I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.

Table VII-31--Annual Fuel Savings in Calendar Years 2025, 2035 and 2050--
          Alternative 4 vs. Alt 1a using Analysis Method B \a\
------------------------------------------------------------------------
                                                   Diesel      Gasoline
                                                  savings      savings
                      CY                          (billion     (billion
                                                  gallons)     gallons)
------------------------------------------------------------------------
2025..........................................          3.1          0.3
2035..........................................          8.8          0.9
2050..........................................         12.3          1.1
------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.

(ii) Upstream (Fuel Production and Distribution) Emissions Projections
    The upstream GHG emission reductions associated with the production
and distribution of gasoline and diesel from crude oil were based on
emission factors from DOE's ``Greenhouse Gases, Regulated Emissions,
and Energy Use in Transportation'' (GREET) model. In some cases, the
GREET values were modified or updated by the agencies to be consistent
with EPA's National Emissions Inventory (NEI), and emission factors
from MOVES. More information regarding these modifications can be found
in Chapter 5 of the draft RIA. These estimates show the impacts for
domestic emission reductions only. Additionally, since this rulemaking
is not expected to impact biofuel volumes mandated by the Annual
Renewable Fuel Standards (RFS) regulations \391\, the impacts on
upstream emissions from changes in biofuel feedstock (i.e.,
agricultural sources such as fertilizer, fugitive dust, and livestock)
are not shown. GHG emission reductions from upstream sources can be
found in Table VII-32 and Table VII-33 for preferred alternative and
Alternative 4, respectively.
---------------------------------------------------------------------------

    \391\ U.S. EPA. 2014 Standards for the Renewable Fuel Standard
Program. 40 CFR part 80. EPA-HQ-OAR-2013-0479; FRL-9900-90-OAR, RIN
2060-AR76.

Table VII-32--Annual Upstream GHG Emissions Impacts in Calendar Years 2025, 2035 and 2050--Preferred Alternative
                                     vs. Alt 1a using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                                                                Total
                             CY                                CO2 (MMT)     CH4 (MMT     N2O (MMT     uptream
                                                                              CO2eq)       CO2eq)    (MMT CO2eq)
----------------------------------------------------------------------------------------------------------------
2025........................................................         -8.4         -0.9        -0.04         -9.3
2035........................................................        -29.1         -3.0        -0.14        -32.2
2050........................................................        -41.9         -4.4        -0.20        -46.5
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

Table VII-33--Annual Upstream GHG Emissions Impacts in Calendar Years 2025, 2035 and 2050--Alternative 4 vs. Alt
                                         1a using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                                                                Total
                             CY                                CO2 (MMT)     CH4 (MMT     N2O (MMT     uptream
                                                                              CO2eq)       CO2eq)    (MMT CO2eq)
----------------------------------------------------------------------------------------------------------------
2025........................................................        -10.4         -1.0         -0.1        -11.5
2035........................................................        -30.1         -3.2         -0.1        -33.4
2050........................................................        -42.0         -4.4         -0.2        -46.6
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

(iii) HFC Emissions Projections
    Based on projected HFC emission reductions due to the proposed AC
leakage standards, EPA estimates the HFC reductions to be 93,272 metric
tons of CO2eq in 2025, 253,118 metric tons of
CO2eq in 2035, and 299,590 metric tons CO2eq in
2050, as detailed in Chapters 5.3.4 of the draft RIA. EPA welcomes
comments on the methodology used to quantify the HFC emissions
benefits, as detailed in Chapter 5 of the draft RIA.
(iv) Total (Downstream + Upstream + HFC) Emissions Projections
    Table VII-34 combines the impacts of the preferred alternative from
downstream (Table VII-28), upstream (Table VII-32), and HFC to
summarize the total GHG reductions in calendar years 2025, 2035 and
2050, relative to Alternative 1a. The combined impact of Alternative 4
on total GHG emissions are shown in Table VII-35.
    Because of the differences in lead time, as expected, Alternative 4
shows greater annual GHG reductions in earlier years (i.e., calendar
year 2025), but by

2050, the preferred alternative and Alternative 4 show the same
magnitude of reductions in annual GHG emissions.

Table VII-34--Annual Total GHG Emissions Impacts in Calendar Years 2025,
 2035 and 2050--Preferred Alternative vs. Alt 1a using Analysis Method B
                                   \a\
------------------------------------------------------------------------
                                    2025 (MMT    2035 (MMT    2050 (MMT
                CY                    CO2eq)       CO2eq)       CO2eq)
------------------------------------------------------------------------
Downstream.......................        -27.4        -94.7       -136.5
Upstream.........................         -9.3        -32.2        -46.5
HFC..............................         -0.1        -0.25         -0.3
    Total........................        -36.8       -127.2       -183.3
------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.

Table VII-35--Annual Total GHG Emissions Impacts in Calendar Years 2025,
   2035 and 2050--Alternative 4 vs. Alt 1a using Analysis Method B \a\
------------------------------------------------------------------------
                                    2025 (MMT    2035 (MMT    2050 (MMT
                CY                    CO2eq)       CO2eq)       CO2eq)
------------------------------------------------------------------------
Downstream.......................        -33.7        -98.3       -136.9
Upstream.........................        -11.5        -33.4        -46.6
HFC..............................         -0.1        -0.25         -0.3
    Total........................        -45.3       -132.0       -183.8
------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.

(b) Model Year Lifetime Analysis
    In addition to the annual GHG emissions and fuel consumption
reductions expected from the proposed rules and Alternative 4, the
combined (downstream and upstream) GHG and fuel consumption impacts for
the lifetime of the impacted vehicles were estimated. Table VII-36
shows the fleet-wide GHG reductions and fuel savings from the preferred
alternative and Alternative 4, relative to Alternative 1a, through the
lifetime \392\ of heavy-duty vehicles. Compared to the preferred
alternative, Alternative 4 shows greater lifetime GHG reductions and
fuels savings by 12 percent and 13 percent, respectively. For the
lifetime GHG reductions and fuel savings by vehicle categories, see
Chapter 5 of the draft RIA.
---------------------------------------------------------------------------

    \392\ A lifetime of 30 years is assumed in MOVES.

  Table VII-36--Lifetime GHG Reductions and Fuel Savings using Analysis
             Method B--Summary for Model Years 2018-2029 \a\
------------------------------------------------------------------------
                  Model years                   Alternative  Alternative
-----------------------------------------------      3            4
                                                 (proposed) ------------
                                               -------------
       No-action alternative (baseline)           1a (less     1a (less
                                                  dynamic)     dynamic)
------------------------------------------------------------------------
Fuel Savings (Billion Gallons)................         75.8         85.4
    Total GHG Reductions (MMT CO2eq)..........      1,036.4      1,163.1
        Downstream (MMT CO2eq)................        772.6        867.3
        Upstream (MMT CO2eq)..................        263.8        295.8
------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.

D. Climate Impacts and Indicators
(1) Climate Change Impacts From GHG Emissions
    The impact of GHG emissions on the climate has been reviewed in the
2009 Endangerment and Cause or Contribute Findings for Greenhouse Gases
under Section 202(a) of the Clean Air Act, the 2012-2016 light-duty
vehicle rulemaking, the 2014-2018 heavy-duty vehicle GHG and Fuel
Efficiency rulemaking, and the 2017-2025 light-duty vehicle rulemaking,
and the proposed standards for new electricity utility generating
units. See 74 FR 66496; 75 FR 25491; 76 FR 57294; 77 FR 62894; 79 FR
1456-1459 (January 8, 2014). This section briefly discusses again some
of the climate impact of EPA's proposed actions in context of
transportation emissions. NHTSA has analyzed the climate impacts of its
specific proposed actions (i.e., excluding EPA's HFC regulatory
provisions) as well as reasonable alternative in its DEIS that
accompanies

this proposed rule. DOT has considered the potential climate impacts
documented in the DEIS as part of the rulemaking process.
    Once emitted, GHGs that are the subject of this proposed regulation
can remain in the atmosphere for decades to millennia, meaning that (1)
their concentrations become well-mixed throughout the global atmosphere
regardless of emission origin, and (2) their effects on climate are
long lasting. GHG emissions come mainly from the combustion of fossil
fuels (coal, oil, and gas), with additional contributions from the
clearing of forests, agricultural activities, cement production, and
some industrial activities. Transportation activities, in aggregate,
were the second largest contributor to total U.S. GHG emissions in 2010
(27 percent of total emissions).\393\
---------------------------------------------------------------------------

    \393\ U.S. EPA (2012) Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990-2010. EPA 430-R-12-001. Available at http://epa.gov/climatechange/emissions/downloads12/US-GHG-Inventory-2012-Main-Text.pdf.
---------------------------------------------------------------------------

    The EPA Administrator relied on thorough and peer-reviewed
assessments of climate change science prepared by the Intergovernmental
Panel on Climate Change (``IPCC''), the United States Global Change
Research Program (``USGCRP''), and the National Research Council of the
National Academies (``NRC'') \394\ as the primary scientific and
technical basis for the Endangerment and Cause or Contribute Findings
for Greenhouse Gases Under Section 202(a) of the Clean Air Act (74 FR
66496, December 15, 2009). These assessments comprehensively address
the scientific issues the EPA Administrator had to examine, providing
her data and information on a wide range of issues pertinent to the
Endangerment Finding. These assessments have been rigorously reviewed
by the expert community, and also by United States government agencies
and scientists, including by EPA itself.
---------------------------------------------------------------------------

    \394\ For a complete list of core references from IPCC, USGCRP/
CCSP, NRC and others relied upon for development of the TSD for
EPA's Endangerment and Cause or Contribute Findings see section
1(b), specifically, Table 1.1 of the TSD. (Docket EPA-HQ-OAR-2010-
0799)
---------------------------------------------------------------------------

