Air quality alerts were issued across much of the western United States on Sunday. Wildfire smoke and elevated ozone levels led to unhealthy breathing conditions in states including Oregon, Idaho, Washington, Montana, Colorado, and California.
Environmental Protection Agency (EPA) data from AirNow, its monitoring platform, revealed “unhealthy” air levels resulting mainly from fires in Canada and the Pacific Northwest. Officials urged people in affected areas to stay indoors, avoid strenuous outdoor activities, and take precautions if they have asthma, heart disease, or other respiratory issues.
The main health concern is fine particulate matter, PM2.5, which can penetrate deep into lung tissue.
“Stay inside if possible. Keep windows and doors closed,” warned an alert from the Oregon Department of Environmental Quality for Baker County.
AirNow mapping showed central and eastern Oregon experiencing extreme pollution levels, including “Hazardous” on the Air Quality Index (AQI), indicating emergency conditions where health risks are elevated for all.
Oregon officials reported that particulate concentrations may shift rapidly with changing wind and weather patterns.
Idaho Experiences “Unhealthy” Air Levels
Idaho faced deteriorating conditions, moving into “unhealthy” and “very unhealthy” AQI ranges. The Idaho Department of Environmental Quality (DEQ) advised Ada, Adams, Boise, Canyon, Elmore, Gem, Owyhee, Payette, Valley, and Washington counties through Tuesday afternoon.
Additional alerts for northern Idaho and the Nez Perce Reservation warned of hazardous particulate levels for sensitive groups.
“Air pollutants can cause breathing difficulties for children, the elderly, and individuals with respiratory problems,” the Idaho DEQ stated.
Open burning is not allowed by air quality rules. People sensitive to particulate matter or smoke should avoid prolonged outdoor activities, and others should limit strenuous activity outdoors.
Washington, Montana, Colorado, and California Alerts
Washington state dealt with wildfire smoke, with AirNow flagging “unhealthy” air in north-central regions and “unhealthy for sensitive groups” across the northeast.
Montana’s DEQ issued air quality alerts for several counties, including Choteau, Granite, Hill, Lewis and Clark, and others, due to wildfire smoke particulates. These alerts will expire at 9 a.m. on Monday.
In Colorado and California, pollution problems stemmed from smog rather than smoke. An Ozone Action Day Alert was declared for the Denver metro area and the Front Range Urban Corridor. Additionally, the South Coast Air Quality Management District in California warned of persistent smog through Monday in Los Angeles County areas such as the San Fernando, San Gabriel, and Santa Clarita valleys.
Monitoring Air Quality
Authorities advise residents under alerts to regularly check local AQI readings as weather changes can quickly affect conditions. According to AirNow forecasts, heavy smoke will further impact Idaho and Washington, whereas Oregon’s air is expected to improve. Public health agencies continue to recommend minimizing outdoor exertion and using indoor air filtration systems for vulnerable groups until alerts end.
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