Wildfire smoke
2020-09-10 3-area wildfire-smoke episode
Daily PM2.5 peaked at 513.4 µg/m³ near Portland across 3 covered metros home to 7.3 million people. 2 metros recorded their worst day on record; 3 placed a top-ten day.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 68.9 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 502 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
Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode. Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode.
Sequence: Portland (Sep 10) → Seattle (Sep 11) → Spokane (Sep 12)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Portland-Vancouver-Hillsboro, OR-WA | 513.4 µg/m³ | 112.7 | Sep 13, 2020 | Worst day on record |
| Spokane-Spokane Valley, WA | 396.8 µg/m³ | 71.3 | Sep 13, 2020 | Worst day on record |
| Seattle-Tacoma-Bellevue, WA | 188.2 µg/m³ | 46.2 | Sep 14, 2020 | #2 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
Official records
- NOAA Storm Events Wildfire, WASHINGTON, Sep 7, 2020 "Around Labor Day and through the first full week of September, an anomalous upper level ridge set up over the Northwest US, with a thermal trough developing along the Pacific Northwest Coast with high pressure east of th…" record →
- NOAA Storm Events Wildfire, WASHINGTON, Sep 7, 2020 "Around Labor Day and through the first full week of September, an anomalous upper level ridge set up over the Northwest US, with a thermal trough developing along the Pacific Northwest Coast with high pressure east of th…" record →
- NOAA Storm Events Dense Smoke, WASHINGTON, Sep 11, 2020 "After an anomalous period of strong offshore flow and warm, dry weather, numerous wildfires ignited across the Pacific Northwest. As the large scale weather pattern began to shift into mid September, conditions become fa…" record →
- NOAA Storm Events Wildfire, WASHINGTON, Sep 7, 2020 "Very dry and critical fire conditions over Eastern Washington during July and August produced dry fuels across the region. These fuels, with an incoming cold front's strong winds, created an outbreak of wildfires, blowin…" record →
- NOAA Storm Events Wildfire, WASHINGTON, Sep 7, 2020 "Very dry and critical fire conditions over Eastern Washington during July and August produced dry fuels across the region. These fuels, with an incoming cold front's strong winds, created an outbreak of wildfires, blowin…" record →
- NOAA Storm Events Dense Smoke, WASHINGTON, Sep 12, 2020 "Multiple large wildfires in Washington, Oregon, and surrounding states produced copious quantities of dense smoke throughout the month of September. Due to poor ventilation and a gradual return to southwest winds, there …" record →
- NOAA Storm Events Dense Smoke, WASHINGTON, Sep 12, 2020 "Multiple large wildfires in Washington, Oregon, and surrounding states produced copious quantities of dense smoke throughout the month of September. Due to poor ventilation and a gradual return to southwest winds, there …" record →
EPA AQS monitor qualifier 23
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 405 PM2.5 samples in the candidate CBSA on 2020-09-16, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 192 PM2.5 samples in the candidate CBSA on 2020-09-16, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 387 PM2.5 samples in the candidate CBSA on 2020-09-14, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 404 PM2.5 samples in the candidate CBSA on 2020-09-15, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 384 PM2.5 samples in the candidate CBSA on 2020-09-13, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 195 PM2.5 samples in the candidate CBSA on 2020-09-15, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 192 PM2.5 samples in the candidate CBSA on 2020-09-10, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 218 PM2.5 samples in the candidate CBSA on 2020-09-12, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 192 PM2.5 samples in the candidate CBSA on 2020-09-17, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 214 PM2.5 samples in the candidate CBSA on 2020-09-14, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 228 PM2.5 samples in the candidate CBSA on 2020-09-13, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 374 PM2.5 samples in the candidate CBSA on 2020-09-10, 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.
- +11 more EPA AQS records on file
NWS Air Quality Alert 2
- Air Quality Alert AQASEW An archived NWS Air Quality Alert for Seattle-Tacoma-Bellevue, WA, issued 2020-09-08T10:20Z, explicitly identifies wildfire smoke. IEM is the archive, not the official system of record.
- Air Quality Alert AQAOTX An archived NWS Air Quality Alert for Spokane-Spokane Valley, WA, issued 2020-09-14T17:55Z, explicitly identifies wildfire smoke. IEM is the archive, not the official system of record.
Agency and publisher pages 3
- Smoky siege Washington Ecology reports that smoke from Oregon wildfires moved into Washington beginning September 10 and that statewide PM2.5 monitors were above the federal 24-hour standard September 12-17.
- Air quality update: Advisory lifted for Oregon Coast, smoke to remain elsewhere next couple of days Oregon DEQ attributed the Portland-Vancouver regional advisory to smoke from fires in Oregon, Washington, and California and reported recent hazardous-to-very-unhealthy smoke levels.
- Joint press release: Wildfire Smoke Regional agency press release identifies wildfire smoke as the cause of the September health alert in Washington.
What remains uncertain
- An AQS informational qualifier is an official submitting-agency flag, not an EPA-concurred exclusion determination.
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.