Wildfire smoke
October 2007 Southern California wildfire-smoke episode
Daily PM2.5 peaked at 126.2 µg/m³ near San Diego across 1 covered metro home to 3.3 million people. 1 metro placed a top-ten day in their record.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 13.2 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 43 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 root cause; the Witch Creek and Guejito fires are retained as specific contributing sources rather than used as the grouping key.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| San Diego-Carlsbad, CA | 126.2 µg/m³ | 14.9 | Oct 23, 2007 | #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
EPA AQS monitor qualifier 3
- AQS PM2.5 qualifier RT — Wildfire-U. S. EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 2 PM2.5 samples in the candidate CBSA on 2007-10-23, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
- AQS PM2.5 qualifier RT — Wildfire-U. S. EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 4 PM2.5 samples in the candidate CBSA on 2007-10-24, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
- AQS PM2.5 qualifier RT — Wildfire-U. S. EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 2 PM2.5 samples in the candidate CBSA on 2007-10-22, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
Agency and publisher pages 3
- 2007 Exceptional Events - Wildfire Smoke and High Winds - July through November 2007 CARB's exceptional-events documentation identifies the Southern California wildfires and records elevated PM2.5 at San Diego-area monitors, including an Escondido concentration of 126 µg/m³ on 23 October 2007.
- 2007 - Witch Creek and Guejito Fires The City documents the Witch Creek and Guejito fires beginning 21 October 2007 in and near San Diego County, contemporaneous with the PM2.5 episode.
- Fires in Southern California NASA satellite imagery from 23 October 2007 documents smoke from the Southern California fires during the event period.
Cited authorities: City of San Diego
What remains uncertain
- AQS qualifiers are submitting-agency causal flags and do not by themselves establish EPA concurrence.
- CARB describes the wider Southern California wildfire complex; the supplied records do not isolate the contribution of each named fire.
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.