Document ID: EPA-HQ-OAR-2007-0225-0031
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-08-02T04:00Z

Chapter 3:  Modeled Control Strategy:  Design and Analytical Results			

Synopsis

In order to estimate the costs and benefits of alternate ozone
standards, EPA has analyzed one possible hypothetical scenario to
illustrate the control strategies that areas across the country might
employ to attain an alternative more stringent primary standard of 0.070
ppm.  Specifically, EPA has modeled the impact that additional emissions
controls across numerous sectors would have on predicted ambient ozone
concentrations, incremental to meeting the current standard (baseline). 
Thus, the modeled analysis for a revised standard focuses specifically
on incremental improvements beyond the current standard, and uses
control options that might be available to states for application by
2020.  The hypothetical scenario presented in this RIA is one
illustrative option for achieving emissions reductions to move towards a
national attainment of a tighter standard.  It is not a recommendation
for how a tighter ozone standard should be implemented, and states will
make all final decisions regarding implementation strategies once a
final NAAQS has been set.  

In order to model a hypothetical control strategy to achieve national
attainment of 0.070 ppm incremental to attainment of the current
standard, EPA approached the analysis in stages.  First, EPA identified
controls to be included in the baseline (current state and federal
programs plus controls to attain the current ozone and PM standards). 
Then, EPA applied additional known controls within geographic areas
designed to bring areas predicted to exceed 0.070 ppm in 2020 into
attainment.  This chapter presents the hypothetical control strategy,
the geographic areas where controls were applied, and the results of the
modeling which predicted ozone concentrations in 2020 after application
of the strategy.  The strategy to attain a 0.070 ppm level was the only
strategy modeled by EPA.  EPA did not expect the modeled control
strategy to result in attainment at 0.070 ppm everywhere, so the control
will result in only partial attainment.  Chapter 4 will explain how EPA
used the results of the modeled control strategy for 0.070 ppm to
estimate total tons of emissions reductions needed to achieve ozone
concentrations for the bounds of the range of the proposed more
stringent standard (0.075 and 0.070 ppm, and the more stringent option
analyzed of 0.065 ppm). Chapters 5 and 6 present the estimated costs and
benefits of the modeled costs and benefits for partial attainment.

Because EPA’s baseline indicated that some areas were not likely to be
in attainment with the current standard by 2020 (0.08 ppm, effectively
0.084 ppm based on current rounding conventions) – (Fig 3.4) EPA
expected that known controls would not be enough to bring those areas,
and likely others, into attainment with 0.070 ppm in 2020.  Modeling
results showed that to be the case (see Fig 3.13).  

Because it was impossible to meet either the current or any tighter
ozone standard nationwide using only known controls, EPA conducted a
second step in the analysis, and estimated the number of further tons of
emission reductions needed to attain 0.070 ppm (presented in Chapter 4).
 It is uncertain what controls States would put in place to attain a
tighter standard, since additional control measures are not currently
recognized as being commercially available.   However, existing
emissions inventories for the areas that were predicted to be in
non-attainment after application of all known controls, do indicate that
substantial amounts of ozone precursor emissions (i.e. tons of NOx or
VOC) are available for control, pending future technology.  Chapter 4
describes the methodology EPA used to estimate the amount of tons
available for control to reach attainment, and Chapters 5 and 6 present
the extrapolation-based costs and benefits of achieving the reductions
in ozone necessary to fully attain the standards, except for a few areas
in California, which will be more fully explained in Chapter 4.

3.1 	Establishing the Baseline

The regulatory impact analysis (RIA) is intended to evaluate the costs
and benefits of reaching attainment with potential alternative ozone
standards.  In order to develop and evaluate a control strategy for
attaining a more stringent (0.070 ppm) primary standard, it is important
to first estimate ozone levels in 2020 given the current ozone standard
and trends (more information is provided in chapter 1).  This scenario
is known as the baseline.  Establishing this baseline allows us to
estimate the incremental costs and benefits of attaining any alternative
standard.  

This focus on the assessment of the incremental costs and benefits of
attaining any alternative standard is an important difference from the
focus of the risk assessment used in developing the standard.  For
purposes of the Staff Paper-risk assessment, risks are estimated
associated with just meeting recent air quality and upon just meeting
the current and alternative standards as well as incremental reductions
in risks in going from the current standard to more stringent
alternative standards.  When considering risk estimates remaining upon
attaining a given standard, EPA is only interested in the risks in
excess of policy relevant background (PRB).   PRB is defined in the
ozone Criteria Document and Staff Paper as including (1) O3 in the U.S.
from natural sources of emissions in the U.S., Canada, and Mexico, and
(2) O3 in the U.S. from the transport of O3 or the transport of
emissions from both natural and man-made sources, from outside of the
U.S. and its neighboring countries (Staff Paper, p.2-54). 

In contrast, the RIA only examines the incremental reduction, not the
remaining risk, which results from changes in U.S. anthropogenic
emissions.  The air quality modeling used to establish the baseline for
the RIA explicitly includes contributions from natural and anthropogenic
emissions in Canada, Mexico, and other countries abroad, as well as the
contributions to ozone levels from natural sources in the U.S. Since the
RIA does not attempt to estimate the risk remaining upon meeting a given
standard, and the alternative standards are clearly above any estimate
of PRB, there is no role for PRB in the RIA estimates.  

In developing the baseline it was important to recognize that there are
several areas that are not required to meet the current standard by
2020.  The Clean Air Act allows areas with more significant air quality
problems to take additional time to reach the current standard.  Some
areas, such as Southern California, are not planning to meet the current
standard by 2020, so the estimated emission reductions for these areas
are based on reaching an estimated progress point in 2020 (their
“glidepath” targets).  We provide an estimate of the additional
amount of tons these areas would need to reduce to meet the standard and
the additional costs and benefits of reducing those tons in those few
areas.  

