IAQng
← Air events

Other Documented

2024-04-09 Wichita, KS another explicitly identified source episode

April 9, 2024

Daily PM2.5 peaked at 38.2 µg/m³ near Wichita across 1 covered metro home to 661,217 people.

Why we think this happened

The basis for “Other”

KDHE attributes the Wichita-metro exceedance as likely influenced by wildland fires within the Flint Hills but does not distinguish prescribed fire from wildfire and notes other contributors. The supported broad cause therefore remains other.

Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.

Kansas Department of Health and Environment · May 7, 2024 official

Flint Hills Wildland Fire Update: 2024 Summary

KDHE lists an April 9 preliminary PM2.5 exceedance of 38 ug/m3 at Peck in the Wichita metro and assesses the listed exceedances as likely influenced by wildland fires within the Flint Hills. It cautions that regional pollution, other sources, and smoke from fires beyond the Flint Hills also likely contributed, and its acreage analysis does not distinguish prescribed fire from wildfire.

See every retained source and limitation ↓

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.

Open the evidence ledger ↓
  1. 1

    Source or mechanism

    Other

    KDHE lists an April 9 preliminary PM2.5 exceedance of 38 ug/m3 at Peck in the Wichita metro and assesses the listed exceedances as likely influenced by wildland fires within the Flint Hills. It cautions that regional pollution, other sources, and…

    View supporting source ↗
    Documented
  2. 2

    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.

    Research gap
  3. 3

    Local response

    38.2 µg/m³ near Wichita

    EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 1.7 cigarette-equivalents at the outdoor daily rate.

    Inspect the pollutant and weather signals ↓
    Documented

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 “Other” explanation; it does not assign the cause by itself.

Observed context · not attribution

Wichita, KS

Monitor comparison window 2024-04-06 to 2024-04-12 · PM2.5 target: PECK

5 pollutant signals
Fine-particle pulse 29.3 µg/m³

125% above nearby days

PM10 50.5 µg/m³

6% higher than surrounding days

Pollution fingerprint

Metro-wide median of reporting monitors
PM2.5 29.3 µg/m³

125% higher than surrounding days

Before5.15 µg/m³ Event29.3 µg/m³ After13 µg/m³
2 monitors · 1 HOUR
PM10 50.5 µg/m³

6% higher than surrounding days

Before43.5 µg/m³ Event50.5 µg/m³ After47.5 µg/m³
2 monitors · 24-HR BLK AVG
Nitrogen dioxide 4.78 ppb

About the same as surrounding days

Before3.71 ppb Event4.78 ppb After8.18 ppb
2 monitors · 1 HOUR
Sulfur dioxide 0.179 ppb

817% higher than surrounding days

Before-0.037 ppb Event0.179 ppb After-0.025 ppb
1 monitor · 1 HOUR
Ozone 0.045 ppm

16% higher than surrounding days

Before0.037 ppm Event0.045 ppm After0.039 ppm
3 monitors · 8-HR RUN AVG BEGIN HOUR

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.
—

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

MetroPeak PM2.5Cigarettes, whole eventPeak dayAll-time standing
Wichita, KS 38.2 µg/m³ 1.7 Apr 9, 2024 #20 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

  • Flint Hills Wildland Fire Update: 2024 Summary

    Kansas Department of Health and Environment · May 7, 2024 official government

    KDHE lists an April 9 preliminary PM2.5 exceedance of 38 ug/m3 at Peck in the Wichita metro and assesses the listed exceedances as likely influenced by wildland fires within the Flint Hills. It cautions that regional pollution, other sources, and smoke from fires beyond the Flint Hills also likely contributed, and its acreage analysis does not distinguish prescribed fire from wildfire.

Cited authorities: Kansas Department of Health and Environment

What remains uncertain

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.