Fireworks
2025-07-04 fireworks episode affecting Cincinnati, OH-KY-IN, Indianapolis-Carmel-Anderson, IN, Dayton, OH, Louisville/Jefferson County, KY-IN
Daily PM2.5 peaked at 82.1 µg/m³ near Indianapolis across 4 covered metros home to 6.7 million people. 3 metros 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 ≈ 3.6 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 24 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.
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.
What happened, in the record
The supplied retained evidence supports fireworks for this event; no supplied evidence establishes membership in a broader time-bounded episode.
Sequence: Indianapolis (Jul 4) → Cincinnati (Jul 4) → Louisville/Jefferson County (Jul 5) → Dayton (Jul 5)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Indianapolis-Carmel-Anderson, IN | 82.1 µg/m³ | 6.5 | Jul 5, 2025 | #4 of its top days |
| Cincinnati, OH-KY-IN | 60 µg/m³ | 4.9 | Jul 5, 2025 | #3 of its top days |
| Louisville/Jefferson County, KY-IN | 58 µg/m³ | 2.6 | Jul 5, 2025 | #8 of its top days |
| Dayton, OH | 47 µg/m³ | 2.1 | Jul 5, 2025 | #18 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.
The evidence
EPA AQS monitor qualifier 4
- AQS PM2.5 qualifier IH — Fireworks. EPA AQS carries an agency-submitted informational qualifier (IH, Fireworks.) on 107 PM2.5 samples in the candidate CBSA on 2025-07-05, identifying fireworks as affecting the samples. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
- AQS PM2.5 qualifier IH — Fireworks. EPA AQS carries an agency-submitted informational qualifier (IH, Fireworks.) on 44 PM2.5 samples in the candidate CBSA on 2025-07-05, identifying fireworks as affecting the samples. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
- AQS PM2.5 qualifier IH — Fireworks. EPA AQS carries an agency-submitted informational qualifier (IH, Fireworks.) on 17 PM2.5 samples in the candidate CBSA on 2025-07-04, identifying fireworks as affecting the samples. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
- AQS PM2.5 qualifier IH — Fireworks. EPA AQS carries an agency-submitted informational qualifier (IH, Fireworks.) on 60 PM2.5 samples in the candidate CBSA on 2025-07-04, identifying fireworks as affecting the samples. An informational qualifier is an official submitting-agency flag, not a request for exclusion or an EPA-concurred determination.
News discovery (GDELT) 1
- IDEM forecasts Air Quality Action Day for July 4 in two Indiana regions A local report relaying IDEM's July 4 forecast said stable conditions plus fireworks emissions could push central Indiana PM2.5 into the Unhealthy for Sensitive Groups range; this directly covers the Indianapolis member only.
Status and provenance
Research preview: this record carries research-only status and its boundaries, cause, and name may change as evidence review completes. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula.