with respiratory problems and children are the most likely to suffer from high ozone levels, SCAPCA reports. To avoid ozone exposure, Edgar suggests staying indoors.

To help lessen ozone levels, the agency suggests refueling vehicles in the evening, using gas-powered lawn equipment in the evening, combining errands to reduce car trips, and using an electric probe instead of lighter fluid to ignite a charcoal barbecue.