    Based on these assessments, the EPA Administrator determined that
the emissions from new motor vehicles and engines contributes to
elevated concentrations of greenhouse gases, that these greenhouse
gases cause warming; that the recent warming has been attributed to the
increase in greenhouse gases; and that warming of the climate endangers
the public health and welfare of current and future generations. See
Coalition for Responsible Regulation v. EPA, 684 F. 3d 102, 121 (D.C.
Cir. 2012) (upholding all of EPA's findings and stating ``EPA had
before it substantial record evidence that anthropogenic emissions of
greenhouse gases `very likely' caused warming of the climate over the
last several decades. EPA further had evidence of current and future
effects of this warming on public health and welfare. Relying again
upon substantial scientific evidence, EPA determined that
anthropogenically induced climate change threatens both public health
and public welfare. It found that extreme weather events, changes in
air quality, increases in food- and water-borne pathogens, and
increases in temperatures are likely to have adverse health effects.
The record also supports EPA's conclusion that climate change endangers
human welfare by creating risk to food production and agriculture,
forestry, energy, infrastructure, ecosystems, and wildlife. Substantial
evidence further supported EPA's conclusion that the warming resulting
from the greenhouse gas emissions could be expected to create risks to
water resources and in general to coastal areas as a result of expected
increase in sea level.'')
    A number of major peer-reviewed scientific assessments have been
released since the administrative record concerning the Endangerment
Finding closed following EPA's 2010 Reconsideration Denial.\395\ These
assessments include the ``Special Report on Managing the Risks of
Extreme Events and Disasters to Advance Climate Change Adaptation''
\396\, the 2013-14 Fifth Assessment Report (AR5),\397\ the 2014
National Climate Assessment report,\398\ the ``Ocean Acidification: A
National Strategy to Meet the Challenges of a Changing Ocean,'' \399\
``Report on Climate Stabilization Targets: Emissions, Concentrations,
and Impacts over Decades to Millennia,'' \400\ ``National Security
Implications for U.S. Naval Forces'' (National Security
Implications),\401\ ``Understanding Earth's Deep Past: Lessons for Our
Climate Future,'' \402\ ``Sea Level Rise for the Coasts of California,
Oregon, and Washington: Past, Present, and Future,'' \403\ ``Climate
and Social Stress: Implications for Security Analysis,'' \404\ and
``Abrupt Impacts of Climate Change'' (Abrupt Impacts) assessments.\405\
---------------------------------------------------------------------------

    \395\ ``EPA's Denial of the Petitions to Reconsider the
Endangerment and Cause or Contribute Findings for Greenhouse Gases
under Section 202(a) of the Clean Air Act'', 75 FR 49,556 (Aug. 13,
2010) (``Reconsideration Denial'').
    \396\ Intergovernmental Panel on Climate Change (IPCC). 2012:
Managing the Risks of Extreme Events and Disasters to Advance
Climate Change Adaption. A Special Report of Working Groups I and II
of the Intergovernmental Panel on Climate Change. Cambridge
University Press, Cambridge, UK, and New York, NY, USA.
    \397\ Intergovernmental Panel on Climate Change (IPCC). 2013.
Climate Change 2013: The Physical Science Basis. Contribution of
Working Group I to the Fifth Assessment Report of the
Intergovernmental Panel on Climate Change. Cambridge University
Press, Cambridge, United Kingdom and New York, NY, USA,
Intergovernmental Panel on Climate Change (IPCC). 2014. Climate
Change 2014: Impacts, Adaptation, and Vulnerability. Contribution of
Working Group II to the Fifth Assessment Report of the
Intergovernmental Panel on Climate Change. Cambridge University
Press, Cambridge, United Kingdom and New York, NY, USA,
Intergovernmental Panel on Climate Change (IPCC). 2014. Climate
Change 2014: Mitigation of Climate Change. Contribution of Working
Group III to the Fifth Assessment Report of the Intergovernmental
Panel on Climate Change. Cambridge University Press, Cambridge,
United Kingdom and New York, NY, USA.
    \398\ Melillo, Jerry M., Terese (T.C.) Richmond, and Gary W.
Yohe, Eds. 2014. Climate Change Impacts in the United States: The
Third National Climate Assessment. U.S. Global Change Research
Program. Available at http://nca2014.globalchange.gov.
    \399\ National Research Council (NRC). 2010. Ocean
Acidification: A National Strategy to Meet the Challenges of a
Changing Ocean. National Academies Press. Washington, DC.
    \400\ National Research Council (NRC). 2011. Climate
Stabilization Targets: Emissions, Concentrations, and Impacts over
Decades to Millennia. National Academies Press, Washington, DC.
    \401\ National Research Council (NRC) 2011. National Security
Implications of Climate Change for U.S. Naval Forces. National
Academies Press. Washington, DC.
    \402\ National Research Council (NRC). 2012. Sea-Level Rise for
the Coasts of California, Oregon, and Washington: Past, Present, and
Future. National Academies Press. Washington, DC.
    \403\ National Research Council (NRC). 2012. Sea-Level Rise for
the Coasts of California, Oregon, and Washington: Past, Present, and
Future. National Academies Press. Washington, DC.
    \404\ National Research Council (NRC). 2013. Climate and Social
Stress: Implications for Security Analysis. National Academies
Press. Washington, DC.
    \405\ National Research Council (NRC). 2013. Abrupt Impacts of
Climate Change: Anticipating Surprises. National Academies Press.
Washington, DC.
---------------------------------------------------------------------------

    EPA has reviewed these assessments and finds that in general, the
improved understanding of the climate system they present are
consistent with the assessments underlying the 2009 Endangerment
Finding.
    The most recent assessments released were the IPCC AR5 assessments
between September 2013 and April 2014, the NRC Abrupt Impacts
assessment in December of 2013, and the U.S. National Climate
Assessment in May of 2014. The NRC Abrupt Impacts report examines the
potential for tipping points, thresholds beyond which major and rapid
changes occur in the Earth's climate system or other systems impacted
by the climate. The Abrupt

Impacts report did find less cause for concern than some previous
assessments regarding some abrupt events within the next century such
as disruption of the Atlantic Meridional Overturning Circulation (AMOC)
and sudden releases of high-latitude methane from hydrates and
permafrost, but found that the potential for abrupt changes in
ecosystems, weather and climate extremes, and groundwater supplies
critical for agriculture now seem more likely, severe, and imminent.
The assessment found that some abrupt changes were already underway
(Arctic sea ice retreat and increases in extinction risk due to the
speed of climate change), but cautioned that even abrupt changes such
as the AMOC disruption that are not expected in this century can have
severe impacts when they happen.
    The IPCC AR5 assessments are also generally consistent with the
underlying science supporting the 2009 Endangerment Finding. For
example, confidence in attributing recent warming to human causes has
increased: The IPCC stated that it is extremely likely (>95 percent
confidence) that human influences have been the dominant cause of
recent warming. Moreover, the IPCC found that the last 30 years were
likely (>66 percent confidence) the warmest 30 year period in the
Northern Hemisphere of the past 1400 years, that the rate of ice loss
of worldwide glaciers and the Greenland and Antarctic ice sheets has
likely increased, that there is medium confidence that the recent
summer sea ice retreat in the Arctic is larger than it has been in 1450
years, and that concentrations of carbon dioxide and several other of
the major greenhouse gases are higher than they have been in at least
800,000 years. Climate-change induced impacts have been observed in
changing precipitation patterns, melting snow and ice, species
migration, negative impacts on crops, increased heat and decreased cold
mortality, and altered ranges for water-borne illnesses and disease
vectors. Additional risks from future changes include death, injury,
and disrupted livelihoods in coastal zones and regions vulnerable to
inland flooding, food insecurity linked to warming, drought, and
flooding, especially for poor populations, reduced access to drinking
and irrigation water for those with minimal capital in semi-arid
regions, and decreased biodiversity in marine ecosystems, especially in
the Arctic and tropics, with implications for coastal livelihoods. The
IPCC determined that ``[c]ontinued emissions of greenhouse gases will
cause further warming and changes in all components of the climate
system. Limiting climate change will require substantial and sustained
reductions of greenhouse gases emissions.''
    Finally, the recently released National Climate Assessment stated,
``Climate change is already affecting the American people in far
reaching ways. Certain types of extreme weather events with links to
climate change have become more frequent and/or intense, including
prolonged periods of heat, heavy downpours, and, in some regions,
floods and droughts. In addition, warming is causing sea level to rise
and glaciers and Arctic sea ice to melt, and oceans are becoming more
acidic as they absorb carbon dioxide. These and other aspects of
climate change are disrupting people's lives and damaging some sectors
of our economy.''
    Assessments from these bodies represent the current state of
knowledge, comprehensively cover and synthesize thousands of individual
studies to obtain the majority conclusions from the body of scientific
literature and undergo a rigorous and exacting standard of review by
the peer expert community and U.S. government.
    Based on modeling analysis performed by the agencies, reductions in
CO2 and other GHG emissions associated with these proposed
rules will affect future climate change. Since GHGs are well-mixed in
the atmosphere and have long atmospheric lifetimes, changes in GHG
emissions will affect atmospheric concentrations of greenhouse gases
and future climate for decades to millennia, depending on the gas. This
section provides estimates of the projected change in atmospheric
CO2 concentrations based on the emission reductions
estimated for these proposed rules, compared to the reference case. In
addition, this section analyzes the response to the changes in GHG
concentrations of the following climate-related variables: Global mean
temperature, sea level rise, and ocean pH.
(2) Projected Change in Atmospheric CO2 Concentrations,
Global Mean Surface Temperature and Sea Level Rise
    To assess the impact of the emissions reductions from the proposed
rules, EPA estimated changes in projected atmospheric CO2
concentrations, global mean surface temperature and sea-level rise to
2100 using the GCAM (Global Change Assessment Model, formerly MiniCAM),
integrated assessment model \406\ coupled with the MAGICC (Model for
the Assessment of Greenhouse-gas Induced Climate Change) simple climate
model.\407\ GCAM was used to create the globally and temporally
consistent set of climate relevant emissions required for running
MAGICC. MAGICC was then used to estimate the projected change in
relevant climate variables over time. Given the magnitude of the
estimated emissions reductions associated with these rules, a simple
climate model such as MAGICC is appropriate for estimating the
atmospheric and climate response.
---------------------------------------------------------------------------

