Wildfire smoke Recent provisional
July 15–20, 2026 Great Lakes and eastern U.S. wildfire-smoke episode
Daily PM2.5 peaked at 387.8 µg/m³ near Toledo across 32 covered metros home to 86 million people. 14 metros recorded their worst day on record; 27 placed a top-ten day.
Counting the extra PM2.5 above each metro's typical day, this event handed the average affected resident ≈ 13.0 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 1.1 billion 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 evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence across the proposed members. The supplied evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence across the proposed members. The supplied evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence across the proposed members. The supplied evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence across the proposed members. The supplied evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence across the proposed members. The supplied evidence supports wildfire smoke and documents an overlapping or continuing regional occurrence a
Sequence: Detroit (Jul 15) → Milwaukee (Jul 15) → Minneapolis (Jul 15) → New York (Jul 15) → Rochester (Jul 15) → Toledo (Jul 16) → Chicago (Jul 16) → Grand Rapids (Jul 16) → Cleveland (Jul 16) → Columbus (Jul 16) → +22 more metros
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Toledo, OH | 387.8 µg/m³ | 33.0 | Jul 16, 2026 | Worst day on record |
| Chicago-Naperville-Elgin, IL-IN-WI | 330.9 µg/m³ | 27.6 | Jul 16, 2026 | Worst day on record |
| Detroit-Warren-Dearborn, MI | 320.6 µg/m³ | 30.7 | Jul 16, 2026 | Worst day on record |
| Grand Rapids-Wyoming, MI | 316.5 µg/m³ | 28.8 | Jul 16, 2026 | Worst day on record |
| Milwaukee-Waukesha-West Allis, WI | 282.3 µg/m³ | 31.1 | Jul 16, 2026 | Worst day on record |
| Cleveland-Elyria, OH | 224 µg/m³ | 20.3 | Jul 17, 2026 | Worst day on record |
| Columbus, OH | 197.2 µg/m³ | 11.6 | Jul 17, 2026 | Worst day on record |
| Pittsburgh, PA | 190.4 µg/m³ | 15.8 | Jul 17, 2026 | Worst day on record |
| Madison, WI | 187.7 µg/m³ | 17.1 | Jul 16, 2026 | #2 of its top days |
| Minneapolis-St. Paul-Bloomington, MN-WI | 175.6 µg/m³ | 13.3 | Jul 16, 2026 | Worst day on record |
| Washington-Arlington-Alexandria, DC-VA-MD-WV | 170.8 µg/m³ | 10.4 | Jul 17, 2026 | Worst day on record |
| Philadelphia-Camden-Wilmington, PA-NJ-DE-MD | 169.3 µg/m³ | 17.6 | Jul 17, 2026 | #3 of its top days |
| Akron, OH | 164.2 µg/m³ | 14.2 | Jul 17, 2026 | Worst day on record |
| Harrisburg-Carlisle, PA | 148.8 µg/m³ | 15.7 | Jul 17, 2026 | #3 of its top days |
| Allentown-Bethlehem-Easton, PA-NJ | 132 µg/m³ | 12.5 | Jul 16, 2026 | #2 of its top days |
| Buffalo-Cheektowaga-Niagara Falls, NY | 131 µg/m³ | 12.2 | Jul 16, 2026 | Worst day on record |
| Baltimore-Columbia-Towson, MD | 114.7 µg/m³ | 7.5 | Jul 17, 2026 | #2 of its top days |
| New York-Newark-Jersey City, NY-NJ-PA | 109.8 µg/m³ | 13.3 | Jul 16, 2026 | #3 of its top days |
| Richmond, VA | 109.6 µg/m³ | 5.0 | Jul 17, 2026 | Worst day on record |
| Rochester, NY | 103.4 µg/m³ | 8.6 | Jul 16, 2026 | Worst day on record |
| Dayton, OH | 99.3 µg/m³ | 4.5 | Jul 17, 2026 | #2 of its top days |
| Scranton--Wilkes-Barre--Hazleton, PA | 80.4 µg/m³ | 3.7 | Jul 16, 2026 | #6 of its top days |
| Syracuse, NY | 78.9 µg/m³ | 3.6 | Jul 16, 2026 | #4 of its top days |
| Virginia Beach-Norfolk-Newport News, VA-NC | 71 µg/m³ | 3.2 | Jul 17, 2026 | #5 of its top days |
| Bridgeport-Stamford-Norwalk, CT | 69.5 µg/m³ | 5.8 | Jul 16, 2026 | #5 of its top days |
| New Haven-Milford, CT | 64.9 µg/m³ | 5.3 | Jul 16, 2026 | #5 of its top days |
| Hartford-West Hartford-East Hartford, CT | 53.4 µg/m³ | 4.8 | Jul 18, 2026 | #6 of its top days |
| Indianapolis-Carmel-Anderson, IN | 52.2 µg/m³ | 2.4 | Jul 19, 2026 | #17 of its top days |
| Springfield, MA | 48.1 µg/m³ | 2.2 | Jul 18, 2026 | #15 of its top days |
| Boston-Cambridge-Newton, MA-NH | 43.8 µg/m³ | 2.0 | Jul 18, 2026 | #20 of its top days |
| Albany-Schenectady-Troy, NY | 42.6 µg/m³ | 1.9 | Jul 16, 2026 | #19 of its top days |
| Worcester, MA-CT | 41.6 µg/m³ | 1.9 | Jul 18, 2026 | #12 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 1
- AQS PM2.5 qualifier IF — Fire - Canadian. EPA AQS carries an agency-submitted informational qualifier (IF, Fire - Canadian.) on 4 PM2.5 samples in the candidate CBSA on 2026-07-17, 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.
NWS Air Quality Alert 6
- Michigan fine-particle alert due to wildfire smoke Michigan EGLE's July 16 update kept a PM2.5 alert in effect through July 17 and explicitly attributed the fine particles to wildfire smoke; this directly covers Detroit. IEM is the archive, not the official system of record.
- Michigan PM2.5 alert due to wildfire smoke Michigan EGLE issued a July 16-17 fine-particle alert explicitly due to wildfire smoke, directly covering Grand Rapids. IEM is the archive, not the official system of record.
- Illinois Air Quality Action Day for wildfire smoke and PM2.5 Illinois EPA issued a July 17 Air Quality Action Day explicitly for wildfire smoke and PM2.5, directly covering Chicago. IEM is the archive, not the official system of record.
- West Virginia fine-particle alert due to wildfire smoke West Virginia's alert attributed unhealthy to very unhealthy fine-particle concentrations during July 17-18 to wildfire smoke. It supports only the West Virginia portion of the Washington regional metro candidate. IEM is the archive, not the official system of record.
- Indiana PM2.5 alert for wildfire smoke Indiana's July 19 alert tied observed and forecast high PM2.5 to wildfire-smoke exposure and applied to Indianapolis. IEM is the archive, not the official system of record.
- Illinois PM2.5 alert for wildfire smoke Illinois EPA's July 19 alert linked observed and forecast elevated PM2.5 to wildfire smoke, directly covering Chicago. IEM is the archive, not the official system of record.
Agency and publisher pages 6
- EPA Statement on Cross-Border Wildfire Smoke and Air Quality Impact on U.S. EPA described a contemporaneous U.S. air-quality impact from Canadian wildfires and directed the public to wildfire-smoke and air-quality information.
- Michigan air quality impacted by smoke and fires this week Michigan EGLE issued a statewide fine-particle alert and identified ongoing Canadian wildfires as the source of a potential multiday smoke event.
- New Jersey Department of Health Cautions Public to Stay Indoors, Take Precautions As Wildfire Smoke Causes Poor Air Quality New Jersey Health reported that smoke from ongoing Canadian wildfires was drifting across the state and region, causing unhealthy air quality and hazy skies.
- DEP: Air Quality Improving Across Most of Pennsylvania; Code Orange Remains in Effect for Southeastern Counties on Saturday, July 18, 2026 Pennsylvania DEP attributed the prior day's Code Purple and Code Red conditions, including southeastern Pennsylvania, to wildfire smoke from Canada and the northern U.S.
- Wildfire smoke makes air unhealthy from the US Midwest to East Coast. Officials say stay inside Contemporaneous reporting identified heavy smoke from fires primarily in Canada and northern Minnesota extending from the Great Lakes to the East Coast.
- Wildfire smoke is forecast to clear from the Northeast just in time for World Cup final The report described a storm front moving smoke out of the Northeast while noting hundreds of active fires in Canada and northern Minnesota.
What remains uncertain
- The supplied evidence does not identify or quantify every specific source contributing across all proposed members.
Status and provenance
Research preview: this record carries research-only status and its boundaries, cause, and name may change as evidence review completes. Recent days are preliminary AirNow readings and re-rank once EPA certifies them. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula.