Wildfire smoke
2020-08-22 2-area wildfire-smoke episode
Named source Cameron Peak Fire 208,913 acres , CO · IRWIN 2020-COARF-000636
Daily PM2.5 peaked at 51.6 µg/m³ near Denver across 2 covered metros home to 3.8 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 3.5 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 13 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 22) → Colorado Springs (Aug 22)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Denver-Aurora-Lakewood, CO | 51.6 µg/m³ | 4.6 | Aug 22, 2020 | #16 of its top days |
| Colorado Springs, CO | 28.7 µg/m³ | 2.6 | Aug 22, 2020 | #14 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 1
- Air Quality Alert AQABOU An archived NWS Air Quality Alert for Denver-Aurora-Lakewood, CO, issued 2020-08-22T15:10Z, explicitly identifies wildfire smoke. IEM is the archive, not the official system of record.
Agency and publisher pages 2
- Cameron Peak fire 18,287 acres, 0% contained in Larimer County Contemporaneous coverage relayed a National Weather Service forecast that Cameron Peak Fire smoke would drift south toward Denver, with unhealthy visibility conditions.
- A Smoky Inferno NASA documented the widespread early-September western wildfire-smoke episode and specifically noted Colorado fire activity and unhealthy-air warnings; it does not directly attribute the August 22 metro measurements.
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.