Wildfire smoke EPA monitor flag
Daily PM2.5 peaked at 58.9 µg/m³ near Cincinnati across 7 covered metros home to 11 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 ≈ 39 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.
Why we think this happened
Qualified frozen evidence supports wildfire smoke as the broad root cause and supports grouping the contemporaneous affected events into one time-bounded episode. Qualified frozen evidence supports wildfire smoke as the broad root cause and supports grouping the contemporaneous affected events into one time-bo
EPA monitor flag EPA attached an exceptional-event qualifier to the affected samples. The agency flagged the measurement itself; no separate agency record describes the event.
U.S. EPA Air Quality System and the submitting air monitoring agency · Sep 10, 2005 official
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 3 PM2.5 samples in the candidate CBSA on 2005-09-10, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
U.S. EPA Air Quality System and the submitting air monitoring agency · Sep 10, 2005 official
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 2 PM2.5 samples in the candidate CBSA on 2005-09-10, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
U.S. EPA Air Quality System and the submitting air monitoring agency · Sep 13, 2005 official
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 2 PM2.5 samples in the candidate CBSA on 2005-09-13, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
See every retained source and limitation ↓
Sequence: Memphis (Sep 9) → Louisville/Jefferson County (Sep 9) → Little Rock (Sep 9) → Nashville (Sep 9) → Cincinnati (Sep 10) → Indianapolis (Sep 10) → Dayton (Sep 13)
Evidence path
A cause is more convincing when the record connects three things: something happened, the air mass moved toward the region, and local instruments responded. Here is how much of that chain is documented for this event.
Source or mechanism
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 3 PM2.5 samples in the candidate CBSA on 2005-09-10, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official…
View supporting source ↗Air-mass movement
Satellite analysis observed thin smoke from the prior week's Idaho and Montana fires in the Mississippi, Ohio, and Tennessee river valleys, including northeast Arkansas, northern Mississippi, and western Tennessee. It supports wildfire-smoke…
View transport source ↗Local response
EPA monitors recorded the event across 7 metros. The peak daily concentration is roughly 2.7 cigarette-equivalents at the outdoor daily rate.
Inspect the pollutant and weather signals ↓Event autopsy
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Wildfire smoke” explanation; it does not assign the cause by itself.
Louisville/Jefferson County, KY-IN
Monitor comparison window 2005-09-07 to 2005-09-14 · PM2.5 target: Wyandotte Park
9% above nearby days
About the same as surrounding days
9% higher than surrounding days
About the same as surrounding days
53% lower than surrounding days
22% higher than surrounding days
26% lower than surrounding days
12% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
Cincinnati, OH-KY-IN
Monitor comparison window 2005-09-07 to 2005-09-14 · PM2.5 target: Lower Price Hill
14% above nearby days
17% lower than surrounding days
14% higher than surrounding days
17% lower than surrounding days
14% lower than surrounding days
11% lower than surrounding days
9% lower than surrounding days
About the same as surrounding days
About the same as surrounding days
Indianapolis-Carmel-Anderson, IN
Monitor comparison window 2005-09-07 to 2005-09-14 · PM2.5 target: Indpls- Washington Park/ in parking lot next to police station
22% above nearby days
About the same as surrounding days
22% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
5% lower than surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
Dayton, OH
Monitor comparison window 2005-09-10 to 2005-09-16 · PM2.5 target: LIBRARY (DAYTON PUBLIC
7% above nearby days
No adjacent-day comparison
7% higher than surrounding days
No adjacent-day comparison
17% higher than surrounding days
20% higher than surrounding days
Little Rock-North Little Rock-Conway, AR
Monitor comparison window 2005-09-06 to 2005-09-14 · PM2.5 target: ADEQ
24% above nearby days
10% higher than surrounding days
24% higher than surrounding days
10% higher than surrounding days
25% higher than surrounding days
16% higher than surrounding days
About the same as surrounding days
Memphis, TN-MS-AR
Monitor comparison window 2005-09-06 to 2005-09-14
37% above nearby days
29% higher than surrounding days
37% higher than surrounding days
29% higher than surrounding days
22% higher than surrounding days
About the same as surrounding days
17% higher than surrounding days
Nashville-Davidson--Murfreesboro--Franklin, TN
Monitor comparison window 2005-09-06 to 2005-09-13 · PM2.5 target: Lockeland
24% above nearby days
About the same as surrounding days
24% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
18% higher than surrounding days
About the same as surrounding days
Source: U.S. EPA AirData daily observations and, where available, nearby ASOS/AWOS surface observations. Values are descriptive medians over the retained monitor set; missing measurements remain missing. Transport and source evidence remain separate layers because this instrument pattern does not assign a cause by itself.
