A runner wears a mask at Tom McCall Waterfront Park in Portland, Ore., on Aug. 4, 2026. The National Weather Service issued a warning that air quality will reach unhealthy levels over the next couple of days as wildfires continue to burn accross Oregon.
Saskia Hatvany / OPB
The international air quality ranking site IQAir listed Portland’s air quality as the worst in the world at one point Wednesday morning, among the approximately 120 major cities it tracks.
Portland’s average air quality index was listed at an “unhealthy” 160 as of 7 a.m. Wednesday. By 10 a.m. the city dropped to fifth-worst in the world — not because its air improved, but because the air quality in four other major cities worsened.
Generally, if the AQI lists an area’s air pollution level at 50 or lower, the air quality is “good.” Between 51 and 100 is “moderate,” and 101 to 150 is considered “unhealthy for sensitive groups.”
Negative health impacts increase as the scale goes up, and anything over 301 is considered “hazardous.”
In areas near the massive Rowe Creek Fire Complex in Central Oregon, including Prineville, the AQI was registering a “very unhealthy” 200 Wednesday morning.
About 20 miles southeast, in Post, Oregon, a monitoring station registered a “hazardous” 460 AQI.
Smoke blankets downtown Portland.
Saskia Hatvany / OPB
As firefighters continue working to contain wildfires that are burning more than 2 million acres in Oregon, most of the state will be blanketed with smoky air through at least Wednesday night.
The National Weather Service is warning that in many areas the air quality will hover at unhealthy levels over the next couple of days.
“Pollutants in smoke can cause burning eyes, runny nose, aggravate heart and lung diseases, and aggravate other serious health problems,” the NWA alert reads. “Limit outdoor activities and keep children indoors if it is smoky. Please follow medical advice if you have a heart or lung condition.”
Protect yourself from wildfire smoke. Stay indoors and keep windows closed. Keep your pets indoors too! If you go outside, avoid exertion and consider wearing a respirator. Monitor the air quality for your zip code at https://t.co/3lFMcsMVF7 #ORwx #WAwx pic.twitter.com/yLkZqJUn02
— NWS Portland (@NWSPortland) August 4, 2026
In Clackamas County, C-COM, the area’s 911 operator, began receiving smoke-related calls on Monday. Air quality in the county varied on Wednesday morning, from about 181 in Damascus to 153 in Estacada. As the Grasshopper Fire on Mount Hood entered Clackamas County territory, Welches and Rhododendron registered well over 700.
In Washington County, the poor air quality and heat prompted the county to open additional shelter capacity at Project Homeless Connect in Hillsboro and Just Compassion in Tigard. The additional capacity will last through noon Thursday.
“Shelters will remain open 24 hours throughout the severe weather event,” the county said in an announcement Tuesday. “Hot meals are provided for guests, no one will be turned away, and domestic pets are okay.”
Check the air quality forecast where you live.
The Oregon Department of Environmental Quality issued an air quality advisory Tuesday morning impacting 27 of Oregon’s 36 counties.
Air quality alerts are also in place for the Vancouver area and most of Washington east of the Cascades. The Southwest Clean Air Agency extended its air quality advisories Wednesday for wildfire smoke in Clark, Cowlitz, Lewis, Skamania and Wahkiakum counties.
On Wednesday, DEQ issued another air quality advisory for several areas across the state due to elevated levels of ozone pollution, or smog. That advisory is expected to last until 10 p.m. Thursday.
In some areas of Oregon, including Medford, the air quality alerts are in effect at the same time as red flag warnings for fire danger.
Critical fire weather conditions are expected today due to low RHs during the afternoons, and east winds with poor recoveries over the mountains during the overnight periods. Do your part to prevent a spark…one less spark, one less fire! #ORwx #CAwx pic.twitter.com/gKMMNjEwNN
— NWS Medford (@NWSMedford) August 5, 2026
In other areas, including the Portland metro area, the air quality advisories are overlapping with heat advisories for temperatures potentially reaching triple digits through Thursday.
Noah Alviz is a meteorologist with the National Weather Service in Portland. He said a wind shift coming from the west will help push smoke back out east starting as early as Wednesday night.
But he warned not all the smoke will go away at once.
“For now, western Oregon will be smoky through [Thursday] but things will improve heading into the weekend,” Alviz said. “We’re not expecting the smoke to linger through Saturday or Sunday.”
Much of the smoke across western Oregon is expected to clear out by Thursday night, according to Alviz.
Resources: Stay safe and informed during wildfire season with OPB’s wildfire guide at opb.org/wildfires. This resource offers essential safety tips and preparedness guidance to help you navigate fire and smoke events. This resource was created as part of our commitment to serving the public as wildfire seasons become longer and more dangerous.
