Wildfire smoke Possible
Daily PM2.5 peaked at 45.7 µg/m³ near Oklahoma City across 2 covered metros home to 2.6 million 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 ≈ 1.5 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 3.7 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
Manual research connected 2 source events to one wildfire-smoke episode using the deterministic grouping rule.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
Journal of Geophysical Research: Atmospheres · Jul 26, 2006 corroborates
The peer-reviewed reconstruction identifies April 27 through May 12 as one of four major 2003 Central American biomass-burning smoke events, with PM2.5 peaking May 8-10 at nearly all evaluated stations outside western and northern Texas. It identifies Oklahoma as part of the nearby smoke-pathway region frequently covered during the study period.
National Weather Service Norman via Iowa Environmental Mesonet · May 8, 2003 hypothesis
The exact-date NWS roundup reported haze at Tulsa and several other Oklahoma stations while Oklahoma City-area stations reported haze, fog, or storms, confirming a broad visibility-reducing episode on the event date.
Inference, not direct attribution
regional_smoke_pathway_exact_window_fingerprint_possible.v1: This inference is recorded in the catalog methodology.
See every retained source and limitation ↓
Sequence: Oklahoma City (May 8) → Tulsa (May 8)
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
The peer-reviewed reconstruction identifies April 27 through May 12 as one of four major 2003 Central American biomass-burning smoke events, with PM2.5 peaking May 8-10 at nearly all evaluated stations outside western and northern Texas. It…
View supporting source ↗Air-mass movement
The peer-reviewed reconstruction identifies April 27 through May 12 as one of four major 2003 Central American biomass-burning smoke events, with PM2.5 peaking May 8-10 at nearly all evaluated stations outside western and northern Texas. It…
View transport source ↗Local response
EPA monitors recorded the event across 2 metros. 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.
Oklahoma City, OK
Monitor comparison window 2003-05-05 to 2003-05-11 · PM2.5 target: MESONET WEATHER STATION LOCATED 2 MILES ENE OF SPENCER
327% above nearby days
19 kt maximum
Haze reported during 10 hours
327% higher than surrounding days
39% higher than surrounding days
5% lower than surrounding days
48% higher than surrounding days
About the same as surrounding days
19 kt maximum · No calm observed hours
7 observed hours at or below 3 miles
69.8°F to 82.4°F
100% maximum
Tulsa, OK
Monitor comparison window 2003-05-05 to 2003-05-11
100% above nearby days
23 kt maximum
Haze reported during 11 hours
100% higher than surrounding days
7% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
23 kt maximum · No calm observed hours
0 observed hours at or below 3 miles
70°F to 83°F
100% maximum
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 |
|---|---|---|---|---|
| Oklahoma City, OK | 45.7 µg/m³ | 2.1 | May 8, 2003 | #4 of its top days |
| Tulsa, OK | 36.1 µg/m³ | 1.6 | May 8, 2003 | #19 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 Weather Service Norman via Iowa Environmental Mesonet
The exact-date NWS roundup reported haze at Tulsa and several other Oklahoma stations while Oklahoma City-area stations reported haze, fog, or storms, confirming a broad visibility-reducing episode on the event date.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Weather observations confirm the timing and footprint of haze but do not identify its emissions source.
National Weather Service Norman via Iowa Environmental Mesonet
The exact-date NWS roundup reported haze at Tulsa and several other Oklahoma stations while Oklahoma City-area stations reported haze, fog, or storms, confirming a broad visibility-reducing episode on the event date.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Weather observations confirm the timing and footprint of haze but do not identify its emissions source.
Journal of Geophysical Research: Atmospheres
The peer-reviewed reconstruction identifies April 27 through May 12 as one of four major 2003 Central American biomass-burning smoke events, with PM2.5 peaking May 8-10 at nearly all evaluated stations outside western and northern Texas. It identifies Oklahoma as part of the nearby smoke-pathway region frequently covered during the study period.
A retained source supports the attributed cause for the stated place and dates.
The paper's quantitative PM2.5 comparison is based on Texas monitors; Oklahoma is identified as part of the smoke pathway but is not given a metro-specific source fraction.
Journal of Geophysical Research: Atmospheres
The peer-reviewed reconstruction identifies April 27 through May 12 as one of four major 2003 Central American biomass-burning smoke events, with PM2.5 peaking May 8-10 at nearly all evaluated stations outside western and northern Texas. It identifies Oklahoma as part of the nearby smoke-pathway region frequently covered during the study period.
A retained source supports the attributed cause for the stated place and dates.
The paper's quantitative PM2.5 comparison is based on Texas monitors; Oklahoma is identified as part of the smoke pathway but is not given a metro-specific source fraction.
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.