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.
Views from the selected metro
Select a metro on the map to see nearby cameras. Where an operator archive reaches the event, drag the divider to compare two moments, adjust either date and time, or play the available event-day frames. Camera imagery is visual context, not an air-quality measurement or proof of smoke.
No useful public camera views are currently available within 80 km of this metro.
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| Cincinnati, OH-KY-IN | 58.9 µg/m³ | 5.0 | Sep 10, 2005 | #4 of its top days |
| Indianapolis-Carmel-Anderson, IN | 54 µg/m³ | 4.8 | Sep 10, 2005 | #15 of its top days |
| Memphis, TN-MS-AR | 49.7 µg/m³ | 4.3 | Sep 10, 2005 | #5 of its top days |
| Dayton, OH | 49.1 µg/m³ | 2.2 | Sep 13, 2005 | #11 of its top days |
| Louisville/Jefferson County, KY-IN | 48.9 µg/m³ | 4.4 | Sep 11, 2005 | #19 of its top days |
| Little Rock-North Little Rock-Conway, AR | 45 µg/m³ | 5.7 | Sep 11, 2005 | #5 of its top days |
| Nashville-Davidson--Murfreesboro--Franklin, TN | 41 µg/m³ | 5.7 | Sep 10, 2005 | #15 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.
Public evidence library
Each card states what a source supports—and what it does not. Official records, research, reporting, community observations, and transparent inferences remain visibly different kinds of evidence.
AQS PM2.5 qualifier E — Forest Fire.
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 3 PM2.5 samples in the candidate CBSA on 2005-09-10, identifying wildfire smoke 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 E — Forest Fire.
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 2 PM2.5 samples in the candidate CBSA on 2005-09-10, identifying wildfire smoke 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 E — Forest Fire.
EPA AQS carries an agency-submitted request-exclusion qualifier (E, Forest Fire.) on 2 PM2.5 samples in the candidate CBSA on 2005-09-13, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official submitting-agency causal claim, but this endpoint does not establish EPA concurrence.
A retrospective scientific assessment identifies September 9–11, 2005 as a Midwest extreme aerosol event with elevated PM2.5 at many EPA sites. It supports grouping this event with the broader Midwest episode, while not assigning a city-specific source.
Smoke Text Product — September 10, 2005
Satellite analysis observed thin smoke from the prior week's Idaho and Montana fires in the Mississippi, Ohio, and Tennessee river valleys, including northeast Arkansas, northern Mississippi, and western Tennessee. It supports wildfire-smoke transport over the Little Rock–Memphis event area, but describes smoke at mid-levels and does not establish its contribution to surface PM2.5.
Smoke Text Product — September 9, 2005
Satellite analysis observed thin smoke from Idaho and Montana fires over most of Ohio, Indiana, and Kentucky during the event window. It supports wildfire-smoke transport across the Cincinnati–Indianapolis–Louisville area, but places the smoke in the middle to upper troposphere and does not establish a surface-PM2.5 contribution.
Tennessee recommended nonattainment counties—EPA’s intended nonattainment counties
EPA documented a widespread eastern-U.S. sulfate event on September 13, 2005, while rejecting the assessed wildfire-smoke claim in Chattanooga. It does not directly attribute PM2.5 in Cincinnati or Dayton.
EPA monitor flag EPA attached an exceptional-event qualifier to the affected samples. The agency flagged the measurement itself; no separate agency record describes the event.
This episode was grouped from the monitor record by the catalog pipeline and given its cause from the evidence listed above. It has not been individually reviewed and signed off, so its boundaries, cause, and name may change as evidence accumulates. Grouping policy common_sense_root_cause_grouping.v2. The cause label reflects the assembled evidence above, not an IAQng detection formula. If it is wrong, tell us.