Wildfire smoke
2020-09-08 Bakersfield wildfire-smoke episode
Daily PM2.5 peaked at 125.4 µg/m³ near Bakersfield across 1 covered metro home to 922,529 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 ≈ 5.1 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 4.7 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.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Bakersfield, CA | 125.4 µg/m³ | 5.7 | Sep 8, 2020 | #7 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 2
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 22 PM2.5 samples in the candidate CBSA on 2020-09-08, 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 RT — Wildfire-U. S. EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 1 PM2.5 sample in the candidate CBSA on 2020-09-08, identifying wildfire smoke as affecting the sample. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
Agency and publisher pages 2
- Public Health Officials Urge Californians to Stay Indoors When Possible due to Unhealthy Air Quality in Wildfire Areas State release establishes wildfire smoke as the unhealthy-air hazard in California fire-stricken and surrounding regions during the active 2020 fire period.
- A Smoky Inferno NASA satellite account documents smoke-filled skies across western states on September 7 and notes the Creek Fire near Fresno; it supplies regional context rather than a Bakersfield-specific apportionment.
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.