U.S. Environmental Protection Agency official
Attachment 1
EPA's technical support document says the monitored PM2.5 mass at Louisville's Barret site on July 4, 2006 was impacted by fireworks displays and concurs with flagging that value.
Fireworks Documented
2006-07-20 fireworks episode affecting Louisville/Jefferson County, KY-IN
Daily PM2.5 peaked at 48.9 µg/m³ near Louisville/Jefferson County across 1 covered metro home to 1.4 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 1.7 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 2.3 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”
Qualified frozen evidence supports fireworks as the broad root cause.
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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
EPA's technical support document says the monitored PM2.5 mass at Louisville's Barret site on July 4, 2006 was impacted by fireworks displays and concurs with flagging that value.
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
48.9 µg/m³ near Louisville/Jefferson County
EPA monitors recorded the event across 1 metro. The peak daily concentration is roughly 2.2 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.
Louisville/Jefferson County, KY-IN
Monitor comparison window 2006-07-17 to 2006-07-23 · PM2.5 target: Wyandotte Park
62% above nearby days
63% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 48.2 µg/m³
62% higher than surrounding days
Before38.3 µg/m³ Event48.2 µg/m³ After10.5 µg/m³
PM10 67 µg/m³
63% higher than surrounding days
Before52 µg/m³ Event67 µg/m³ After14 µg/m³
Carbon monoxide 0.935 ppm
17% higher than surrounding days
Before0.798 ppm Event0.935 ppm After0.713 ppm
Nitrogen dioxide 17.1 ppb
56% higher than surrounding days
Before11.8 ppb Event17.1 ppb After6.56 ppb
Sulfur dioxide 2.30 ppb
About the same as surrounding days
Before4.43 ppb Event2.30 ppb After1.91 ppb
Ozone 0.034 ppm
9% lower than surrounding days
Before0.041 ppm Event0.034 ppm After0.029 ppm
Atmospheric conditions
Nearby EPA weather observations17% higher than surrounding days
About the same as surrounding days
About the same as 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.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Louisville/Jefferson County, KY-IN | 48.9 µg/m³ | 2.2 | Jul 20, 2006 | #20 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.
Agency and publisher pages 1
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EPA's technical support document says the monitored PM2.5 mass at Louisville's Barret site on July 4, 2006 was impacted by fireworks displays and concurs with flagging that value.
Status and provenance
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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.