# Portland, OR Air Quality Index (AQI) Today > Source: https://breathecheck.com/air-quality/us/oregon/portland/ > Live AQI for Portland, OR with a plain verdict — go, short and unloaded, or don't go — plus the monitor behind it and our own hourly record. # Portland, OR Air Quality Index (AQI) Today Readings collected automatically every hour; text written and checked by BreatheCheck Editorial . How this page is made → Right now: Portland is at 26 , good . ## Is the air safe to breathe in Portland today? In Portland, BreatheCheck reads 26 as Go . The cutoffs: go below 101 , keep it short and easy from 101 to 150 , move it indoors above 150 . These are our own thresholds, drawn on the EPA bands — EPA itself classifies 101–150 as Unhealthy for Sensitive Groups and does not tell you how long to stay out. Go AQI 0–100 Normal outdoor plans. No change needed. Short & unloaded AQI 101–150 A 20-minute dog walk, not a 2.5-hour run. Keep it brief and easy. Don’t go AQI 151+ Move it indoors. Above 200 that becomes everyone, not just sensitive groups. Above 200 this stops being a personal call: everyone indoors. Duration and intensity are two separate dials | Under 20 min | 20–60 min | Over an hour | | Easy | Go | Go | Go | | Moderate | Go | Go | Go | | Hard | Go | Go | Go | Go Every combination lands the same way at this reading — a hard hour is no different from an easy twenty minutes. The two dials separate above 80 . Where people actually draw the line **All the thresholds people reported, and who reported them** - 60 Asthmatic runner one runner’s own 156-run log - 75–100 Daycare / school parents and staff in one r/toddlers thread, Aug 2025 — not a published rule - 100 Parent community-reported, escalating at 150 and 200 - 110 Runner community-reported EPA classifies 101–150 as Unhealthy for Sensitive Groups. That is an attributed classification, not a verdict on your lungs specifically. If you’re staying in, filter the room you’re actually in A portable HEPA unit or a Corsi-Rosenthal box — one builder put theirs at about $130 for a 12×14 bedroom. We don’t default to a MERV-13 swap in whole-house HVAC: it can restrict airflow, and the safe version needs a static-pressure check first. Dominant pollutant PM2.5 UV index 2 low · modelled UV hour by hour in Portland → Days above AQI 100 2 of 30 days we have recorded The record, day by day → ### Winter Woodsmoke, Then Smoke Through The Gorge Portland occupies the Portland Basin at the northern end of the Willamette Valley, with the Coast Range to the west, the Cascades to the east, and the Tualatin Mountains — the West Hills locally — rising at the city’s own western edge. The basin holds air whenever the wind stops, and that is what the bad days here have in common. Two mechanisms fill it, at opposite ends of the year. The winter one is routine. On still, cold nights a warmer layer caps the colder air near the ground and stops it mixing out, and Oregon DEQ attributes this area’s cool-season PM2.5 spikes to that inversion combined with residential wood burning, most often in November and December. It accumulates over days and lifts when the weather pattern changes, not before. The other is wildfire smoke, and the Columbia River Gorge is why it can be extreme. The Gorge is the one near-sea-level gap through the Cascades, so an east wind the range would otherwise block accelerates through the gap instead and carries smoke straight into the basin. Before 2020 the Portland area had never recorded air worse than Unhealthy. In September of that year, during exactly that kind of east-wind event, DEQ logged three Very Unhealthy days and five Hazardous ones. A westerly flushes the basin in an afternoon; an easterly means whatever is in the air is staying. ## Where this number sits Of the 121 US metros reporting to us right now, Portland is number 103 and number 2 of the 2 we track in Oregon. The pollutant driving it today is PM2.5 . Nearby metros we also measure, and what they read at the same hour: - Eugene, OR — 104 miles away, AQI 28 - Seattle, WA — 145 miles away, AQI 37 - Spokane, WA — 290 miles away, AQI 34 - Boise, ID — 345 miles away, AQI 32 Why a metro a short drive away reads differently → Where this reading comes from AirNow’s Portland reporting area, about 1.7 miles from the metro centre. ## What has air quality in Portland actually been? Daily maximum, our own readings. 30 days since 2026-08-16; nothing back-filled. Why we keep our own → 2 of the 30 days we have recorded so far went above AQI 100. | Date | Daily max AQI | EPA band | Hours read | | 2026-09-14 | 49 | Good | 23 | | 2026-09-13 | 77 | Moderate | 23 | | 2026-09-12 | 102 | Unhealthy for Sensitive Groups | 23 | | 2026-09-11 | 57 | Moderate | 23 | | 2026-09-10 | 49 | Good | 23 | | 2026-09-09 | 62 | Moderate | 23 | | 2026-09-08 | 41 | Good | 23 | | 2026-09-07 | 44 | Good | 23 | | 2026-09-06 | 52 | Moderate | 23 | | 2026-09-05 | 57 | Moderate | 23 | | 2026-09-04 | 51 | Moderate | 23 | | 2026-09-03 | 52 | Moderate | 24 | | 2026-09-02 | 55 | Moderate | 14 — partial day | | 2026-09-01 | 221 | Very Unhealthy | 23 | | 2026-08-31 | 81 | Moderate | 23 | | 2026-08-30 | 42 | Good | 23 | | 2026-08-29 | 44 | Good | 23 | | 2026-08-28 | 32 | Good | 22 | | 2026-08-27 | 29 | Good | 23 | | 2026-08-26 | 80 | Moderate | 23 | | 2026-08-25 | 61 | Moderate | 23 | | 2026-08-24 | 55 | Moderate | 24 | | 2026-08-23 | 29 | Good | 23 | | 2026-08-22 | 53 | Moderate | 24 | | 2026-08-21 | 60 | Moderate | 24 | | 2026-08-20 | 63 | Moderate | 24 | | 2026-08-19 | 73 | Moderate | 23 | | 2026-08-18 | 76 | Moderate | 23 | | 2026-08-17 | 71 | Moderate | 26 | | 2026-08-16 | 54 | Moderate | 7 — partial day | ## Questions about Portland **What is the air quality in Portland right now?** AQI 26 — Good. That is number 103 of the 121 US metros reporting to us at this hour. **Which monitor does this number come from?** Portland, about 1.7 miles from the metro centre. One instrument reports for the whole metro, so the side farthest from it is the least well described. **How does Portland compare with metros nearby?** At this hour: Eugene 28, Seattle 37, Spokane 34, Boise 32. Readings that close together suggest one airshed rather than local sources. **Does this include pollen?** No. The AQI covers PM2.5 , PM10 , ozone, NO₂, SO₂ and CO. A high-pollen day can read clean here and still put someone in bed. What the number means, band by band → · UV in Portland → · Why apps disagree → ## Put this number in context On this page Alert me when Portland turns One email when it crosses your threshold. Updated 14 Sep 2026, 22:12 UTC