Other Documented
Daily PM2.5 peaked at 81.6 µg/m³ near Detroit across 14 covered metros home to 34 million people. 7 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 ≈ 5.1 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 176 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 other documented PM source or accumulation mechanism as the broad root cause and supports grouping the contemporaneous affected events into one time-bounded episode. Qualified frozen evidence supports other documented PM source or accumulation mechanism as the broad root cause and supports grouping the contemporaneous affected events into one time-bounded episo
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
Aerosol and Air Quality Research · Mar 31, 2010 official
Scientific assessment identifies a January 31–February 6, 2005 Midwest episode driven by meteorological stagnation and nitrate; it explicitly covers Iowa and Missouri, supporting the Des Moines and Kansas City portion of this multi-place event, but not an attribution for Omaha.
See every retained source and limitation ↓
Sequence: Des Moines (Jan 30) → Kansas City (Jan 30) → Grand Rapids (Jan 31) → Minneapolis (Jan 31) → Indianapolis (Jan 31) → Chicago (Jan 31) → Cincinnati (Jan 31) → Columbus (Jan 31) → Omaha (Jan 31) → Dayton (Jan 31) → +4 more metros
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
Scientific assessment identifies a January 31–February 6, 2005 Midwest episode driven by meteorological stagnation and nitrate; it explicitly covers Iowa and Missouri, supporting the Des Moines and Kansas City portion of this multi-place event, but…
View supporting source ↗Air-mass movement
The retained record does not yet show how air traveled from the proposed source to these metros. A trajectory replay or dated plume analysis belongs here.
Local response
EPA monitors recorded the event across 14 metros. The peak daily concentration is roughly 3.7 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 “Other” explanation; it does not assign the cause by itself.
Grand Rapids-Wyoming, MI
Monitor comparison window 2005-01-31 to 2005-02-09 · PM2.5 target: GR-MONROE
55% above nearby days
16% higher than surrounding days
70% higher than surrounding days
55% higher than surrounding days
70% higher than surrounding days
69% higher than surrounding days
28% higher than surrounding days
274% higher than surrounding days
About the same as surrounding days
16% higher than surrounding days
16% higher than surrounding days
Detroit-Warren-Dearborn, MI
Monitor comparison window 2005-01-31 to 2005-02-09 · PM2.5 target: Allen Park
43% above nearby days
About the same as surrounding days
83% higher than surrounding days
43% higher than surrounding days
83% higher than surrounding days
9% higher than surrounding days
27% higher than surrounding days
171% higher than surrounding days
9% lower than surrounding days
About the same as surrounding days
8% higher than surrounding days
About the same as surrounding days
Toledo, OH
Monitor comparison window 2005-01-31 to 2005-02-09 · PM2.5 target: RAPS
19% above nearby days
63% higher than surrounding days
19% higher than surrounding days
63% higher than surrounding days
31% higher than surrounding days
Minneapolis-St. Paul-Bloomington, MN-WI
Monitor comparison window 2005-01-28 to 2005-02-03 · PM2.5 target: Harding High School
185% above nearby days
29% higher than surrounding days
185% higher than surrounding days
29% higher than surrounding days
35% higher than surrounding days
28% higher than surrounding days
39% lower than surrounding days
38% lower than surrounding days
About the same as surrounding days
Cincinnati, OH-KY-IN
Monitor comparison window 2005-01-28 to 2005-02-03 · PM2.5 target: Sacred Heart Elem
53% above nearby days
About the same as surrounding days
53% higher than surrounding days
About the same as surrounding days
14% higher than surrounding days
About the same as surrounding days
11% higher than surrounding days
45% lower than surrounding days
6% lower than surrounding days
Columbus, OH
Monitor comparison window 2005-01-28 to 2005-02-03 · PM2.5 target: ANN ST.
9% above nearby days
28% higher than surrounding days
9% higher than surrounding days
28% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
Dayton, OH
Monitor comparison window 2005-01-28 to 2005-02-03 · PM2.5 target: Preble NCore
9% above nearby days
13% higher than surrounding days
9% higher than surrounding days
13% higher than surrounding days
Indianapolis-Carmel-Anderson, IN
Monitor comparison window 2005-01-28 to 2005-02-03 · PM2.5 target: Indpls- West St.
