Fireworks
Fireworks episode, 2017-12-31 through 2018-01-02
Daily PM2.5 peaked at 111 µg/m³ near Los Angeles across 3 covered metros home to 19 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 ≈ 4.1 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 75 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
Qualified frozen evidence supports fireworks as the broad cause for this time-bounded episode and supports grouping 2 overlapping event records.
Sequence: Los Angeles (Jan 1) → Riverside (Jan 1) → Bakersfield (Jan 2)
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Los Angeles-Long Beach-Anaheim, CA | 111 µg/m³ | 5.0 | Jan 1, 2018 | #5 of its top days |
| Bakersfield, CA | 100.9 µg/m³ | 4.6 | Jan 2, 2018 | #25 of its top days |
| Riverside-San Bernardino-Ontario, CA | 89.1 µg/m³ | 4.0 | Jan 1, 2018 | #14 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 5
- AQS PM2.5 qualifier IH — Fireworks. EPA AQS carries an agency-submitted informational qualifier (IH, Fireworks.) on 41 PM2.5 samples in the candidate CBSA on 2018-01-01, 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 27 PM2.5 samples in the candidate CBSA on 2018-01-02, 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 IE — Demolition. EPA AQS carries an agency-submitted informational qualifier (IE, Demolition.) on 1 PM2.5 sample in the candidate CBSA on 2018-01-02, identifying demolition as affecting the sample. 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 41 PM2.5 samples in the candidate CBSA on 2018-01-01, 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 36 PM2.5 samples in the candidate CBSA on 2018-01-02, 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.
Agency and publisher pages 1
- Draft 2021 PM2.5 Redesignation Request and Maintenance Plan for the South Coast Air Basin The district identifies January 1 fireworks as a possible source of select PM2.5 exceedances in the South Coast basin, but this document does not assess the January 1–2, 2018 event specifically.
What remains uncertain
- AQS qualifiers are submitting-agency causal flags and do not by themselves establish EPA concurrence.
- The evidence resolves the broad cause but does not require a named fire, facility, or incident.
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.