Response
to
Comments
on
EPA's
Designations
and
Classifications
Of
Areas
for
the
Particulate
Matter
(
PM2.5)
National
Ambient
Air
Quality
Standards
U.
S.
Environmental
Protection
Agency
December
17,
2004
i
A.
INTRODUCTION
This
document,
together
with
the
notice
of
final
rulemaking
(
NFR)
"
Designation
and
Classification
of
Areas
for
the
PM2.5
National
Ambient
Air
Quality
Standard
(
NAAQS)"
presents
the
responses
to
more
than
160
comments
received
by
the
Environmental
Protection
Agency
(
EPA)
on
designations
of
the
PM2.5
NAAQS.

B.
BACKGROUND
The
Clean
Air
Act
(
CAA)
establishes
a
process
for
air
quality
management
through
the
NAAQS.
Area
designations
are
required
after
promulgation
of
a
new
or
revised
NAAQS.
After
evaluating
numerous
health
studies
and
conducting
an
extensive
peer
review
process,
on
July
18,
1997,
EPA
promulgated
a
PM2.5
standard
of
15
micrograms
per
cubic
meter,
based
on
the
3­
year
average
of
annual
mean
PM2.5
concentrations.
The
24­
hour
standard
for
PM2.5
is
65
micrograms
per
cubic
meter,
determined
by
the
3­
year
average
of
the
annual
98th
percentile
concentrations.

Several
events
occurred
which
delayed
designations
for
the
PM2.5
NAAQS.
EPA's
new
standards
were
challenged
by
the
American
Trucking
Association,
the
U.
S.
Chamber
of
Commerce
and
other
state
and
business
groups.
Additionally,
the
Transportation
Equity
Act
for
the
Twenty­
first
Century
(
TEA­
21)
revised
the
deadline
to
publish
nonattainment
designations
in
order
to
provide
additional
time
to
collect
three
years
of
air
quality
monitoring
data.

In
February
2001,
the
Supreme
Court
upheld
EPA's
authority
under
the
Clean
Air
Act
to
set
National
Ambient
Air
Quality
Standards
that
protect
the
American
public
from
harmful
effects
of
air
pollution.
The
Supreme
Court
also
remanded
the
case
to
the
D.
C.
Circuit
Court
of
Appeals
to
resolve
several
additional
issues.
In
March
2002,
the
DC
Circuit
Court
rejected
all
remaining
legal
challenges
to
EPA's
1997
ambient
air
quality
standards
for
PM2.5.
These
actions
extended
the
deadlines
for
designating
nonattainment
areas
under
the
PM2.5
NAAQS
until
December
31,
2004.

On
April
1,
2003,
EPA
issued
a
memorandum
outlining
the
schedule
for
designating
areas
under
the
PM2.5
standard
and
related
guidance
on
nine
factors
to
consider
in
identifying
nonattainment
areas.
The
CAA
provides
for
states
and
tribes
to
submit
designation
recommendations
to
EPA,
and
it
requires
EPA
to
provide
time
for
consultation
in
cases
where
the
Administrator
plans
to
promulgate
a
designation
that
modifies
the
state
or
tribal
recommendation.
(
Tribes
are
not
required
to
provide
recommendations
but
are
invited
to
do
so
and
participate
in
the
process.)

On
June
28
and
29,
2004,
the
Environmental
Protection
Agency
(
EPA)
sent
letters
to
state
and
tribal
representatives
responding
to
their
recommendations
for
areas
meeting
and
not
meeting
the
national
air
quality
standards
for
fine
particles
(
PM2.5).
This
action
started
a
120­
day
period
for
the
states
and
tribes
to
respond
to
EPA's
modifications
to
their
attainment/
nonattainment
area
recommendations.
EPA
requested
that
states
and
tribes
submit
any
responses
by
September
1,
2004.
ii
C.
Response
to
Comments
on
PM2.5
Designations
The
following
document
contains
responses
to
comment
letters
received
on
the
PM2.5
designation
process.
Responses
to
"
Controlled
Correspondences"
and
comments
received
prior
to
September
1,
2004
are
found
in
Appendix
A.
Summaries
of
the
comments
and
EPA
responses
are
sorted
by
EPA
Region,
by
state,
and
by
area.
The
comment
numbers
were
assigned
randomly
to
the
comments.