The baseline includes controls which EPA estimates need to be included
to attain the current standard (0.08 ppm, effectively 0.084 ppm based on
current rounding conventions) for 2020.  Two steps were used to develop
the baseline.  First, the reductions expected in national ozone
concentrations from national rules in effect or proposed today were
considered.  Because these alone were not predicted to bring all areas
into attainment with the tighter standard, EPA used a hypothetical
control strategy to apply additional known controls.  Additional control
measures were used in four sectors to establish the baseline:
Non-Electricity Generating Unit Point Sources (Non-EGUs), Non-Point Area
Sources (Area), Onroad Mobile Sources and Nonroad Mobile Sources.  A
fifth sector was used in the subsequent control strategy for a tighter
alternative standard:  Electricity Generating Unit Point Sources (EGUs).
 Each of these sectors is defined below for clarity.

NonEGU point sources are stationary sources that emit at least one
criteria pollutant with emissions of 100 tons per year or higher.  
NonEGU point sources are found across a wide variety of industries, such
as chemical manufacturing, cement manufacturing, petroleum refineries,
and iron and steel mills.  

Non-Point Area Sources (Area) are stationary sources that are too
numerous or whose emissions are too small to be individually included in
a stationary source emissions inventory.  Area sources are the
activities where aggregated source emissions information is maintained
for the entire source category instead of each point source, and are
reported at the county level.

Onroad Mobile Sources are mobile sources that travel on roadways.  These
sources include automobiles, buses, trucks, and motorcycles traveling on
roads and highways.

Nonroad Mobile Sources are any portable engine that travels by other
means than roadways.  These sources include railroad locomotives; marine
vessels; aircraft; off-road motorcycles; snowmobiles; pleasure craft;
and farm, construction, industrial and lawn/garden equipment.

Electricity Generating Unit Point Sources (EGUs) are stationary sources
producing electricity, such as fossil-fuel-fired boilers and combustion
turbines.

3.1.1  National Rules

To reduce ambient ozone concentrations, it was necessary to control
emissions of ozone precursors, NOx and VOC.  Establishing the baseline
required identifying the national rules which were expected to
contribute to reductions in NOx and VOCs between now and 2020.   Some of
these include the Clean Air Interstate Rule (CAIR), Clean Air Mercury
Rule (CAMR), and the Clean Air Visibility Rule (CAVR); and the 2007
proposed Locomotive/Marine rule. A complete listing of these rules is
provided in table 3.1.  In addition, EPA included the control set
developed for the hypothetical national attainment strategy presented in
the PM NAAQS RIA in the baseline for this ozone analysis.   

At the time that EPA established the regulatory baseline -- to capture
how existing rules affect the emissions inventory over time even in the
absence of this new NAAQS standard -- EPA focused on information that
was readily available in the emission inventories and other data
sources.  Typically, a RIA analysis baseline includes only reductions
from final rules and not reductions from regulatory proposals or other
actions being contemplated.  However, for this analysis, EPA did not
include the recently promulgated Renewable Fuel Standard (RFS), due to a
lack of readily available quantitative information.  In addition, EPA
did include reductions from some upcoming rules in an attempt to better
characterize reductions that we anticipate to occur in the future (e.g.
Ocean Going Vessel Rule).  For the analysis to support the Final Rule,
EPA will be using an updated emission inventory and improved models and
sets of control information.  The starting point for the analysis will
include only and all promulgated rules, including the Renewable Fuel
Standard rule.  Any potential reductions resulting from proposed or
upcoming rules will be discussed separately.

The RFS RIA provides an analysis of the energy, emissions, air quality,
and economic impacts of expanding the use of renewable fuels in
comparison to a reference case of 4 billion gallons of renewable fuel
use that represents 2004 conditions projected out to 2012. Depending on
the anticipated volume of renewable fuel usage in 2012, EPA estimates
that this transition to renewable fuels will reduce petroleum
consumption between 2.0 and 3.9 billion gallons or roughly 0.8 to 1.6
percent of the petroleum that would otherwise be used by the
transportation sector.

With regard to emissions impacts, carbon monoxide emissions from
gasoline-powered vehicles and equipment will be reduced between 0.9 and
2.5 percent. Emissions of benzene (a mobile source air toxic) will be
reduced between 1.8 and 4.0 percent. Further, the use of renewable fuel
will reduce carbon dioxide equivalent greenhouse gas emissions between
8.0 and 13.1 million metric tons, about 0.4 to 0.6 percent of the
anticipated greenhouse gas emissions from the transportation sector in
the United States in 2012.

At the same time, other vehicle emissions may increase as a result of
greater renewable fuel use. Nationwide, EPA estimates an increase in
total emissions of volatile organic compounds and nitrogen oxides (VOC +
NOx) between 41,000 and 83,000 tons. However, the effects will vary
significantly by region. Areas that already are using ethanol will
experience little or no change in emissions or air quality. In some
contexts and situations, however, the use of renewable fuels may impact
compliance with a reduced ozone NAAQS standard.

In addition to changes in NOx and VOC emissions resulting from increased
use of ethanol in gasoline, fugitive ethanol emissions may also increase
peroxacetyl nitrate (PAN) concentrations.  Fugitive emissions of ethanol
in a photochemical smog polluted environment will generate acetaldehyde,
a precursor to PAN.  PAN, in turn, can lead to increase ozone levels. 
As part of the analysis to support the final rule, EPA will examine
whether this increase in PAN will affect baseline ozone concentrations
in some areas and how this effect can be quantified and incorporated
into the baseline.

For the final analysis, EPA will be using an updated emission inventory
and improved models and sets of control information.  The starting point
for the analysis will include all promulgated rules, including the
increases in regional VOC and NOx emissions from increased combustion of
ethanol.

