Wildfire smoke Likely
Daily PM2.5 peaked at 32.6 µg/m³ near Orlando across 1 covered metro home to 2.9 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 1.1 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 3.4 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
Orlando's airport reported smoke during the PM2.5 event. The next-morning federal incident report identifies the active Green Swamp Grove wildfire in southern Lake County east of Orlando, with aircraft and ground crews working the fire amid long-distance spotting.
Likely Applicable reporting or a supported inference makes this the best current causal explanation.
National Interagency Coordination Center · May 25, 2000 hypothesis
The federal incident report issued early May 25 says the Green Swamp Grove fire was burning in southern Lake County east of Orlando. It reports 275 acres, 50% containment, aircraft and ground resources, strong winds, and long-distance spotting problems.
NOAA/NWS surface observations via Iowa Environmental Mesonet · May 24, 2000 hypothesis
ORLANDO/HERNDON, 6.3 km from the PM2.5 target monitor, reported the official present-weather code FU (smoke) during 1 observed hour inside the catalog event window.
Inference, not direct attribution
official_surface_smoke_plus_exact_window_source_occurrence.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
official_surface_smoke_plus_exact_window_source_occurrence.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 1.5 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.
Orlando-Kissimmee-Sanford, FL
Monitor comparison window 2000-05-21 to 2000-05-27 · PM2.5 target: WINTER PARK
0% above nearby days
33% lower than surrounding days
About the same as surrounding days
33% lower than surrounding days
15% higher than surrounding days
About the same as surrounding days
69% higher than surrounding days
20% 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.
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.
Views from the selected metro
Select a metro on the map to see nearby cameras. Where an operator archive reaches the event, drag the divider to compare two moments, adjust either date and time, or play the available event-day frames. Camera imagery is visual context, not an air-quality measurement or proof of smoke.
No useful public camera views are currently available within 80 km of this metro.
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Orlando-Kissimmee-Sanford, FL | 32.6 µg/m³ | 1.5 | May 24, 2000 | #21 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
The federal incident report issued early May 25 says the Green Swamp Grove fire was burning in southern Lake County east of Orlando. It reports 275 acres, 50% containment, aircraft and ground resources, strong winds, and long-distance spotting problems.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The report establishes an active same-window fire near Orlando but does not explicitly connect its plume to the regulatory PM2.5 monitor.
NOAA/NWS surface observations via Iowa Environmental Mesonet
ORLANDO/HERNDON, 6.3 km from the PM2.5 target monitor, reported the official present-weather code FU (smoke) during 1 observed hour 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.
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.