    \406\ GCAM is a long-term, global integrated assessment model of
energy, economy, agriculture and land use that considers the sources
of emissions of a suite of greenhouse gases (GHG's), emitted in 14
globally disaggregated regions, the fate of emissions to the
atmosphere, and the consequences of changing concentrations of
greenhouse related gases for climate change. GCAM begins with a
representation of demographic and economic developments in each
region and combines these with assumptions about technology
development to describe an internally consistent representation of
energy, agriculture, land-use, and economic developments that in
turn shape global emissions.
    \407\ MAGICC consists of a suite of coupled gas-cycle, climate
and ice-melt models integrated into a single framework. The
framework allows the user to determine changes in greenhouse-gas
concentrations, global-mean surface air temperature and sea-level
resulting from anthropogenic emissions of carbon dioxide
(CO2), methane (CH4), nitrous oxide (N2O), reactive gases
(CO, NOX, VOCs), the halocarbons (e.g. HCFCs, HFCs, PFCs)
and sulfur dioxide (SO2). MAGICC emulates the global-mean
temperature responses of more sophisticated coupled Atmosphere/Ocean
General Circulation Models (AOGCMs) with high accuracy.
---------------------------------------------------------------------------

    The analysis projects that the proposed rules would reduce
atmospheric concentrations of CO2, global climate warming,
ocean acidification, and sea level rise relative to the reference case.
Although the projected reductions and improvements are small in
comparison to the total projected climate change, they are
quantifiable, directionally consistent, and will contribute to reducing
the risks associated with climate change. Climate change is a global
phenomenon and EPA recognizes that this one national action alone will
not prevent it; EPA notes this would be true for any given GHG
mitigation action when taken alone or when considered in isolation. EPA
also notes that a substantial portion of CO2 emitted into
the atmosphere is not removed by natural processes for millennia, and
therefore each unit of CO2 not emitted into the atmosphere
due to this rules avoids essentially permanent climate change on
centennial time scales.
    EPA determines that the projected reductions in atmospheric
CO2, global mean temperature, sea level rise, and ocean pH
are meaningful in the context of this action. The results of the
analysis, summarized in Table VII-37, demonstrate that relative to the

reference case, by 2100 projected atmospheric CO2
concentrations are estimated to be reduced by 1.1 to 1.2 part per
million by volume (ppmv), global mean temperature is estimated to be
reduced by 0.0026 to 0.0065 [deg]C, and sea-level rise is projected to
be reduced by approximately 0.023 to 0.057 cm, based on a range of
climate sensitivities (described below). Details about this modeling
analysis can be found in the draft RIA Chapter 6.3.

Table VII-37--Impact of GHG Emissions Reductions on Projected Changes in Global Climate Associated With Proposed
                                       Phase 2 Standards for MY 2018-2024
                          [Based on a range of climate sensitivities from 1.5-6 [deg]C]
----------------------------------------------------------------------------------------------------------------
              Variable                         Units                Year                Projected change
----------------------------------------------------------------------------------------------------------------
Atmospheric CO2 CONCENTRATION.......  ppmv...................            2100  -1.1 to -1.2
Global Mean Surface Temperature.....  [deg]C.................            2100  -0.0026 to -0.0065
Sea Level Rise......................  cm.....................            2100  -0.023 to -0.057
Ocean pH............................  pH units...............            2100  +0.0006 \a\
----------------------------------------------------------------------------------------------------------------
Note:
\a\ The value for projected change in ocean pH is based on a climate sensitivity of 3.0.

    The projected reductions are small relative to the change in
temperature (1.8-4.8 [deg]C), CO2 concentration (404 to 470
ppm), sea level rise (23-56 cm), and ocean acidity (-0.30 pH units)
from 1990 to 2100 from the MAGICC simulations for the GCAM reference
case. However, this is to be expected given the magnitude of emissions
reductions expected from the program in the context of global
emissions. Moreover, these effects are occurring everywhere around the
globe, so benefits that appear to be marginal for any one location,
such as a reduction in seal level rise of half a millimeter, can be
sizable when the effects are summed along thousands of miles of
coastline. This uncertainty range does not include the effects of
uncertainty in future emissions. It should also be noted that the
calculations in MAGICC do not include the possible effects of
accelerated ice flow in Greenland and/or Antarctica: Estimates of sea
level rise from the recent NRC, IPCC, and NCA assessments range from 26
cm to 2 meters depending on the emissions scenario, the processes
included, and the likelihood range assessed; inclusion of these effects
would lead to correspondingly larger benefits of mitigation. Further
discussion of EPA's modeling analysis is found in the RIA, Chapter 6.3.
    Based on the projected atmospheric CO2 concentration
reductions resulting from these proposed rules, EPA calculates an
increase in ocean pH of 0.0006 pH units in 2100 relative to the
baseline case (this is a reduction in the expected acidification of the
ocean of a decrease of 0.3 pH units from 1990 to 2100 in the baseline
case). Thus, this analysis indicates the projected decrease in
atmospheric CO2 concentrations from the proposed Phase 2
standards would result in an increase in ocean pH (i.e., a reduction in
the expected acidification of the ocean in the reference case). A more
detailed discussion of the modeling analysis associated with ocean pH
is provided in the draft RIA, Chapter 6.3.
    The 2011 NRC assessment on ``Climate Stabilization Targets:
Emissions, Concentrations, and Impacts over Decades to Millennia''
determined how a number of climate impacts--such as heaviest daily
rainfalls, crop yields, and Arctic sea ice extent--would change with a
temperature change of 1 degree Celsius (C) of warming. These
relationships of impacts with temperature change could be combined with
the calculated reductions in warming in Table VII-37 to estimate
changes in these impacts associated with this proposed rulemaking.
    As a substantial portion of CO2 emitted into the
atmosphere is not removed by natural processes for millennia, each unit
of CO2 not emitted into the atmosphere avoids some degree of
effectively permanent climate change. Therefore, reductions in
emissions in the near-term are important in determining climate impacts
experienced not just over the next decades but over thousands of
years.\408\ Though the magnitude of the avoided climate change
projected here in isolation is small in comparison to the total
projected changes, these reductions represent a reduction in the
adverse risks associated with climate change (though these risks were
not formally estimated for this action) across a range of equilibrium
climate sensitivities.
---------------------------------------------------------------------------

    \408\ National Research Council (NRC) (2011). Climate
Stabilization Targets: Emissions, Concentrations, and Impacts over
Decades to Millennia. National Academy Press. Washington, DC.
(Docket EPA-HQ-OAR-2010-0799)
---------------------------------------------------------------------------

    EPA's analysis of this proposed rule's impact on global climate
conditions is intended to quantify these potential reductions using the
best available science. EPA's modeling results show consistent
reductions relative to the baseline case in changes of CO2
concentration, temperature, sea-level rise, and ocean pH over the next
century.

VIII. How will this proposed action impact non-GHG emissions and their
associated effects?

    The proposed heavy-duty vehicle standards are expected to influence
the emissions of criteria air pollutants and several air toxics. This
section describes the projected impacts of the proposed rules and
Alternative 4 on non-GHG emissions and air quality, and the health and
environmental effects associated with these pollutants. NHTSA further
analyzes these projected health and environmental effects resulting
from its proposed rules and reasonable alternatives in Chapter 4 of its
DEIS.

A. Emissions Inventory Impacts

    As described in Section VII, the agencies conducted coordinated and
complementary analyses for these rules by employing both DOT's CAFE
model and EPA's MOVES model, relative to different reference cases
(i.e., different baselines). The agencies used EPA's MOVES model to
estimate the non-GHG impacts for tractor-trailers (including the engine
that powers the vehicle), and vocational vehicles (including the engine
that powers the vehicle). For heavy-duty pickups and vans, the agencies
performed complementary analyses using the CAFE model (``Method A'')
and the MOVES model (``Method B'') to estimate non-GHG emissions from
these vehicles. For both methods, the agencies analyzed the impact of
the proposed rules, relative to two different reference cases--less
dynamic and more dynamic. The less dynamic baseline projects very
little improvement in new vehicles in the absence of new Phase 2
standards. In contrast, the more dynamic baseline

projects more improvements in vehicle fuel efficiency. The agencies
considered both reference cases. The results for all of the regulatory
alternatives relative to both reference cases, derived via the same
methodologies discussed in Section VII of the Preamble, are presented
in Section X of the Preamble.
    For brevity, a subset of these analyses are presented in this
section and the reader is referred to both the RIA Chapter 11 and
NHTSA's DEIS Chapters 3 and 5 for complete sets of these analyses. In
this section, Method A is presented for both the proposed standards
(i.e., Alternative 3--the agencies' preferred alternative) and for the
standards the agencies considered in Alternative 4, relative to both
the more dynamic baseline (Alternative 1b) and the less dynamic
baseline (Alternative 1a). Method B is presented also for the proposed
standards and Alternative 4, but relative only to the less dynamic
baseline. The agencies' intention for presenting both of these
complementary and coordinated analyses is to offer interested readers
the opportunity to compare the regulatory alternatives considered for
Phase 2 in both the context of our HD Phase 1 analytical approaches and
our light-duty vehicle analytical approaches. The agencies view these
analyses as corroborative and reinforcing: Both support agencies'
conclusion that the proposed standards are appropriate and at the
maximum feasible levels.
    The following subsections summarize two slightly different analyses
of the annual non-GHG emissions reductions expected from the proposed
standards and Alternative 4. Section VIII. A. (1) presents the impacts
of the proposed rules and Alternative 4 on non-GHG emissions using the
analytical Method A, relative to two different reference cases--less
dynamic and more dynamic. Section VIII. A. (2) presents the impacts of
the proposed standards and Alternative 4, relative to the less dynamic
reference case only, using the MOVES model for all heavy-duty vehicle
categories.
(1) Impacts of the Proposed Rules and Alternative 4 Using Analysis
Method A
(a) Calendar Year Analysis
(i) Upstream Impacts of the Proposed Program and Alternative 4
    Increasing efficiency in heavy-duty vehicles would result in
reduced fuel demand, and therefore, reductions in the emissions
associated with all processes involved in getting petroleum to the
pump. Both Method A and Method B project these impacts for fuel
consumed by vocational vehicles and combination tractor-trailers, using
the same methods. See Section VIII.A.(2) (a)(i) for the description of
this methodology. To project these impacts for fuel consumed by HD
pickups and vans, Method A used similar calculations and inputs
applicable to the CAFE model, as discussed above in Section VI. More
information on the development of the emission factors used in this
analysis can be found in Chapter 5 of the draft RIA.
    The following four tables summarize the projected upstream emission
impacts of the preferred alternative and Alternative 4 on both criteria
pollutants and air toxics from the heavy-duty sector, relative to
Alternative 1b (more dynamic baseline conditions under the No-Action
Alternative) and Alternative 1a (less dynamic baseline conditions under
the No-Action Alternative).

