[MEMORANDUM]{.underline}

SUBJECT: Treatment of Data Influenced By Exceptional and Natural Events

FROM: The Connecticut Department of Environmental Protection

Bureau of Air Management

Michael Geigert, Air Pollution Control Engineer

August 31, 2005

TO: Larry Wallace (EPA)

Thank you for the opportunity to comment on the "Staff Work Paper on the
Use of Air Quality Data Related to Exceptional and Natural Events for
the Particulate Matter Standards" (Updated August 11, 2005, US EPA OAR,
OAQPS). As you already know, the different parts of the Country will
have differing needs with regard to the flagging of such data. Within
recent memory, Connecticut, as well as several other nearby States had
successfully flagged the PM~2.5~ data during a 2002 wildfire event in
Quebec, Canada. The guidance in place at the time (The 1996 PM~10~
Natural Events Policy) worked well, and this current draft guidance
appears to be a natural extension of that policy.

Unlike some of the western States, Connecticut is not likely to be as
frequently impacted by so-called natural or exceptional events. Although
Connecticut may occasionally be impacted by regional wildfires, the case
of the Quebec wildfires was indeed exceptional: smoke from numerous
fires in the Quebec wilderness was driven due south by an unusually
strong high pressure in July, and even affected States as far south as
Virginia. We feel that your draft guidance adequately addresses this
type of situation, especially section 6.11, which addresses transport
from international sources.

Another area of concern for Connecticut would be the flagging of
emissions caused by fireworks or other celebratory events. This was
addressed in section 7.3 (Infrequent Large Gatherings), but should be
further elaborated with regards to the fireworks. We have definitely
noticed elevated PM~2.5~ levels during some Fourth of July fireworks
displays, but none have exceeded the current 24-hour PM~2.5~ standard.
With the expectance of the 24-hour PM~2.5~ standards being revised
downward, there is a possibility that an exceedance may occur during
certain conditions. As currently written into this section, prior to an
event: "all reasonable available control measures must be used and
documented." More specific guidance for this type of event would be
helpful as Connecticut has not regulated emissions from these events in
the past.

Another section of concern for Connecticut is **Section 5.1:** The
guidance proposes that air quality agencies submit detailed, compelling
documentation to justify the flagging in AQS of high concentration PM
samples that are linked to exceptional or natural events within 60 days
of the end of the calendar quarter in which the event occurred. In
accordance with 40CFR section 58.35, the agency deadline for submittal
of validated data to AQS is 90 days after the end of a calendar quarter.
For the PM manual methods, analytical laboratory sample turnaround
times, manual entering of field and laboratory data sheets into computer
databases and the required review and validation process would likely
preclude an agency's evaluation of the ambient sample data significantly
earlier than the 90-day deadline. If the proposed guidance were
accepted, data inaccessibility in the 60 days following the quarter
could also cause an agency to miss the deadline for filing for an
extension, depending on whether there was prior awareness of probable
high concentrations or the potential for a cause and effect relationship
between a natural event and ambient concentration data.

In addition to data access issues, an adequate time allowance must be
made for the agency to perform studies (data analyses, modeling),
complete the technical document, and secure management approval. Given
the potential time needed for reviewing the data and submitting the
request, the State recommends that agency requests for exceptional or
natural event flags and submission of supporting documentation be
required **no less than** 90 days following the end of the quarter in
which the event occurred, and that the agency may submit a request for a
30 day extension for the exceptional/natural event submission within the
90 days following the end of the quarter.

The other issues that you requested comment on: The level of
documentation that should be required to substantiate an exceptional or
natural event claim and the flagging of data below the standard that may
affect the annual average for an area are difficult to quantify and
should be negotiated on a case by case basis. Regarding whether should
there be a bright line test associated with high wind events,
Connecticut is rarely impacted by high wind events that would raise
PM~2.5~ levels and so has no comment on this.

Best Regards,

Michael Geigert

Cc: Amy Royden-Bloom