Reddit / r/Houston corroborates
New Year's Eve fireworks visible on radar
Houston residents documented widespread fireworks and smoke during the exact New Year's Eve window.
Fireworks Possible
2019-12-31 to 2020-01-01 Houston-The Woodlands-Sugar Land, TX fireworks episode
Daily PM2.5 peaked at 110.6 µg/m³ near Houston across 1 covered metro home to 7.8 million people. 1 metro recorded their worst day on record.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 6.0 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 47 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-night Houston community posts and radar discussion identify widespread fireworks smoke. No agency attribution was recovered, so confidence 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.
- 1Documented
Source or mechanism
Fireworks
Houston residents documented widespread fireworks and smoke during the exact New Year's Eve window.
View supporting source ↗ - 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
110.6 µg/m³ near Houston
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 5.0 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.
Houston-The Woodlands-Sugar Land, TX
Monitor comparison window 2019-12-28 to 2020-01-04 · PM2.5 target: Houston Aldine
369% above nearby days
19% lower than surrounding days
29% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 32.9 µg/m³
369% higher than surrounding days
Before4 µg/m³ Event32.9 µg/m³ After7.53 µg/m³
Carbon monoxide 0.404 ppm
29% higher than surrounding days
Before0.162 ppm Event0.404 ppm After0.314 ppm
Nitrogen dioxide 16.8 ppb
46% higher than surrounding days
Before4.13 ppb Event16.8 ppb After10.7 ppb
Sulfur dioxide 0.429 ppb
580% higher than surrounding days
Before0.015 ppb Event0.429 ppb After0.048 ppb
Ozone 0.023 ppm
10% higher than surrounding days
Before0.024 ppm Event0.023 ppm After0.018 ppm
Atmospheric conditions
Nearby EPA weather observations23% lower than surrounding days
About the same as surrounding days
8% lower than surrounding days
19% 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.
—
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 |
|---|---|---|---|---|
| Houston-The Woodlands-Sugar Land, TX | 110.6 µg/m³ | 7.1 | Jan 1, 2020 | Worst day on record |
"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.
At least there's one upside to Houston being so flat: NYE fireworks from Grand Parkway in Katy
Reddit r/houston
A public, exact-date community post presents a local photograph of New Year's fireworks viewed from the Grand Parkway in Katy within the Houston metro.
What it supports
Fireworks activity occurred in the event geography and time window.
Limit
One community post establishes local fireworks occurrence only. It does not establish the source of the regional PM2.5 measurement or the scale of emissions.
So many fireworks were set off at midnight NYE that NWS Houston radar easily detects the smoke
Reddit r/houston
A public, exact-date Houston community post links the midnight fireworks activity to a shared NWS Houston radar image described as detecting the resulting smoke.
What it supports
Fireworks activity occurred in the event geography and time window.
Limit
This is a community report and indirect radar interpretation, not an independently retained official meteorological or causal assessment.
New Year's Eve fireworks visible on radar
Reddit / r/Houston
Houston residents documented widespread fireworks and smoke during the exact New Year's Eve window.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Holiday timing pattern
IAQng deterministic inference policy
The event peak falls on 2019-12-31 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
- The retained evidence is scoped to the places and dates stated; it is not a catalog promotion.
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.