Table 3.1 National Rules and Control Measures, by Sector, Contributing
to the Baseline,

Sector	Sources of Controls-National

	NOx	VOC

Non-EGUs	PM 15/35* (west only)	(none used)

Area	PM 15/35* (west only)	(none used)

Onroad Mobile	-Onroad Diesel Particulate Filters  and Retirement

- Commuter Reduction Strategies

-Idling Elimination

-Intermodal Transfer from Trucks to Rail	-Onroad Diesel Particulate
Filters and Retirement

- Commuter Reduction Strategies

Nonroad Mobile	-Diesel Marine & Locomotives Rule

-Ocean-Going Vessels Rule

-Small Spark-Ignition Engine Rule

-Nonroad Diesel Particulate Filters & Engine Rebuilds	-Small
Spark-Ignition Engine Rule

-Nonroad Diesel Particulate Filters & Engine Rebuilds

EGU	-CAIR/CAMR/ CAVR

-PM 15/35* (West only)	(none used)

	*hypothetical control scenario modeled in 2006 PM NAAQS RIA

3.1.2 Additional Controls

Additional known controls were also included as needed in the baseline,
to simulate attainment with current ozone NAAQS.  The applicable
controls and their respective sectors are listed in table 3.2 and
described below.  Details regarding the individual controls are provided
in appendix 3.  Due to the extensive reductions from EGUs already
implemented in CAIR/CAMR/CAVR, no additional EGU controls were included
in the baseline.  The East was evaluated separately from the West, due
to the nature of the controls available in each area and the specific
features of the areas needing reductions in ozone, as explained in more
detail below. 

In the East, controls included in the baseline for Non-EGU and area
sources came from a variety of geographic areas and scales.  Almost all
available controls in Chicago, Houston, and the Northeast Corridor were
included in the baseline because these areas contain counties that were
projected to be nonattainment of the current ozone NAAQS in 2020 (based
on air quality modeling performed as part of the PM NAAQS RIA).

dly reduced by local VOC controls (≥ 0.5 ppb) by local VOC controls of
25%.  Two additional counties that did not meet these criteria were also
included.  In the West, Non-EGU and Area Controls were included in the
baseline only for California, where they were included state-wide.  In
California, all controllable tons of NOx and VOC emissions were reduced
using known Non-EGU and Area Controls in the baseline.  (See Fig 3.1 and
Fig 3.2)

Fig. 3.1 Counties Where Controls for Nitrogen Oxides (NOx) Were Included
for Non-EGU Point and Area Sources, for the Baseline 

(Current Standard, 0.08 ppm)

Fig. 3.2 Counties Where Controls for Volatile Organic Chemicals (VOCs)
Were Applied to Non-EGU Point and Area Sources in Baseline 

(Current Standard, 0.08 ppm)

In the Onroad Mobile sector, local controls were included as necessary
in the baseline for both East and West.  Counties projected to have a
monitor that exceeded the current standard were surrounded by a 200km
buffer zone, and controls were included in the counties within this
buffer that were within the same state as the exceeding monitor.  Where
some control measures overlapped for a given county, controls with the
lowest costs were included first. This is the only instance in which
controls were included in a certain order.  For a complete list of the
controls and the order in which they were included, see Appendix 3. 
Both onroad and nonroad diesel retrofits and idling elimination were
included statewide in California with an assumed 75% market penetration,
and elsewhere in the nation with an assumed 25% market penetration for
all states with a county projected to be in nonattainment with the
current standard in 2020. EPA determined that 25% would have a
significant impact, but was reasonably easy to achieve and was applied
for reduction areas outside of California.  EPA further determined that
for southern California a higher level of reduction was required.  75%
was the highest penetration rate that EPA felt could be reasonably
accomplished. The remainder of mobile controls were included statewide
in Ozone Transport Commission (OTC) states (see section 3.2.2 for more
information on OTC states), with the exceptions of Vermont, Maine, New
Hampshire, and Massachusetts, which were not projected to have counties
in nonattainment with the current standard in 2020.  These additional
mobile controls were included statewide in California (See Fig. 3.3)

Fig. 3.3 Areas Where NOx and VOC Controls Were Included for Mobile
Onroad and Nonroad Sources in Addition to National Mobile Controls in
Baseline 

(Current Standard, 0.08 ppm)

*Onroad retrofits and elimination of long duration idling

**Onroad retrofits, elimination of long duration idling, nonroad
retrofits, Best Workplace Commuter program (BWC) and Reid Vapor Pressure
(RVP)

Table 3.2 Controls by Sector Included in the Baseline Determination for
2020

Sector	Controls- East	Controls- West

	NOx	VOC	NOx	VOC

Non-EGUs	-LEC (Low Emission Combustion)

-LNB (Low NOx Burner)

-LNB + FGR (Flu-Gas Sulfurization)

-LNB + SCR (Selective Catalytic Reduction)

-Mid-Kiln Firing

-NSCR (Non-selective Catalytic Reduction)

-OXY-Firing

-SCR

-SCR + Steam Injection

-SCR + Water Injection

-SNCR (Selective Non-catalytic Reduction) 

-SNCR - Urea

-SNCR - Urea Based	(none used)	-LNB

-Mid-Kiln Firing

-NSCR

-OXY-Firing

-SCR

-SCR + Steam Injection

-SNCR

-SNCR - Urea Based	(none used)

Area	-RACT to 25 tpy (LNB)

-Water Heater + LNB Space Heaters	-CARB Long-Term Limits

-Catalytic Oxidizer

-Equipment and Maintenance

-Gas Collection (SCAQMD/ BAAQMD)

-Incineration

-Incineration >100,000 lbs bread

-Low Pressure/Vacuum Relief Valve

-OTC Mobile Equipment Repair and Refinishing Rule

-OTC Solvent Cleaning Rule

-SCAQMD - Low VOC

-SCAQMD Limits

-SCAQMD Rule 1168

-Switch to Emulsified Asphalts

-Use of Low or No VOC Materials	-RACT to 25 tpy (LNB)

-Switch to Low Sulfur Fuel

-Water Heater + LNB Space Heaters	-Add-On Controls

-Airtight Degreasing System

-Catalytic Oxidizer

-Equipment and Maintenance

-FIP Rule (VOC content & TE)

-Gas Collection (SCAQMD/BAAQMD)

