# Chapter 2: Characterizing Ozone and Modeling Tools Used in This Analysis 

## Synopsis

This chapter describes the chemical and physical properties of ozone,
general ozone air quality patterns, key health and environmental impacts
associated with exposure to ozone, and key sources of ozone precursor
emissions. In order to evaluate the health and environmental impacts of
trying to reach a tighter ozone standard in the year 2020, it was
necessary to use models to predict concentrations in the future. The
tools and methodology used for the air quality modeling are described in
this chapter. Subsequent chapters of this RIA rely heavily on the
results of this modeling.

## 2.1 Ozone Chemistry

Ozone occurs both naturally in the stratosphere to provide a protective
layer high above the earth, and at ground-level (troposphere) as the
prime ingredient of smog. Tropospheric ozone, which is regulated by the
NAAQS, is formed by both naturally occurring and anthropogenic sources.
Ozone is not emitted directly into the air, but is created when its two
primary components, volatile organic compounds (VOC) and oxides of
nitrogen (NOx), combine in the presence of sunlight. VOC and NOx are
often referred to as ozone precursors, which are, for the most part,
emitted directly into the atmosphere.

Ambient ozone concentrations are directly affected by temperature, solar
radiation, wind speed and other meteorological factors. Ultraviolet
radiation from the sun plays a key role in initiating the processes
leading to ozone formation. However, there is little empirical evidence
directly linking day-to-day variations in observed surface ultraviolet
radiation levels with variations in tropospheric ozone levels.

The rate of ozone production can be limited by either VOCs or NOx. In
general, ozone formation using these two precursors is reliant upon the
relative sources of hydroxide (OH) and NOx. When the rate of OH
production is greater than the rate of production of NOx, indicating
that NOx is in short supply, the rate of ozone production is
NOx-limited. In this situation, ozone concentrations are most
effectively reduced by lowering current and future NOx emissions, rather
than lowering emissions of VOCs. When the rate of OH production is less
than the rate of production of NOx, ozone production is VOC-limited.
Here, ozone is most effectively reduced by lowering VOCs. Between the
NOx- and VOC-limited extremes there is a transitional region where ozone
is nearly equally sensitive to each species. However ozone is relatively
insensitive to marginal changes in both NOx and VOC in this situation.
In urban areas with a high population concentration, ozone is often
VOC-limited. Ozone is generally NOx-limited in rural areas and downwind
suburban areas. Additional information on ozone formation can be found
in "Atmospheric Chemistry and Physics" (Seinfeld et. al., 1998).

Due to the complex photochemistry of ozone production, NOx emissions
lead to both the formation and destruction of ozone, depending on the
local quantities of NOx, VOC, and ozone catalysts such as the OH and HO2
radicals. In areas dominated by fresh emissions of NOx, ozone catalysts
are removed via the production of nitric acid, which slows the ozone
formation rate. Because NOx is generally depleted more rapidly than VOC,
this effect is usually short-lived and the emitted NOx can lead to ozone
formation later and further downwind. The terms "NOx disbenefits" or
"ozone disbenefits" refer to the ozone increases that can result from
NOx emission reductions in these localized areas.[^1]

### 2.1.1 Temporal Scale

Ground-level ozone forms readily in the atmosphere, usually during hot
weather. The effects of sunlight on ozone formation depend on its
intensity and its spectral distribution. Ozone levels tend to be highest
during the daytime, during the summer or warm season. Changing weather
patterns contribute to day to day and interannual differences in ozone
concentrations. Differences in climatic regime, amount and mixture of
emissions, and the extent of transport contribute to variations in ozone
from city to city.

### 2.1.2 Geographic Scale and Transport

In many urban areas, ozone nonattainment is not caused by emissions from
the local area alone. Due to atmospheric transport, contributions of
precursors from the surrounding region can also be important. Thus, in
designing control strategies to reduce ozone concentrations in a local
area, it is often necessary to account for regional transport within the
U.S.

In some areas, such as California, global transport of ozone from beyond
North America can contribute to nonattainment areas. In a very limited
number of areas, including areas such as Buffalo, Detroit and El Paso,
which are located near borders, emissions from Canada or Mexico may
contribute to nonattainment. In these areas, our illustrative
implementation strategies may have included more controls on domestic
sources than would be required if cross-border transport did not occur.
However, we have not conducted formal analysis, and as such cannot
determine the contribution of non-U.S. sources to ozone design values.
The transport of ozone is determined by meteorological and chemical
processes which typically extend over spatial scales of several hundred
kilometers. Additionally, convection is capable of transporting ozone
and its precursors vertically through the troposphere, with resulting
mixing of stratospheric ozone for periods of a month or more with
tropospheric ozone.

