Wildfire smoke
2021-08-07 2-area wildfire-smoke episode
Daily PM2.5 peaked at 64.8 µg/m³ near Denver across 2 covered metros home to 3.8 million people. 2 metros 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 ≈ 4.4 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 17 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: Denver (Aug 7) → Colorado Springs (Aug 7)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Denver-Aurora-Lakewood, CO | 64.8 µg/m³ | 5.5 | Aug 8, 2021 | #4 of its top days |
| Colorado Springs, CO | 44.6 µg/m³ | 3.5 | Aug 8, 2021 | #3 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
NWS Air Quality Alert 2
- Air Quality Alert AQABOU An archived NWS Air Quality Alert for Colorado Springs, CO, issued 2021-08-07T02:10Z, explicitly identifies wildfire smoke. IEM is the archive, not the official system of record.
- Air Quality Alert AQAPUB An archived NWS Air Quality Alert for Colorado Springs, CO, issued 2021-08-07T02:10Z, explicitly identifies wildfire smoke. IEM is the archive, not the official system of record.
Agency and publisher pages 1
- How Bad is the Smoke? Current Fires and Air Quality Resources CIRES reported that smoke from western wildfires blanketed Denver on August 7, 2021, corroborating the wildfire-smoke source for the Denver–Colorado Springs event.
What remains uncertain
- 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.