& EPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park, NC 27711
EPA-452/R-92-005
October 1992
Air
GUIDANCE ON THE ADJUSTED
BASE YEAR EMISSIONS
INVENTORY AND THE
1996 TARGET FOR THE
15 PERCENT
RATE OF PROGRESS PLANS
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Guidance on the Adjusted Base
Year Emissions Inventory and the
1996 Target for the 15 Percent
Rate-of-Progress Plans
Ozone/Carbon Monoxide Programs Branch
U.S. Environmental Protection Agency
Office of Air Quality Planning and
Standards
Research Triangle Park, NC 27*711
U S Environmental Protection Agency
Region 5, Library (P1.12J)
77 West Jackwn Boulevard,
Chicago, ti 60604-3590
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Guidance on the Adjusted Base
Year Emissions Inventory and the
1996 Target for the 15 Percent
Rate-of-Progress Plans
Ozone/Carbon Monoxide Programs Branch
U.S. Environmental Protection Agency
Office of Air Quality Planning and
Standards
Research Triangle Park, NC 27711
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TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS V
LIST OF TABLES vi
LIST OF FIGURES vii
ACRONYMS AND ABBREVIATIONS viii
EXECUTIVE SUMMARY 1
1.0 INTRODUCTION 5
1 .1 Purpose 6
1 .2 Background 7
1.3 Organization of Report 8
2.0 CALCULATION OF THE 1996 TARGET 9
2.1 Calculation of the 1990 Adjusted Base Year
Inventory 9
Mobile Source Adjustments 12
RACT Rule Corrections 14
I/M Program Corrections 15
2.2 1996 Target Level of'Emissions 15
2.3 Requirements of Section 1 82 (b) (1) (A) (ii) 17
2.4 Emissions Factor Adjustments 17
•3.0 RATE-OF-PROGRESS PLAN ELEMENTS 19
3.1 Base Year Inventory , . 20
Guidance Documents for Preparing Base Year
Inventory 20
Documentation Requirements of Base Year Inventory . 22
3.2 Additional Rate-of-Progress Plan Elements 22
1990 Rate-of-Progress Base Year Inventory 23
1990 Adjusted Base Year Inventory 23
Required 15 Percent Reductions 24
Total Expected Reductions 24
Target Level for 1996 25
Economic Activity and Growth: Determinants and
Indicators 25
Control Measures/Factors . . 26
3.3 Attainment Demonstration 28
4.0 CREDITABILITY OF EMISSIONS REDUCTIONS 29
4.1 RACT Programs 30
RACT Fix-Ups 30
RACT Catch-UpS 31
4.2 Inspection and Maintenance Programs 32
4.3 Preenactment Banked Emissions Reduction Credits . . 32
4.4 Maximum Achievable Control Technology (MACT)
Standards 34
General Requirements 34
Early Reductions Program 34
4.5 Rule Effectiveness Improvements 35
- iii
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5.0 PREVIEW OF THE DEVELOPMENT OF EMISSIONS PROJECTIONS,
CONTROL STRATEGY, AND 1996 MILESTONE COMPLIANCE
DEMONSTRATION 37
•REFERENCES 39
APPENDIX A: DEFINITION OF TERMS A-1
APPENDIX B: CALCULATION OF EMISSIONS REDUCTIONS FROM RACT
RULE CORRECTIONS B-1
APPENDIX C: CALCULATION OF EMISSIONS REDUCTIONS FROM I/M
PROGRAM CORRECTIONS C-1
IV
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ACKNOWLEDGEMENTS
This report was prepared by Andrew D. Bollman and Randy
Strait of E.H. Pechan and Associates, Inc. of Durham, North
Carolina. The work was conducted under EPA Contract No. 68-DO-
0120, Work Assignment No. 2-43; with contributions from the
following EPA Offices: Ozone/Carbon Monoxide Programs Branch and
Emission Inventory Branch of the Office of Air Quality Planning
and Standards, and the Emission Planning and Strategies Division
of the Office of Mobile Sources.
v
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LIST OF TABLES
•Number Page
1. PROJECTION AND CONTROL FACTOR FORMATS 27
A-1. MAJOR SOURCE THRESHOLDS AND MINIMUM EMISSIONS OFFSET
RATIO REQUIREMENTS FOR OZONE NONATTAINMENT AREA
CLASSIFICATIONS A-3
C-1. INSPECTION AND MAINTENANCE (I/M) PROGRAM INPUTS . . . . C-1
VI
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LIST OF FIGURES
Number Page
Figure 1. Flow chart for rate-of-progress calculations. . . 10
Figure 2. Flow chart for example rate-of-progress
calculations 16
Figure 3. Example of use of preenactment banked emissions
credits 33
VII
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ACRONYMS AND ABBREVIATIONS
Act
AFS
AIRS
AMS
BEA
CAAA
CO
•CTG
EKMA
EPA
FIPS
FMVCP
FR
gal
I/M
Ib
MACT
NAAQS
NOX
OCS
psi
RACT
RFP
ROM
RVP
SIP
SSCD
tpy
UAM
VMT
VOC
Clean Air Act
AIRS Facility Subsystem
Aerometric Information Retrieval System
AIRS Area and Mobile Source Subsystem
Bureau of Economic Analysis
1990 Clean Air Act Amendments
Carbon Monoxide
Control Technique Guideline
Empirical Kinetic Modeling Approach
U.S. Environmental Protection Agency
Federal Information Processing Standards
Federal Motor Vehicle Control Program
Federal Register
gallon(s)
Inspection and Maintenance
pound(s)
Maximum Achievable Control Technology
National Ambient Air Quality Standard(s)
Nitrogen Oxides
Outer Continental Shelf
pounds per square inch
Reasonably Available Control Technology
Reasonable Further Progress
Regional Oxidant Modeling
Reid Vapor Pressure
State Implementation Plan
Stationary Source Compliance Division
tons per year
Urban Airshed Model
vehicle miles traveled
Volatile Organic Compound(s)
VI11
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EXECUTIVE SUMMARY
Section 182(b)(1) of the Clean Air Act (Act) Amendments of
1990 (CAAA) requires all ozone nonattainment areas classified as
moderate and above to submit a State implementation plan (SIP)
revision by November 15, 1993, which describes, in part, how the
areas will achieve an actual emissions reduction of at least
15 percent during the first 6 years after enactment of the CAAA
(November 15, 1996). The portion of the SIP revision that
illustrates the plan for the achievement of this emissions
reduction is subsequently defined in this document as the "rate-
of-progress plan."
The focus of this guidance document is on the requirements
due November 1992 relative to the rate-of-progress plan,
including adjustments that must be made to the base year (1990)
emissions inventories. This document clarifies guidance provided
in an August 7, 1992 memorandum from Mr. J. David Mobley, Chief,
Emissions Inventory Branch, to U.S. Environmental Protection
Agency (EPA) Regional Chiefs, regarding "November 15, 1992,
Deliverables for RFP and Modeling Emission Inventories."
Section 182(a)(1) of the CAAA requires all nonattainment
•areas to submit within 2 years of enactment (November 15, 1992),
a comprehensive, accurate, and current inventory of ozone season
typical weekday emissions from all sources. State agencies are
responsible for the development of this "base year inventory."
Draft base year inventories were scheduled to be submitted to EPA
during the period of January'1 to May 1, 1992. Final base year
inventories, which incorporate comments from EPA's review of the •
draft inventory, and draft adjusted base year inventories,
described in this guidance document, are due no later than
November 15, 1992.
