Temperature inversion Possible
Daily PM2.5 peaked at 38.5 µg/m³ near Jacksonville across 1 covered metro home to 1.8 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 1.4 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 2.4 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 discussion documents calm winds and a shallow surface inversion over northeast Florida during a certified mixed-pollutant episode. The evidence supports a possible morning accumulation mechanism but not an emitting source or an all-day inversion.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
National Weather Service Jacksonville via Iowa Environmental Mesonet · Oct 28, 2000 hypothesis
On the morning of October 28, NWS Jacksonville reported that calm winds and a shallow surface inversion were keeping fog over northeast Florida and southeast Georgia longer than expected. It expected rising temperatures and mixing to remove the inversion later that morning.
U.S. EPA AirData hypothesis
IAQng's reproducible aggregation of certified EPA rows found Jacksonville-area PM2.5 averaging about 37.0 µg/m³ on October 28, versus 5.6 the preceding comparison day. PM10 was 58 µg/m³ versus 28, while CO, NO2, and SO2 were also higher; the highest PM2.5 site reached 38.5 µg/m³.
Inference, not direct attribution
Documented inversion overlap: The event overlaps a documented inversion period, but the retained material does not directly attribute the measured PM2.5 episode.
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 inversion overlap. The event overlaps a documented inversion period, but the retained material does not directly attribute the measured PM2.5 episode.
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 1.8 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 “Temperature inversion” explanation; it does not assign the cause by itself.
Jacksonville, FL
Monitor comparison window 2000-10-25 to 2000-10-31 · PM2.5 target: Sunny Acres
233% above nearby days
93% higher than surrounding days
233% higher than surrounding days
93% higher than surrounding days
34% higher than surrounding days
25% higher than surrounding days
42% higher than surrounding days
9% 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 |
|---|---|---|---|---|
| Jacksonville, FL | 38.5 µg/m³ | 1.8 | Oct 28, 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 Weather Service Jacksonville via Iowa Environmental Mesonet
On the morning of October 28, NWS Jacksonville reported that calm winds and a shallow surface inversion were keeping fog over northeast Florida and southeast Georgia longer than expected. It expected rising temperatures and mixing to remove the inversion later that morning.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The discussion documents a morning trapping layer, not an all-day inversion or a specific emissions source.
U.S. EPA AirData
IAQng's reproducible aggregation of certified EPA rows found Jacksonville-area PM2.5 averaging about 37.0 µg/m³ on October 28, versus 5.6 the preceding comparison day. PM10 was 58 µg/m³ versus 28, while CO, NO2, and SO2 were also higher; the highest PM2.5 site reached 38.5 µg/m³.
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
The fingerprint demonstrates a mixed pollution buildup but does not apportion the PM2.5 to particular sources or prove that the morning inversion caused the complete daily average.
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.