442% above nearby days
Fireworks Possible
2016-01-01 Lakeland-Winter Haven, FL fireworks episode
Daily PM2.5 peaked at 25.2 µg/m³ near Lakeland across 1 covered metro home to 852,878 people.
Why we think this happened
The basis for “Fireworks”
The certified episode is a one-day January 1 PM2.5 pulse and satisfies the versioned holiday-fireworks rule. Contemporaneous local listings independently document a December 31 fireworks display inside the Lakeland-Winter Haven metro, but that show occurred at 7 p.m., before the January 1 monitor day. It is retained as local context rather than direct causal evidence, so the estimate remains possible.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
Inference, not direct attribution
Holiday timing: The event falls in the July 3–5 or December 31–January 1 fireworks window. That makes fireworks a reasonable hypothesis, but no retained source directly attributes this event.
Evidence path
From source to city
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.
- 1Inferred
Source or mechanism
Pattern-based explanation
Holiday timing. The event falls in the July 3–5 or December 31–January 1 fireworks window. That makes fireworks a reasonable hypothesis, but no retained source directly attributes this event.
- 2Research gap
Air-mass movement
The transport path has not been reconstructed
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.
- 3Documented
Local response
25.2 µg/m³ near Lakeland
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 1.1 cigarette-equivalents at the outdoor daily rate.
Inspect the pollutant and weather signals ↓
Event autopsy
What the instruments saw
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Fireworks” explanation; it does not assign the cause by itself.
Lakeland-Winter Haven, FL
Monitor comparison window 2015-12-29 to 2016-01-04 · PM2.5 target: Baptist Childrens' Home
12 calm hours observed
8 hours at or below 3 miles
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 24.9 µg/m³
442% higher than surrounding days
Before4.40 µg/m³ Event24.9 µg/m³ After4.60 µg/m³
PM10 32 µg/m³
146% higher than surrounding days
Before16 µg/m³ Event32 µg/m³ After8 µg/m³
Sulfur dioxide 1.79 ppb
72% higher than surrounding days
Before1 ppb Event1.79 ppb After1.04 ppb
Ozone 0.015 ppm
27% lower than surrounding days
Before0.017 ppm Event0.015 ppm After0.023 ppm
Atmospheric conditions
LAKELAND REGIONAL, 6.4 km from the PM2.5 target9 kt maximum · 12 of 23 observed hours calm
8 observed hours at or below 3 miles
66.2°F to 82.4°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.
Measured daily PM2.5 at EPA monitors, as cigarette-equivalents
EPA monitors sit in metro areas, so the colour clusters there. Land between and beyond
them is unmeasured, not clean: this map shows where IAQng has readings, not the extent
of the smoke.
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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
Camera views near
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.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Lakeland-Winter Haven, FL | 25.2 µg/m³ | 1.1 | Jan 1, 2016 | #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
What supports this account
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.
Effects of Independence Day fireworks on atmospheric concentrations of fine particulate matter in the United States
Atmospheric Environment
The nationwide monitor study establishes that holiday fireworks can produce abrupt, short-lived PM2.5 increases around celebration hours. Lakeland's January 1 value shows that same sharp one-day shape, supporting—but not proving—the existing possible-fireworks estimate.
What it supports
Context for the event; this item does not establish the attributed cause by itself.
Limit
The study analyzes Independence Day nationally, not Lakeland on New Year's Day 2016; the event remains a versioned common-sense estimate at possible confidence.
Bay area New Year's Eve 2015 events
Spectrum News / Bay News 9
A contemporaneous Bay News 9 holiday guide and a separate Polk County community calendar both listed a December 31, 2015 fireworks show at LEGOLAND Florida in Winter Haven, within the catalog metro.
What it supports
Context for the event; this item does not establish the attributed cause by itself.
Limit
The listed display was scheduled for 7 p.m. on December 31, before the January 1 monitor day, so it is not treated as exact-event occurrence evidence.
Holiday timing pattern
IAQng deterministic inference policy
The event peak falls on 2016-01-01 and the event lasts no more than two days. Under holiday_fireworks_possible.v1, that timing is consistent with a possible fireworks contribution.
What it supports
A possible fireworks contribution; this is a reproducible inference, not direct occurrence or causal evidence.
Limit
Pre-event and post-event temporal-shape data were not supplied.
What remains uncertain
- No exact-date incident report, chemical-composition result, or causal assessment was recovered for the January 1 monitor value.
- The public page must label fireworks as a possible estimate and keep the December 31 timing limitation visible.
Status and provenance
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.