 Table VIII-1--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
             Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1b using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1           -5           -3          -14           -5          -17
Acetaldehyde......................           -3           -3          -10          -11          -15          -13
Acrolein..........................            0           -4           -1          -12           -2          -15
Benzene...........................          -21           -4          -74          -13         -104          -15
CO................................       -3,798           -5      -12,087          -14      -17,120          -17
Formaldehyde......................          -19           -5          -59          -14          -84          -17
NOX...............................       -9,472           -5      -30,333          -14      -42,839          -17
PM2.5.............................       -1,019           -5       -3,257          -14       -4,609          -17
SOX...............................       -5,983           -5      -19,190          -14      -27,074          -17
VOC...............................       -3,066           -4      -11,029          -13      -15,386          -15
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-2--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
                 Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1b using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1           -6           -3          -15           -5          -17
Acetaldehyde......................           -4           -5          -11          -12          -15          -14
Acrolein..........................           -1           -5           -1          -13           -2          -15
Benzene...........................          -28           -5          -78          -13         -105          -16
CO................................       -4,679           -6      -12,640          -15      -17,263          -17
Formaldehyde......................          -23           -6          -62          -15          -85          -17
NOX...............................      -11,708           -6      -31,769          -15      -43,263          -17
PM2.5.............................       -1,259           -6       -3,408          -15       -4,649          -17
SOX...............................       -7,402           -6      -20,107          -15      -27,356          -17

VOC...............................       -4,081           -5      -11,717          -13      -15,645          -15
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-3--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
             Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1           -5           -4          -15           -5          -18
Acetaldehyde......................           -3           -3          -11          -12          -16          -14
Acrolein..........................            0           -4           -1          -13           -2          -15
Benzene...........................          -22           -4          -80          -14         -113          -16
CO................................       -3,911           -5      -13,153          -15      -18,794          -18
Formaldehyde......................          -19           -5          -65          -15          -92          -18
NOX...............................       -9,787           -5      -33,021          -15      -47,028          -18
PM2.5.............................       -1,051           -5       -3,545          -15       -5,058          -18
SOX...............................       -6,189           -5      -20,896          -15      -29,726          -18
VOC...............................       -3,193           -4      -11,848          -13      -16,625          -16
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-4--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
                 Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1a using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1           -6           -4          -16           -5          -18
Acetaldehyde......................           -4           -5          -12          -12          -16          -14
Acrolein..........................           -1           -5           -1          -13           -2          -16
Benzene...........................          -29           -5          -84          -14         -114          -17
CO................................       -4,816           -6      -13,720          -16      -18,945          -18
Formaldehyde......................          -24           -6          -67          -16          -93          -18
NOX...............................      -12,098           -6      -34,501          -16      -47,477          -18
PM2.5.............................       -1,298           -6       -3,700          -16       -5,101          -18
SOX...............................       -7,658           -6      -21,843          -16      -30,024          -18
VOC...............................       -4,251           -5      -12,541          -14      -16,870          -16
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

(ii) Downstream Impacts of the Proposed Program and Alternative 4
    For vocational vehicles and tractor-trailers, the agencies used the
MOVES model to determine non-GHG emissions inventories. The
improvements in engine efficiency and road load, the increased use of
APUs, and VMT rebound were included in the MOVES analysis. For the
analysis presented in this section, the DOT CAFE model was used for HD
pickups and vans. Further information about DOT's CAFE model is
available in Section VI.C and Chapter 10 of the draft RIA. The
following four tables summarize the projected downstream emission
impacts of the preferred alternative and Alternative 4 on both criteria
pollutants and air toxics from the heavy-duty sector, relative to
Alternative 1b and Alternative 1a.

Table VIII-5--Annual Downstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
             Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1b using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8           -3          -21          -12          -30          -16
Acetaldehyde......................         -669          -10       -1,882          -31       -2,667          -36
Acrolein..........................          -97          -10         -272          -31         -385          -37
Benzene...........................         -123           -6         -347          -19         -490          -24
CO................................      -26,485           -3      -75,199           -8     -106,756           -9
Formaldehyde......................       -2,100          -12       -5,910          -32       -8,376          -37
NOX...............................      -92,444           -7     -260,949          -28     -370,663          -34
PM2.5 \b\.........................          643            2        1,722            8        2,410           10
SOX...............................         -229           -4         -715          -13       -1,026          -15
VOC...............................      -13,161           -6      -38,051          -21      -54,139          -26
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

Table VIII-6--Annual Downstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
                 Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1b using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8           -2          -21          -12          -30          -16
Acetaldehyde......................         -669          -10       -1,882          -31       -2,667          -36
Acrolein..........................          -97          -10         -271          -31         -385          -37
Benzene...........................         -124           -6         -347          -19         -490          -24
CO................................      -26,705           -3      -75,407           -8     -106,874           -9
Formaldehyde......................       -2,100          -12       -5,908          -32       -8,375          -37
NOX...............................      -93,984           -8     -262,150          -28     -370,704          -34
PM2.5 \b\.........................          619            2        1,705            8        2,412           10
SOX...............................         -280           -5         -742          -13       -1,029          -15
VOC...............................      -13,925           -7      -38,472          -22      -54,150          -26
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

Table VIII-7--Annual Downstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
             Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8           -3          -21          -12          -30          -16
Acetaldehyde......................         -669          -10       -1,880          -31       -2,664          -36
Acrolein..........................          -97          -10         -271          -31         -384          -37
Benzene...........................         -123           -6         -346          -19         -490          -24
CO................................      -26,576           -3      -75,571           -8     -107,287           -9
Formaldehyde......................       -2,100          -12       -5,904          -32       -8,369          -37
NOX...............................      -93,197           -8     -266,890          -29     -380,303          -35
PM2.5 \b\.........................          632            2        1,635            8        2,267            9
SOX...............................         -232           -4         -776          -14       -1,125          -16
VOC...............................      -13,210           -6      -38,964          -22      -55,628          -26
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

Table VIII-8--Annual Downstream Impacts on Criteria Pollutants and Air Toxics from Heavy-Duty Sector in Calendar
                 Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1a using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8           -2          -21          -12          -29          -16
Acetaldehyde......................         -668          -10       -1,880          -31       -2,664          -36
Acrolein..........................          -97          -10         -271          -31         -384          -37
Benzene...........................         -124           -6         -346          -19         -489          -24
CO................................      -26,821           -3      -75,795           -8     -107,414           -9
Formaldehyde......................       -2,099          -12       -5,902          -32       -8,367          -37
NOX...............................      -94,724           -8     -268,075          -29     -380,328          -35
PM2.5 \b\.........................          609            2        1,618            8        2,269            9
SOX...............................         -282           -5         -803          -14       -1,127          -16
VOC...............................      -13,971           -7      -39,383          -22      -55,638          -26
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

(iii) Total Impacts of the Proposed Program and Alternative 4
    The following four tables summarize the projected upstream emission
impacts of the preferred alternative and Alternative 4 on both criteria
pollutants and air toxics from the heavy-duty sector, relative to
Alternative 1b and Alternative 1a.

 Table VIII-9--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-
 Duty Sector in Calendar Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1b Using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % reduction      tons     % reduction      tons     % reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -9           -3          -25          -13          -34          -16
Acetaldehyde......................         -672          -10       -1,893          -30       -2,682          -36
Acrolein..........................          -97          -10         -273          -31         -387          -37
Benzene...........................         -145           -5         -421          -18         -595          -22
CO................................      -30,282           -3      -87,286           -8     -123,876          -10
Formaldehyde......................       -2,119          -11       -5,969          -32       -8,460          -37
NOX...............................     -101,916           -7     -291,282          -26     -413,501          -31
PM2.5.............................         -376           -1       -1,535           -3       -2,199           -4
SOX...............................       -6,213           -5      -19,905          -14      -28,101          -17
VOC...............................      -16,227           -6      -49,080          -18      -69,525          -22

----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-10--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-
     Duty Sector in Calendar Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1b Using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % reduction      tons     % reduction      tons     % reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -9           -3          -25          -13          -34          -16
Acetaldehyde......................         -673          -10       -1,893          -30       -2,682          -36
Acrolein..........................          -97          -10         -273          -31         -387          -37
Benzene...........................         -152           -6         -426          -18         -595          -22
CO................................      -31,383           -3      -88,047           -8     -124,137          -10
Formaldehyde......................       -2,123          -11       -5,970          -32       -8,460          -37
NOX...............................     -105,693           -7     -293,918          -26     -413,967          -31
PM2.5.............................         -639           -1       -1,703           -4       -2,237           -4
SOX...............................       -7,682           -6      -20,849          -15      -28,385          -17

VOC...............................      -18,006           -6      -50,189          -19      -69,796          -22
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-11--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-
 Duty Sector in Calendar Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a Using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % reduction      tons     % reduction      tons     % reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -9           -3          -25          -13          -35          -16
Acetaldehyde......................         -672          -10       -1,891          -30       -2,680          -36
Acrolein..........................          -97          -10         -273          -31         -386          -37
Benzene...........................         -145           -5         -425          -18         -603          -22
CO................................      -30,487           -3      -88,724           -8     -126,081          -10
Formaldehyde......................       -2,119          -11       -5,969          -32       -8,461          -37
NOX...............................     -102,983           -7     -299,911          -26     -427,332          -32
PM2.5.............................         -419           -1       -1,910           -4       -2,791           -5
SOX...............................       -6,421           -5      -21,672          -15      -30,850          -18
VOC...............................      -16,403           -6      -50,812          -19      -72,253          -23
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-12--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-
     Duty Sector in Calendar Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1a Using Analysis Method A \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % reduction      tons     % reduction      tons     % reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -9           -3          -25          -13          -35          -16
Acetaldehyde......................         -672          -10       -1,891          -30       -2,679          -36
Acrolein..........................          -97          -10         -273          -31         -386          -37
Benzene...........................         -153           -6         -430          -18         -603          -22
CO................................      -31,637           -3      -89,514           -8     -126,360          -10
Formaldehyde......................       -2,123          -11       -5,969          -32       -8,460          -37
NOX...............................     -106,822           -7     -302,575          -26     -427,805          -32
PM2.5.............................         -689           -1       -2,082           -5       -2,833           -5
SOX...............................       -7,941           -6      -22,646          -16      -31,151          -18
VOC...............................      -18,222           -6      -51,924          -19      -72,509          -23
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

(b) Model Year Lifetime Analysis

 Table VIII-13--Lifetime Non-GHG Reductions Using Analysis Method A--Summary for Model Years 2018-2029 (US Short
                                                    Tons) \a\
----------------------------------------------------------------------------------------------------------------
                                               Alternative 3 (proposed)                  Alternative 4
                                         -----------------------------------------------------------------------
    No-action alternative (baseline)          1b (more          1a (less          1b (more          1a (less
                                              dynamic)          dynamic)          dynamic)          dynamic)
----------------------------------------------------------------------------------------------------------------
NOX.....................................         2,359,548         2,409,738         2,420,931         2,472,021
    Downstream..........................         2,103,163         2,137,232         2,130,659         2,164,458

    Upstream............................           256,385           272,506           290,272           307,563
PM2.5...................................            13,496            15,706            17,524            19,839
    Downstream \b\......................           -14,051           -13,546           -13,649           -13,153
    Upstream............................            27,547            29,252            31,173            32,992
SOX.....................................           167,415           177,948           189,670           200,992
    Downstream..........................             5,326             5,562             6,079             6,311
    Upstream............................           162,089           172,386           183,591           194,681
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Negative number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

(2) Impacts of the Proposed Rules and Alternative 4 using Analysis
Method B
(a) Calendar Year Analysis
(i) Upstream Impacts of the Proposed Program and Alternative 4
    Increasing efficiency in heavy-duty vehicles would result in
reduced fuel demand, and therefore, reductions in the emissions
associated with all processes involved in getting petroleum to the
pump. To project these impacts, Method B estimated the impact of
reduced petroleum volumes on the extraction and transportation of crude
oil as well as the production and distribution of finished gasoline and
diesel. For the purpose of assessing domestic-only emission reductions,
it was necessary to estimate the fraction of fuel savings attributable
to domestic finished gasoline and diesel, and of this fuel, what
fraction is produced from domestic crude. Method B estimated the
emissions associated with production and distribution of gasoline and
diesel from crude oil based on emission factors in the ``Greenhouse
Gases, Regulated Emissions, and Energy used in Transportation'' model
(GREET) developed by DOE's Argonne National Laboratory. In some cases,
the GREET values were modified or updated by the agencies to be
consistent with the National Emission Inventory (NEI) and emission
factors from MOVES. Method B estimated the projected corresponding
changes in upstream emissions using the same tools originally created
for the Renewable Fuel Standard 2 (RFS2) rulemaking analysis,\409\ used
in the LD GHG rulemakings,\410\ HD GHG Phase 1,\411\ and updated for
the current analysis. More information on the development of the
emission factors used in this analysis can be found in Chapter 5 of the
draft RIA.
---------------------------------------------------------------------------

    \409\ U.S. EPA. Draft Regulatory Impact Analysis: Changes to
Renewable Fuel Standard Program. Chapters 2 and 3. May 26, 2009.
Docket ID: EPA-HQ-OAR-2009-0472-0119.
    \410\ 2017 and Later Model Year Light-Duty Vehicle Greenhouse
Gas Emissions and Corporate Average Fuel Economy Standards (77 FR
62623, October 15, 2012).
    \411\ Greenhouse Gas Emission Standards and Fuel Efficiency
Standards for Medium- and Heavy-Duty Engines and Vehicles (76 FR
57106, September 15, 2011).
---------------------------------------------------------------------------

    Table VIII-14 and Table VIII-15 summarizes the projected upstream
emission impacts of the Preferred Alternative and Alternative 4 on both
criteria pollutants and air toxics from the heavy-duty sector, relative
to Alternative 1a. The comparable estimates relative to Alternative 1b
are presented in Section VIII. A. (1).

 Table VIII-14--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
             Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a Using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1         -5.0           -4        -15.3           -5        -18.4
Acetaldehyde......................           -4         -3.0          -18        -11.9          -26        -14.6
Acrolein..........................         -0.5         -3.4           -2        -12.7           -3        -15.5
Benzene...........................          -24         -3.8          -92        -13.4         -132        -16.3
CO................................       -3,798         -4.9      -13,001        -15.3      -18,772        -18.4
Formaldehyde......................          -19         -4.7          -67        -14.9          -98        -18.0
NOX...............................       -9,282         -4.9      -31,782        -15.3      -45,888        -18.4
PM2.5.............................       -1,020         -4.9       -3,514        -15.2       -5,072        -18.2
SOX...............................       -5,817         -4.9      -19,902        -15.3      -28,736        -18.4
VOC...............................       -3,283         -3.7      -12,724        -13.2      -18,214        -16.1
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-15--Annual Upstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar
                 Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1a Using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -1         -6.1           -4        -15.9           -5        -18.4
Acetaldehyde......................           -6         -4.3          -20        -12.6          -26        -14.7
Acrolein..........................           -1         -4.7           -2        -13.3           -3        -15.5
Benzene...........................          -32         -5.0          -97        -14.0         -133        -16.3
CO................................       -4,661         -6.1      -13,485        -15.9      -18,812        -18.4
Formaldehyde......................          -24         -5.9          -70        -15.5          -97        -18.0
NOX...............................      -11,393         -6.1      -32,965        -15.9      -45,986        -18.4
PM2.5.............................       -1,256         -6.0       -3,647        -15.7       -5,083        -18.3
SOX...............................       -7,137         -6.1      -20,641        -15.9      -28,797        -18.4
VOC...............................       -4,342         -4.9      -13,326        -13.8      -18,273        -16.1
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

(ii) Downstream Impacts of the Proposed Program and Alternative 4
    Both the proposed program and Alternative 4 would impact the
downstream emissions of non-GHG pollutants. These pollutants include
oxides of nitrogen (NOX), oxides of sulfur (SOX),
volatile organic compounds (VOC), carbon monoxide (CO), fine
particulate matter (PM2.5), and air toxics. The agencies are
expecting reductions in downstream emissions of NOX, VOC,
SOX, CO, and air toxics. Much of these estimated net
reductions are a result of the agencies' anticipation of increased use
of auxiliary power units (APUs) in combination tractors during extended
idling; APUs emit these pollutants at a lower rate than on-road engines
during extended idle operation, with the exception of PM2.5.
Additional reductions in tailpipe emissions of NOX and CO
and refueling emissions of VOC would be achieved through improvements
in engine efficiency and reduced road load (improved aerodynamics and
tire rolling resistance), which reduces the amount of work required to
travel a given distance and increases fuel economy. For vehicle types
not affected by road load improvements, such as HD pickups and
vans,\412\ non-GHG emissions would increase very slightly due to VMT
rebound. In addition, brake wear and tire wear emissions of
PM2.5 would also increase very slightly due to VMT rebound.
The agencies estimate that downstream emissions of SOX would
be reduced, because they are roughly proportional to fuel consumption.
Alternative 4 would have directionally similar effects as the preferred
alternative.
---------------------------------------------------------------------------

    \412\ HD pickups and vans are subject to gram per mile
(distance) emission standards, as opposed to larger heavy-duty
vehicles which are certified to a gram per brake horsepower (work)
standard.
---------------------------------------------------------------------------

    For vocational vehicles and tractor-trailers, agencies used MOVES
to determine non-GHG emissions impacts of the proposed rules and
Alternative 4, relative to the less dynamic baseline (Alternative 1a).
The improvements in engine efficiency and road load, the increased use
of APUs, and VMT rebound were included in the MOVES analysis. For this
analysis, Method B also used the MOVES model for HD pickups and vans.
(Note that for the comparable analysis as described in Section VIII. A.
(1), Method A used DOT's CAFE model). Further information about the
modeling using DOT's CAFE and MOVES model is available in Section VII
and Chapter 5 of the draft RIA.
    The downstream criteria pollutant and air toxics impacts of the
Preferred Alternative and Alternative 4, relative to Alternative 1a,
are presented in Table VIII-16 and Table VIII-17, respectively.

    Table VIII-16--Annual Downstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in
        Calendar Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a Using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8         -2.6          -22        -15.1          -31        -19.6
Acetaldehyde......................         -670        -10.3       -1,884        -31.0       -2,671        -36.5
Acrolein..........................          -97         -9.9         -272        -31.6         -385        -37.3
Benzene...........................         -125         -5.9         -353        -21.0         -501        -25.7
CO................................      -25,824         -1.7      -72,960         -6.0     -103,887         -7.6
Formaldehyde......................       -2,102        -11.5       -5,911        -32.1       -8,379        -37.5
NOX...............................      -93,220         -7.5     -267,125        -29.1     -380,721        -35.2
PM2.5 \b\.........................          634          1.6        1,631          7.6        2,257          9.1
SOX...............................         -254         -4.8         -876        -15.0       -1,264        -18.1
VOC...............................      -13,440         -6.4      -40,148        -21.7      -57,308        -26.1
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

    Table VIII-17--Annual Downstream Impacts on Criteria Pollutants and Air Toxics From Heavy-Duty Sector in
             Calendar Years 2025, 2035 and 2050--Alternative 4 vs. Alt 1aUsing Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                US short                  US short                  US short
                                        tons     % Reduction      tons     % Reduction      tons     % Reduction
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -8         -2.6          -22        -15.1          -31        -19.6
Acetaldehyde......................         -670        -10.3       -1,884        -31.0       -2,671        -36.5
Acrolein..........................          -97         -9.9         -272        -31.6         -385        -37.3
Benzene...........................         -126         -5.9         -354        -21.0         -501        -25.7
CO................................      -25,919         -1.7      -73,041         -6.0     -103,891         -7.6
Formaldehyde......................       -2,101        -11.5       -5,910        -32.1       -8,378        -37.5
NOX...............................      -94,787         -7.6     -268,373        -29.2     -380,810        -35.2
PM2.5 \b\.........................          610          1.5        1,611          7.5        2,256          9.1
SOX...............................         -313         -5.9         -909        -15.6       -1,267        -18.1
VOC...............................      -14,310         -6.8      -40,640        -22.0      -57,348        -26.1
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number means emissions would increase from reference to control case. PM2.5 from tire wear and
  brake wear are included.

    As shown in Table VIII-16, a net increase in downstream
PM2.5 emissions is expected. Although the improvements in
engine efficiency and road load are expected to reduce tailpipe
emissions of PM2.5, the projected increased use \413\ of
APUs would lead to higher PM2.5 emissions that more than
offset the reductions from the tailpipe, since engines powering APUs
are currently required to meet less stringent PM standards than on-road
engines. Therefore, EPA conducted an evaluation of a program that would
reduce the unintended consequence of increase in PM2.5
emissions from increased APU use by fitting the APU with a diesel
particulate filter or having the APU exhaust plumbed into the vehicle's
exhaust system upstream of the particulate matter aftertreatment
device. Such program requiring additional PM2.5 controls on
APU could significantly reduce PM2.5 emissions, as shown in
Table VIII-18 below. For additional details, see Section III.C.3 of the
preamble.
---------------------------------------------------------------------------

    \413\ The projected use of APU during extended idling is
presented in Table VII-3 of the preamble.

 Table VIII-18--Projected Impact on PM2.5 Emissions of Further PM2.5 Control on APUs--Preferred Alternative vs.
                               Alt 1a Using Analysis Method B (US Short Tons) \a\
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed
                                                                      program        Proposed
                                                                     inventory        program      Net impact of
                               CY                                     without     inventory with   further PM2.5
                                                                   further PM2.5   further PM2.5    control on
                                                                    control on      control on         APUs
                                                                       APUs            APUs
----------------------------------------------------------------------------------------------------------------
2035............................................................          23,083          19,999          -3,084
2050............................................................          26,932          22,588          -4,344
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

    It is worth noting that the emission reductions shown in Table
VIII-16 are not incremental to the emissions reductions projected in
the Phase 1 rulemaking. This is because, as described in Sections
III.D.2.a of the preamble, the agencies have revised their assumptions
about the adoption rate of APUs. This proposal assumes that without the
proposed Phase 2 program (i.e., in the Phase 2 reference case), the APU
adoption rate will be 30 percent for model years 2010 and later, which
is the value used in the Phase 1 reference case. EPA conducted an
analysis to estimate the combined emissions impacts of the Phase 1 and
the proposed Phase 2 programs for NOX, VOC, SOX
and PM2.5 in calendar year 2050 using MOVES2014. The results
are shown in Table VIII-19. For NOX and PM2.5
only, we estimated the combined Phase 1 and Phase 2 downstream and
upstream emissions impacts for calendar year 2025, and project that the
two rules combined would reduce NOX by up to 120,000 tons
and PM2.5 by up to 2,000 tons in that year. For additional
details, see Chapter 5 of the draft RIA.

  Table VIII-19--Combined Phase 1 and Phase 2 Annual Downstream Impacts on Criteria Pollutants From Heavy-Duty
             Sector in Calendar Year 2050--Preferred Alternative vs. Alt 1a Using Analysis Method B
                                               [US short tons] \a\
----------------------------------------------------------------------------------------------------------------
                     CY                             NOX              VOC              SOX             PM2.5b
----------------------------------------------------------------------------------------------------------------
2050........................................        -403,915          -69,415           -2,111            1,890
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Positive number reflects an increase in emissions.

(iii) Total Impacts of the Proposed Program and Alternative 4
    As shown in Table VIII-20 and Table VIII-21, agencies estimate that
both the proposed program and Alternative 4 would result in overall net
reductions of NOX, VOC, SOX, CO,
PM2.5, and air toxics emissions. The downstream increase in
PM2.5 due to APU use is expected to be more than offset by
reductions in PM2.5 from upstream.\414\ The results are
shown both in changes in absolute tons and in percent reductions from
the less dynamic reference to the alternatives for the heavy-duty
sector. By 2050, the total impacts of the proposed program and
Alternative 4 on criteria pollutants and air toxics are
indistinguishable.
---------------------------------------------------------------------------

    \414\ Although net reduction in PM2.5 is expected at
the national level, it is unlikely that the geographic location of
increases in downstream PM2.5 emissions will coincide
with the location of decreases in upstream PM2.5
emissions. For further details, see Section VIII.D of this preamble
and in Chapter 8 of the draft RIA.

 Table VIII-20--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-
 Duty Sector in Calendar Years 2025, 2035 and 2050--Preferred Alternative vs. Alt 1a Using Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                             CY2025                    CY2035                    CY2050
                                   -----------------------------------------------------------------------------
             Pollutant                             US short                  US short                  US short
                                    % Reduction      tons     % Reduction      tons     % Reduction      tons
----------------------------------------------------------------------------------------------------------------
1,3-Butadiene.....................           -9         -2.7          -25        -15.1          -36        -19.4
Acetaldehyde......................         -674        -10.1       -1,902        -30.5       -2,697        -36.0
Acrolein..........................          -97         -9.8         -274        -31.3         -388        -36.9
Benzene...........................         -149         -5.4         -445        -18.8         -633        -22.9
CO................................      -29,622         -1.9      -85,961         -6.6     -122,659         -8.4
Formaldehyde......................       -2,121        -11.4       -5,978        -31.7       -8,475        -37.0
NOX...............................     -102,502         -7.2     -298,907        -26.6     -426,610        -32.1
PM2.5.............................         -386         -0.6       -1,883         -4.2       -2,815         -5.4
SOX...............................       -6,070         -4.9      -20,777        -15.3      -30,000        -18.4
VOC...............................      -16,724         -5.6      -52,872        -18.8      -75,521        -22.7
----------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.

 Table VIII-21--Annual Total Impacts (Upstream and Downstream) of Criteria Pollutants and Air Toxics From Heavy-Duty Sector in Calendar Years 2025, 2035
                                             and 2050--Alternative 4 vs. Alt 1a Using Analysis Method B \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      CY2025                          CY2035                          CY2050
                        Pollutant                        -----------------------------------------------------------------------------------------------
                                                           US short tons    % Reduction    US short tons    % Reduction    US short tons    % Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
1,3-Butadiene...........................................              -9            -2.8             -26           -15.2             -36           -19.4
Acetaldehyde............................................            -676           -10.1          -1,903           -30.6          -2,697           -36.0
Acrolein................................................             -97            -9.8            -274           -31.3            -388           -36.9
Benzene.................................................            -157            -5.7            -450           -18.9            -634           -22.9
CO......................................................         -30,580            -1.9         -86,526            -6.6        -122,703            -8.4
Formaldehyde............................................          -2,125           -11.4          -5,980           -31.7          -8,476           -37.0
NOX.....................................................        -106,180            -7.4        -301,339           -26.8        -426,796           -32.1
PM2.5...................................................            -646            -1.1          -2,036            -4.6          -2,827            -5.4
SOX.....................................................          -7,450            -6.1         -21,550           -15.9         -30,064           -18.4
VOC.....................................................         -18,652            -6.2         -53,966           -19.2         -75,621           -22.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less dynamic baseline, 1a, and more dynamic
  baseline, 1b, please see Section X.A.1.

(b) Model Year Lifetime Analysis
    In addition to the annual non-GHG emissions reductions expected
from the proposed rules and Alternative 4, the combined (downstream and
upstream) non-GHG impacts for the lifetime of the impacted vehicles
were estimated. Table VIII-22 shows the fleet-wide reductions of
NOX, PM2.5 and SOX from the preferred
alternative and Alternative 4, relative to Alternative 1a, through the
lifetime \415\ of heavy-duty vehicles. For the lifetime non-GHG
reductions by vehicle categories, see Chapter 5 of the draft RIA.
---------------------------------------------------------------------------

    \415\ A lifetime of 30 years is assumed in MOVES.

  Table VIII-22--Lifetime Non-GHG Reductions Using Analysis Method B--
                    Summary for Model Years 2018-2029
                           [US short tons] \a\
------------------------------------------------------------------------
                                      Alternative 3      Alternative 4
                                        (proposed)    ------------------
 No-action alternative (baseline)  -------------------
                                        1a  (Less          1a  (Less
                                         dynamic)           dynamic)
------------------------------------------------------------------------
NOX...............................          2,399,990          2,459,497
    Downstream....................          2,139,331          2,167,512
    Upstream......................            260,659            291,986
PM2.5.............................             15,206             19,151
    Downstream \b\................            -13,528            -13,089
    Upstream......................             28,733             32,240
SOX...............................            169,436            189,904
    Downstream....................              6,158              7,035
    Upstream......................            163,278            182,869
------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.
\b\ Negative number means emissions would increase from reference to
  control case. PM2.5 from tire wear and brake wear are included.