The Technical Support Document (TSD) for the Clean Air Interstate Rule
(CAIR) suggests that ozone transport constitutes a sizable portion of
projected nonattainment in most eastern areas based on a 2010 analysis.
A listing of Eastern states and the extent of transported ozone they
receive in the CAIR analysis is located in the CAIR TSD.[^2] We used
this information to help guide the design of emissions control
strategies in this analysis.

## 2.2 Sources of Ozone

The anthropogenic precursors of ozone originate from a wide variety of
stationary and mobile sources. In urban areas, both biogenic (natural)
and anthropogenic VOCs are important for ozone formation. Hundreds of
VOCs are emitted by evaporation and combustion processes from a large
number of anthropogenic sources. Current data show that solvent use and
highway vehicles are the two main sources of VOCs, with roughly equal
contributions to total emissions. Emissions of VOCs from highway
vehicles account for roughly two-thirds of the transportation-related
emissions.[^3] By 2020, EPA emission projections show that VOC emissions
from highway vehicles decrease significantly. Solvent use VOC decreases
as well, but by 2020 solvent use VOC is projected to be a slightly more
significant VOC contributor than mobile VOC. On the regional and global
scales, emissions of VOCs from vegetation are much larger than those
from anthropogenic sources.

Anthropogenic NOx emissions are associated with combustion processes.
The two largest sources of NOx are electric power generation plants
(EGUs) and motor vehicles. EGU NOx is approximately 40% less than onroad
mobile NOx in 2001. Both decrease between 2001 and 2020, with onroad
mobile NOx decreasing more, so that their emissions are similar in 2020.
It is not possible to make an overall statement about their relative
impacts on ozone in all local areas because EGUs are more sparse than
mobile sources, particularly in the west and south (See Chapter 3 for a
discussion of emission reductions projected in 2020 for the 8-hr ozone
current standard baseline and the more stringent alternative control
scenario). Natural NOx sources include stratospheric intrusions,
lightning, soils, and wildfires. Lightning, fertilized soils, and
wildfires are the major natural sources of NOx in the United States.
Uncertainties in natural NOx inventories are much larger than for
anthropogenic NOx emissions.

A complete list of emissions source categories, for both NOx and VOCs,
is compiled in the final ozone Staff Paper (EPA, 2007a, pp. 2-3 to 2-6).

## 2.3 Modeling Ozone Levels in the Future

In order to evaluate the predicted air quality in 2020, it is necessary
to use modeling to derive estimated air quality concentrations. The
modeling analysis uses an emissions inventory and historical
meteorological conditions to simulate pollutant concentrations. The
predictions from the modeling are used to (a) project future ozone
design values (a representation of the resultant air quality
concentration in 2020 representing the 4^th^ highest maximum 8-hr
concentration) and (b) create spatial fields of ozone and PM~2.5~ for
characterizing human health impacts from reducing ozone precursors,
which in the case of NOx will also affect the formation of PM~2.5~. The
air quality model used in this RIA is the Community Multi-Scale Air
Quality (CMAQ) model[^4]. The modeling for ozone and PM~2.5~ was
performed for a one year time period. All controls in the illustrative
0.070 scenario were applied similarly to all months. There were no
controls applied specifically for PM~2.5~ co-benefits because the
controls developed to reduce summer ozone were applied to all months
(see Chapter 3).

### 2.3.1 CMAQ Model and Inputs

A national scale air quality modeling analysis was performed to estimate
future year attainment/nonattainment of the current and alternative
ozone standards. In addition, the model-based projections of ozone and
PM~2.5~ were used as inputs to the calculation of expected incremental
benefits from the alternative ozone standards considered in this
assessment. The 2002-based modeling platform (EPA, 2008) was used as the
basis for air quality modeling of the future baseline emissions and
illustrative control scenario. This modeling platform includes a number
of updates and improvements to data and tools compared to the 2001-based
platform that was used for the proposal modeling. For the final rule
modeling we used the new 2002 National Emissions Inventory along with
updated versions of the models used to project future emissions from
electric generating units (EGUs) and onroad and nonroad vehicles. The
proposal modeling was based on the 2001 National Emissions Inventory.
The new platform also includes 2002 meteorology and more recent ambient
design values which were used as the starting point for projecting
future air quality. For proposal, we used meteorology for 2001 for
modeling the East and 2002 for modeling the West. The updates[^5] to
CMAQ between proposal and final include (1) an in-cloud sulfate
chemistry module that accounts for the nonlinear sensitivity of sulfate
formation to varying pH; (2) improved vertical convective mixing; (3)
heterogeneous reaction involving nitrate formation; (4) an updated
gas-phase chemistry mechanism, Carbon Bond 2005 (CB05); and (5) an
aqueous chemistry mechanism that provides a comprehensive simulation of
aerosol precursor oxidants.

The key non-emissions inputs to the CMAQ model include meteorological
data, and initial and boundary concentrations. The CMAQ meteorological
input files were derived from simulations of the Pennsylvania State
University/National Center for Atmospheric Research Mesoscale Model
(Grell, Dudhia, and Stauffer, 1994). This model, commonly referred to as
MM5, is a limited-area, nonhydrostatic, terrain-following system that
solves for the full set of physical and thermodynamic equations which
govern atmospheric motions. The lateral boundary and initial species
concentrations for the 36 km continental scale modeling domain,
described below, were obtained from a three-dimensional global
atmospheric chemistry model, the GEOSChem model (Yantosca, 2004). The
global GEOSChem model simulates atmospheric chemical and physical
processes driven by assimilated meteorological observations from the
NASA's Goddard Earth Observing System (GEOS). We used GEOSChem results
for 2002 to provide initial and boundary concentrations for our final
rule air quality modeling. For proposal we used GEOSChem results for
2001.

EPA performed an extensive evaluation of CMAQ using the 2002 inputs for
emissions, meteorology, and boundary conditions. Details of the model
performance methodology and results are described in the 2002-Based
Modeling Platform Report (EPA, 2008). As in the evaluation for previous
model applications, the "acceptability" of model performance for the
ozone RIA modeling was judged by comparing the results to those found in
recent regional ozone model applications for other EPA and non-EPA
studies (see Appendix B of EPA, 2007b). Overall, the performance for the
CMAQ application is generally within the range of these other
applications.

Figure 2.1 shows the modeling domains that were used as a part of this
analysis. The geographic specifications for these domains are provided
in Table 2.1. All three modeling domains contain 14 vertical layers with
a top at about 16,200 meters, or 100 mb. Two domains with 12 km
horizontal resolution were used for modeling the 2002 base year, 2020
baseline and 2020 control strategy scenarios. These domains are labeled
as the East and West 12 km domains in Figure 2.1. Simulations for the 36
km domain were only used to provide initial and boundary concentrations
for the 12 km domains. As indicated above, the model produces spatial
fields of gridded air quality concentrations on an hourly basis for the
entire modeling domain. These gridded concentrations can be processed to
produce a number of air quality metrics, including the 8-hr ozone design
values, and can be used as inputs for the analysis of costs and
benefits. The air quality modeling results are used in a relative sense
to project concentrations for the future year scenarios using procedures
consistent with EPA guidance (EPA, 2007b). For the final rule
projections we used ambient design values for the period 2000 through
2004 as the starting point for projections. For the proposal, design
values from 1999 through 2003 were used. The change between proposal and
final in terms of the period of design values was made, in accordance
with EPA guidance, in order to align the central year of design values
with the base year of the emissions (i.e., 2001 for the proposed rule
and 2002 for the final rule).

For this analysis, predictions from the East domain were used to provide
data for all areas that are east of approximately 104 degrees longitude.
Model predictions from the West domain we used for all areas west of
this longitude.

Figure 2.1: Map of the CMAQ Modeling Domains Used for Ozone NAAQS RIA

![](media/image1.wmf){width="4.997916666666667in" height="3.75in"}

Table 2.1: Geographic Specifications of Modeling Domains

  ---------- --------- --------- ---------- --------- --------- ---------- ---------- ---------
  **36 km                        **12 km                        **12 km               
  Domain\                        East                           West                  
  (148 x 112                     Domain\                        Domain\               
  Grid                           (279 x 240                     (213 x 192            
  Cells)**                       Grid                           Grid                  
                                 Cells)**                       Cells)**              

             **Lon**   **lat**              **lon**   **lat**              **lon**    **lat**

  SW         −121.77   18.17     SW         −106.79   24.99     SW         −121.65    28.29

  NE         −58.54    52.41     NE         −65.32    47.63     NE         −94.94     51.91
  ---------- --------- --------- ---------- --------- --------- ---------- ---------- ---------

### 2.3.2 Emissions Inventory

The 2020 inventory, projected from the 2002 Version 3 emissions modeling
platform (EPA, 2008), is the starting point for the baseline and control
strategy for the Final Ozone NAAQS emissions inventory. The 2002
documentation describes the 2002 base year inventory as well as the
projection methodology and controls applied to create year 2020
emissions. The 2020 inventory includes activity growth for some sectors,
and controls 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, known plant closures, and consent decrees and settlements. Table
2.2 provides a comprehensive list of the rules/control strategies and
projection assumptions in the 2020 inventory; full discussion of the
2020 inventory is provided in the 2002 Version 3 emissions modeling
platform (EPA, 2008a). The data for the controls and projection
strategies can be found in the Loco-Marine docket (EPA, 2008b).

Table 2.2: Control Strategies and Projection Assumptions in the 2020
Emissions Inventory

+-----------------------------------------------+----------+----------+
| **Control Strategies\                         | **Po     | **       |
| (Grouped by Affected Pollutants or Standard   | llutants | Approach |
| and Approach Used to Apply to the             | Af       | or       |
| Inventory)**                                  | fected** | Ref      |
|                                               |          | erence** |
+===============================================+==========+==========+
| **Non-EGU Point Controls**                    |          |          |
+-----------------------------------------------+----------+----------+
| **NOx SIP Call (Phase II):\                   | NOx      | 1        |
| **Cement Manufacturing\                       |          |          |
| Large Boiler/Turbine Units\                   |          |          |
| Large IC Engines                              |          |          |
+-----------------------------------------------+----------+----------+
| **DOJ Settlements: plant SCC controls\        | NOx,     | 2        |
| **Alcoa, TX\                                  | SO~2~    |          |
| MOTIVA, DE                                    |          |          |
+-----------------------------------------------+----------+----------+
| **Refinery Consent Decrees: plant/SCC         | NOx, PM, | 3        |
| controls**                                    | SO~2~    |          |
+-----------------------------------------------+----------+----------+
| **Closures, pre-2007: plant control of 100%\  | all      | 4        |
| **Auto plants\                                |          |          |
| Pulp and Paper                                |          |          |
|                                               |          |          |
| Municipal Waste Combustors\                   |          |          |
| Plants closed in preparation for 2005         |          |          |
| inventory                                     |          |          |
+-----------------------------------------------+----------+----------+
| **Industrial Boiler/Process Heater plant/SCC  | PM       | 5        |
| controls for PM**                             |          |          |
+-----------------------------------------------+----------+----------+
| **MACT rules, national, VOC: national applied | VOC      | EPA,     |
| by SCC, MACT\                                 |          | 2007f    |
| **Boat Manufacturing\                         |          |          |
| Polymers and Resins III (Phenolic Resins)\    |          |          |
| Polymers and Resins IV (Phenolic Resins)\     |          |          |
| Wood Building Products Surface Coating\       |          |          |
| Generic MACT II: Spandex Production, Ethylene |          |          |
| manufacture\                                  |          |          |
| Large Appliances\                             |          |          |
| Miscellaneous Organic NESHAP (MON): Alkyd     |          |          |
| Resins, Chelating Agents, Explosives,         |          |          |
| Phthalate Plasicizers, Polyester Resins,      |          |          |
| Polymerized Vinylidene Chloride\              |          |          |
| Manufacturing Nutritional Yeast\              |          |          |
| Oil and Natural Gas\                          |          |          |
| Petroleum Refineries---Catalytic Cracking,    |          |          |
| Catalytic Reforming, & Sulfur Plant Units\    |          |          |
| Pesticide Active Ingredient Production\       |          |          |
| Publicly Owned Treatment Works\               |          |          |
| Reinforced Plastics\                          |          |          |
| Rubber Tire Manufacturing\                    |          |          |
| Asphalt Processing & Roofing\                 |          |          |
| Combustion Sources at Kraft, Soda, and        |          |          |
| Sulfite Paper Mills\                          |          |          |
| Fabric Printing, Coating and Dyeing\          |          |          |
| Iron & Steel Foundries\                       |          |          |
| Metal: Can, Coil\                             |          |          |
| Metal Furniture\                              |          |          |
| Miscellaneous Metal Parts & Products\         |          |          |
| Municipal Solid Waste Landfills\              |          |          |
| Paper and Other Web\                          |          |          |
| Plastic Parts\                                |          |          |
| Plywood and Composite Wood Products\          |          |          |
| Wet Formed Fiberglass Production\             |          |          |
| Wood Building Products Surface Coating\       |          |          |
| Carbon Black Production\                      |          |          |
| Cellulose Products Manufacturing\             |          |          |
| Cyanide Chemical Manufacturing                |          |          |
+-----------------------------------------------+----------+----------+

(continued)

Table 2.2: Control Strategies and Projection Assumptions in the 2020
Emissions Inventory (continued)

+-----------------------------------------------+----------+----------+
| **Control Strategies\                         | **Po     | **       |
| (Grouped by Affected Pollutants or Standard   | llutants | Approach |
| and Approach Used to Apply to the             | Af       | or       |
| Inventory)**                                  | fected** | Ref      |
|                                               |          | erence** |
+===============================================+==========+==========+
| Friction Products Manufacturing\              |          |          |
| Leather Finishing Operations\                 |          |          |
| Miscellaneous Coating Manufacturing\          |          |          |
| Organic Liquids Distribution (Non-Gasoline)\  |          |          |
| Refractory Products Manufacturing\            |          |          |
| Sites Remediation                             |          |          |
+-----------------------------------------------+----------+----------+
| **Solid Waste Rules (Section 129d/111d)**     | NOx, PM, | EPA,     |
|                                               | SO~2~    | 2005     |
| Hospital/Medical/Infectious Waste Incinerator |          |          |
| Regulations                                   |          |          |
+-----------------------------------------------+----------+----------+
| **MACT rules, national, PM:\                  | PM       | 6        |
| **Portland Cement Manufacturing\              |          |          |
| Secondary Aluminum                            |          |          |
+-----------------------------------------------+----------+----------+
| **MACT rules, plant-level, VOC:\              | VOC      | 7        |
| **Auto Plants                                 |          |          |
+-----------------------------------------------+----------+----------+
| **MACT rules, plant-level, PM & SO~2~:\       | PM,      | 8        |
| **Lime Manufacturing                          | SO~2~    |          |
+-----------------------------------------------+----------+----------+
| **MACT rules, plant-level, PM:\               | PM       | 9        |
| **Taconite Ore                                |          |          |
+-----------------------------------------------+----------+----------+
| **Stationary Non-point (Area) Assumptions**   |          |          |
+-----------------------------------------------+----------+----------+
| **Municipal Waste Landfills:** projection     | VOC      | EPA,     |
| factor of 0.25 applied                        |          | 2007f    |
+-----------------------------------------------+----------+----------+
| **Livestock Emissions Growth**                | NH~3~,   | 10       |
|                                               | PM       |          |
+-----------------------------------------------+----------+----------+
| **Residential Wood Combustion Growth**        | all      | 11       |
|                                               |          |          |
| reflects increase in use of lower polluting   |          |          |
| wood stoves, and decrease in use of higher    |          |          |
| polluting stoves                              |          |          |
+-----------------------------------------------+----------+----------+
| **Gasoline Stage II growth and control**      | VOC      | 12       |
|                                               |          |          |
| (also impacts non-EGU point sources in a      |          |          |
| couple of states)                             |          |          |
+-----------------------------------------------+----------+----------+
| **Portable Fuel Container growth and          | VOC      | 13       |
| control**                                     |          |          |
+-----------------------------------------------+----------+----------+
| **EGU Point Controls**                        |          |          |
+-----------------------------------------------+----------+----------+
| **CAIR/CAMR/CAVR**                            | NOx,     | 14       |
|                                               | SO~2~,   |          |
| IPM Model 3.0                                 | PM       |          |
+-----------------------------------------------+----------+----------+
| **Onroad Mobile and Nonroad Mobile Growth and |          |          |
| Controls**                                    |          |          |
+-----------------------------------------------+----------+----------+
| **Onroad and Nonroad Growth:**                | all      |          |
|                                               |          |          |
| Onroad growth is based on VMT growth from     |          |          |
| Annual Energy Outlook (AEO) 2006 estimates of |          |          |
| growth by vehicle type. Nonroad growth is     |          |          |
| based on activity increases from NONROAD      |          |          |
| model default growth estimates                |          |          |
+-----------------------------------------------+----------+----------+
| **National Onroad Rules:**                    | all      |          |
|                                               |          |          |
| Tier 2 Rule                                   |          |          |
|                                               |          |          |
| 2007 Onroad Heavy-Duty Rule                   |          |          |
|                                               |          |          |
| Final Mobile Source Air Toxics Rule (MSAT2)   |          |          |
|                                               |          |          |
| Renewable Fuel Standard                       |          |          |
+-----------------------------------------------+----------+----------+
| **Local Onroad Programs:**                    | VOC      | 15       |
|                                               |          |          |
| National Low Emission Vehicle Program (NLEV)  |          |          |
|                                               |          |          |
| Ozone Transport Commission (OTC) LEV Program  |          |          |
+-----------------------------------------------+----------+----------+

(continued)

Table 2.2: Control Strategies and Projection Assumptions in the 2020
Emissions Inventory (continued)

+--------------------------------------------------+---------+---------+
| **Control Strategies\                            | **Pol   | **A     |
| (Grouped by Affected Pollutants or Standard and  | lutants | pproach |
| Approach Used to Apply to the Inventory)**       | Aff     | or      |
|                                                  | ected** | Refe    |
|                                                  |         | rence** |
+==================================================+=========+=========+
| **National Nonroad Controls:**                   | all     | 16      |
|                                                  |         |         |
| Clean Air Nonroad Diesel Final Rule---Tier 4     |         |         |
|                                                  |         |         |
| Control of Emissions from Nonroad Large-Spark    |         |         |
| Ignition Engines and Recreational Engines        |         |         |
| (Marine and Land Based): "Pentathalon Rule"      |         |         |
+--------------------------------------------------+---------+---------+
| **Aircraft, Locomotives, and Commercial Marine   |         |         |
| Assumptions**                                    |         |         |
+--------------------------------------------------+---------+---------+
| **Aircraft:**                                    | all     | 17      |
|                                                  |         |         |
| Itinerant (ITN) operations at airports           |         |         |
+--------------------------------------------------+---------+---------+
| **Locomotives:**                                 | all     | EPA,    |
|                                                  |         | 2007e,  |
| Energy Information Administration (EIA) fuel     |         | 18      |
| consumption projections for freight rail         |         |         |
|                                                  |         |         |
| Clean Air Nonroad Diesel Final Rule---Tier 4     |         |         |
|                                                  |         |         |
| Locomotive Final Rulemaking, December 17, 1997   |         |         |
+--------------------------------------------------+---------+---------+
| **Commercial Marine:**                           | all     | 18,     |
|                                                  |         | (EPA,   |
| EIA fuel consumption projections for             |         | 2007e)  |
| diesel-fueled vessels                            |         |         |
|                                                  |         |         |
| Freight-tonnage growth estimates fro             |         |         |
| residual-fueled vessels                          |         |         |
|                                                  |         |         |
| Clean Air Nonroad Diesel Final Rule---Tier 4     |         |         |
|                                                  |         |         |
| Emissions Standards for Commercial Marine Diesel |         |         |
| Engines, December 29, 1999                       |         |         |
|                                                  |         |         |
| Tier 1 Marine Diesel Engines, February 28, 2003  |         |         |
+--------------------------------------------------+---------+---------+
| **APPROACHES:**                                  |         |         |
+--------------------------------------------------+---------+---------+
| 1.  Used *Emission Budget Inventories* report    |         |         |
|     (EPA, 1999) for list of SCCs for application |         |         |
|     of controls, and for percent reductions      |         |         |
|     (except IC Engines). Used Federal Register   |         |         |
|     on Response to Court decisions (Federal      |         |         |
|     Register, 2004) for IC Engine percent        |         |         |
|     reductions and geographic applicability      |         |         |
|                                                  |         |         |
| 2.  For ALCOA consent decree, used http://       |         |         |
|     cfpub.epa.gov/compliance/cases/index.cfm;    |         |         |
|     for MOTIVA: used information sent by State   |         |         |
|     of Delaware                                  |         |         |
|                                                  |         |         |
| 3.  Used data provided by Brenda Shine, EPA,     |         |         |
|     OAQPS                                        |         |         |
|                                                  |         |         |
| 4.  Closures obtained from EPA sector leads;     |         |         |
|     most verified using the world wide web.      |         |         |
|                                                  |         |         |
| 5.  Used data list of plants provided by project |         |         |
|     lead from 2001-based platform; required      |         |         |
|     mapping the 2001 plants to 2002 NEI plants   |         |         |
|     due to plant id changes across inventory     |         |         |
|     years                                        |         |         |
|                                                  |         |         |
| 6.  Same as used in CAIR, except added SCCs      |         |         |
|     appeared to be covered by the rule: both     |         |         |
|     reductions based on preamble to final rule.  |         |         |
|     (Portland Cement used a weighted average     |         |         |
|     across two processes )                       |         |         |
|                                                  |         |         |
| 7.  Percent reductions recommended and plants to |         |         |
|     apply to reduction to were based on          |         |         |
|     recommendations by rule lead engineer, and   |         |         |
|     are consistent with the reference: EPA,      |         |         |
|     2007e                                        |         |         |
|                                                  |         |         |
| 8.  Percent reductions recommended are           |         |         |
|     determined from the existing plant estimated |         |         |
|     baselines and estimated reductions as shown  |         |         |
|     in the Federal Register Notice for the rule. |         |         |
|     SO2 % reduction will therefore be            |         |         |
|     6147/30,783 = 20% and PM10 and PM~2.5~       |         |         |
|     reductions will both be 3786/13588 = 28%     |         |         |
|                                                  |         |         |
| 9.  Same approach used in CAIR: FR notice        |         |         |
|     estimates reductions of "PM emissions by     |         |         |
|     10,538 tpy, a reduction of about 62%." Used  |         |         |
|     same list of plants as were identified based |         |         |
|     on tonnage and SCC from CAIR.                |         |         |
|                                                  |         |         |
| 10. Except for dairy cows and turkeys (no        |         |         |
|     growth), based in animal population growth   |         |         |
|     estimates from USDA and Food and Agriculture |         |         |
|     Policy and Research Institute.               |         |         |
|                                                  |         |         |
| 11. Expected benefits of woodstoves change-out   |         |         |
|     program:                                     |         |         |
|     <http://www.epa.gov/woodstoves/index.html>   |         |         |
|                                                  |         |         |
| 12. VOC emission ratios of year 2020 to year     |         |         |
|     2002 from the National Mobile Inventory      |         |         |
|     Model (NMIM) results for onroad refueling    |         |         |
|     including activity growth from VMT, Stage II |         |         |
|     control programs at gasoline stations, and   |         |         |
|     phase in of newer vehicles with onboard      |         |         |
|     Stage II vehicle controls.                   |         |         |
|                                                  |         |         |
| 13. VOC emission ratios of year 2020 to year     |         |         |
|     2002 from MSAT rule (EPA, 2007c, EPA, 2007d) |         |         |
|                                                  |         |         |
| 14. <http://www.epa.gov/ai                       |         |         |
| rmarkets/progsregs/epa-ipm/docs/summary2006.pdf> |         |         |
|                                                  |         |         |
| 15. Only for states submitting these inputs:     |         |         |
|     <http://www.epa.gov/otaq/lev-nlev.htm>       |         |         |
|                                                  |         |         |
| 16                                               |         |         |
| . <http://www.epa.gov/nonroad-diesel/2004fr.htm> |         |         |
|                                                  |         |         |
| 17. Federal Aviation Administration (FAA)        |         |         |
|     Terminal Area Forecast (TAF) System,         |         |         |
|     February 2006:                               |         |         |
|     <http://www.apo.data.faa.gov/main/taf.asp>   |         |         |
|                                                  |         |         |
| 18                                               |         |         |
| . <http://www.epa.gov/nonroad-diesel/2004fr.htm> |         |         |
+--------------------------------------------------+---------+---------+

Differences between the 2020 emissions modeling platforms---particularly
the inventories---used in the Ozone NAAQS Proposal and here in the Ozone
NAAQS Final are discussed in the Appendix for Chapter 2.

The development of the 2020 baseline inventory and the modeled control
scenarios are discussed in Chapter 3. The 2020 baseline inventory
includes the same year 2020 Canada and year 1999 Mexico emissions as the
Final PM NAAQS (EPA, 2006b).

## 2.4 References

Amar, P., R. Bornstein, H. Feldman, H. Jeffries, D. Steyn, R. Yamartino,
and Y. Zhang. 2004. Final Report Summary: December 2003 Peer Review of
the CMAQ Model. pp. 7.

Byun, D.W., and K.L. Schere. 2006. "Review of the Governing Equations,
Computational Algorithms, and Other Components of the Models-3 Community
Multiscale Air Quality (CMAQ) Modeling System." *J. Applied Mechanics
Reviews* 59(2):51-77.

Dennis, R.L., D.W. Byun, J.H. Novak, K.J. Galluppi, C.J. Coats, and M.A.
Vouk. 1996. "The next generation of integrated air quality modeling:
EPA's Models-3." *Atmospheric Environment* 30:1925-1938.

Grell, G., J. Dudhia, and D. Stauffer, 1994: A Description of the
Fifth-Generation Penn State/NCAR Mesoscale Model (MM5),
*NCAR/TN-398+STR*., 138 pp, National Center for Atmospheric Research,
Boulder CO.

Seinfeld, J.H. and S. N. Pandis, 1998: Atmospheric Chemistry and
Physics. John Wiley & Sons, New York.

U.S. Environmental Protection Agency (EPA). 1999. "Science Algorithms of
EPA Models-3 Community Multiscale Air Quality." (CMAQ Modeling System
D.W. Byun and J.K.S. Ching, Eds. EPA/600/R-99/030, Office of Research
and Development).

U.S. Environmental Protection Agency (EPA). 2005. *Clean Air Interstate
Rule Emissions Inventory Technical Support Document*, U.S. Environmental
Protection Agency, Office of Air Quality Planning and Standards, March
2005. Available at <http://www.epa.gov/cair/pdfs/finaltech01.pdf>.

U.S. Environmental Protection Agency (EPA). 2006a. Air Quality Criteria
for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-05/004aF-cF.

U.S. Environmental Protection Agency (EPA). 2006b. "Regulatory Impact
Analysis for the Review of the Particulate Matter National Ambient Air
Quality Standards (Chapter 2: Defining the PM~2.5~ Air Quality
Problem)." EPA-HQ-OAR-2006-0834-0048.3.

U.S. Environmental Protection Agency (EPA). 2007a. Review of the
National Ambient Air Quality Standards for Ozone: Policy Assessment of
Scientific and Technical Information. OAQPS Staff Paper. North Carolina.
EPA-452/R-07-003.

U.S. Environmental Protection Agency (EPA). 2007b. "Guidance on the Use
of Models and Other Analyses for Demonstrating Attainment of Air Quality
Goals for Ozone, PM~2.5~, and Regional Haze." EPA-454/B-07-002,
<http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf>.

U.S. Environmental Protection Agency (EPA). 2007c. *Regulatory Impact
Analysis for Final Rule: Control of Hazardous Air Pollutants from Mobile
Sources*, U.S. Environmental Protection Agency, Office of Transportation
and Air Quality, Assessment and Standards Division, Ann Arbor, MI 48105,
EPA420-R-07-002, February 2007. Available at
<http://www.epa.gov/otaq/regs/toxics/420r07002.pdf>.

U.S. Environmental Protection Agency (EPA). 2007d. *National Scale
Modeling for the Final Mobile Source Air Toxics Rule*, Office of Air
Quality Planning and Standards, Emissions Analysis and Monitoring
Division, Research Triangle Park, NC 27711, EPA 454/R-07-002, February
2007. Available at <http://www.epa.gov/otaq/regs/toxics/454r07002.pdf>.

U.S. Environmental Protection Agency (EPA). 2007e. *Draft Regulatory
Impact Analysis: Control of Emissions of Air Pollution from Locomotive
Engines and Marine Compression-Ignition Engines Less than 30 Liters per
Cylinder, Chapter 3: Emission Inventory*, U.S. Environmental Protection
Agency, Office of Transportation and Air Quality, Assessment and
Standards Division, Ann Arbor, MI 48105. EPA420-D-07-001, March 2007.
Available at <http://www.epa.gov/otaq/regs/nonroad/420d07001chp3.pdf>.

U.S. Environmental Protection Agency (EPA). 2007f. *Guidance for
Estimating VOC and NOx Emission Changes from MACT Rules,* U.S.
Environmental Protection Agency Office of Air Quality Planning and
Standards, Air Quality Policy Division, Research Triangle Park, NC
27711, EPA-457/B-07-001, May 2007. Available at
<http://www.epa.gov/ttn/naaqs/ozone/o3imp8hr/documents/guidance/200705_epa457_b-07-001_emission_changes_mact_rules.pdf>.

U.S. Environmental Projections Agency (EPA). 2008a. Air Quality Modeling
Platform for the Ozone National Ambient Air Quality Standard Final Rule
Regulatory Impact Assessment.

U.S. Environmental Projections Agency (EPA). 2008b. Technical Support
Document: Preparation of Emissions Inventories For the 2002-based
Platform, Version 3, Criteria Air Pollutants, USEPA, January, 2008.

Yantosca, B. 2004. GEOS-CHEMv7-01-02 User's Guide, Atmospheric Chemistry
Modeling Group, Harvard University, Cambridge, MA, October 15, 2004.

[^1]: U.S. EPA. Final Regulatory Impact Analysis: Control of Emissions
    from Nonroad Diesel Engines. EPA420-R-04-007. May 2004.

[^2]: <http://www.epa.gov/interstateairquality/pdfs/finaltech02.pdf>,
    Table VI-2.

[^3]: U.S EPA. 2007. Review of the National Ambient Air Quality
    Standards for Ozone: Policy Assessment of Scientific and Technical
    Information. OAQPS Staff Paper. North Carolina. EPA-452/R-07-003.

[^4]: See CMAQ references listed at end of this chapter.

[^5]: Additional documentation on the updates in CMAQ version 4.6 can be
    found at the following web site: http://www.cmascenter.org/.