This document assists States in determining the 1996 target
- level of emissions under the rate-of-progress plan requirement
for moderate and above ozone nonattainment areas. States will
use this target emissions level in determining what strategies
will be necessary to control emissions so that the nonattainment
area will comply with the 15 percent volatile organic compounds
CVOC) emissions reduction requirement. This document uses an
example 1996 target emissions calculation to describe the
procedures that States should follow to calculate the 1996 target
level. It also describes EPA's documentation requirements for
the November 1992 submittals relative to the rate-of-progress
.plan. The schedule for rate-of-progress plan deliverables is
listed below:
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November 1992:
• Final 1 990 base year inventory..1
• 1990 rate-of-progress base year inventory (limited
to nonattainment area and excluding biogenic
emissions).2
Initial 1990 adjusted base year inventory.3
Required 15 percent reductions.3
Total expected reductions by 1996.3
Target level for 1996.3
Growth factors for developing projected rate-of-
progress and attainment modeling inventories.3
CAAA mandated control measures and their
associated control efficiencies.3
1 States must allow for public review of the base year inventories
if they are to be used in a regulatory exercise such as rate-of-
progress plans, attainment demonstrations, or maintenance plans.
While 1990 base year inventories must be submitted to EPA by
November 15, 1992, EPA will allow the public review process to
occur after this date (because of the length of time generally
required for scheduling and completing the public review
process). If public review is held after the November 15
submittal, then prior to November 15, 1993, and prior to
application in any regulatory activities, the inventory must be
revised to reflect responses to public review comments.
2The rate-of-progress inventory is a subset of the final 1990
base year inventory and should be identified within the base year
inventory documentation. This means that within the base year
inventory submittal, emissions from anthropogenic sources (i.e.,
.excluding biogenics) within the nonattainment area (excluding
sources within the 25-mile buffer zone and sources in a model
domain but outside of the nonattainment area) should, be
identified. This can be accomplished by summarizing emissions in
the inventory for nonattainment area anthropogenic sources and
then summarizing emissions for all other sources. Thus, the
rate-of-progress inventory should be submitted as part of the
1990 base year inventory package due by November 15, 1992.
3The EPA stated in an August 7, 1992 memorandum from Mr. J. David
Mobley, Chief, Emission Inventory Branch, to EPA Regional Office
Chiefs, regarding "November 15, 1992, Deliverables for RFP and
Modeling Emission Inventories," that these items (initial 1990
adjusted base year inventory through remaining items under
November 1992) are required by November 15, 1992. If, however, a
State will be submitting a full draft 15 percent rate-of-progress
plan for public review in early 1993 (i.e., no later than March
1993), they may wait and submit the draft plan to EPA at the
beginning of the public review period rather than submitting
these items in November 1992. Please note, however, that for
areas involved in regional oxidant modeling (ROM) exercises,
growth and control factors need to be submitted to EPA by
November 15, 1992.
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May 1993:
• Draft 1996 projected emissions inventory with
controls.
November 1993:
• Fully adopted rate-of-progress plan, .including
attainment demonstration for moderate areas not
using the urban airshed model (UAM).
Various reductions will result from implementation of the
1990 CAAA. Some of these reductions are creditable toward the
15 percent VOC emissions reduction requirements while others are
not creditable. This document incorporates a review of the
creditability of emissions control programs mentioned in the
CAAA. This discussion assists States in planning a control
•strategy to meet the 1996 target emissions level. All real,
permanent, and enforceable post-1990 VOC emissions reductions are
creditable toward the 15 percent requirement except for
reductions resulting from the following:
1. The Federal motor vehicle control program (FMVCP)
tailpipe or evaporative standards promulgated prior to
1990.
2. Federal regulations specifying Reid vapor pressure
(RVP) limits for nonattainment areas (55 FR 23666, June
11, 1990).
3. State regulations required under section 182(a)(2)(A)
to correct deficiencies in existing reasonably
available control technology (RACT) rules.
4. State regulations required under section 182(a)(2)(B)
to establish an inspection and maintenance (I/M)
program or correct deficiencies in existing I/M
programs.
Finally, this document provides a brief preview of the
development of emissions projections and control strategies,
along with a discussion of the 1996 milestone compliance
demonstration. The EPA is not requiring that a complete draft
control strategy be included in the rate-of-progress plan until
May 1993. However, CAAA mandated control measures and their
associated control efficiencies are required in November 1992;
additional control measures to meet the 15 percent emissions
reduction requirement are encouraged, but not required for the
November 1992 submittal. Guidance for the May and November 1993
submittals will be released in the fall of 1992.
The EPA may require States to make corrections to the final
1990 base year, 1990 rate-of-progress base year, initial 1990
adjusted base year inventories, as well as the 1996 target level
of emissions. These corrections will only be required if
emissions factors or methodologies change significantly, and
these changes occur before such time that it is impossible for
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States to make adjustments to their 15 percent emissions
reduction calculations and associated control strategies. For
example, a revised MOBILE model (MOBILES.0) is due for release
this fall. Its use will not be required in the November 1992
submittal, but will be required in the November 1993 submittal.
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1 .0 INTRODUCTION
Section 182(b)(1) of the CAAA requires all ozone
nonattainment areas classified as moderate and above to submit a
SIP revision by November 15, 1993, which describes, in part, how
the areas will achieve an actual emissions reduction of at least
15 percent during the first 6 years after enactment of the CAAA
(November 15, 1996). Emissions and emissions reductions shall be
calculated on a typical weekday basis for the "peak" 3-month
ozone period (generally June through August). The 15 percent VOC
emissions reduction required by November 15, 1996 is defined
within this document as "rate of progress."4 Furthermore, the
portion of the SIP revision that illustrates the plan for the
achievement of the emissions reduction is subsequently defined in
this document as the "rate-of-progress plan."
Additionally, States with intrastate moderate ozone
nonattainment areas will generally be required to submit
attainment demonstrations with their SIP revisions due by
November 15, 1993 (such areas choosing to use the UAM to prepare
their attainment demonstrations will be allowed to submit
attainment demonstrations by November 15, 1994). States choosing
to run UAM for their intrastate moderate areas must submit their
15 percent rate-of-progress plan and a committal SIP addressing
the attainment demonstration. The committal SIP subject to a
section 110(k)(4) approval would include, at a minimum, evidence
that grid modeling is well under way and a commitment, with
schedule, to complete the modeling and submit it as a SIP
revision by November 1994. The completed attainment
demonstration would include any additional controls needed for
attainment.
It.is important to note that section 182(b)(1) also requires
the SIP for' moderate areas to provide for reductions in VOC and
nitrogen oxide (NOX) emissions "as necessary to attain the
national primary ambient air quality standard for ozone" by
4The EPA recognizes that the CAAA term, both the 15 percent VOC
emissions reduction requirement of section 182(b)(1) and the
section 182(c)(2)(B) requirement for 3 percent per year VOC
emissions reductions averaged over each consecutive 3-year period
from November 15, 1996 until the attainment date, as reasonable
further progress requirements. However, because the CAAA require
SIP revisions for the 15 percent reduction to be submitted in
1993 and SIP revisions for the 3 percent per year reductions to
be submitted in 1994, EPA believes that it would be clearer,
within the context of both the 15 percent rate-of-progress plan
and the post-1996 rate-of-progress plan guidance documents that
EPA is producing, to create distinct labels for these two
seemingly similar reductions. The 1994 SIP revisions describing
the requirement for 3 percent VOC emissions reductions averaged
over each consecutive 3-year period from November 15, 1996 until
the attainment date, constitute the post-1996 rate-of-progress
plan.
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November 15, 1996. This requirement can be met through the use
of EPA-approved modeling techniques and the adoption of any
additional control measures beyond those needed to meet the
15 percent emissions reduction requirements.
Section 182(c)(2) requires all ozone nonattainment areas
classified as serious and above to submit a SIP revision by
'November 15, 1994 which describes, in part, how each area will
achieve additional VOC emissions reductions of 3 percent per year
averaged over each consecutive 3-year period from November 15,
1996 until the area's attainment date. It is important to note
that section 182(c)(2)(C) allows for actual NOX emissions
reductions (exceeding growth) that occur after the base year of
1990 to be used to meet post-1996 emissions reduction
requirements for ozone nonattainment areas classified as serious
and above, provided that such NOX reductions meet the criteria
outlined in forthcoming substitution guidance. The portion of
the SIP revision (due in 1994) that illustrates the plan for the
achievement of these post-1996 reductions in VOC or NOX is
subsequently defined in this document as the "post-1996 rate-of-
progress plan." This plan must also contain an attainment
demonstration based on photochemical grid modeling. The EPA will
distribute a separate guidance document on the development of the
post-1996 rate-of-progress plan in early 1993,
Demonstrating achievement of the 15 percent VOC emissions
reductions by November 15, 1996, and then subsequently
demonstrating achievement of the 3 percent per year VOC emissions
reductions averaged over each consecutive 3-year period from
'November 15, 1996 until the attainment date, are termed milestone
demonstrations. Achievement of the milestones must be
demonstrated within 90 days of the milestone date (i.e., the
15 percent VOC emissions reductions must be demonstrated by
February 13, 1997). Rules regarding the development of the
milestone demonstrations will be promulgated in the summer of
1993 and will address the timing problem of developing a full
emissions inventory to meet the milestone demonstration
requirement.
1.1 Purpose
The purpose of this document is to provide guidance on the
calculation and presentation of the adjusted base year inventory
and the 1996 target level of emissions. The 1996 target
emissions "level facilitates planning for the 15 percent VOC
emissions reduction requirement. This guidance document alerts
the reader to special circumstances regarding emissions
inventories and emissions estimates that should be considered
during the development of the rate-of-progress plan, including
the procedures to follow in adjusting the 1990 base year
inventory to calculate the 1996 target level of emissions. It
•also provides information on the creditability of emissions
reductions for various control programs. This document assists
States in preparing the required information in the proper
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States in preparing the required information in the proper
format. Finally, this guidance presents an example 1996 target
emissions calculation.
It is important to note that the scope of this document
comprises the preparation of the November 1992 rate-of-progress
plan deliverables. Therefore, it does not discuss the May and
November 1993 submittals that involve the calculation of the
projected 1996 inventory and development of the control strategy.
A separate guidance document entitled, "Growth Factors,
Projections, and Control Strategies," will discuss these topics
as they relate to the 1993 submittals. The EPA will publish the
requirements for the 1996 milestone demonstration in a rulemaking
expected in the summer of 1993.
This document addresses many programs and procedures that
are more fully addressed in other guidance documents. This
guidance does not supersede these other guidance documents;
rather, it intends to pull together the relative material
pertaining to the development of the rate-of-progress plan.
1.2 Background
Facilities, States, and the EPA currently estimate emissions
for various purposes. Under the CAAA, facilities have new
requirements in terms of permits, annual emissions statements,
and compliance certifications. State agencies are currently
responsible for the production of a base year emissions
inventory, periodic inventories, and annual aerometric
information retrieval system (AIRS) facility subsystem (AFS)
inventories. The EPA develops and utilizes emissions estimates
and emissions inventories in virtually all of their air programs.
The focal point for this guidance document is adjusting the 1990
base year inventory for the rate-of-progress SIP revision.
The 1990 base year- inventory emissions are reported on an
annual and seasonal basis. For determination of the 15 percent
VOC emissions reduction, emissions are based on typical ozone
season weekday emissions. For the base year inventory, these
emissions are measured for a typical weekday during the 1990 peak
ozone season. The peak ozone season is the contiguous 3-month
period for which the highest ozone exceedance days have occurred
in the previous 3 to 4 years. The EPA's focus on typical ozone
season weekday VOC emissions (an interpretation of the definition
in section 182(b)(l)(B) of baseline actual emissions during the
"calendar year" of enactment) is consistent with prior EPA
guidance. This stems from the fact that the ozone national
ambient air quality standard (NAAQS) is an hourly standard that
is generally violated during ozone season weekdays when
conditions are conducive for ozone formation. These ozone
seasons are typically the summer months.
With the 15 percent VOC emissions reduction, moderate
nonattainment areas are generally expected to be able to attain
the ozone NAAQS within the applicable timeframe. Therefore, the
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base program that all areas classified as moderate and above
nonattainment must meet is the 15 percent rate-of-progress
reduction. In cases where modeling shows VOC emissions
reductions greater than 15 percent and/or NOX reductions are
necessary to attain the standard, additional emissions reductions
will be required on a schedule that is sufficient to meet the
attainment deadline. Section 182(c)(2)(C) allows for actual NOX
emissions reductions (exceeding growth) that occur after the base
year of 1990 to be used to meet post-1996 emissions reduction
requirements for ozone nonattainment areas classified as serious
and above. Therefore, it is recommended that State agencies
track the actual NOX emissions reductions occurring between 1990
and 1996. More specific guidance regarding NOX substitutions is
currently under development within the EPA.
1.3 Organization of Report
The organization of this report is as follows. Section 2 of
this document provides a sample calculation of the 1996 target
level of emissions. Section 3 of this document presents the
rate-of-progress plan elements. This section highlights
information on documenting the adjustments to the 1990 base year
inventory for calculation of the 1996 target level of emissions.
Section 4 of this document discusses the creditability of
emissions reductions from various programs to the 15 percent
requirement. The final section of this document provides a
preview of the development of emissions projections, the control
strategy, and the milestone demonstration that is due in 1997.
Appendix A of this document provides a list of definitions for
EPA terms used throughout this document. Appendix B describes
the calculation of emissions reductions from RACT rule
corrections, and Appendix C outlines this procedure for I/M
program corrections.
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2.0 CALCULATION OF THE 1996 TARGET
To determine their control strategies for achieving the
required VOC emissions reductions, States will need to calculate
the 1996 target level of emissions—the maximum amount of
emissions allowed in 1996 given the rate-of-progress requirement.
Figure 1 provides an overview of how this target level is
derived. Sections 2.1 and 2.2 of this document detail the
calculation of this target using a hypothetical example.
2.1 Calculation of the 1990 Adjusted Base Year Inventory
The CAAA specify the emissions "baseline" from which the
'15 percent reduction is calculated. This baseline value is
termed the 1990 adjusted base year inventory.
Section 182(b)(1)(B) defines baseline emissions (for purposes of
calculating the 15 percent VOC emissions reduction) as "the total
amount of actual VOC or NOX emissions from all anthropogenic
sources in the area during the calendar year of enactment."
Section 182(b)(1)(D) excludes from the baseline the emissions
that would be eliminated by FMVCP regulations promulgated by
January 1, 1990, and RVP regulations (55 FR 23666, June 11,
1990), which require maximum RVP limits in nonattainment areas
during the peak ozone season.
The 1990 base year inventory is first adjusted by removing
all biogenic emissions as well as emissions from sources located
outside of the designated nonattainment boundary (e.g., within
the modeling domain). This inventory, which contains only actual
anthropogenic emissions occurring within the designated
nonattainment boundaries during the base year, is termed the
rate-of-progress base year inventory. The adjusted base year
inventory is derived from the rate-of-progress base year
inventory by removing the expected FMVCP and RVP reductions from
the rate-of-progress base year inventory. Preenactment banked
'emissions credits should not be included in any of these
inventories because they do not represent actual emissions in
1990. The following illustrates the general procedure for
determining the 1990 adjusted base year inventory.