-Incineration

-Incineration >100,000 lbs bread

-Low Pressure/ Vacuum Relief Valve

-OTC Solvent Cleaning Rule

-Reformulation - FIP Rule

-SCAQMD Limits

-SCAQMD Rule 1168

-South Coast Phase III

-Switch to Emulsified Asphalts

-Use of Low or No VOC Materials

Onroad Mobile	-Onroad Selective Catalytic Reduction (SCR) and Diesel
Particulate Filters (DPF)

-Reduce Gasoline Reid Vapor Pressure (RVP)	-Onroad Selective Catalytic
Reduction (SCR) and Diesel Particulate Filters (DPF) 6

-Reduce Gasoline Reid Vapor Pressure (RVP)

Nonroad Mobile	-Nonroad Selective Catalytic Reduction (SCR) and Diesel
Particulate Filters (DPF) 6

-Reduce Gasoline Reid Vapor Pressure (RVP)

	-Nonroad Selective Catalytic Reduction (SCR) and Diesel Particulate
Filters (DPF) 6

-Reduce Gasoline Reid Vapor Pressure (RVP)

	-Aircraft NOx Engine Standard

-Ocean-Going Vessels – reductions for vessels burning residual fuels
(none used for VOC only)	-Aircraft NOx Engine Standard	(none used for
VOC only)

EGU	(none used)	(none used)	(none used)	(none used)

3.1.3 Ozone Levels for Baseline

Establishing the baseline required design values (predicted
concentrations) of ozone across the country.  Because the intention of
this evaluation was to achieve attainment of the current ozone standard,
controls were included to reduce ambient ozone concentrations to 0.08
ppm (effectively 0.084 ppm based on current rounding conventions).  A
map of the country is presented in figure 3.4, which shows predicted
concentrations for the 491 counties with ozone monitors that were
included in the baseline.  Modeling projections were developed for all
appropriate counties according to procedures outline in EPA modeling
guidance.

The baseline shows that 10 counties would not meet the current ozone
standard in 2020, even after inclusion of all known controls.  After
including known controls as described above, the analysis predicted that
the remaining 481 counties would attain the current standard by 2020. 
The baseline forms the foundation for the cost-benefit analysis
conducted in this RIA, where EPA compares more stringent primary ozone
standard alternatives incrementally to national attainment of the
current standard.

Fig. 3.4  Baseline Annual Ozone Air Quality in 2020

 

a Modeled emissions reflect the expected reductions from federal
programs including the Clean Air Interstate Rule, the Clean Air Mercury
Rule, the Clean Air Visibility Rule, the Clean Air Nonroad Diesel Rule,
the Light-Duty Vehicle Tier 2 Rule, the Heavy Duty Diesel Rule, proposed
rules for Locomotive and Marine Vessels and for Small Spark-Ignition
Engines, and state and local level mobile and stationary source controls
identified for additional reductions in emissions for the purpose of
attaining the current PM 2.5 and Ozone  standards.  

b Controls applied are illustrative.  States may choose to apply
different control strategies for implementation. 

c The current standard of 0.08 ppm is effectively expressed as 0.084 ppm
when rounding conventions are applied.  

d Modeled design values in ppm are only interpreted up to 3 decimal
places.

e Map shows results from a total of 491 counties with projected design
values. Consistent with current modeling guidance, EPA did not project
2020 concentrations for counties where 2001 base year concentrations
were less than recommended criterion.  Such projections may not
represent expected future levels.  

3.2 	Developing the Control Strategy Analysis

After developing the baseline, EPA developed a hypothetical control
strategy to illustrate one possible national control strategy that could
be adopted to reach an alternative primary standard of 0.070 ppm by
2020.  The stricter standard alternative of 0.070 ppm was chosen as
being representative of the set of alternatives being considered by EPA
in its notice of proposed rulemaking on the ozone NAAQS.  Controls for
five sectors were used in developing the control analysis, as discussed
previously:  non-EGU stationary, Area, onroad mobile and nonroad mobile,
along with EGU controls only in the East (EGU controls for the West were
included in the hypothetical PM NAAQS 15/35 national control strategy,
and were therefore already in the ozone baseline).  Reductions in both
NOx and VOC ozone precursors were needed in all four remaining sectors
to meet a tighter standard.

As depicted in the flow diagram in figure 1.1, the control strategy
modeled in this RIA first applied and exhausted nearly all known
controls (see section 3.2.1 an explanation of which controls were
excluded from this analysis).  After controls were identified, the
expected emissions reductions were input to an air quality model that
projected design values for ozone in 2020.  Following the control
strategy, there were some areas projected not to attain 0.070 ppm in
2020 using all known control measures.  EPA was then required to
extrapolate the additional emission reductions required to reach
attainment.  The methodology used to develop those estimates and those
calculations are presented in Chapter 4.

As in the analysis for the baseline, parts of the hypothetical national
control strategy for 0.070 ppm focused on the Eastern (East) United
States (U.S.) separately from the Western U.S. (West).    However, this
RIA presents estimates of the costs and benefits of attaining
alternative ozone standards on a national basis.  Table 3.3 presents the
specific control technologies that were applied within each sector for
the 0.070 ppm control strategy.

Controls- East	Controls- West

	NOx	VOC	NOx	VOC

Non-EGUs	-Biosolid Injection Technology

-LEC (Low Emission Combustion)

-LNB

-LNB + FGR

-LNB + SCR

-LNB+SCR

-Mid-Kiln Firing

-NGR

-NSCR

-OXY-Firing

-SCR

-SCR + Steam Injection

-SCR + Water Injection

-SNCR

-SNCR - Urea

-SNCR - Urea Based	-LDAR (Leak Detection and Repair)

-Enhanced LDAR

-Flares Gas Recovery

Monitoring Program

-Permanent Total Enclosure (PTE)

-Wastewater Drain Control	-Biosolid Injection Technology

-LNB

-LNB + FGR

-LNB + SCR

-Mid-Kiln Firing

-NSCR

-OXY-Firing

-SCR

-SCR + Steam Injection

-SCR + Water Injection

-SNCR

-SNCR - Urea Based	(none used)

Area	-RACT to 25 tpy (LNB)

-Water Heater + LNB Space Heaters	-CARB Long-Term Limits

-Catalytic Oxidizer

-Equipment and Maintenance

-Gas Collection (SCAQMD/BAAQMD)

-Incineration

-Incineration >100,000 lbs bread

-Low Pressure/Vacuum Relief Valve

-OTC Mobile Equipment Repair and Refinishing Rule

-OTC Portable Gas Container Rule

-OTC Solvent Cleaning Rule

-SCAQMD - Low VOC

-SCAQMD Limits

-SCAQMD Rule 1168

-Switch to Emulsified Asphalts

-Use of Low or No VOC Materials	-RACT to 25 tpy (LNB)

-Switch to Low Sulfur Fuel

-Water Heater + LNB Space Heaters	(none used)

Onroad Mobile	-Increased Penetration of Onroad SCR and DPF from 25% to
75%

-Continuous Inspection and Maintenance (OBD)	-Continuous Inspection and
Maintenance (OBD)

Nonroad Mobile9	-Increased Penetration of Nonroad SCR and DPF from 25%
to 75%

	-Ocean-Going Vessels – reductions for vessels burning residual fuels

	EGU	-Lower nested caps in OTC and MWRPO states

-Application of SCR and SNCR in coal fired units in NA counties outside
of OTC and MWRPO

3.2.1 Controls Applied for a 0.070 ppm Standard: Non-EGU and Area
Sectors

Non-EGU and Area control measures were identified using AirControlNET
4.1.,  To reduce NOx and VOC levels, all known control measures, within
a given cost-cap, were applied, allowing for the largest emission
reduction per source over the widest geographic area. The cost-caps were
pollutant specific and applicable only in the East portion of the
analysis.  For reductions of NOx emissions the cap was $16,000/ton,
based upon the approximate benefit per ton of reductions.  In some
instances, controls were too costly due to the large capital component
of installing these controls.  A similar process was followed for
reductions from VOCs.  The marginal cost curve was analyzed, and there
was a clear break in the curve at approximately $6,000/ton.  Because all
available controls up to the cost cap were used in counties needing
emission reductions, there was no ordering of which controls were
applied first. VOCs were cut at this level because approximately 75% of
reductions were coming from controls below that number. Additionally,
the relative effectiveness of VOC controls is not high. See Chapter 5
for more information on cost caps

Additionally, controls were added that appeared in preliminary State
Implementation Plans (SIPs) from States and Regional Planning Bodies.
Supplemental controls that estimated near-term source controls based on
similar technology were included in the Non-EGU and Area Source sectors
as well. Supplemental controls are described in further detail in
Appendix 3.

NOx controls were applied in the East for the 233 counties that were
projected to have concentrations of greater than 0.070 ppm in the 2020
baseline.  Additional controls were applied in surrounding counties
within 200 km of the county projected to be out of attainment (at 0.070
ppm), but not crossing state boundaries.  In the West, NOx controls were
applied statewide, rather than only to counties with violating monitors
and their immediate neighbors (See Fig. 3.5).  This was due to modeling
methodology, in which the 200 km buffer was only validated for the East.

Fig 3.5  Counties Where Controls for Nitrogen Oxides (NOx) Were Applied
to Non-EGU Point and Areas Sources for RIA Control Strategy Designed to
Meet 0.070 ppm (Incremental to Baseline)

In the East, VOC controls were applied (for area sources only) in 47
counties where the following criteria were met (including the 26
counties which included VOC controls in their baselines):  VOC emissions
within the county or an adjacent county were high (e.g. >5000 tons per
year of area source emissions), and screening analyses indicated that
ozone design values would be markedly reduced (> 0.5 ppb) by local VOC
controls of 25%, and the county design value was projected to be ≥
0.070 ppm in the 2020 baseline (See Fig 3.6).  No VOC controls were used
in the West. 

Fig. 3.6  Counties Where VOC Controls Were Applied to Non-EGU Point and
Areas Sources for the Control Strategy Designed to Meet 0.070 ppm
(Incremental to Baseline)

3.2.2 Controls Applied for a 0.070 ppm Standard: EGU Sector

For the East only, a control strategy was applied for the EGU sector
(Fig. 3.7) (EGU controls for the West were already included in the ozone
baseline since they were applied for the hypothetical national control
strategy in the PM NAAQS RIA.)  Annual and ozone season CAIR caps
remained unchanged, but coal-fired units were targeted for this shifted
strategy within those caps.  This strategy was appropriate to consider
because transport of NOx pollution is more of a concern in the East, and
NOx from EGUs still accounts for a significant portion of emissions in
this region. California, while in need of reductions as well, was not
included in this strategy because all known controls (including EGU
controls) had already been applied in the baseline.  The development of
an EGU-component to this control strategy was based exclusively on NOx
emissions during the ozone season, although the hypothetical controls
applied would operate year-round.    The EGU sector used the Integrated
Planning Model (IPM) to evaluate the reductions that are predicted from
a specific control strategy.  Details of this tool and subsequent
analysis can be found in appendix 3.4.  

Reductions in the EGU sector are influenced significantly by the 2003
Clean Air Interstate Rule (CAIR) (see appendix 3.4 for more details on
CAIR).  CAIR will bring significant emission reductions in NOx, and a
result, ambient ozone concentrations in the eastern U.S. by 2020.  A map
of the CAIR region is presented in appendix 3.4.  Emissions and air
quality impacts of CAIR are documented in detail in the Regulatory
Impact Analysis of the Final Clean Air Interstate Rule 

To address nonattainment in the CAIR region (especially the Midwest,
Mid-Atlantic, and Northeast), lower nested caps (a limit lower than the
current CAIR cap) were applied in these areas for NOx, while holding the
CAIR cap unchanged for the entire region.  This provides an opportunity
to reduce emissions in a cost effective manner in targeted regions.  Two
geographic regions were targeted for emissions reductions: the Midwest
Regional Planning Organization (MWRPO) consisting WI, IL, IN, MI, and
OH; and the Ozone Transport Commission (OTC), consisting of DC, MD, PA,
DE, NJ, CT, NY, RI, MA, VT, NH, and ME.  These areas were chosen because
the MWRPO and OTC states are currently investigating ways of reducing
EGU emissions further in their states and because most of the potential
ozone nonattainment areas are found within these two regions.
Considering transport, as well as the local effects, reducing emissions
in these areas expected to help bringing the Lake Michigan and Northeast
corridor nonattainment areas into attainment. 

Lower nested caps were applied in the MWRPO and OTC states, for the
ozone season only. The caps that were applied lead to reductions that
could be obtained by installing post-combustion controls to all of the
coal-fired units that were not projected to have previously installed
post-combustion controls in the base-case.  Following this, 75% of the
reduction that could be obtained from these units was subtracted from
the sum of State level ozone control season NOx caps in CAIR.  The CAIR
cap for the entire region was kept unchanged.

In order to address non-attainment in the CAIR region outside of the
MWRPO and OTC, a “command and control” type strategy for coal-fired
units has been designed.  Annual and ozone season CAIR caps remained
unchanged, and coal-fired units were targeted for this reduction. 
Preliminary analysis showed that most of the needed NOx reductions in
the EGU sector can be achieved through application of post-combustion
controls (e.g. Selective Catalytic Reductions (SCR) and Selective
Non-Catalytic Reductions (SNCR)) on coal units that are projected to
remain without controls under the CAIR/CAMR/CAVR cap-and-trade scheme.  

Fig 3.7 States Where Nitrogen Oxide (NOx) Controls Were Applied to
Electrical Generating Units (EGUs) for the Control Strategy Designed to
Meet 0.070 ppm (Incremental to Baseline)

3.2.3 Controls Applied for a 0.070 ppm Standard: Onroad and Nonroad
Mobile Sectors

As in other sectors, there are several mobile source control strategies
that have been, or are expected to be, implemented through previous
national or regional rules.  Although many expected reductions from
these rules are included in the baseline, additional mobile source
controls were required to illustrate attainment of a 0.070 ppm standard
(See Fig 3.8). Modeling of the onroad and nonroad mobile sectors was
done using MOBILE6.  See Appendix 3 for more information.

All of the local mobile source controls included in the ozone baseline
were expanded for the hypothetical national control strategy to attain
0.070 ppm standard.  In the case of onroad and nonroad Selective
Catalytic Reduction (SCR) and Diesel Particulate Filters (DPF), the
measure was applied at a greater penetration rate – to 75% of the
equipment population.  75% was the highest penetration rate that EPA
felt could be reasonably accomplished. All local measures were applied
to sources in additional geographic areas.  Continuous inspection and
maintenance, which allows for much more rapid identification of vehicles
failing their emissions standard, was added.  Descriptions of the mobile
source rules and measures can be found in appendix 3.3.  

As in the baseline, onroad SCR and DPF and elimination of idling were
applied statewide for all states with a county projected to exceed the
0.070 ppm standard.  All other controls were applied to counties within
a 200 km buffer from counties projected to exceed the 0.070 ppm
alternative standard with the following exceptions:

counties in neighboring states were omitted from the buffer zone

controls were applied statewide to Ozone Transport Commission (OTC)
states, with the exception of Vermont

controls were applied statewide in California, Colorado, Utah, New
Mexico, Arizona, and Nevada .

Fig.  3.8  Areas Where NOx and VOC Controls Were Applied to Mobile
Onroad and Nonroad Sources in Addition to National Mobile Controls for
the 0.070 ppm Control Strategy (incremental to Baseline)

*Onroad retrofits and elimination of long duration idling

**Onroad retrofits, elimination of long duration idling, nonroad
retrofits, Best Workplace for Commuters programs (BWC), low Reid Vapor
Pressure (RVP)

3.2.4 Data Quality for this Analysis

The estimates of emission reductions associated with our control
strategies above are subject to important limitations and uncertainties.
 EPA’s analysis is based on its best judgment for various input
assumptions that are uncertain.  As a general matter, the Agency selects
the best available information from available engineering studies of air
pollution controls and has set up what it believes is the most
reasonable framework for analyzing the cost, emission changes, and other
impacts of regulatory controls.  EPA is working on approaches to
quantify the uncertainties in these areas and will incorporate them in
future RIAs as appropriate.  

3.3 	Geographic Distribution of Emissions Reductions 

The following maps break out NOx and VOC reductions into the controlling
sectors.  The maps for NOx and VOC reductions are presented in Figures
3.9 and 3.11, respectively.  Figures 3.10 and 3.12 indicate the emission
reductions attributed to each sector. Appendix 3 contains maps of
emissions reductions by sector, nationwide.

Prior to reading the maps, there is an important caveat to consider. 
The control strategy above focuses on reducing emissions of VOCs and
NOx, the two precursors to ozone formation.  However, in some cases, the
application of the control strategy actually increased the level of NOx
or VOC emissions.  This is due to controls that affect multiple
pollutants and complex interactions between air pollutants, as well as
trading aspects under the CAIR rule. 

Emissions of NOx do not decrease everywhere within the CAIR region. As
explained earlier, the NOx EGU control strategy was designed to achieve
emission reductions specifically in the non-attainment areas, while
retaining the overall CAIR cap. Application of nested and lower (ozone
season) caps for the states in the MWRPO and OTC regions and local
controls (SCR and SNCR) on the uncontrolled coal units in the
non-attainment counties outside of the OTC and MWRPO within CAIR region
result in increase of emissions elsewhere within CAIR region.  While
there are substantial NOx emission reductions within the OTC and MWRPO
expected for the 2020 ozone season (roughly 55,500 tons) as a result of
cap-and-trade program with lower caps and local command-and-control
reductions in other non-attainment counties where uncontrolled coal
units exist, there is the possibility of increased emissions from the
remainder of sources within CAIR region.   This approach provides a cost
effective opportunity for reducing emissions where the reductions are
most needed to help reach attainment.  It is important to recall that
this is a hypothetical control strategy, the states or other authorities
may take additional steps to minimize these increases if warranted.

