Oregon air quality today

Most of where Oregonians live is a floor with mountains on either side. The Willamette Valley runs between the Coast Range and the Cascades, the Rogue Valley sits in a bowl around Medford, and the Klamath Basin closes the state’s southern edge. Those shapes behave the same way in both of the state’s polluted seasons, keeping whatever is in the air near the ground rather than letting it out.

Winter is fine particulate, and a great deal of it is domestic. EPA designated the Klamath Falls area nonattainment for the 2006 24-hour PM2.5 standard, and the source named was residential wood heat burned during winter stagnation, not industry or traffic. The Oregon Department of Environmental Quality has worked on woodstove change-outs there since, and the state asked EPA in August 2024 to redesignate the area to attainment; EPA proposed to approve that request in March 2026, so the nonattainment label still stands until the approval is final. Oregon also enforces an air rule that runs through a real estate closing rather than a permit: an uncertified wood stove must be removed and destroyed when the house holding it is sold, with the removal reported to DEQ. Summer reverses the source entirely. Wildfire smoke arrives from inside the state and from well outside it, and the valleys that trap wood smoke in January hold it in August.

Our coverage follows population, which puts the Willamette corridor first and leaves Klamath Falls — the part of Oregon carrying a federal nonattainment label — without a page here. That ordering is a build queue, not a ranking of which Oregon air is worth watching.