DOT
Comments
on
the
Conformity
Rule
DOT
offers
the
following
comments.
I
have
identified
the
office
or
modal
administration
offering
each
comment:

OST
Policy
In
general,
DOT
supports
the
creation
of
a
de
minimis
threshold
for
PM
2.5
.

The
proposed
threshold
levels
above
which
conformity
determination
would
be
required
calls
out
ammonia
as
a
precursor
to
PM
2.5
and
sets
limits.

Ammonia
is
not
a
regulated
pollutant
from
internal
combustion
engines
as
found
on
air
or
surface
transportation
vehicles.
Further,
although
transportation
is
believed
to
be
a
minimal
contributor
to
ammonia
emissions,
the
rule
as
written
would
require
ammonia
emissions
to
be
analyzed
and
estimated
to
reach
a
determination
whether
a
proposed
action
exceeds
the
specified
de
minimis
levels.
At
best,
only
limited
data
are
available
on
ammonia
emissions
associated
with
marine
and
rail
propulsion
engines,
and
no
data
is
available
for
aircraft
engines.
The
analysis
to
determine
whether
de
minimis
thresholds
are
met
for
ammonia
would
unnecessarily
increase
cost
and
complexity.
Therefore,
DOT
recommends
that
transportation­
related
actions
be
exempted
from
considering
ammonia
emissions
in
reaching
a
determination
whether
de
minimis
thresholds
are
met.

Further,
consideration
of
ammonia
or
other
Volatile
Organic
Compounds
(
VOC)
appears
to
be
required
only
when
they
are
deemed
to
be
significant
precursors.
DOT
would
like
to
know
how
the
determination
of
significance
is
to
be
made
and
by
what
entity.

FHWA
1.
EPA
needs
to
include
the
latest
information
on
their
E­
docket
which
refers
the
user
to
the
correct
website.
2.
EPA
should
consider
including
in
the
general
conformity
rule
the
12­
month
grace
period
for
newly
designated
nonattainment
areas
before
conformity
applies
(
CAA
section
176(
c)(
6).

[
One
general
comment
(
not
directly
related
to
this
rule
making.)
­­
While
we
don't
disagree
with
EPA's
proposed
PM2.5
de
minimis
levels
for
general
conformity,
we
feel
strongly
about
expanding
a
comparable
de
minimis
provision
for
Transportation
Conformity
and
would
like
to
work
with
EPA
on
this.]
FAA
First,
the
new
pollutant
to
consider
as
a
possible
contributor
to
PM2.5
concentration
is
ammonia.
Aircraft
engine
emissions
factors
for
ammonia
are
not
available.
As
we
understand
it,
ammonia
is
a
by­
product
of
agricultural
and
human
wastes
(
e.
g.,
fertilizers,
sewage
treatment
plants),
household
products,
and
industrial
processes.
Motor
vehicles
only
account
for
about
3
percent
of
ammonia
releases,
and
given
the
general
relationship
of
levels
motor
vehicles
emissions
vs.
aircraft
emissions,
then
aviation
sources
would
be
much
less.
Given
that
aircraft
engine
emission
factors
for
ammonia
do
not
exist,
thus
causing
a
situation
of
"
no
available
data"
in
our
environmental
assessments,
is
it
possible
to
exempt
aviation
environmental
assessments
from
a
quantitative
analysis
of
ammonia?
It
would
be
beneficial
to
accomplish
this
through
the
rulemaking.
At
the
very
least,
the
EPA
should
include
a
statement
to
this
effect
or
at
least
discuss
the
fact
that
ammonia
is
not
a
criteria
pollutant
and
a
new
factor
for
general
conformity
evaluations.

Second,
under
the
paperwork
reduction
section
there
is
discussion
about
a
voluntary
approach
of
setting
up
an
emissions
budget
for
commercial
service
airports
as
an
example
of
a
facility­
wide
emissions
budget.
We
think
it
should
be
dropped.
The
issue
of
doing
emissions
budgets
for
airports
could
have
wide
ramifications­
and
if
that
is
something
EPA
wants
to
suggest­
there
should
be
the
proper
discussion
and
vetting
of
the
idea­
not
as
an
add
on
in
the
paperwork
reduction
section.
Further,
while
this
discussion
refers
to
a
proposed
facility­
wide
emissions
budget,
the
proposed
amendment
to
the
rule
does
not
include
such
a
proposal.
