Wildfire smoke
Thomas Fire smoke episode, 2017-12-13 through 2017-12-16
Named source Thomas Fire 281,893 acres , CA · IRWIN 2017-CAVNC-103156
Daily PM2.5 peaked at 100.7 µg/m³ near Oxnard across 1 covered metro home to 835,427 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 ≈ 7.2 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 6.0 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 and supports grouping 2 records into the same time-bounded occurrence. Qualified frozen evidence supports wildfire smoke as the broad cause and supports grouping 2 records into the same time-bounded occurrence.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Oxnard-Thousand Oaks-Ventura, CA | 100.7 µg/m³ | 8.6 | Dec 16, 2017 | #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 48 PM2.5 samples in the candidate CBSA on 2017-12-13, 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 48 PM2.5 samples in the candidate CBSA on 2017-12-16, 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 48 PM2.5 samples in the candidate CBSA on 2017-12-15, 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 4
- Thomas Fire CAL FIRE identifies the Thomas Fire as an active December 2017 wildfire in Ventura and Santa Barbara counties, placing the Oxnard-area event within the fire's smoke-impacted period.
- Smoke Advisory for the Thomas Fire The air district issued a December 16 smoke advisory citing shifting winds and ongoing smoke from the Thomas Fire burning in Ventura and Santa Barbara counties.
- Thomas Fire Information The City of Ventura states that the December 2017 Thomas Fire moved through Ventura County and records smoke and ash impacts.
- Smoke Text Product - Satellite Services Division NOAA satellite-smoke analysis identified the observed southern California smoke as almost certainly from the Thomas Fire in Ventura County.
Cited authorities: CAL FIRE
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.
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.