Wildfire smoke Possible
Daily PM2.5 peaked at 46.4 µg/m³ near Wichita across 1 covered metro home to 661,217 people. 1 metro 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 ≈ 1.7 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 1.1 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
McConnell AFB reported smoke for five hours during the PM2.5 event. FPA-FOD records the 4,000-acre Birch Reservoir fire on the exact date and in the upwind sector, and NIFC independently confirms the incident and final acreage. This supports wildfire smoke as possible, but the evidence does not prove that this one fire supplied all observed smoke or quantify its PM2.5 contribution.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
National Interagency Coordination Center · Mar 25, 2005 hypothesis
NIFC's official situation report lists the Birch Reservoir incident in Oklahoma under the Osage Agency at 4,000 acres and 100% contained, independently confirming the large-fire identity and reported size retained by FPA-FOD.
USDA Forest Service Rocky Mountain Research Station hypothesis
FPA-FOD dates the 4,000-acre Birch Reservoir fire in Osage County, Oklahoma, to March 20, 94.7 miles southeast of the Wichita surface station. The source bearing was 140.6 degrees from the station while the event-window wind came consistently from 122.3 degrees, an 18.3-degree alignment.
NOAA/NWS surface observations via Iowa Environmental Mesonet · Mar 20, 2005 hypothesis
MCCONNELL_AFB, 18.4 km from the PM2.5 target monitor, reported the official present-weather code FU (smoke) during 5 observed hours inside the catalog event window.
Inference, not direct attribution
surface_smoke_plus_bounded_fire_occurrences_possible.v1: This inference is recorded in the catalog methodology.
Evidence path
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.
Source or mechanism
surface_smoke_plus_bounded_fire_occurrences_possible.v1. This inference is recorded in the catalog methodology.
Air-mass movement
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.
Local response
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 2.1 cigarette-equivalents at the outdoor daily rate.
Inspect the pollutant and weather signals ↓Event autopsy
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Wildfire smoke” explanation; it does not assign the cause by itself.
Wichita, KS
Monitor comparison window 2005-03-17 to 2005-03-23 · PM2.5 target: PECK
124% above nearby days
About the same as surrounding days
119% higher than surrounding days
124% higher than surrounding days
119% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
126% higher than surrounding days
64% higher than surrounding days
14% lower than surrounding days
About the same as surrounding days
11% higher than surrounding days
About the same as 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.
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.
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Wichita, KS | 46.4 µg/m³ | 2.1 | Mar 20, 2005 | #10 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
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.
National Interagency Coordination Center
NIFC's official situation report lists the Birch Reservoir incident in Oklahoma under the Osage Agency at 4,000 acres and 100% contained, independently confirming the large-fire identity and reported size retained by FPA-FOD.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The situation report confirms the incident and acreage but does not state that its smoke reached Wichita.
NOAA/NWS surface observations via Iowa Environmental Mesonet
MCCONNELL_AFB, 18.4 km from the PM2.5 target monitor, reported the official present-weather code FU (smoke) during 5 observed hours inside the catalog event window.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The surface code establishes smoke at the nearby airport; it does not identify whether the source was a wildfire, prescribed burn, agricultural fire, or another local fire.
USDA Forest Service Rocky Mountain Research Station
FPA-FOD dates the 4,000-acre Birch Reservoir fire in Osage County, Oklahoma, to March 20, 94.7 miles southeast of the Wichita surface station. The source bearing was 140.6 degrees from the station while the event-window wind came consistently from 122.3 degrees, an 18.3-degree alignment.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
FPA-FOD is a fire-occurrence inventory, not a smoke-transport or PM2.5 source-apportionment product.
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.