Editor’s note: The KOIN 6 Weather system initially advised an air quality warning based on the Oregon Department of Environment note, when it was an air quality advisory. The story has been corrected.

PORTLAND, Ore. (KOIN) —  The Oregon Department of Environmental Quality has issued an air quality advisory for the Willamette Valley until Thursday night due to a mix of city smog and wildfire smoke.

Moderate air-quality conditions will be possible around Portland today as smoke settles into the Willamette Valley from the Rum Creek Fire burning in Josephine County.

KOIN 6 Meteorologist Kelley Bayern reports that fluctuating hazy conditions will be possible in Portland due to a lack of wind that might otherwise push smoke out of the area.

“Our high-pressure pattern that’s anchored over the PNW has not only resulted in excessive heat across the valley this week, but worsening air quality as well,” Bayern said. “We have a stagnant air column, in other words, little-to-no winds to help mix out any pollutants or wildfire smoke.”

Smoky conditions across the Pacific Northwest today. | EPA

While air quality could be better in the Willamette Valley, conditions are worse for all of Portland’s large neighboring cities, including Seattle, Eugene, Medford, Bend and Boise. The Oregon Department of Environmental Quality notes that conditions are especially bad in areas of Josephine, Jackson and Curry Counties.

“The heaviest smoke will stay south near the southern counties of the Rogue Valley over the next few days with an expected drop in air quality to unhealthy levels,” Bayern said. “But hazy sunshine and a drop to moderate air quality is also possible today as wildfire smoke shifts north. We’ll also pair the wildfire smoke with smog and pollutants from cars hitting the roads during rush hour.”

Those sensitive to poorer air quality are urged to keep track of Wednesday’s changing conditions.

“Forecasts are still showing that air quality levels will stay in a safe zone to go outdoors here in Portland,” Bayern said. “Those with sensitivities or respiratory issues should keep activity light, especially this afternoon and evening.”