Fig 3.9  Annual Tons of Nitrogen Oxide (NOx) Emission Reductions From
Controls Designed to Meet 0.070 ppm Standard,* incremental to the
current standard

*Reductions are negative and increases are positive

**The -99 - +100 range is shown without color because these are small
county-level NOx reductions or increases that likely had little to no
impact on ozone estimates.  Most counties in this range had NOx
differences less than 1 ton.

Fig. 3.10 Percentage of Total Annual NOx Emissions Reduced from Various
Sources

* Note that on a national basis, NOx emissions are reduced by <1%. 
However, the EGU strategy used in this analysis gains reductions in
nonattainment areas, balanced by increases in attainment areas
(described in Section 3.3)

Fig. 3.11 Annual Tons of Volatile Organic Compound (VOC) Emission
Reductions From Controls Designed to Meet 0.070 ppm Standard*,
incremental to the current standard

*Reductions are negative and increases are positive

**The -99 - +57 range is shown without color because these are small
county-level VOC reductions or increases that likely had little to no
impact on ozone estimates.  Most counties in this range had VOC
differences less than 1 ton.

Fig. 3.12 Percentage of Total Annual VOC Emissions Reduced from Various
Sources*

           

3.4 	Ozone Design Values for partial attainment

After determining the emissions reductions from NOx and VOC, we used
modeling tools (see section 2.3.2) to determine ozone design values for
2020.  Figure 3.13 shows a map of the design values after modeling the
control strategy to reach 0.070 ppm.  The map legend is broken out to
demonstrate under this control strategy, with no adjustments, which
counties would reach the targeted standard of 0.070 ppm, the more
stringent alternative standard analyzed (0.065 ppm), and the other end
of the proposal range (0.075 ppm).  It is understood that this
illustrative strategy would not be the exact hypothetical strategy used
to try to attain either of these alternative standards, due to over- and
under-attainment in many counties.  (Chapter 4 describes EPA’s
methodology for estimating tons of reductions needed to hypothetically
attain these other two possible alternative standards.)  In addition,
because ozone formation is dependent on a variety of factors, it is not
possible to directly attribute changes in predicted ozone concentrations
to emission reductions of a specific precursor from a specific sector.

A full listing of the counties and their design values is provided in
Appendix 3.

Figures 3.14 and 3.15 show the tons of emissions reduced by the
hypothetical RIA 0.070 ppm control strategy, and the tons of emissions
remaining after application of those controls, by sector.  

Using this strategy, it is possible to reach attainment in 365 counties.
 However, there are still an additional 126 counties that will remain
out of attainment with an alternative standard of 0.070 ppm using this
control strategy.  All known controls were applied to this scenario, but
attainment was not achieved everywhere.  Because of this partial
attainment outcome, it will be necessary to identify additional
reductions in NOx and VOC in order to assess the costs and benefits of
full attainment nationwide.  Chapter 4 will address the methodology for
determining the additional tons that were needed to reach full
attainment. 

Fig. 3.13  Projected Ozone Air Quality in 2020 After Application of
Known Controls

 

1 Modeled emissions reflect the expected reductions from federal
programs including the Clean Air Interstate Rule, the Clean Air Mercury
Rule, the Clean Air Visibility Rule, the Clean Air Nonroad Diesel Rule,
the Light-Duty Vehicle Tier 2 Rule, the Heavy Duty Diesel Rule, proposed
rules for Locomotive and Marine Vessels and for Small Spark-Ignition
Engines, and state and local level mobile and stationary source controls
identified for additional reductions in emissions for the purpose of
attaining the current PM 2.5 and Ozone  standards.  

2 Controls applied are illustrative.  States may choose to apply
different control strategies for implementation. 

3 The current standard of 0.08 ppm is effectively expressed as 0.084 ppm
when rounding conventions are applied.  

4 Modeled design values in ppm are only interpreted up to 3 decimal
places.

5 Map shows results from a total of 491 counties with projected design
values. Consistent with current modeling guidance, EPA did not project
2020 concentrations for counties where 2001 base year concentrations
were less than recommended criterion.  Such projections may not
represent expected future levels.  

  Table 3.4 Annual Tons of Emissions Remaining after Application of the
0.070 ppm Control Strategy (35 States + DC Analysis Area)

Pollutant	Sector	2020 Emissions After Controls Applied for PM2.5 15/35
(tons)

	2020 Emissions After Controls Applied for  PM2.5 15/35 and Ozone 0.084
Control Strategy Baseline (tons)

	0.070 ppm  Reductions (tons)

	2020 Emissions After Controls Applied for  PM2.5 15/35 and Ozone 0.070
ppm Control Strategy (tons)

NOX	Area 	1,200,000	1,200,000	30,000	1,200,000

	Onroad 	1,800,000	1,700,000	170,000	1,600,000

	Nonroad 	1,900,000	1,800,000	8,000	1,800,000

	EGU	1,500,000	1,500,000	7,800	1,500,000

	Non-EGU 	2,200,000	1,900,000	800,000	1,100,000

VOC	Area 	5,800,000 	5,600,000 	84,000 	5,500,000 

	Onroad 	1,500,000 	1,500,000 	86,000 	1,400,000 

	Nonroad 	1,000,000 	1,000,000 	12,000 	1,000,000 

	EGU	39,000 	39,000 	26 	38,000 

	Non-EGU 	1,100,000 	1,100,000 	3,400 	1,100,000 



Fig 3.14  Annual NOx Emissions Remaining after PM NAAQS 15/35, Ozone
Current Standard, and 0.070 ppm Control Strategies

(35 States + DC Analysis Area)

Fig. 3.16  Annual VOC Emissions Remaining after PM NAAQS 15/35, Ozone
Current Standard, and 0.070 ppm Control Strategies 

(35 States + DC Analysis Area)

3.5 	References

Michigan Department of Environmental Quality and Southeast Michigan
Council of Governments. Proposed Revision to State of Michigan State
Implementation Plan for 7.0 Low Vapor Pressure Gasoline Vapor Request
for Southeast Michigan.  May 24, 2006.

