KGOU / NPR corroborates
The Western Wildfires Are Affecting People 3,000 Miles Away
Oklahoma public radio reported on July 21 that smoke from western U.S. and Canadian wildfires was crossing the continent and degrading air quality.
Wildfire smoke Likely
2021-07-21 to 2021-07-22 Oklahoma City, OK wildfire-smoke episode
Daily PM2.5 peaked at 35.8 µg/m³ near Oklahoma City across 1 covered metro home to 1.5 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 2.3 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 3.5 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 “Wildfire smoke”
Contemporaneous Oklahoma public-radio reporting attributes the nationwide haze and poor air quality to western U.S. and Canadian wildfires.
Likely Applicable reporting or a supported inference makes this the best current causal explanation.
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
Wildfire smoke
Oklahoma public radio reported on July 21 that smoke from western U.S. and Canadian wildfires was crossing the continent and degrading air quality.
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
35.8 µg/m³ near Oklahoma City
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 1.6 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 “Wildfire smoke” explanation; it does not assign the cause by itself.
Oklahoma City, OK
Monitor comparison window 2021-07-18 to 2021-07-25 · PM2.5 target: OKC Near Road
52% above nearby days
30% lower than surrounding days
22% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 26.1 µg/m³
52% higher than surrounding days
Before13.2 µg/m³ Event26.1 µg/m³ After19.1 µg/m³
PM10 39.5 µg/m³
22% higher than surrounding days
Before23 µg/m³ Event39.5 µg/m³ After53 µg/m³
Carbon monoxide 0.718 ppm
10% higher than surrounding days
Before0.596 ppm Event0.718 ppm After0.677 ppm
Nitrogen dioxide 10.8 ppb
64% higher than surrounding days
Before5.85 ppb Event10.8 ppb After6.83 ppb
Sulfur dioxide 0 ppb
Adjacent observations available
Before0 ppb Event0 ppb After0 ppb
Ozone 0.045 ppm
14% higher than surrounding days
Before0.039 ppm Event0.045 ppm After0.035 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
About the same as surrounding days
30% 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.
—
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 |
|---|---|---|---|---|
| Oklahoma City, OK | 35.8 µg/m³ | 3.2 | Jul 21, 2021 | #15 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.
The Western Wildfires Are Affecting People 3,000 Miles Away
KGOU / NPR
Oklahoma public radio reported on July 21 that smoke from western U.S. and Canadian wildfires was crossing the continent and degrading air quality.
What it supports
A retained source supports the attributed cause for the stated place and dates.
What remains uncertain
- The classification is bounded to the retained evidence and does not apportion every source contributing to the daily PM2.5 value.
Status and provenance
Likely Applicable reporting or a supported inference makes this the best current causal explanation.
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.