B. Health Effects of Non-GHG Pollutants

    In this section, we discuss health effects associated with exposure
to some of the criteria and air toxic pollutants impacted by the
proposed and alternative heavy-duty vehicle standards.
(1) Particulate Matter
(a) Background
    Particulate matter is a highly complex mixture of solid particles
and liquid droplets distributed among numerous atmospheric gases which
interact with solid and liquid phases. Particles range in size from
those smaller than 1 nanometer (10-9 meter) to over 100
micrometer ([micro]m, or 10-6 meter) in diameter (for
reference, a typical strand of human hair is 70 [micro]m in diameter
and a grain of salt is about 100 [micro]m). Atmospheric particles can
be grouped into several classes according to their aerodynamic and
physical sizes. Generally, the three broad classes of particles
considered by EPA include ultrafine particles (UFP, aerodynamic
diameter <0.1 [micro]m), ``fine'' particles (PM2.5;
particles with a nominal mean aerodynamic diameter less than or equal
to 2.5 [micro]m), and ``thoracic'' particles (PM10;
particles with a nominal mean aerodynamic diameter less than or equal
to 10 [micro]m).\416\ Particles that fall within the size range between
PM2.5 and PM10, are referred to as ``thoracic
coarse particles'' (PM10-2.5, particles with a nominal mean
aerodynamic diameter less than or equal to 10 [micro]m and greater than
2.5 [micro]m). EPA currently has standards that regulate
PM2.5 and PM10.\417\
---------------------------------------------------------------------------

    \416\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Figure 3-1.
    \417\ Regulatory definitions of PM size fractions, and
information on reference and equivalent methods for measuring PM in
ambient air, are provided in 40 CFR parts 50, 53, and 58. With
regard to national ambient air quality standards (NAAQS) which
provide protection against health and welfare effects, the 24-hour
PM10 standard provides protection against effects
associated with short-term exposure to thoracic coarse particles
(i.e., PM10-2.5).
---------------------------------------------------------------------------

    Particles span many sizes and shapes and may consist of hundreds of
different chemicals. Particles are emitted directly from sources and
are also formed through atmospheric chemical reactions; the former are
often referred to as ``primary'' particles, and the latter as
``secondary'' particles. Particle concentration and composition varies
by time of year and location, and in addition to differences in source
emissions, is affected by several weather-related factors, such as
temperature, clouds, humidity, and wind. A further layer of complexity
comes from particles' ability to shift between solid/liquid and gaseous
phases, which is influenced by concentration and meteorology,
especially temperature.
    Fine particles are produced primarily by combustion processes and
by transformations of gaseous emissions (e.g., sulfur oxides
(SOX), oxides of nitrogen, and volatile organic compounds
(VOC)) in the atmosphere. The chemical and physical properties of
PM2.5 may vary greatly with time, region, meteorology, and
source category. Thus, PM2.5 may include a complex mixture
of different components including sulfates, nitrates, organic
compounds, elemental carbon and metal compounds. These particles can
remain in the atmosphere for days to weeks and travel hundreds to
thousands of kilometers.
(b) Health Effects of PM
    Scientific studies show ambient PM is associated with a broad range
of health effects. These health effects are discussed in detail in the
December 2009 Integrated Science Assessment for Particulate Matter (PM
ISA).\418\ The PM ISA summarizes health effects evidence associated
with both short- and long-term exposures to PM2.5,
PM10-2.5, and ultrafine particles. The PM ISA concludes that
human exposures to ambient PM2.5 concentrations are
associated with a number of adverse health effects and characterizes
the weight of evidence for these health

outcomes.\419\ The discussion below highlights the PM ISA's conclusions
pertaining to health effects associated with both short- and long-term
PM exposures. Further discussion of health effects associated with
PM2.5 can also be found in the rulemaking documents for the
most recent review of the PM NAAQS completed in 2012.420 421
---------------------------------------------------------------------------

    \418\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F.
    \419\ The causal framework draws upon the assessment and
integration of evidence from across epidemiological, controlled
human exposure, and toxicological studies, and the related
uncertainties that ultimately influence our understanding of the
evidence. This framework employs a five-level hierarchy that
classifies the overall weight of evidence and causality using the
following categorizations: causal relationship, likely to be causal
relationship, suggestive of a causal relationship, inadequate to
infer a causal relationship, and not likely to be a causal
relationship (U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Table 1-3).
    \420\ 78 FR 3103-3104, January 15, 2013.
    \421\ 77 FR 38906-38911, June 29, 2012.
---------------------------------------------------------------------------

    EPA has concluded that a causal relationship exists between both
long- and short-term exposures to PM2.5 and premature
mortality and cardiovascular effects and a likely causal relationship
exists between long- and short-term PM2.5 exposures and
respiratory effects. Further, there is evidence suggestive of a causal
relationship between long-term PM2.5 exposures and other
health effects, including developmental and reproductive effects (e.g.,
low birth weight, infant mortality) and carcinogenic, mutagenic, and
genotoxic effects (e.g., lung cancer mortality).\422\
---------------------------------------------------------------------------

    \422\ These causal inferences are based not only on the more
expansive epidemiological evidence available in this review but also
reflect consideration of important progress that has been made to
advance our understanding of a number of potential biologic modes of
action or pathways for PM-related cardiovascular and respiratory
effects (U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Chapter 5).
---------------------------------------------------------------------------

    As summarized in the Final PM NAAQS rule, and discussed extensively
in the 2009 p.m. ISA, the available scientific evidence significantly
strengthens the link between long- and short-term exposure to
PM2.5 and premature mortality, while providing indications
that the magnitude of the PM2.5- mortality association with
long-term exposures may be larger than previously estimated.
423 424 The strongest evidence comes from recent studies
investigating long-term exposure to PM2.5 and
cardiovascular-related mortality. The evidence supporting a causal
relationship between long-term PM2.5 exposure and mortality
also includes consideration of new studies that demonstrated an
improvement in community health following reductions in ambient fine
particles.
---------------------------------------------------------------------------

    \423\ 78 FR 3103-3104, January 15, 2013.
    \424\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Chapter 6 (Section 6.5)
and Chapter 7 (Section 7.6).
---------------------------------------------------------------------------

    Several studies evaluated in the 2009 p.m. ISA have examined the
association between cardiovascular effects and long-term
PM2.5 exposures in multi-city epidemiological studies
conducted in the U.S. and Europe. These studies have provided new
evidence linking long-term exposure to PM2.5 with an array
of cardiovascular effects such as heart attacks, congestive heart
failure, stroke, and mortality. This evidence is coherent with studies
of effects associated with short-term exposure to PM2.5 that
have observed associations with a continuum of effects ranging from
subtle changes in indicators of cardiovascular health to serious
clinical events, such as increased hospitalizations and emergency
department visits due to cardiovascular disease and cardiovascular
mortality.\425\
---------------------------------------------------------------------------

    \425\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Chapter 2 (Section 2.3.1
and 2.3.2) and Chapter 6.
---------------------------------------------------------------------------

    As detailed in the 2009 p.m. ISA, extended analyses of seminal
epidemiological studies, as well as more recent epidemiological studies
conducted in the U.S. and abroad, provide strong evidence of
respiratory-related morbidity effects associated with long-term
PM2.5 exposure. The strongest evidence for respiratory-
related effects is from studies that evaluated decrements in lung
function growth (in children), increased respiratory symptoms, and
asthma development. The strongest evidence from short-term
PM2.5 exposure studies has been observed for increased
respiratory-related emergency department visits and hospital admissions
for chronic obstructive pulmonary disease (COPD) and respiratory
infections.\426\
---------------------------------------------------------------------------

    \426\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Chapter 2 (Section 2.3.1
and 2.3.2) and Chapter 6.
---------------------------------------------------------------------------

    The body of scientific evidence detailed in the 2009 p.m. ISA is
still limited with respect to associations between long-term
PM2.5 exposures and developmental and reproductive effects
as well as cancer, mutagenic, and genotoxic effects. The strongest
evidence for an association between PM2.5 and developmental
and reproductive effects comes from epidemiological studies of low
birth weight and infant mortality, especially due to respiratory causes
during the post-neonatal period (i.e., 1 month to 12 months of
age).\427\ With regard to cancer effects, ``[m]ultiple epidemiologic
studies have shown a consistent positive association between
PM2.5 and lung cancer mortality, but studies have generally
not reported associations between PM2.5 and lung cancer
incidence.'' \428\
---------------------------------------------------------------------------

    \427\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F, Chapter 2 (Section 2.3.1
and 2.3.2) and Chapter 7.
    \428\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. pg 2-13
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    Specific groups within the general population are at increased risk
for experiencing adverse health effects related to PM
exposures.429 430 431 432 The evidence detailed in the 2009
p.m. ISA expands our understanding of previously identified at-risk
populations and lifestages (i.e., children, older adults, and
individuals with pre-existing heart and lung disease) and supports the
identification of additional at-risk populations (e.g., persons with
lower socioeconomic status, genetic differences). Additionally, there
is emerging, though still limited, evidence for additional potentially
at-risk populations and lifestages, such as those with diabetes, people
who are obese, pregnant women, and the developing fetus.\433\
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    \429\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2.
    \430\ 77 FR 38890, June 29, 2012.
    \431\ 78 FR 3104, January 15, 2013.
    \432\ U.S. EPA. (2011). Policy Assessment for the Review of the
PM NAAQS. U.S. Environmental Protection Agency, Washington, DC, EPA/
452/R-11-003. Section 2.2.1.
    \433\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2
(Section 2.4.1).
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    For PM10-2.5, the 2009 p.m. ISA concluded that available
evidence was suggestive of a causal relationship between short-term
exposures to PM10-2.5 and cardiovascular effects (e.g.,
hospital admissions and ED visits, changes in cardiovascular function),
respiratory effects (e.g., ED visits and hospital admissions, increase
in markers of pulmonary inflammation), and premature mortality. Data
were inadequate to draw conclusions regarding the relationships between
long-term exposure to PM10-2.5 and various health
effects.434 435 436
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    \434\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.4 and Table
2-6.
    \435\ 78 FR 3167-3168, January 15, 2013.
    \436\ 77 FR 38947-38951, June 29, 2012.

