foxsanantonio.com · Jan 9, 2026 corroborates
Fireworks Likely
2026-01-01 San Antonio-New Braunfels, TX fireworks episode
Daily PM2.5 peaked at 67.8 µg/m³ near San Antonio across 1 covered metro home to 2.8 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 ≈ 2.7 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 7.4 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
The basis for “Fireworks”
Exact-date local reporting confirms widespread fireworks, combined with the versioned holiday inference.
Likely Applicable reporting or a supported inference makes this the best current causal explanation.
KSAT · Jan 1, 2026 hypothesis
Drone footage, viewer videos capture fireworks across San Antonio
KSAT documented widespread fireworks across San Antonio immediately after midnight on the event date.
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
67.8 µg/m³ near San Antonio
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 3.1 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.
San Antonio-New Braunfels, TX
Monitor comparison window 2025-12-29 to 2026-01-04 · PM2.5 target: Old Hwy 90
420% above nearby days
8% lower than surrounding days
24% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 27.1 µg/m³
420% higher than surrounding days
Before4.11 µg/m³ Event27.1 µg/m³ After5.22 µg/m³
PM10 31 µg/m³
24% higher than surrounding days
Before14 µg/m³ Event31 µg/m³ After26 µg/m³
Carbon monoxide 0.412 ppm
43% higher than surrounding days
Before0.225 ppm Event0.412 ppm After0.287 ppm
Nitrogen dioxide 9.59 ppb
25% higher than surrounding days
Before6.42 ppb Event9.59 ppb After7.67 ppb
Sulfur dioxide 0.113 ppb
93% higher than surrounding days
Before-0.048 ppb Event0.113 ppb After0.120 ppb
Ozone 0.034 ppm
11% higher than surrounding days
Before0.030 ppm Event0.034 ppm After0.032 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
8% 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.
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 |
|---|---|---|---|---|
| San Antonio-New Braunfels, TX | 67.8 µg/m³ | 3.1 | Jan 1, 2026 | #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
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.
Drone footage, viewer videos capture fireworks across San Antonio
KSAT
KSAT reports and shows fireworks across San Antonio after midnight, including the far West Side, Edgewood, Loop 410 and Culebra Road, and the downtown CelebrateSA display.
What it supports
Fireworks activity occurred in the event geography and time window.
Limit
The report establishes widespread local fireworks activity, not that fireworks caused the event's measured PM2.5.
Drone footage, viewer videos capture fireworks across San Antonio
KSAT
KSAT documented widespread fireworks across San Antonio immediately after midnight on the event date.
What it supports
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Limit
The report establishes occurrence, not measured contribution to PM2.5.
Holiday timing pattern
IAQng deterministic inference policy
The event peak falls on 2026-01-01 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 event-specific chemical tracer or agency causal determination was recovered.
Status and provenance
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.