Step 1: Develop the 1990 Base Year Inventory
(includes all emissions within the UAM modeling domain)
Final 1990 Base Year VOC Emissions Inventory
[pounds/day (Ib/day)]
Point Sources 1,000
Area Sources 2,500
Mobile Sources 3,500
Biogenic Sources + 5,000
Total 12,000
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As shown, the first step records the total 1990 base year
inventory emissions from the four emissions source types: point,
area, mobile, and biogenic. The EPA required that the 1990 base
year inventory be submitted by the States in draft form by May
.1992, and in final form by November 15, 1992. However, EPA is
allowing additional time for States to complete the public
hearing process. In the example presented above, the modeling
domain is larger than the nonattainment area boundaries so the
emissions for the modeling domain are presented. Here, the total
point-source inventory is 1,000 Ib/day. Area sources account for
2,500 Ib/day. The 1990 base year mobile source inventory is
3,500 Ib/day. In documenting the base year inventory, States
must also specify which sources and emissions are located within
the nonattainment area and which are not. This is an important
requirement for documenting the inventory, as ozone inventories
will include either point sources outside of the nonattainment
area (in the 25-mile buffer zone) or all sources in the UAM
modeling domain (if UAM modeling is to be performed).
Step 2: Develop 1990 Rate-of-Progress Base Year Inventory for
Nonattainment Area
1990 Rate-of-Progress Base Year Inventory (Ib/day)
Point Sources (-200 from outside nonattainment area) 800
Area Sources (-500 from outside nonattainment area) 2,000
Mobile Sources (-500 from outside nonattainment area) + 3,000
Total 5,800
The second step develops the 1990 rate-of-progress base year
inventory for the nonattainment area. This inventory comprises
the anthropogenic stationary (point and area) and mobile sources
in the nonattainment area; all biogenic emissions are removed
from the base year inventory. In the example presented above,
200 Ib/day, 500 Ib/day, and 500 Ib/day were contributed from VOC
point, area, and mobile sources, respectively, that are located
in the modeling domain but outside of the nonattainment area
boundary. In this example, there were no outer continental shelf
(OCS) sources (any DCS sources that were not located within the
designated nonattainment area would also be removed from the base
year inventory).
Step 3: Develop Adjusted Base Year Inventory
- 1990 Adjusted Base Year Inventory (Ib/day)
Point Sources 800
Area Sources 2,000
Mobile Sources (-FMVCP and RVP — 500) + 2,500
Total 5,300
The third step consists of developing the 1990 adjusted base
year inventory from which the 15 percent reduction is calculated.
11
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First, the mobile source portion of the 1990 rate-of-progress
base year inventory calculated in Step 2 must be adjusted as
•required by section 182(b)(1)(B) and (D) of the CAAA. This
adjustment excludes emissions reductions that would occur by 1996
as a result of the FMVCP promulgated prior to the CAAA. In other
words, the adjusted base year inventory excludes the emissions
reductions that would occur as a result of fleet turnover between
1990 and 1996 even without the CAAA.
The 1990 adjusted base year inventory must also exclude
emissions reductions that would result in 1996 from RVP
regulations promulgated by November 15, 1990, or required under
section 211(h) of the Act. The pertinent regulations (55 FR
23666, June 11, 1990) specify maximum RVP's of 9.0 or 7.8 pounds
per square inch (psi) for each State during the summer months,
beginning in 1992. In other words, the 1990 adjusted base year
inventory must also exclude the emissions reductions that would
occur as a result of the difference between the actual RVP in
place in 1990 and the required 9.0 or 7.8 psi RVP in 1996.
Deleting these mobile source emissions reductions from the
adjusted inventory decreases the adjusted inventory and thus,
also the 15 percent emissions reductions required. However,
these mobile source emissions reductions are fully included in
the total emissions reductions and thus, serve to reduce the
.total emissions allowed (as determined by calculating the target
level of emissions).
