Wildfire Smoke Continues to Choke Pacific Northwest Cities: What Residents Need to Know

The 2026 wildfire season has delivered some of the worst air quality in Pacific Northwest history, with smoke from dozens of large fires blanketing communities from Puget Sound to the Treasure Valley. As the season continues into mid-September, health officials and air quality agencies urge residents to stay vigilant and take protective measures on smoky days.

Seattle and Western Washington

The Puget Sound Clean Air Agency has issued multiple air quality advisories this season as smoke from inland fires — particularly those burning in Chelan and Okanogan counties — drifted westward on prevailing winds. At peak periods, Seattle-Tacoma recorded air quality in the Unhealthy and Very Unhealthy categories (AQI 150–200+), briefly placing the metro area among the world's most polluted major cities. The pattern has been consistent: winds off the Cascades push smoke toward Puget Sound communities during afternoon hours, with some overnight clearing as winds shift.

Portland and the Willamette Valley

Portland residents have faced repeated smoke intrusions from fires burning in the Cascades and eastern Oregon. Oregon's large fires — including the Grasshopper Fire in Wasco County and the Austin Fire in the Mount Hood National Forest — have pushed smoke plumes across the Cascade crest and into the valley. At times, smoke drifting out of eastern Oregon and northern Idaho pushed Portland onto lists of the world's most polluted major cities. Oregon's BLM Medford District issued a fire prevention order on September 5 — restricting campfires, charcoal fires, and smoking materials on public lands — partly in response to extreme fire weather risk and ongoing smoke impacts.

Boise and the Treasure Valley

Boise spent much of the summer under a persistent veil of wildfire smoke, according to reporting by the Arbiter. The U.S. Wildland Fire Service identified multiple fires across Idaho and Oregon that contributed to Treasure Valley smoke events, with prevailing westerly winds pushing particulate plumes directly toward the Boise metropolitan area. Residents with respiratory conditions — including asthma, COPD, and heart disease — were advised to limit time outdoors on the worst days.

North Central Washington

Communities in north central Washington — including Wenatchee, Chelan, and the upper Methow Valley — have been among the hardest hit. With numerous large fires burning in Chelan, Okanogan, and Skagit counties, smoke outlooks from the AirFire group warned that fire activity was expected to remain active and that associated smoke would continue to impact the region. Cooler temperatures in recent days have reduced active fire behavior, but smoke from smoldering areas can still create localized air quality concerns.

Protecting Your Health on Smoky Days

Health departments across the region recommend the following steps when smoke is present:

Check your local Air Quality Index (AQI) at AirNow.gov before heading outside
Keep windows and doors closed; use air conditioning with a clean filter if available
Run a HEPA air purifier indoors to reduce fine particle concentrations
Wear a properly fitted N95 or P100 respirator if you must be outdoors — cloth masks do not filter fine particles effectively
Avoid strenuous outdoor activity when AQI is above 100 (Unhealthy for Sensitive Groups)
Check on neighbors, elderly relatives, and those with chronic conditions