Wildfire smoke
2021-07-20 11-area wildfire-smoke episode
Daily PM2.5 peaked at 62.1 µg/m³ near New York across 11 covered metros home to 34 million people.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 2.1 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 72 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
Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode. Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode. Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode. Supplied qualified evidence supports wildfire-smoke as the root cause. The grouping includes only events linked by explicit shared episode evidence; otherwise this remains a single-event episode. Supplied qualifi
Sequence: New York (Jul 20) → Allentown (Jul 20) → Philadelphia (Jul 20) → New Haven (Jul 20) → Scranton (Jul 20) → Bridgeport (Jul 20) → Hartford (Jul 20) → Albany (Jul 20) → Syracuse (Jul 20) → Worcester (Jul 20) → +1 more metros
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| New York-Newark-Jersey City, NY-NJ-PA | 62.1 µg/m³ | 2.8 | Jul 20, 2021 | #11 of its top days |
| Allentown-Bethlehem-Easton, PA-NJ | 60.2 µg/m³ | 2.7 | Jul 20, 2021 | #15 of its top days |
| Philadelphia-Camden-Wilmington, PA-NJ-DE-MD | 57.8 µg/m³ | 2.6 | Jul 20, 2021 | #20 of its top days |
| New Haven-Milford, CT | 52.6 µg/m³ | 2.4 | Jul 20, 2021 | #13 of its top days |
| Scranton--Wilkes-Barre--Hazleton, PA | 50.3 µg/m³ | 2.3 | Jul 20, 2021 | #16 of its top days |
| Bridgeport-Stamford-Norwalk, CT | 49.5 µg/m³ | 2.3 | Jul 20, 2021 | #14 of its top days |
| Hartford-West Hartford-East Hartford, CT | 43.9 µg/m³ | 2.0 | Jul 20, 2021 | #20 of its top days |
| Albany-Schenectady-Troy, NY | 42.3 µg/m³ | 1.9 | Jul 20, 2021 | #20 of its top days |
| Syracuse, NY | 40.2 µg/m³ | 1.8 | Jul 20, 2021 | #14 of its top days |
| Richmond, VA | 40 µg/m³ | 1.8 | Jul 21, 2021 | #21 of its top days |
| Worcester, MA-CT | 36.5 µg/m³ | 1.7 | Jul 20, 2021 | #22 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 7
- AQS PM2.5 qualifier IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 143 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 64 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 92 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IF — Fire - Canadian. EPA AQS carries an agency-submitted informational qualifier (IF, Fire - Canadian.) on 24 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IF — Fire - Canadian. EPA AQS carries an agency-submitted informational qualifier (IF, Fire - Canadian.) on 48 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IT — Wildfire-U. S. EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 56 PM2.5 samples in the candidate CBSA on 2021-07-20, identifying wildfire smoke 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 IF — Fire - Canadian. EPA AQS carries an agency-submitted informational qualifier (IF, Fire - Canadian.) on 78 PM2.5 samples in the candidate CBSA on 2021-07-21, identifying wildfire smoke 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 2
- Smoke Across North America NASA reported smoke from Canadian fires pouring into the eastern U.S. on July 20-21 and identified Philadelphia among the Northeast cities with the haziest skies.
- Air Quality Advisory - Tuesday, July 20, 2021 NYSDEC issued a July 20 air-quality advisory covering Central New York, which includes the Syracuse region; the advisory does not state a source attribution.
What remains uncertain
- An AQS informational qualifier is an official submitting-agency flag, not an EPA-concurred exclusion determination.
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.