Stagnant pollution mixture Possible
Daily PM2.5 peaked at 75.3 µg/m³ near Tampa across 1 covered metro home to 3.4 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 ≈ 4.8 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 16 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
Exact-window NWS discussions document persistent haze under weak flow and blocking high pressure. Certified EPA observations independently show simultaneous elevations across PM2.5, PM10, CO, NO2, and SO2. This supports a mixed-pollution accumulation mechanism, but not a dominant source.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
National Weather Service Tampa Bay via Iowa Environmental Mesonet · Oct 30, 2000 hypothesis
Across the October 29-30 event window, NWS Tampa Bay repeatedly described lingering or patchy haze, light or nearly calm low-level winds, an omega blocking pattern and upper ridge, surface high pressure, and a weak front expected to stall or dissipate. Haze was still present early October 31.
U.S. EPA AirData hypothesis
IAQng's reproducible aggregation of certified EPA rows found that Tampa-area PM2.5 rose during October 29-30 along with PM10, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Event-window averages were approximately 44.9 µg/m³ PM2.5, 64.5 µg/m³ PM10, 0.88 ppm CO, 22.2 ppb NO2, and 4.9 ppb SO2, all above the immediately preceding comparison window; one PM2.5 site reached 75.3 µg/m³.
Inference, not direct attribution
documented_stagnation_overlap_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
documented_stagnation_overlap_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 3.4 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 “Stagnant pollution mixture” explanation; it does not assign the cause by itself.
Tampa-St. Petersburg-Clearwater, FL
Monitor comparison window 2000-10-26 to 2000-11-02 · PM2.5 target: DUNEDIN HIGHLAND MIDDLE SCHOOL
127% above nearby days
50% higher than surrounding days
127% higher than surrounding days
50% higher than surrounding days
15% higher than surrounding days
21% higher than surrounding days
61% higher than surrounding days
17% 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.
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 |
|---|---|---|---|---|
| Tampa-St. Petersburg-Clearwater, FL | 75.3 µg/m³ | 5.6 | Oct 30, 2000 | #2 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 Tampa Bay via Iowa Environmental Mesonet
Across the October 29-30 event window, NWS Tampa Bay repeatedly described lingering or patchy haze, light or nearly calm low-level winds, an omega blocking pattern and upper ridge, surface high pressure, and a weak front expected to stall or dissipate. Haze was still present early October 31.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The discussions establish a locally relevant weak-ventilation and haze setting but do not chemically identify the particles or name the dominant emissions source.
U.S. EPA AirData
IAQng's reproducible aggregation of certified EPA rows found that Tampa-area PM2.5 rose during October 29-30 along with PM10, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Event-window averages were approximately 44.9 µg/m³ PM2.5, 64.5 µg/m³ PM10, 0.88 ppm CO, 22.2 ppb NO2, and 4.9 ppb SO2, all above the immediately preceding comparison window; one PM2.5 site reached 75.3 µg/m³.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The fingerprint demonstrates a mixed pollution episode but does not apportion the PM2.5 to particular sources.
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.