NASA Earth Observatory · Jun 30, 2003 corroborates
Haze over the Atlantic Seaboard
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
Mixed causes Possible
2003-06-26 to 2003-06-27 Albany-Schenectady-Troy, NY, Bridgeport-Stamford-Norwalk, CT, and 5 other metros mixed-source pollution episode
Daily PM2.5 peaked at 58.9 µg/m³ near New York across 7 covered metros home to 25 million 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 ≈ 3.7 cigarettes. Across everyone living in the affected metros, that is the collective equivalent of ≈ 94 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
The basis for “Mixed causes”
Manual research connected 7 source events to one mixed-source pollution episode using the deterministic grouping rule.
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
National Weather Service New York via Iowa Environmental Mesonet · Jun 27, 2003 hypothesis
Area Forecast Discussion: widespread haze across the New York forecast area
NWS New York documented widespread haze with roughly 4-mile visibility overnight and 3-5-mile visibility into June 27, with improvement expected after a cold-front passage.
See every retained source and limitation ↓
Sequence: New York (Jun 26) → New Haven (Jun 26) → Albany (Jun 26) → Hartford (Jun 26) → Syracuse (Jun 26) → Bridgeport (Jun 26) → Rochester (Jun 26)
Evidence path
From source to city
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.
- 1Documented
Source or mechanism
Mixed causes
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
View supporting source ↗ - 2Documented
Air-mass movement
Transport into the affected region is documented
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
View transport source ↗ - 3Documented
Local response
58.9 µg/m³ near New York
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
What the instruments saw
Before, during, and after the episode: nearby pollutant monitors and surface-weather stations show what changed. This context tests the “Mixed causes” explanation; it does not assign the cause by itself.
New York-Newark-Jersey City, NY-NJ-PA
Monitor comparison window 2003-06-23 to 2003-06-30 · PM2.5 target: CANAL STREET
89% above nearby days
About the same as surrounding days
72% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 52.3 µg/m³
89% higher than surrounding days
Before28 µg/m³ Event52.3 µg/m³ After23.7 µg/m³
PM10 76.5 µg/m³
72% higher than surrounding days
Before45 µg/m³ Event76.5 µg/m³ After34 µg/m³
Carbon monoxide 0.833 ppm
About the same as surrounding days
Before0.904 ppm Event0.833 ppm After0.715 ppm
Nitrogen dioxide 30.7 ppb
About the same as surrounding days
Before37.8 ppb Event30.7 ppb After25.3 ppb
Sulfur dioxide 8.75 ppb
44% higher than surrounding days
Before6.03 ppb Event8.75 ppb After5.10 ppb
Ozone 0.065 ppm
26% higher than surrounding days
Before0.047 ppm Event0.065 ppm After0.050 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
About the same as surrounding days
8% higher than surrounding days
About the same as surrounding days
New Haven-Milford, CT
Monitor comparison window 2003-06-23 to 2003-06-30 · PM2.5 target: State St-New Haven
68% above nearby days
No adjacent-day comparison
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 49.4 µg/m³
68% higher than surrounding days
Before31 µg/m³ Event49.4 µg/m³ After22.3 µg/m³
PM10 54.5 µg/m³
No adjacent-day comparison
Before— Event54.5 µg/m³ After—
Carbon monoxide 0.806 ppm
9% higher than surrounding days
Before0.871 ppm Event0.806 ppm After0.608 ppm
Nitrogen dioxide 25.4 ppb
17% higher than surrounding days
Before27 ppb Event25.4 ppb After20.5 ppb
Sulfur dioxide 2.98 ppb
16% higher than surrounding days
Before1.88 ppb Event2.98 ppb After2.44 ppb
Ozone 0.079 ppm
44% higher than surrounding days
Before0.055 ppm Event0.079 ppm After0.051 ppm
Atmospheric conditions
Nearby EPA weather observations7% higher than surrounding days
About the same as surrounding days
11% higher than surrounding days
Albany-Schenectady-Troy, NY
Monitor comparison window 2003-06-23 to 2003-06-29 · PM2.5 target: ALBANY COUNTY HEALTH DEPT
64% above nearby days
17% lower than surrounding days
31% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 47.2 µg/m³
64% higher than surrounding days
Before15.6 µg/m³ Event47.2 µg/m³ After28.7 µg/m³
Carbon monoxide 0.650 ppm
31% higher than surrounding days
Before0.485 ppm Event0.650 ppm After0.517 ppm
Sulfur dioxide 2.38 ppb
6% higher than surrounding days
Before2.21 ppb Event2.38 ppb After2.25 ppb
Ozone 0.067 ppm
About the same as surrounding days
Before0.067 ppm Event0.067 ppm After0.058 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
About the same as surrounding days
12% higher than surrounding days
17% lower than surrounding days
Hartford-West Hartford-East Hartford, CT
Monitor comparison window 2003-06-23 to 2003-06-30 · PM2.5 target: McAuliffe Park
99% above nearby days
No adjacent-day comparison
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 45.7 µg/m³
99% higher than surrounding days
Before23.1 µg/m³ Event45.7 µg/m³ After21.2 µg/m³
PM10 51 µg/m³
No adjacent-day comparison
Before— Event51 µg/m³ After—
Carbon monoxide 1.28 ppm
15% higher than surrounding days
Before1.32 ppm Event1.28 ppm After0.944 ppm
Nitrogen dioxide 18.1 ppb
14% higher than surrounding days
Before16.2 ppb Event18.1 ppb After13 ppb
Sulfur dioxide 3.08 ppb
90% higher than surrounding days
Before1.08 ppb Event3.08 ppb After1.63 ppb
Ozone 0.065 ppm
9% higher than surrounding days
Before0.060 ppm Event0.065 ppm After0.053 ppm
Atmospheric conditions
Nearby EPA weather observations9% higher than surrounding days
About the same as surrounding days
11% higher than surrounding days
Syracuse, NY
Monitor comparison window 2003-06-23 to 2003-06-29 · PM2.5 target: EAST SYRACUSE
0% above nearby days
34% lower than surrounding days
6% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 46.9 µg/m³
No adjacent-day comparison
Before— Event46.9 µg/m³ After—
Carbon monoxide 0.708 ppm
6% higher than surrounding days
Before0.688 ppm Event0.708 ppm After0.646 ppm
Sulfur dioxide 4.37 ppb
37% higher than surrounding days
Before3.19 ppb Event4.37 ppb After2.40 ppb
Ozone 0.068 ppm
17% higher than surrounding days
Before0.059 ppm Event0.068 ppm After0.053 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
About the same as surrounding days
12% higher than surrounding days
34% lower than surrounding days
Bridgeport-Stamford-Norwalk, CT
Monitor comparison window 2003-06-23 to 2003-06-29 · PM2.5 target: Sherwood Island Connector
93% above nearby days
No adjacent-day comparison
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 43.4 µg/m³
93% higher than surrounding days
Before14.2 µg/m³ Event43.4 µg/m³ After22.5 µg/m³
PM10 58 µg/m³
No adjacent-day comparison
Before— Event58 µg/m³ After—
Carbon monoxide 0.999 ppm
About the same as surrounding days
Before1.02 ppm Event0.999 ppm After0.827 ppm
Nitrogen dioxide 22.4 ppb
24% higher than surrounding days
Before20 ppb Event22.4 ppb After17.6 ppb
Sulfur dioxide 2.17 ppb
126% higher than surrounding days
Before0.917 ppb Event2.17 ppb After0.958 ppb
Ozone 0.080 ppm
42% higher than surrounding days
Before0.056 ppm Event0.080 ppm After0.056 ppm
Atmospheric conditions
Nearby EPA weather observations10% higher than surrounding days
8% higher than surrounding days
Rochester, NY
Monitor comparison window 2003-06-23 to 2003-06-29
78% above nearby days
About the same as surrounding days
21% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors PM2.5 41 µg/m³
78% higher than surrounding days
Before14.7 µg/m³ Event41 µg/m³ After23 µg/m³
Carbon monoxide 0.625 ppm
21% higher than surrounding days
Before0.525 ppm Event0.625 ppm After0.483 ppm
Sulfur dioxide 5.71 ppb
About the same as surrounding days
Before7.01 ppb Event5.71 ppb After3.73 ppb
Ozone 0.069 ppm
9% higher than surrounding days
Before0.080 ppm Event0.069 ppm After0.049 ppm
Atmospheric conditions
Nearby EPA weather observationsAbout the same as surrounding days
About the same as surrounding days
10% 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.
Measured daily PM2.5 at EPA monitors, as cigarette-equivalents
EPA monitors sit in metro areas, so the colour clusters there. Land between and beyond
them is unmeasured, not clean: this map shows where IAQng has readings, not the extent
of the smoke.
—
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
Camera views near
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.
Affected metros
| Metro | Peak PM2.5 | Cigarettes, whole event | Peak day | All-time standing |
|---|---|---|---|---|
| New York-Newark-Jersey City, NY-NJ-PA | 58.9 µg/m³ | 5.2 | Jun 27, 2003 | #13 of its top days |
| New Haven-Milford, CT | 52.2 µg/m³ | 4.6 | Jun 27, 2003 | #14 of its top days |
| Albany-Schenectady-Troy, NY | 47.7 µg/m³ | 2.2 | Jun 26, 2003 | #14 of its top days |
| Hartford-West Hartford-East Hartford, CT | 47.1 µg/m³ | 4.2 | Jun 27, 2003 | #11 of its top days |
| Syracuse, NY | 46.9 µg/m³ | 2.1 | Jun 26, 2003 | #7 of its top days |
| Bridgeport-Stamford-Norwalk, CT | 44.8 µg/m³ | 2.0 | Jun 26, 2003 | #20 of its top days |
| Rochester, NY | 41 µg/m³ | 1.9 | Jun 26, 2003 | #16 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
What supports this account
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.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not name its emitting sources, resolve vertical distribution, or quantify metro-specific PM2.5.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not name its emitting sources, resolve vertical distribution, or quantify metro-specific PM2.5.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The account establishes a combustion-associated regional mixture but not its emitting sources, vertical distribution, or Rochester-specific PM2.5 fraction.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not identify its emitting sources, vertical distribution, or metro-specific PM2.5 fraction.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not identify its emitting sources, vertical distribution, or metro-specific PM2.5 fraction.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not identify its emitting sources, vertical distribution, or metro-specific PM2.5 fraction.
Haze over the Atlantic Seaboard
NASA Earth Observatory
NASA's June 26 satellite account shows a broad haze pall over the eastern United States and reports elevated carbon monoxide associated with the haze.
What it supports
A retained source supports the attributed cause for the stated place and dates.
Limit
The satellite account establishes a combustion-associated regional haze mixture but does not identify its emitting sources, vertical distribution, or metro-specific PM2.5 fraction.
Area Forecast Discussion: widespread haze across the New York forecast area
National Weather Service New York via Iowa Environmental Mesonet
NWS New York documented widespread haze with roughly 4-mile visibility overnight and 3-5-mile visibility into June 27, with improvement expected after a cold-front passage.
What it supports
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Limit
The discussion verifies the local haze chronology but does not identify the haze's emissions sources.
Show 1 more retained source
Area Forecast Discussion: widespread haze across the New York forecast area
National Weather Service New York via Iowa Environmental Mesonet
NWS New York documented widespread haze with roughly 4-mile visibility overnight and 3-5-mile visibility into June 27, with improvement expected after a cold-front passage.
What it supports
This source supports a possible mechanism or occurrence; it does not establish the cause by itself.
Limit
The discussion verifies the local haze chronology but does not identify the haze's emissions sources.
What remains uncertain
- The account establishes a combustion-associated regional mixture but not its emitting sources, vertical distribution, or Rochester-specific PM2.5 fraction.
- The discussion verifies the local haze chronology but does not identify the haze's emissions sources.
- The satellite account establishes a combustion-associated regional haze mixture but does not identify its emitting sources, vertical distribution, or metro-specific PM2.5 fraction.
- The satellite account establishes a combustion-associated regional haze mixture but does not name its emitting sources, resolve vertical distribution, or quantify metro-specific PM2.5.
Status and provenance
Possible This is a transparent hypothesis supported by limited evidence or an explicit inference, not a definitive attribution.
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.