2008-07-05 wildfire smoke episode affecting Virginia Beach-Norfolk-Newport News, VA-NC
July 5, 2008
Daily PM2.5 peaked at 70.7 µg/m³ near Virginia Beach across
1 covered metro home to 1.8 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 ≈ 2.8 cigarettes.
Across everyone living in the affected metros, that is the collective equivalent of
≈ 5.1 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”
Qualified frozen evidence supports wildfire smoke as the broad root cause.
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 · Jul 5, 2008official
EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 3 PM2.5 samples in the candidate CBSA on 2008-07-05, 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.
The South One Fire began June 9 and its smoke reportedly lingered over surrounding communities for many weeks; this documents a plausible continuing smoke source but does not attribute the July 5 observation.
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 request-exclusion qualifier (RT, Wildfire-U. S.) on 3 PM2.5 samples in the candidate CBSA on 2008-07-05, identifying wildfire smoke as affecting the samples. A request-exclusion qualifier is an official…
The South One Fire began June 9 and its smoke reportedly lingered over surrounding communities for many weeks; this documents a plausible continuing smoke source but does not attribute the July 5 observation.
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
Virginia Beach-Norfolk-Newport News, VA-NC
Monitor comparison window 2008-07-02 to 2008-07-08 · PM2.5 target: NOAA
6 pollutant signals
Fine-particle pulse55.4 µg/m³
230% above nearby days
PM1088 µg/m³
No adjacent-day comparison
Pollution fingerprint
Metro-wide median of reporting monitors
PM2.555.4 µg/m³
230% higher than surrounding days
Before25.8 µg/m³ Event55.4 µg/m³ After10.4 µg/m³
PM1088 µg/m³
No adjacent-day comparison
Before— Event88 µg/m³ After—
Carbon monoxide0.508 ppm
56% higher than surrounding days
Before0.325 ppm Event0.508 ppm After0.186 ppm
Nitrogen dioxide7.38 ppb
33% higher than surrounding days
Before7.25 ppb Event7.38 ppb After5.08 ppb
Sulfur dioxide2.98 ppb
About the same as surrounding days
Before4.10 ppb Event2.98 ppb After1.67 ppb
Ozone0.032 ppm
16% lower than surrounding days
Before0.052 ppm Event0.032 ppm After0.037 ppm
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 · Jul 5, 2008officialgovernment
EPA AQS carries an agency-submitted request-exclusion qualifier (RT, Wildfire-U. S.) on 3 PM2.5 samples in the candidate CBSA on 2008-07-05, 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.
Forests and Rangelands · Jan 1, 2008hypothesisgovernment
The South One Fire began June 9 and its smoke reportedly lingered over surrounding communities for many weeks; this documents a plausible continuing smoke source but does not attribute the July 5 observation.
What remains uncertain
AQS qualifiers are submitting-agency causal flags and 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.