Wildfire smoke
Wildfire Smoke episode, 2017-08-03
Daily PM2.5 peaked at 68.5 µg/m³ near Seattle across 2 covered metros home to 6.7 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 2.5 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 17 million cigarettes. An awareness illustration of outdoor exposure at 22 µg/m³ per cigarette (Berkeley Earth), counting only the event's ranked days; not a medical dose.
Episode peak
-- cigarettes
The smoke map's scale, replayed over this event: the surface interpolates between covered metros' daily records, framed to the affected region. Hover for a reading, click a metro to pin it to the card. Days a monitor did not report draw nothing.
What happened, in the record
Qualified frozen evidence supports wildfire smoke as the broad cause for this time-bounded episode.
Sequence: Seattle (Aug 3) → Portland (Aug 3)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Seattle-Tacoma-Bellevue, WA | 68.5 µg/m³ | 3.1 | Aug 3, 2017 | #22 of its top days |
| Portland-Vancouver-Hillsboro, OR-WA | 56 µg/m³ | 2.5 | Aug 3, 2017 | #23 of its top days |
"Cigarettes, whole event" totals a metro's ranked event days at 22 µg/m³ per cigarette: what a person outdoors there breathed across the event, as the illustration. "All-time standing" is where this episode's days sit in each metro's ranked record (worst-area measure, since 1999). Full local context is on each metro's Air Records page.
The evidence
EPA AQS monitor qualifier 1
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 165 PM2.5 samples in the candidate CBSA on 2017-08-03, identifying wildfire smoke as affecting the samples. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
Agency and publisher pages 1
- Agencies issue air pollution advisory for Portland, Vancouver, Salem, Eugene and Medford areas The Oregon DEQ advisory covering August 2–8 identified intrusions of wildfire smoke, active wildfires, and stagnant conditions as contributing to particulate pollution in the Portland–Vancouver area during the event window.
What remains uncertain
- AQS qualifiers are submitting-agency causal flags and do not by themselves establish EPA concurrence.
- The evidence resolves the broad cause but does not require a named fire, facility, or incident.
- The retained official evidence directly covers Portland-Vancouver; it does not independently establish the Seattle portion.
Status and provenance
Research preview: this record carries research-only status and its boundaries, cause, and name may change as evidence review completes. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula.