2011-06-21 through 2011-06-23 wildfire-smoke episode affecting Charleston-North Charleston, SC
June 21, 2011 to June 23, 2011 · Origin: Southeastern Georgia
Named sourceHoney Prairie Fire 309,200 acres , GA · ICS-209-PLUS GA-OKR-000001
Daily PM2.5 peaked at 42.6 µg/m³ near Charleston across
1 covered metro home to 869,940 people.
Counting the extra PM2.5 above each metro's typical day, this event handed the
average affected resident ≈ 4.4 cigarettes.
Across everyone living in the affected metros, that is the collective equivalent of
≈ 3.9 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 “Wildfire smoke”
Official monitor qualifiers support wildfire smoke on June 21-23, and the supplied satellite analysis documents Honey Prairie Fire smoke transport and recirculation in the Charleston plume environment.
EPA monitor flagEPA 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 · Jun 21, 2011official
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 52 PM2.5 samples in the candidate CBSA on 2011-06-21, 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.
U.S. EPA Air Quality System and the submitting air monitoring agency · Jun 22, 2011official
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 53 PM2.5 samples in the candidate CBSA on 2011-06-22, 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.
U.S. EPA Air Quality System and the submitting air monitoring agency · Jun 23, 2011official
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 46 PM2.5 samples in the candidate CBSA on 2011-06-23, 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.
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.
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 52 PM2.5 samples in the candidate CBSA on 2011-06-21, identifying wildfire smoke as affecting the samples. An informational qualifier is an official…
Satellite analysis documented dense smoke from the Honey Prairie Fire in southeastern Georgia on June 20 and substantial smoke transport and recirculation during June 21–22; it used a Charleston sounding to characterize the plume environment.
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.
Observed context · not attribution
Charleston-North Charleston, SC
Monitor comparison window 2011-06-18 to 2011-06-26 · PM2.5 target: CHARLESTON PUBLIC WORKS
5 pollutant signals
Fine-particle pulse36.4 µg/m³
95% above nearby days
Air movement1.66 kt
About the same as surrounding days
PM1049 µg/m³
123% higher than surrounding days
Pollution fingerprint
Metro-wide median of reporting monitors
PM2.536.4 µg/m³
95% higher than surrounding days
Before18.6 µg/m³ Event36.4 µg/m³ After9.90 µg/m³
PM1049 µg/m³
123% higher than surrounding days
Before22 µg/m³ Event49 µg/m³ After14 µg/m³
Nitrogen dioxide4 ppb
50% higher than surrounding days
Before2.46 ppb Event4 ppb After2.96 ppb
Sulfur dioxide0.521 ppb
67% higher than surrounding days
Before0.271 ppb Event0.521 ppb After0.313 ppb
Ozone0.035 ppm
About the same as surrounding days
Before0.032 ppm Event0.035 ppm After0.038 ppm
Atmospheric conditions
Nearby EPA weather observations
Wind1.66 kt
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.
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.
"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.
U.S. EPA Air Quality System and the submitting air monitoring agency · Jun 21, 2011officialgovernment
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 52 PM2.5 samples in the candidate CBSA on 2011-06-21, 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.
U.S. EPA Air Quality System and the submitting air monitoring agency · Jun 22, 2011officialgovernment
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 53 PM2.5 samples in the candidate CBSA on 2011-06-22, 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.
U.S. EPA Air Quality System and the submitting air monitoring agency · Jun 23, 2011officialgovernment
EPA AQS carries an agency-submitted informational qualifier (IT, Wildfire-U. S.) on 46 PM2.5 samples in the candidate CBSA on 2011-06-23, 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.
University of Wisconsin–Madison Cooperative Institute for Meteorological Satellite Studies · Jun 21, 2011corroborates
Satellite analysis documented dense smoke from the Honey Prairie Fire in southeastern Georgia on June 20 and substantial smoke transport and recirculation during June 21–22; it used a Charleston sounding to characterize the plume environment.
What remains uncertain
Agency-submitted AQS qualifiers are causal flags but do not by themselves establish EPA concurrence.
Status and provenance
EPA monitor flagEPA 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.