Wildfire smoke
2022-10-09 Seattle-Tacoma-Bellevue, WA wildfire smoke episode
Daily PM2.5 peaked at 66.5 µg/m³ near Seattle across 1 covered metro home to 4.1 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 2.6 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 11 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 supplied evidence supports wildfire smoke as the root cause of this event. The supplied record does not establish a coherent shared occurrence with neighboring candidates, so the episode remains event-specific.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Seattle-Tacoma-Bellevue, WA | 66.5 µg/m³ | 3.0 | Oct 9, 2022 | #25 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 240 PM2.5 samples in the candidate CBSA on 2022-10-09, 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.
NWS Air Quality Alert 1
- Archived Seattle Air Quality Alert, October 9, 2022 The alert explicitly identified wildfire smoke affecting air quality across Puget Sound during the Seattle event. IEM is the archive, not the official system of record.
Agency and publisher pages 2
- Eyes Over Puget Sound, October 2022 The agency’s October 10 Puget Sound air-quality report identifies smoke lingering in Seattle over the October 9–10 period as wildfire smoke.
- 2022 Data Summary The agency retrospectively identifies October 1–10, 2022 as wildfire-smoke-impacted days at all its monitoring sites.
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.