Other
2001-12-31 other episode affecting Urban Honolulu, HI
Daily PM2.5 peaked at 87.3 µg/m³ near Urban Honolulu across 1 covered metro home to 998,747 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 ≈ 6.0 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 6.0 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 causal evidence supports other as the broad root cause.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Urban Honolulu, HI | 87.3 µg/m³ | 6.4 | Dec 31, 2001 | #6 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 2
- AQS PM2.5 qualifier RK — Infrequent Large Gatherings. EPA AQS carries an agency-submitted request-exclusion qualifier (RK, Infrequent Large Gatherings.) on 2 PM2.5 samples in the candidate CBSA on 2001-12-31, identifying infrequent large gatherings as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
- AQS PM2.5 qualifier RK — Infrequent Large Gatherings. EPA AQS carries an agency-submitted request-exclusion qualifier (RK, Infrequent Large Gatherings.) on 2 PM2.5 samples in the candidate CBSA on 2002-01-01, identifying infrequent large gatherings as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
Agency and publisher pages 2
- Report to the Twenty-First Legislature, State of Hawaii The report says sampling around midnight on New Year’s Eve 1999 showed dramatically elevated particulate levels from fireworks exposure; it does not assess the December 31, 2001 Honolulu event.
- Particulate Pollution from New Year Fireworks in Honolulu This study finds characteristic PM2.5 increases around Honolulu New Year fireworks during 2015–2022, but it does not analyze 2001 and therefore cannot attribute this event.
What remains uncertain
- AQS qualifiers are submitting-agency causal flags and do not by themselves establish EPA concurrence.
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.