Kansas Flint Hills Smoke Management · Apr 10, 2020 official
Flint Hills Prescribed Fire Update, April 10, 2020
The state smoke-management update records Wichita's April 4, 2020 24-hour PM2.5 average of 40.5 µg/m3 in its prescribed-fire smoke update.
Prescribed fire Documented
2020-04-04 Wichita prescribed-fire smoke episode
Daily PM2.5 peaked at 40.5 µg/m³ near Wichita across 1 covered metro home to 661,217 people.
Why we think this happened
The basis for “Prescribed fire”
Supplied qualified evidence supports prescribed-fire smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode.
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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.
- 1Documented
Source or mechanism
Prescribed fire
The state smoke-management update records Wichita's April 4, 2020 24-hour PM2.5 average of 40.5 µg/m3 in its prescribed-fire smoke update.
View supporting source ↗ - 2Research gap
Air-mass movement
The transport path has not been reconstructed
The retained record does not yet show how air traveled from the proposed source to these metros. A trajectory replay or dated plume analysis belongs here.
- 3Documented
Local response
40.5 µg/m³ near Wichita
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.
Wichita, KS
Monitor comparison window 2020-04-01 to 2020-04-07 · PM2.5 target: WICHITA HD
226% above nearby days
114% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 32.9 µg/m³
226% higher than surrounding days
Before4.98 µg/m³ Event32.9 µg/m³ After12.7 µg/m³
PM10 38.5 µg/m³
114% higher than surrounding days
Before12 µg/m³ Event38.5 µg/m³ After27.5 µg/m³
Nitrogen dioxide 5.36 ppb
59% higher than surrounding days
Before2.57 ppb Event5.36 ppb After4.99 ppb
Sulfur dioxide -0.004 ppb
105% lower than surrounding days
Before0.071 ppb Event-0.004 ppb After0.309 ppb
Ozone 0.030 ppm
8% higher than surrounding days
Before0.028 ppm Event0.030 ppm After0.027 ppm
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 |
|---|---|---|---|---|
| Wichita, KS | 40.5 µg/m³ | 1.8 | Apr 4, 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.
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.
Agency and publisher pages 1
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Flint Hills Prescribed Fire Update, April 10, 2020
The state smoke-management update records Wichita's April 4, 2020 24-hour PM2.5 average of 40.5 µg/m3 in its prescribed-fire smoke update.
What remains uncertain
- The supplied evidence resolves cause but does not establish identity with another candidate episode.
Status and provenance
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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.