Wildfire smoke
2020-10-01 3-area wildfire-smoke episode
Named source Glass Fire 67,484 acres , CA · IRWIN 2020-CALNU-015947
Daily PM2.5 peaked at 103.9 µg/m³ near San Francisco across 3 covered metros home to 7.5 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 6.2 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 46 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.
Sequence: Stockton (Oct 1) → San Jose (Oct 1) → San Francisco (Oct 2)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| San Francisco-Oakland-Hayward, CA | 103.9 µg/m³ | 4.7 | Oct 2, 2020 | #13 of its top days |
| Stockton-Lodi, CA | 98.8 µg/m³ | 12.5 | Oct 3, 2020 | #15 of its top days |
| San Jose-Sunnyvale-Santa Clara, CA | 79.7 µg/m³ | 9.8 | Oct 2, 2020 | #13 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 7
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 72 PM2.5 samples in the candidate CBSA on 2020-10-03, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 24 PM2.5 samples in the candidate CBSA on 2020-10-02, 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 70 PM2.5 samples in the candidate CBSA on 2020-10-02, 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 24 PM2.5 samples in the candidate CBSA on 2020-10-03, 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.
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 72 PM2.5 samples in the candidate CBSA on 2020-10-01, 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 24 PM2.5 samples in the candidate CBSA on 2020-10-01, 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 IE — Demolition. EPA AQS carries an agency-submitted informational qualifier (IE, Demolition.) on 1 PM2.5 sample in the candidate CBSA on 2020-10-03, identifying demolition as affecting the sample. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
Agency and publisher pages 2
- Spare the Air Alert extended through Friday Bay Area regulator extended its alert through October 2 because of wildfire smoke from the Glass Fire in Napa and Sonoma counties.
- Spare the Air Alert due to wildfire smoke from fires in northern California Subsequent agency release confirms persistent early-October northern California wildfire-smoke impacts, but is not a direct assessment of October 3 Stockton conditions.
What remains uncertain
- An AQS informational qualifier is an official submitting-agency flag, not an EPA-concurred exclusion determination.
- The supplied evidence resolves cause but does not establish identity with another candidate episode.
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.