1
Memorandum
from
Jeffrey
R.
Holmstead,
Assistant
Administrator,
to
EPA
Regional
Administrators,
"
Designations
for
the
Fine
Particle
National
Ambient
Air
Quality
Standards,"
April
1,
2003.

2
A
list
of
the
2003
OMB
metropolitan
area
definitions
and
associated
information
may
be
found
at:
http://
www.
census.
gov/
population/
www/
estimates/
metroarea.
html.
MEMORANDUM
SUBJECT:
Additional
Guidance
On
Defining
Area
Boundaries
for
PM­
2.5
Designations
FROM:
Lydia
N.
Wegman,
Director
Air
Quality
Strategies
and
Standards
Division
(
C504­
01)

TO:
Air
Division
Directors,
Regions
I­
X
This
memorandum
provides
additional
guidance
for
determining
boundaries
of
PM­
2.5
areas
in
the
PM­
2.5
designations
process.
Our
April
2003
boundary
guidance
establishes
the
metropolitan
area
(
i.
e.
the
larger
of
the
Consolidated
Metropolitan
Statistical
Area
(
CMSA)
or
Metropolitan
Statistical
Area
(
MSA))
as
the
presumptive
boundary
for
PM­
2.5
nonattainment
areas1.
The
boundaries
of
CMSAs
and
MSAs,
which
were
delineated
by
the
Office
of
Management
and
Budget
(
OMB)
in
1999,
include
populated
areas
associated
with
core
urban
areas.
Our
April
2003
guidance
recognized
that
OMB
planned
to
publish
revised
urban
area
definitions
sometime
in
2003,
but,
because
the
specific
release
date
was
not
known
at
that
time,
the
guidance
stated
that
the
Environmental
Protection
Agency
(
EPA)
anticipated
using
the
1999
definitions
for
the
PM­
2.5
designation
process.

OMB
subsequently
issued
revised
urban
area
definitions
on
June
6,
2003.
The
definitions
established
core­
based
statistical
areas
(
CBSAs)
(
or
CBSAs,
comprised
of
"
metropolitan"
and
"
micropolitan"
areas),
and
combined
statistical
areas
(
CSAs)
(
or
CSAs,
comprised
of
two
or
more
core­
based
statistical
areas)
2.
While
we
are
not
requiring
States
and
Tribes
to
use
the
recentlydefined
CSA
and
CBSA
as
the
presumptive
boundaries
for
determining
PM­
2.5
nonattainment
areas,
we
ask
that
in
your
review
of
State
and
Tribal
recommendations
that
you
assess
all
counties
included
in
any
relevant
CSA
or
CBSA
under
the
2003
definitions,
as
well
as
any
adjacent
counties,
using
the
9
factors
identified
in
the
April
1,
2003
guidance.
We
believe
this
approach
is
appropriate
because
the
new
OMB
definitions
group
together
counties
having
a
high
degree
of
social
and
economic
integration
with
a
central
core
area,
reflecting
the
latest
technical
­
2­

3
The
Consolidated
Appropriations
Bill
for
FY­
2004
(
Public
Law
108­
199),
signed
by
the
President
on
January
23,
2004,
codifies
the
dates
for
State
recommendations
and
final
EPA
action
on
PM­
2.5
designations.
information
available
about
significant
growth
and
commuting
rates.
While
EPA
is
not
requiring
that
States
use
the
2003
OMB
boundary
definitions
as
the
presumptive
boundaries,
please
ask
that
your
respective
States
and
Tribes
fully
document
the
basis
for
their
recommendations,
using
the
9
factors
identified
in
the
April
2003
guidance.

All
other
information
contained
in
the
April
boundary
guidance
continues
to
apply,
and
States
and
Tribes
should
continue
to
follow
the
guidance
in
making
the
boundary
recommendations
by
February
15,
2004,
as
required
in
our
guidance
and
the
Consolidated
Appropriations
Bill
for
FY­
2004.3
In
addition,
as
we
requested
in
the
April
2003
guidance
we
encourage
States
and
Tribes
to
make
every
effort
to
process
the
4th
quarter
2003
air
quality
data
as
quickly
as
possible
so
it
can
be
taken
into
account
in
the
February
recommendations.
Also,
stated
in
the
April
2003
guidance,
EPA
will
make
available
on
our
website
information
submitted
in
connection
with
designation
recommendations.
Therefore,
we
request
that
each
State
and
Tribe
submit
to
EPA
its
designation
recommendations,
description
of
the
proposed
area
boundaries,
associated
maps,
and
other
supporting
documentation
in
electronic
format
as
well
as
in
a
hard­
copy
format.

The
Regional
Offices
should
share
this
additional
guidance
with
States
and
Tribes
and
work
closely
with
them
to
resolve
any
issues
related
to
the
submittal
of
their
area
recommendations
and
supporting
information.
Staff
in
OAQPS
are
available
to
provide
assistance
and
consultation
throughout
the
designation
process.
Questions
related
to
this
memorandum
may
be
directed
to
Larry
Wallace
of
my
staff
at
919­
541­
0906
or
Rich
Damberg
at
919­
541­
5592.

cc:
Stephen
D.
Page,
OAQPS
Margo
Oge,
OTAQ
Joe
Paisie,
OAQPS
Kevin
McLean,
OGC
Geoffrey
Wilcox,
OGC
Air
Program
Managers,
Regions
I­
X