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    For ultrafine particles, the 2009 p.m. ISA concluded that the
evidence was suggestive of a causal relationship between short-term
exposures and cardiovascular effects, including changes in heart rhythm
and vasomotor function (the ability of blood vessels to expand and
contract). It also concluded that there was evidence suggestive of a
causal relationship between short-term exposure to ultrafine particles
and respiratory effects, including lung function and pulmonary
inflammation, with limited and inconsistent evidence for increases in
ED visits and hospital admissions. Data were inadequate to draw
conclusions regarding the relationship between short-term exposure to
ultrafine particle and additional health effects including premature
mortality as well as long-term exposure to ultrafine particles and all
health outcomes evaluated.437 438
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    \437\ U.S. EPA. (2009). Integrated Science Assessment for
Particulate Matter (Final Report). U.S. Environmental Protection
Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.5 and Table
2-6.
    \438\ 78 FR 3121, January 15, 2013.
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(2) Ozone
(a) Background
    Ground-level ozone pollution is typically formed through reactions
involving VOC and NOX in the lower atmosphere in the
presence of sunlight. These pollutants, often referred to as ozone
precursors, are emitted by many types of pollution sources, such as
highway and nonroad motor vehicles and engines, power plants, chemical
plants, refineries, makers of consumer and commercial products,
industrial facilities, and smaller area sources.
    The science of ozone formation, transport, and accumulation is
complex. Ground-level ozone is produced and destroyed in a cyclical set
of chemical reactions, many of which are sensitive to temperature and
sunlight. When ambient temperatures and sunlight levels remain high for
several days and the air is relatively stagnant, ozone and its
precursors can build up and result in more ozone than typically occurs
on a single high-temperature day. Ozone and its precursors can be
transported hundreds of miles downwind from precursor emissions,
resulting in elevated ozone levels even in areas with low local VOC or
NOX emissions.
(b) Health Effects of Ozone
    This section provides a summary of the health effects associated
with exposure to ambient concentrations of ozone.\439\ The information
in this section is based on the information and conclusions in the
February 2013 Integrated Science Assessment for Ozone (Ozone ISA).\440\
The Ozone ISA concludes that human exposures to ambient concentrations
of ozone are associated with a number of adverse health effects and
characterizes the weight of evidence for these health effects.\441\ The
discussion below highlights the Ozone ISA's conclusions pertaining to
health effects associated with both short-term and long-term periods of
exposure to ozone.
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    \439\ Human exposure to ozone varies over time due to changes in
ambient ozone concentration and because people move between
locations which have notable different ozone concentrations. Also,
the amount of ozone delivered to the lung is not only influenced by
the ambient concentrations but also by the individuals breathing
route and rate.
    \440\ U.S. EPA. Integrated Science Assessment of Ozone and
Related Photochemical Oxidants (Final Report). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA
is available at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download.
    \441\ The ISA evaluates evidence and draws conclusions on the
causal relationship between relevant pollutant exposures and health
effects, assigning one of five ``weight of evidence''
determinations: causal relationship, likely to be a causal
relationship, suggestive of a causal relationship, inadequate to
infer a causal relationship, and not likely to be a causal
relationship. For more information on these levels of evidence,
please refer to Table II in the Preamble of the ISA.
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    For short-term exposure to ozone, the Ozone ISA concludes that
respiratory effects, including lung function decrements, pulmonary
inflammation, exacerbation of asthma, respiratory-related hospital
admissions, and mortality, are causally associated with ozone exposure.
It also concludes that cardiovascular effects, including decreased
cardiac function and increased vascular disease, and total mortality
are likely to be causally associated with short-term exposure to ozone
and that evidence is suggestive of a causal relationship between
central nervous system effects and short-term exposure to ozone.
    For long-term exposure to ozone, the Ozone ISA concludes that
respiratory effects, including new onset asthma, pulmonary inflammation
and injury, are likely to be causally related with ozone exposure. The
Ozone ISA characterizes the evidence as suggestive of a causal
relationship for associations between long-term ozone exposure and
cardiovascular effects, reproductive and developmental effects, central
nervous system effects and total mortality. The evidence is inadequate
to infer a causal relationship between chronic ozone exposure and
increased risk of lung cancer.
    Finally, interindividual variation in human responses to ozone
exposure can result in some groups being at increased risk for
detrimental effects in response to exposure. The Ozone ISA identified
several groups that are at increased risk for ozone-related health
effects. These groups are people with asthma, children and older
adults, individuals with reduced intake of certain nutrients (i.e.,
Vitamins C and E), outdoor workers, and individuals having certain
genetic variants related to oxidative metabolism or inflammation. Ozone
exposure during childhood can have lasting effects through adulthood.
Such effects include altered function of the respiratory and immune
systems. Children absorb higher doses (normalized to lung surface area)
of ambient ozone, compared to adults, due to their increased time spent
outdoors, higher ventilation rates relative to body size, and a
tendency to breathe a greater fraction of air through the mouth.
Children also have a higher asthma prevalence compared to adults.
Additional children's vulnerability and susceptibility factors are
listed in Section XIV.
(3) Nitrogen Oxides
(a) Background
    Nitrogen dioxide (NO2) is a member of the NOX
family of gases. Most NO2 is formed in the air through the
oxidation of nitric oxide (NO) emitted when fuel is burned at a high
temperature. NO2 and its gas phase oxidation products can
dissolve in water droplets and further oxidize to form nitric acid
which reacts with ammonia to form nitrates, which are important
components of ambient PM. The health effects of ambient PM are
discussed in Section VIII.B.1.b of this preamble. NOX and
VOC are the two major precursors of ozone. The health effects of ozone
are covered in Section VIII.B.2.b.
(b) Health Effects of Nitrogen Oxides
    The most recent review of the health effects of oxides of nitrogen
completed by EPA can be found in the 2008 Integrated Science Assessment
for Oxides of Nitrogen--Health Criteria (Oxides of Nitrogen ISA).\442\
EPA concluded that the findings of epidemiological, controlled human
exposure, and animal toxicological

studies provided evidence that was sufficient to infer a likely causal
relationship between respiratory effects and short-term NO2
exposure. The 2008 ISA for Oxides of Nitrogen concluded that the
strongest evidence for such a relationship comes from epidemiological
studies of respiratory effects including increased respiratory
symptoms, emergency department visits, and hospital admissions. Based
on both short- and long-term exposure studies, the 2008 ISA for Oxides
of Nitrogen concluded that individuals with preexisting pulmonary
conditions (e.g., asthma or COPD), children, and older adults are
potentially at greater risk of NO2-related respiratory
effects. Based on findings from controlled human exposure studies, the
2008 ISA for Oxides of Nitrogen also drew two broad conclusions
regarding airway responsiveness following NO2 exposure.
First, the ISA concluded that NO2 exposure may enhance the
sensitivity to allergen-induced decrements in lung function and
increase the allergen-induced airway inflammatory response following
30-minute exposures of asthmatic adults to NO2
concentrations as low as 260 ppb.\443\ Second, exposure to
NO2 was found to enhance the inherent responsiveness of the
airway to subsequent nonspecific challenges in controlled human
exposure studies of healthy and asthmatic adults. Statistically
significant increases in nonspecific airway responsiveness were
reported for asthmatic adults following 30-minute exposures to 200-300
ppb NO2 and following 1-hour exposures to 100 ppb
NO2.\444\ Enhanced airway responsiveness could have
important clinical implications for asthmatics since transient
increases in airway responsiveness following NO2 exposure
have the potential to increase symptoms and worsen asthma control.
Together, the epidemiological and experimental data sets formed a
plausible, consistent, and coherent description of a relationship
between NO2 exposures and an array of adverse health effects
that range from the onset of respiratory symptoms to hospital
admissions and emergency department visits for respiratory causes,
especially asthma.\445\
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    \442\ U.S. EPA (2008). Integrated Science Assessment for Oxides
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071.
Washington, DC: U.S. EPA.
    \443\ U.S. EPA (2008). Integrated Science Assessment for Oxides
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071.
Washington, DC: U.S. EPA, Section <IP_ADDRESS>.
    \444\ U.S. EPA (2008). Integrated Science Assessment for Oxides
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071.
Washington, DC: U.S.EPA, Section <IP_ADDRESS>.
    \445\ U.S. EPA (2008). Integrated Science Assessment for Oxides
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071.
Washington, DC: U.S. EPA, Section 3.1.7.
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    In evaluating a broader range of health effects, the 2008 ISA for
Oxides of Nitrogen concluded evidence was ``suggestive but not
sufficient to infer a causal relationship'' between short-term
NO2 exposure and premature mortality and between long-term
NO2 exposure and respiratory effects. The latter was based
largely on associations observed between long-term NO2
exposure and decreases in lung function growth in children.
Furthermore, the 2008 ISA for Oxides of Nitrogen concluded that
evidence was ``inadequate to infer the presence or absence of a causal
relationship'' between short-term NO2 exposure and
cardiovascular effects as well as between long-term NO2
exposure and cardiovascular effects, reproductive and developmental
effects, premature mortality, and cancer.\446\ The conclusions for
these health effect categories were informed by uncertainties in the
evidence base such as the independent effects of NO2
exposure within the broader mixture of traffic-related pollutants,
limited evidence from experimental studies, and/or an overall limited
literature base.

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    \446\ U.S. EPA (2008). Integrated Science Assessment for Oxides
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071.
Washington, DC: U.S. EPA.
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(4) Sulfur Oxides
(a) Background
    Sulfur dioxide (SO2), a member of the sulfur oxide
(SOX) family of gases, is formed from burning fuels
containing sulfur (e.g., coal or oil derived), extracting gasoline from
oil, or extracting metals from ore. SO2 and its gas phase
oxidation products can dissolve in water droplets and further oxidize
to form sulfuric acid which reacts with ammonia to form sulfates, which
are important components of ambient PM. The health effects of ambient
PM are discussed in Section VIII.B.1.b of this preamble.
(b) Health Effects of SO2
    Information on the health effects of SO2 can be found in
the 2008 Integrated Science Assessment for Sulfur Oxides--Health
Criteria (SOX ISA).\447\ Short-term peaks of SO2
have long been known to cause adverse respiratory health effects,
particularly among individuals with asthma. In addition to those with
asthma (both children and adults), potentially sensitive groups include
all children and the elderly. During periods of elevated ventilation,
asthmatics may experience symptomatic bronchoconstriction within
minutes of exposure. Following an extensive evaluation of health
evidence from epidemiologic and laboratory studies, EPA concluded that
there is a causal relationship between respiratory health effects and
short-term exposure to SO2. Separately, based on an
evaluation of the epidemiologic evidence of associations between short-
term exposure to SO2 and mortality, EPA concluded that the
overall evidence is suggestive of a causal relationship between short-
term exposure to SO2 and mortality. Additional information
on the health effects of SO2 is available in Chapter
<IP_ADDRESS>.2 of the RIA.

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