Wildfire smoke
2007 Idaho-Montana-Canadian wildfire smoke episode
Daily PM2.5 peaked at 46.4 µg/m³ near Richmond across 3 covered metros home to 2.9 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 ≈ 1.6 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 4.5 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
North Carolina DEQ identifies Idaho, Montana, and Canadian wildfire impacts at Greensboro's Mendenhall monitor on August 5.
Sequence: Richmond (Aug 5) → Greensboro (Aug 5) → Winston (Aug 5)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Richmond, VA | 46.4 µg/m³ | 2.1 | Aug 5, 2007 | #10 of its top days |
| Greensboro-High Point, NC | 42.2 µg/m³ | 1.9 | Aug 5, 2007 | #13 of its top days |
| Winston-Salem, NC | 41.9 µg/m³ | 1.9 | Aug 5, 2007 | #22 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 1
- 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 2007-08-05, 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 1
- Data Proposed For Exclusion From NAAQS Compliance Determinations North Carolina DEQ's exceptional-events inventory identifies Idaho, Montana, and Canadian wildfires as affecting PM2.5 monitoring, including Greensboro's Mendenhall monitor, on August 5, 2007.
What remains uncertain
- AQS qualifiers are submitting-agency causal flags and do not by themselves establish EPA concurrence.
- The supplied evidence specifically names the Greensboro monitor and does not separately assess the other metros in this candidate.
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.