Wildfire smoke High confidence
Daily PM2.5 peaked at 40.6 µg/m³ near Orlando across 1 covered metro home to 2.9 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 ≈ 4.4 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
An exact-date NWS Melbourne discussion attributed smoke odor across metro Orlando to a Polk County fire. NWS Storm Data independently identifies the 11,000-acre Stagecoach wildfire burning February 18-24, and contemporaneous reporting describes dense smoke streaming across central Florida.
High confidence At least two independent causal origins and evidence families agree on this cause.
National Weather Service Melbourne via Iowa Environmental Mesonet · Feb 21, 2001 official
The exact-date NWS discussion said smoke odor across metro Orlando came from a Polk County fire and would diminish slowly because of light low-level winds.
Los Angeles Times · Feb 21, 2001 corroborates
Contemporaneous reporting described the 11,000-acre Polk City blaze sending dense smoke across central Florida and threatening continued closure of Interstate 4 between Tampa and Orlando.
National Weather Service Storm Data · Feb 28, 2001 hypothesis
Storm Data records an approximately 11,000-acre Polk County wildfire burning February 18-24, with its variable smoke plume reducing visibility and closing Interstate 4 between Polk City and Lakeland.
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 exact-date NWS discussion said smoke odor across metro Orlando came from a Polk County fire and would diminish slowly because of light low-level winds.
View supporting source ↗Air-mass movement
NOAA HYSPLIT modeled 12 backward paths across multiple arrival times and heights. They show where the air traveled, not which source polluted it.
Explore the modeled paths ↓Local response
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 1.8 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 2001-02-18 to 2001-02-24 · PM2.5 target: WINTER PARK
275% above nearby days
About the same as surrounding days
275% higher than surrounding days
About the same as surrounding days
23% higher than surrounding days
12% higher than surrounding days
87% higher than surrounding days
11% higher 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.
Air-mass reconstruction
NOAA HYSPLIT traces the air arriving at each metro backward for 72 hours. Multiple arrival times and heights show whether the broad path is stable—or sensitive to assumptions about when and where the polluted layer arrived.
Air arriving near Orlando-Kissimmee-Sanford
Peak-date arrivals · 2001-02-21
Each line begins 72 hours before arrival and points toward the metro. Color represents arrival height; repeated lines represent 00, 06, 12, and 18 UTC arrival assumptions. A path can show where the air traveled, but it cannot prove which source added the PM2.5.
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 | 40.6 µg/m³ | 1.8 | Feb 21, 2001 | #7 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 Storm Data
Storm Data records an approximately 11,000-acre Polk County wildfire burning February 18-24, with its variable smoke plume reducing visibility and closing Interstate 4 between Polk City and Lakeland.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Storm Data documents the fire and smoke impacts; the separate forecast discussion supplies the direct Orlando connection.
National Weather Service Melbourne via Iowa Environmental Mesonet
The exact-date NWS discussion said smoke odor across metro Orlando came from a Polk County fire and would diminish slowly because of light low-level winds.
An official source supports the attributed cause for the stated place and dates.
Los Angeles Times
Contemporaneous reporting described the 11,000-acre Polk City blaze sending dense smoke across central Florida and threatening continued closure of Interstate 4 between Tampa and Orlando.
A retained source supports the attributed cause for the stated place and dates.
High confidence At least two independent causal origins and evidence families agree on this cause.
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.