Officials are warning people in Portland, Vancouver and the Willamette Valley to take extra precautions because of poor air quality. The advisory will be in place until Saturday night.
The problem is elevated levels of ozone pollution or smog.
The Oregon Department of Environmental Quality issued the alert Tuesday saying levels are unhealthy for sensitive groups, including children, people age 65 and older, people who are pregnant, and people with heart disease or respiratory conditions.
Health officials say it’s especially important for people in those groups to limit time outside.
According to DEQ, ozone forms when hot temperatures interact with exhaust from cars, gas-powered engines and chemicals in paints and aerosols. These pollutants then react with sunlight and heat to produce ozone and haze. The situation gets worse when there’s little wind to blow the pollutants away. Because ozone pollution increases with exposure to sunlight, pollution levels tend to be higher during late afternoons and early evenings.
To improve air quality, DEQ recommends turning off idling engines, postponing using lawn mowers or leaf blowers and refueling vehicles during cooler evening hours.
To see the latest air quality readings from your community, check out DEQ’s interactive statewide map.