NOAA Satellite Services Division hypothesis
Smoke analysis through 0335 UTC February 22, 2024
NOAA reported thin to moderate smoke from heavy seasonal fire activity across a corridor including Missouri on February 21.
Prescribed fire Possible
2024-02-21 Kansas City, MO-KS prescribed-fire smoke episode
Daily PM2.5 peaked at 39.1 µg/m³ near Kansas City across 1 covered metro home to 2.3 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 1.3 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 2.9 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.
Why we think this happened
The basis for “Prescribed fire”
NOAA mapped a large central-U.S. smoke layer from heavy seasonal burning across Missouri on the exact date, but did not establish surface attribution at Kansas City.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
Evidence path
From source to city
A cause is more convincing when the record connects three things: something happened, the air mass moved toward the region, and local instruments responded. Here is how much of that chain is documented for this event.
- 1Open question
Source or mechanism
Source not directly documented
The catalog has a grouping hypothesis, but no retained source directly establishes the proposed cause.
- 2Documented
Air-mass movement
Transport into the affected region is documented
NOAA reported thin to moderate smoke from heavy seasonal fire activity across a corridor including Missouri on February 21.
View transport source ↗ - 3Documented
Local response
39.1 µg/m³ near Kansas City
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 1.8 cigarette-equivalents at the outdoor daily rate.
Inspect the pollutant and weather signals ↓
Event autopsy
What the instruments saw
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Prescribed fire” explanation; it does not assign the cause by itself.
Kansas City, MO-KS
Monitor comparison window 2024-02-18 to 2024-02-24 · PM2.5 target: JFK
197% above nearby days
26% lower than surrounding days
142% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 20.9 µg/m³
197% higher than surrounding days
Before6.90 µg/m³ Event20.9 µg/m³ After10.3 µg/m³
PM10 64 µg/m³
142% higher than surrounding days
Before26.5 µg/m³ Event64 µg/m³ After26.5 µg/m³
Nitrogen dioxide 28.8 ppb
12% higher than surrounding days
Before25.7 ppb Event28.8 ppb After20.4 ppb
Sulfur dioxide 1.03 ppb
45% higher than surrounding days
Before0.710 ppb Event1.03 ppb After0.698 ppb
Ozone 0.033 ppm
6% lower than surrounding days
Before0.029 ppm Event0.033 ppm After0.036 ppm
Atmospheric conditions
Nearby EPA weather observations6% higher than surrounding days
About the same as surrounding days
11% higher than surrounding days
26% lower than surrounding days
Source: U.S. EPA AirData daily observations and, where available, nearby ASOS/AWOS surface observations. Values are descriptive medians over the retained monitor set; missing measurements remain missing. Transport and source evidence remain separate layers because this instrument pattern does not assign a cause by itself.
Measured daily PM2.5 at EPA monitors, as cigarette-equivalents
EPA monitors sit in metro areas, so the colour clusters there. Land between and beyond
them is unmeasured, not clean: this map shows where IAQng has readings, not the extent
of the smoke.
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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.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Kansas City, MO-KS | 39.1 µg/m³ | 1.8 | Feb 21, 2024 | #23 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.
Public evidence library
What supports this account
Each card states what a source supports—and what it does not. Official records, research, reporting, community observations, and transparent inferences remain visibly different kinds of evidence.
Smoke analysis through 0335 UTC February 22, 2024
NOAA Satellite Services Division
NOAA reported thin to moderate smoke from heavy seasonal fire activity across a corridor including Missouri on February 21.
What it supports
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Limit
Smoke could have been aloft; the narrative does not name Kansas City or quantify surface impact.
What remains uncertain
- The seasonal-fire description supports prescribed-fire smoke only as a possible broad cause.
Status and provenance
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
This episode was grouped from the monitor record by the catalog pipeline and given its cause from the evidence listed above. It has not been individually reviewed and signed off, so its boundaries, cause, and name may change as evidence accumulates. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula. If it is wrong, tell us.