49% above nearby days
18% higher than surrounding days
49% higher than surrounding days
18% higher than surrounding days
25% higher than surrounding days
26% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
8% lower than surrounding days
Chicago-Naperville-Elgin, IL-IN-WI
Monitor comparison window 2005-01-31 to 2005-02-07 · PM2.5 target: MAYFAIR PUMP STATION
4% above nearby days
About the same as surrounding days
19% higher than surrounding days
About the same as surrounding days
19% higher than surrounding days
15% higher than surrounding days
11% higher than surrounding days
22% lower than surrounding days
12% lower than surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
About the same as surrounding days
Madison, WI
Monitor comparison window 2005-01-31 to 2005-02-07 · PM2.5 target: MADISON - UNIVERSITY AVE WELL #6
20% above nearby days
20% higher than surrounding days
Des Moines-West Des Moines, IA
Monitor comparison window 2005-01-27 to 2005-02-05 · PM2.5 target: R&P SEQ. SAMPLER, CO-LOCATED, CORE SAMPLER, ROOF TOP, SLAMS
76% above nearby days
About the same as surrounding days
76% higher than surrounding days
About the same as surrounding days
10% higher than surrounding days
About the same as surrounding days
Kansas City, MO-KS
Monitor comparison window 2005-01-27 to 2005-02-05 · PM2.5 target: Troost
24% above nearby days
21% lower than surrounding days
About the same as surrounding days
24% higher than surrounding days
About the same as surrounding days
11% higher than surrounding days
8% higher than surrounding days
82% higher than surrounding days
47% lower than surrounding days
14% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
21% lower than surrounding days
Omaha-Council Bluffs, NE-IA
Monitor comparison window 2005-01-27 to 2005-02-05 · PM2.5 target: COUNCIL BLUFFS, FRANKLIN SCH.
55% above nearby days
23% higher than surrounding days
55% higher than surrounding days
23% higher than surrounding days
9% higher than surrounding days
6% lower than surrounding days
St. Louis, MO-IL
Monitor comparison window 2005-01-30 to 2005-02-05 · PM2.5 target: South Broadway
14% above nearby days
5% higher than surrounding days
About the same as surrounding days
14% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
12% higher than surrounding days
23% higher than surrounding days
68% lower than surrounding days
14% higher than surrounding days
About the same as surrounding days
About the same as surrounding days
5% higher than 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 |
|---|---|---|---|---|
| Detroit-Warren-Dearborn, MI | 81.6 µg/m³ | 16.2 | Feb 5, 2005 | #7 of its top days |
| Grand Rapids-Wyoming, MI | 75.3 µg/m³ | 13.4 | Feb 4, 2005 | #6 of its top days |
| Minneapolis-St. Paul-Bloomington, MN-WI | 69.9 µg/m³ | 3.2 | Jan 31, 2005 | #11 of its top days |
| Indianapolis-Carmel-Anderson, IN | 63.2 µg/m³ | 2.9 | Jan 31, 2005 | #8 of its top days |
| Chicago-Naperville-Elgin, IL-IN-WI | 62.6 µg/m³ | 8.3 | Feb 3, 2005 | #16 of its top days |
| Cincinnati, OH-KY-IN | 56.3 µg/m³ | 2.6 | Jan 31, 2005 | #8 of its top days |
| Columbus, OH | 51.8 µg/m³ | 2.4 | Jan 31, 2005 | #15 of its top days |
| Omaha-Council Bluffs, NE-IA | 51.7 µg/m³ | 2.4 | Jan 31, 2005 | #7 of its top days |
| Dayton, OH | 50 µg/m³ | 2.3 | Jan 31, 2005 | #9 of its top days |
| Des Moines-West Des Moines, IA | 48.8 µg/m³ | 8.3 | Jan 31, 2005 | #9 of its top days |
| St. Louis, MO-IL | 48.3 µg/m³ | 2.2 | Feb 2, 2005 | #22 of its top days |
| Toledo, OH | 48.3 µg/m³ | 4.3 | Feb 6, 2005 | #13 of its top days |
| Madison, WI | 43.5 µg/m³ | 2.0 | Feb 3, 2005 | #21 of its top days |
| Kansas City, MO-KS | 39 µg/m³ | 1.8 | Jan 30, 2005 | #24 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.
Scientific assessment identifies a January 31–February 6, 2005 Midwest episode driven by meteorological stagnation and nitrate; it explicitly covers Iowa and Missouri, supporting the Des Moines and Kansas City portion of this multi-place event, but not an attribution for Omaha.
Documented An agency or publisher page assesses this cause, without an agency record naming the event or an EPA qualifier on the data.
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.