Hillsboro residents woke Tuesday to hazy skies and worsening air after wildfire smoke from fires near Spokane, Washington blanketed the metro area overnight. IQAir forecast the Air Quality Index to spike from 50 to 182 within 12 hours Monday evening, a jump from "Good" to "Unhealthy."
The Portland-Hillsboro area ranked No. 10 on IQAir's list of worst air quality among major cities worldwide on Monday, Aug. 3, worse than Wuhan, China, and Cairo, Egypt, according to KOIN 6.
IQAir's outlook shows the AQI remaining in the "Unhealthy" range through Thursday, Aug. 6, with conditions expected to return to normal by Saturday, Aug. 8. Winds are expected to shift westerly late Thursday into Friday, pushing smoke back east of the Cascades.
DEQ advisory covers Washington County
The Oregon Department of Environmental Quality issued an air quality advisory Monday, Aug. 3, covering the Portland metro area, including Washington County. The advisory is expected to remain in effect until at least Tuesday afternoon, though multiple forecasts indicate smoke and haze will persist through Wednesday or Thursday.
The National Weather Service had forecast "extreme" smoke levels arriving around 5 p.m. Monday. Winds shifted from westerly to northeasterly, funneling smoke from Oregon's 2026 wildfire season into the Willamette Valley. So far this year, wildfires have burned 2,014,481 acres statewide, just 67,000 acres short of the all-time record of 2,081,661 acres set in 2024.
Heat compounds the danger
A Heat Advisory takes effect at noon Tuesday for the Willamette Valley, with highs reaching the low to mid-90s Tuesday, potentially the low 100s Wednesday, and upper 90s Thursday. The combination of smoke and extreme heat is more dangerous than either alone: heat increases respiratory rate and cardiac output, accelerating the body's intake of fine particulate matter from smoke.
Travis Knudsen, executive director of the Lane Regional Air Protection Agency, told NBC16 on Monday that the dual hazard creates a particular problem for residents trying to cool their homes. "Smoke tends to settle into the valley overnight, and that is the same window when people open their windows to cool the house," Knudsen said. "Tonight, keeping them closed is the better call."
Local impacts already showing
The Hillsboro Police Department canceled its National Night Out Party Patrols because of the combined heat advisory and poor air quality forecast, KGW reported.
How to stay safe
DEQ warns that cloth, dust, and surgical masks do not protect against wildfire smoke particles. Only NIOSH-approved N95 or P100 respirators offer protection when properly fitted, and those are not available in children's sizes.
People most at risk include infants, young children, older adults, pregnant people, and those with heart or lung disease.
For residents with air conditioning, DEQ recommends setting the system to recirculate rather than fresh-air intake. Those without AC face a dilemma: sealing windows traps heat, but opening them lets smoke in. A HEPA air purifier or a DIY filter made from a box fan and a MERV-13 furnace filter can help.
Residents can find clean air shelters and cooling centers by calling 211 during business hours (8 a.m.–6 p.m., Monday–Friday) or visiting 211info.org. Current air quality conditions are available at aqi.oregon.gov or through the free OregonAIR smartphone app.