National Ambient Air Quality Standards for Particulate Matter, 40 CFR
Part 50 (2006)

Rule To Reduce Interstate Transport of Fine Particulate Matter and Ozone
(Clean Air Interstate Rule); Revisions to Acid Rain Program; Revisions
to the NOX SIP Call; Final Rule, 40 CFR Parts 51, 72, 73, 74, 77, 78 and
96 (2005).

Standards of Performance for New and Existing Stationary Sources:
Electric Utility Steam Generating Units,  40 CFR Parts 60, 63, 72, and
75 (2005)

Regional Haze Regulations and Guidelines for Best Available Retrofit
Technology (BART) Determinations, 40 CFR Part 51 (2005)

Control of Emissions of Air Pollution from Locomotive Engines and Marine
Compression-Ignition Engines Less than 30 Liters per Cylinder, Proposed
rule, 40 CFR Parts 92, 94, 1033, 1039, 1042, 1065 and 1068 (2007)

Control of Emissions from Nonroad Spark-Ignition Engines and Equipment;
proposed rule, 40 CFR Parts 60, 63, 85, 89, 90, 91, 1027, 1045, 1048,
1051, 1054, 1060, 1065, 1068, and 1074 (2007)

USEPA. Guide on Federal and State Summer RVP Standards for Conventional
Gasoline Only. EPA420-B-05-012. November 2005

USEPA. 2007, Regulatory Announcement: EPA Proposal for More Stringent
Emissions Standards for Locomotives and Marine Compression-Ignition
Engines. EPA420-F-07-015

USEPA. 2007, Proposed Emission Standards for New Nonroad Spark-Ignition
Engines, Equipment, and Vessels. EPA420-F-07-032

 In establishing the baseline, we selected a set of cost-effective
controls to simulate attainment of the current ozone and PM2.5
standards.  These control sets are hypothetical as states will
ultimately determine controls as part of the SIP process.

 http;//  HYPERLINK "http://www.epa.gov/otaq/renewablefuels" 
www.epa.gov/otaq/renewablefuels   

 References for these rules are provided at the end of this chapter. 
Controls are explained in Appendix 3.

 0.08 ppm, effectively 0.084 ppm based on current rounding conventions

 Porter County, IN, was included, despite being below the emissions
threshold, due to its close proximity to Chicago.  Harris County, TX,
was included because of local information about the benefits of VOC
control, and concerns about the screening tool performance in the 36km
region of which Houston is a part.

 Onroad and Nonroad DPF were applied in the baseline, and SCR retrofit
technologies were chosen because of the need to reduce NOx emissions..

 Reductions from Ocean-Going Vessels burning residual fuels were applied
in the Baseline analysis for the east, but inadvertently omitted for the
west.  The omission was not identified in time to include it in the
initial Baseline analysis for the west.

 Available online at:   HYPERLINK
"http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf"
 http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf 

 For Onroad and Nonroad Mobile Source control measures, all measures
applied for the Baseline analysis were applied to additional geographic
areas in the .070 analysis.

 Reductions from Ocean-Going Vessels burning diesel fuel were applied in
the Base Case analysis.  However, we inadvertently omitted the
associated reductions that would occur in vessels burning residual
fuels.  These additional reductions were applied in the Baseline
analysis for the east and in the .070 analyses for the east and west. 
The omission was not identified in time to include it in the initial
Baseline analysis for the west, but was included in the Baseline
national PM co-benefits analysis for the east and west.

 See   HYPERLINK "http://www.epa.gov/ttnecas1/AirControlNET.htm" 
http://www.epa.gov/ttnecas1/AirControlNET.htm  for a description of how
AirControlNET operates and what data is included in this tool.

 While AirControlNET has not undergone a formal peer review, this
software tool has undergone substantial review within EPA's OAR and
OAQPS, and by technical staff in EPA's Regional offices.   Much of the
control measure data has been included in a control measure database
that will be distributed to EPA Regional offices for use by States as
they prepare their ozone, regional haze, and PM2.5 SIPs over the next 10
months.  In addition, the control measure data within AirControlNET has
been used by Regional Planning Organizations (RPOs) such as the Lake
Michigan Air District Commission (LADCO), the Ozone Transport Commission
(OTC), and the Visibility Improvement State and Tribal Assocation of the
Southeast (VISTAS) as part of their technical analyses associated with
SIP development over the last 3 years.  All of their technical reports
are available on their web sites.  

  See   HYPERLINK
"http://www.epa.gov/airmarkets/progress/progress-reports.html" 
http://www.epa.gov/airmarkets/progress/progress-reports.html  for more
information 

 See   HYPERLINK "http://www.epa.gov/CAIR/technical.html" 
http://www.epa.gov/CAIR/technical.html 

 Detailed analysis showed that 75% reduction provides the most
cost-effective way of reducing emissions at the targeted non-attainment
areas, considering transport, with the most air quality impacts.

 Numbers may not add up due to rounding

 PAGE   

3- PAGE   29 

Table 3.2 Controls by Sector Included in the Baseline Determination for
2020 (continued)

Non-Electrical Generating Unit Point (2%)

On-Road (46%)

Non-Road (7%)

Area (45%)

Non-Road (<1%)

On-Road (16%)

Electrical Generating Unit Point(<1%)

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Table 3.3 (Continued): Controls for Emissions Reductions, by Sector, for
the 0.070 ppm Control Strategy 

(Incremental to Baseline)

Table 3.3: Controls for Emissions Reductions, by Sector, for the 0.070
ppm Control Strategy (Incremental to Baseline)