Responses to Comments Not Addressed in the Preamble to the Final Rule:

Transportation Conformity Rule PM2.5 and PM10 Amendments 

February 5, 2010

Docket ID No. EPA-HQ-OAR-2008-0540

Comment:

One commenter was concerned that the grace period for newly designated
areas would not leave sufficient time for their agency to complete and
adopt a TIP based on the agency’s schedule.  The commenter wrote that
if the designations were made in “October 2009,” and the one-year
grace period expires in “December 2009,” there would be insufficient
time to demonstrate conformity and adopt the 2010 TIPs.  

Response:  

The preamble to the final rule clarifies the applicable dates.  The
commenter’s assertion that the grace period expires in December of
2009 is incorrect.  EPA’s final rule designating areas nonattainment
for the 2006 PM2.5 NAAQS was published in the Federal Register on
November 13, 2009, and effective December 14, 2009.  The one-year
conformity grace period for newly designated areas begins on December
14, 2009, and ends on December 14, 2010.  

Comment:  

	The commenter notes that serious health impacts are associated with
exposure to fine PM.  More than enough research has been done that shows
that some types of transportation projects can emit enough PM2.5 to
cause or contribute to violations of the NAAQS.  Given the compelling
evidence that diesel exhaust may be the most hazardous of all PM
components, it is imperative that EPA fulfill its responsibility to
control PM2.5 emissions from transportation projects.  

Response:

	EPA has fulfilled its responsibility regarding PM2.5 emissions from
transportation projects by implementing the Clean Air Act conformity
requirements for PM2.5.  

Comment:  

	One commenter thought that EPA’s proposed option to define the
baseline year related to the SIP or AERR process would not reduce
EPA’s need to issue guidance in the future.  

Response:

	EPA intends to issue guidance to clarify the baseline year for any
future new or revised PM2.5 NAAQS.  Such guidance will be needed to
explain how the regulation finalized today (which defines the baseline
year with respect to the AERR) should be implemented for a specific new
or revised PM2.5 NAAQS.  However, today’s regulation removes the need
for EPA to revise its baseline year regulation for any future new or
revised PM2.5 NAAQS.

Comment:

	A commenter suggested that if EPA finalizes the proposed option 2 for
the baseline year, EPA should align the baseline year for the 2008
8-hour ozone NAAQS with the baseline year for the 2006 PM2.5 NAAQS.  

Response:

	EPA did not propose to revise the baseline year for any future new or
revised ozone NAAQS, and therefore this comment is outside the scope of
today’s action.  

Comment:

	A commenter that supported the option finalized in today’s rule noted
that EPA’s Office of Air Quality Planning and Standards has not
recommended a single SIP modeling base year as a reason for their
support of this option.

Response:

	EPA notes that there is no requirement that the baseline year for the
conformity baseline year test and the base year used for SIP modeling be
the same year.  The baseline year for the baseline year test for the
2006 PM2.5 areas is 2008, as described in the preamble of today’s
rule.  

Comment:

	One commenter noted that either interim emissions test is adequate as
long as the same emissions model and assumptions are used for the build
scenario and the comparison scenario, i.e., either the no-build scenario
or the baseline year.  

Response:  

	EPA agrees that the same model has to be used for both the build case
and the comparison case, given differences in model results between
MOBILE6.2 and MOVES using the same or similar inputs.  EPA believes it
is unlikely that any area would want to use different models for the
build and comparison cases in a single regional emissions analysis given
the additional time involved.  In any case, models for conformity
analyses must be decided through the interagency consultation process,
of which EPA is a member, and that consultation process will help ensure
that consistent models and assumptions are used.

Comment:

	The commenter noted that areas are likely to need to use interim tests
in upcoming years because most areas do not have adequate or approved
budgets for the 1997 PM2.5 NAAQS.  In addition, this commenter noted
that the court’s remand of the CAIR program still needs to be
addressed.  This commenter also noted that the introduction of MOVES
will require rerunning some inventories for consistency purposes.  

Response:  

	EPA agrees that many areas will need to use one of the interim
emissions tests because adequate or approved budgets are not yet
available for the 1997 PM2.5 NAAQS.  EPA’s response to the CAIR remand
is outside the scope of today’s rulemaking.  

	In areas that have adequate or approved budgets for the 1997 PM2.5
NAAQS, SIPs may need to be updated using MOVES.  EPA believes that the
2006 PM2.5 NAAQS nonattainment areas must use MOVES in developing SIPs
for this NAAQS, therefore such inventories will not need to be redone
when MOVES is required for transportation conformity (i.e., at the end
of the two-year MOVES grace period).  

Comment:

One commenter was concerned that there is no SIP strategy designed to
reduce emissions near roadways to the levels needed to attain the NAAQS,
and EPA’s proposed interpretation of CAA 176(c)(1)(B)(iii) fails to
require the highway project to reduce emissions in the area affected by
the project.  The commenter suggested that if EPA were to modify its SIP
guidance to require states to model the incremental impact of highway
emissions near highways, and develop a control strategy designed to
remedy these violations, then EPA’s interpretation of CAA
176(c)(1)(B)(iii), to require an air quality assessment focused on
whether emissions from the proposed project would cause or contribute to
new violations or worsen existing violations, would be reasonable. 
However, the commenter believes that EPA has created a set of SIP
policies that allows states to ignore elevated levels of PM2.5 and
resulting NAAQS violations near highways.  And, as long as these
policies remain in effect, the commenter believes that there is no basis
for interpreting (B)(iii) as allowing projects to proceed if emissions
from those project continue to cause or contribute to future NAAQS
violations.

Response:

	For the reasons described in the preamble to today’s action, EPA
disagrees that its regulations fail to satisfy CAA section
176(c)(1)(B)(iii).  Further, the commenter’s assertions regarding the
alleged shortcomings of the SIP process are outside the scope of
today’s rulemaking.	

Comment:  

One commenter was concerned that introduction of MOVES would result in
an inability to pass conformity.  This commenter states that the area
experienced three non-conformity determinations from 1996-2003, because
SIP budgets were initially calculated using MOBILE4 but subsequent EPA
models effectively doubled calculated emissions, resulting in
“technical” mismatch with budgets.  This commenter stated that they
are not yet able to assess their potential situation because MOVES is
not yet available.

Response:  

	Because a new emissions model can produce different emissions results,
the conformity rule includes a provision for a grace period before the
new model must be used for conformity determinations.  This grace period
can be from three months to two years, depending on the degree of change
between the existing model and the new model.  In the case of MOVES, EPA
intends to provide the maximum length grace period of two years.  

	EPA released MOVES2010 in December 2009, and will be establishing a
two-year grace period, which should give areas sufficient time to
address issues.  Furthermore, EPA believes SIPs for the 2006 PM2.5 NAAQS
must be developed using MOVES.  EPA is providing SIP and conformity
guidance for the transition to the MOVES model, as well as other
information and training regarding the use of MOVES. See EPA’s
website:    HYPERLINK
"http://www.epa.gov/otaq/models/moves/trainingsessions.htm" 
http://www.epa.gov/otaq/models/moves/trainingsessions.htm  for
information about upcoming training sessions.  Also note that other
MOVES related guidance, including user guides and other technical
information is available on EPA’s website at:    HYPERLINK
"http://www.epa.gov/otaq/models/moves/index.htm" 
http://www.epa.gov/otaq/models/moves/index.htm , and   HYPERLINK
"http://www.epa.gov/otaq/stateresources/transconf/policy.htm" 
http://www.epa.gov/otaq/stateresources/transconf/policy.htm .  

Comment:

One commenter suggested that air quality modeling process used in
transportation conformity should be reformed to use the most recent air
quality data available, rather than prediction-based models.  

This commenter also suggested that emissions budgets have a built-in
level of flexibility, such as a 10 to 15 percent cushion, to allow for
increases in emissions.  

Third, this commenter suggested that hot-spot analysis should be removed
from the regulations.

Response:

	EPA did not in this rulemaking propose any regulatory revisions
addressing air quality modeling, and therefore the first comment is
outside the scope of this rulemaking.  However, EPA believes that the
current requirements to model future transportation activity and
resulting emissions is required by the Clean Air Act.  Section
176(c)(2)(A) of the Act requires that “emissions expected from
implementation of such plans and programs are consistent with estimates
of emissions from motor vehicles and necessary emissions reductions
contained in the applicable air quality implementation plan...”  In
other words, conformity is to examine future transportation sector
emissions, rather than an area’s overall air quality, which is
affected by not just the transportation sector but other sources of
emissions as well as topographical and meterological factors.  

Furthermore, EPA does not believe that it is possible to use an area’s
current air quality data to estimate emissions as distant as 20 years in
the future.  As described above, an area’s current air quality data
results from all sources of emissions.  While the transportation
sector’s emissions are included, they result from current levels of
vehicle miles traveled (VMT) and the emissions characteristics of the
vehicle fleet on the road today.  Neither VMT nor vehicle emissions will
be the same in the future as they are today.  The conformity rule’s
requirements for preparing a regional emissions analysis result in a
reasonable estimate of future emissions that result from planned
transportation.    

EPA’s new emissions model, MOVES, does include the most recent data
about vehicle emissions under different conditions.  EPA believes that
this model improves the accuracy of predicted emissions.  

	Further, EPA did not propose in this rulemaking any revisions to the
conformity budget test regulations and did not propose substantive
changes to the hot-spot requirements.  Therefore, the comments on those
issues are outside the scope of today’s action.  

Docket ID No. EPA-HQ-OAR-2008-0540

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