Wildfire smoke has triggered a wave of Air Quality Alerts across Idaho, Oregon and Montana.
The worst-hit area is the Treasure Valley around Boise. Air quality there is forecast to reach Very Unhealthy through Friday afternoon.
Dozens of other counties across all three states are also under advisories. Most run through Wednesday.
Boise Area Hits ‘Very Unhealthy’ Air Quality
The Idaho Department of Environmental Quality issued an advisory for Ada, Adams, Boise, Canyon, Elmore, Gem, Owyhee, Payette, Valley and Washington counties.
It runs until 3 PM MDT Friday.
The Air Quality Index there is forecast to hit Very Unhealthy — the second-highest category on the scale.
Officials say the entire population is more likely to be affected, not just sensitive groups. Open burning is banned under state air quality rules for the duration.
Southern and Eastern Idaho Under Multiple Advisories Through Wednesday
South-central Idaho isn’t far behind. Camas, Gooding, Jerome and Twin Falls counties are forecast to reach Unhealthy air quality until 1 PM Wednesday.
Cassia, Lincoln and Minidoka counties are under a similar Unhealthy advisory through Wednesday.
Blaine County, along with Bonneville, Butte, Clark, Custer, Fremont, Jefferson, Madison and Teton counties in eastern Idaho, are forecast to reach Unhealthy for Sensitive Groups through Wednesday.
Clearwater and Idaho counties in the north-central part of the state had their advisory extended. It now runs until noon Wednesday.
Lemhi County’s advisory is shorter, expiring at 3 PM Tuesday.
Oregon Smoke Advisories Cover the Eastern Half of the State
The Oregon Department of Environmental Quality issued an advisory for Baker, Harney and Malheur counties in the state’s far east. It remains in effect until further notice.
A second advisory covers ten counties in north-central and northeast Oregon: Crook, Gilliam, Grant, Jefferson, Morrow, Umatilla, Union, Wallowa, Wasco and Wheeler.
That advisory includes Bend-area communities like Prineville, along with Pendleton, The Dalles, La Grande and Hermiston. It runs until noon Wednesday.
Oregon officials say smoke can cause burning eyes and a runny nose. It can also aggravate heart and lung disease.
Montana Alert Spans More Than 20 Counties
The Montana Department of Environmental Quality issued a sweeping alert covering more than 20 counties, including Cascade, Lewis and Clark, Missoula, Silver Bow and Lake. It runs until 9 AM Wednesday.
As of Tuesday morning, particulate levels in Billings, Hamilton and Helena were Unhealthy for Sensitive Groups.
Levels in Butte, Great Falls, Missoula, Havre and several other cities were Moderate.
State health officials say people with respiratory or heart disease, the elderly and children should limit prolonged exertion outdoors while the alert is active.
What to Do If You’re in a Smoke Advisory
Stay inside if you can. Keep windows and doors closed.
Avoid strenuous outdoor activity, especially if you’re in a sensitive group. That includes children, older adults, and anyone with heart or lung conditions.
A HEPA air purifier can help indoors. If you have asthma or another respiratory condition, follow your doctor’s guidance.
Smoke levels can shift quickly with the wind. Check conditions before heading out at airnow.gov, aqi.oregon.gov or todaysair.mtdeq.us.
