Bethany, Cedar Mill, Oak Hills, and West Haven-Sylvan residents are facing a dangerous combination of wildfire smoke and extreme heat this week, with Tualatin Valley Fire & Rescue's burn ban active and Oregon officials warning that the overlap poses serious risks for infants, older adults, pregnant people, and anyone with heart or lung disease.

The Oregon Department of Environmental Quality issued an air quality advisory Monday, Aug. 3, covering Clackamas, Multnomah, and Washington counties. The advisory is expected to remain in effect through at least Tuesday afternoon, with smoke and haze likely lingering through Wednesday or Thursday before onshore flow pushes it east of the Cascades.

"There is no safe amount of wildfire smoke to breathe in, so keep an eye on that air quality, know what your own symptoms are," Jennifer Horton, a DEQ air quality coordinator, said Monday in an interview with KGW.

A National Weather Service heat advisory takes effect at noon Tuesday, Aug. 4, and runs through 11 p.m. Wednesday, Aug. 5. Daytime highs in the Portland metro area are expected to peak near 98°F on Wednesday.

The danger is the overlap.

Heat increases breathing rate and cardiac output, which accelerates the body's intake of fine particulate matter from smoke. Horton said symptoms can worsen because of the high heat and recommended running air conditioning on the recirculate setting to filter indoor air without drawing smoke from outside.

Residents without AC face a direct conflict: smoke guidance says seal windows and stay indoors, while heat guidance says find cool air. For those households, a climate-controlled clean air shelter is the recommended solution.

John Villella, who runs Trellis, an adult day program for people with disabilities in the Portland metro area, said Monday he moved all upcoming outdoor activities indoors after participants began reporting headaches and fatigue from the smoke.

Washington County has opened cooling centers at Beaverton Public Library and Tigard Public Library, according to the county, open until 9 p.m. Tuesday, Aug. 4, and Wednesday, Aug. 5. Residents can also call 211 (Monday through Friday, 8 a.m. to 6 p.m.) to locate the nearest cooling and clean air shelter.

Real-time air quality data is available at aqi.oregon.gov or through the free OregonAIR app.

Tualatin Valley Fire & Rescue's burn ban remains in effect as of Tuesday, Aug. 4. No outdoor burning of any kind is permitted in the TVF&R service area, which covers Bethany, Cedar Mill, Oak Hills, and West Haven-Sylvan.

Horton said smoke is blowing in from the Grasshopper Fire in Central Oregon and from multiple fires in Washington state. Oregon's 2026 wildfire season has burned 2,014,481 acres across 60 large fires as of Monday, Aug. 3, just 67,000 acres short of the state's all-time record of 2,081,661 acres set in 2024.

The Hillsboro Police Department canceled its National Night Out Party Patrols on Tuesday because of the heat advisory and poor air quality, KGW reported. The City of Beaverton also canceled its National Night Out event.

Oregon DEQ advises that cloth, dust, and surgical masks do not protect against wildfire smoke particles. Properly fitted N95 or P100 respirators may help adults, but DEQ cautions they are not available in children's sizes and should not be used by people with heart or lung conditions without consulting a doctor.

Symptoms of smoke exposure include burning eyes, sore throat, cough, chest tightness, headache, and unusual fatigue. Wheezing, shortness of breath at rest, chest pain, or a rescue inhaler that isn't working as expected are reasons to seek medical attention.

National Weather Service forecasters expect conditions to improve late Thursday into Friday as onshore flow returns.