The net effect of these adjustments is that States are not
able to take credit for emissions reductions that would result
from fleet turnover of current standard cars and trucks, or from
already existing Federal fuel regulations. However, the SIP can
take full credit for the benefits of any new vehicle emissions
standards, as well as any other new Federal or State motor
vehicle or fuel program that will be implemented in the
nonattainment area, including Tier 1 exhaust standards, new
evaporative emissions standards, reformulated gasoline, enhanced
I/M, California low emissions vehicle program, transportation
control measures, etc.
Mobile Source Adjustments
The mobile source portion of the adjusted base year
inventory is calculated using the MOBILE emissions factor model.
States may use MOBILE4.1 to come up with initial estimates of the
adjusted base year inventory. However, as soon as MOBILES
becomes available, States should switch to MOBILES. MOBILE4.1 or
MOBILES must be run in calendar year 1990, and again for calendar
'year 1996 (the 1996 run must not include any new CAAA measures).
Since MOBILE4.1 does not include new CAAA measures, no change in
modeling assumptions other than RVP is needed for the 1996 run.
MOBILES will have a flag that will run the model using the FMVCP
that was in place in 1990 for any calendar year. This flag will
be documented in the MOBILES User's Guide.
12
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The following description uses MOBILE4.1 for reference. The
method for calculating the expected reductions from the FMVCP and
RVP is the same using MOBILES except that the flag described
above must be set to achieve the projected emissions in 1996 in
the absence of any new CAAA measures. Users must still set the
appropriate RVP as described below.
Actual 1990 emissions =
[1990 vehicle miles traveled (VMT)](MOBILE4.1 emissions factors
from A); and
Adjusted 1990 emissions =
(1990 VMT)(MOBILE4.1 emissions factors from B).
(A) MOBILE4.1 run from the 1990 base year inventory. Emissions
factors from this run will be used with actual 1990 VMT to
calculate actual 1990 emissions; and
(B) MOBILE4.1 run as in the 1990 base year inventory run except
that: 1) 1996 will be used as the evaluation year (this
will change the vehicle mix to account for fleet turnover);
and 2) the RVP is set to 9.0 or 7.8 as appropriate for the
area. Emissions factors from this run and 1990 VMT will be
used to calculate the adjusted 1990 emissions.
Expected Reductions from FMVCP and RVP (1990-1996) =
Actual 1990 emissions - Adjusted 1990 emissions
This is the amount that is subtracted from the mobile source
portion in the "rate-of-progress base year inventory" to get the
mobile source portion of the adjusted base year inventory
.(step 3). For Step 5, this amount will be added to the required
15 percent reductions and other required reductions to calculate
the total reductions from the 1990 baseline that must occur to
comply with CAAA requirements.
In the hypothetical example presented in step 3, the FMVCP
and RVP regulations represent a decrease in emissions of
500 Ib/day. This reduction reflects what the 1990 emissions
would be if the same fleet that is projected to be operating in
1996 were operating in 1990. In addition, the effects of RVP
regulations, which will result in lower evaporative losses, are
factored out, even though the regulations were not necessarily in
force in 1990.
The 1990 motor vehicle baseline emissions, after factoring
out the reductions from the effects of the FMVCP and RVP program,
are then added to the 1990 inventory of nonmotor vehicle
anthropogenic VOC emissions to calculate the 1990 adjusted base
year inventory. This composite emissions inventory, an
aggregated total, is the inventory used to calculate the required
15 percent emissions reductions. In the example presented above,
emissions for the 1990 adjusted base year inventory total
5,300 Ib/day.
13
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Step 4: Calculate required (15 percent) creditable reductions
15 percent = 5,300 x 0.15 = 795 Ib/day
For Step 4, the adjusted base year inventory is multiplied
by 0.15 to calculate the amount of the required 15 percent
emissions reduction.
Step 5: Calculate total expected reductions by 1996
Total Expected Reductions by 1996 (Ib/day)
Required 15 percent 795
Expected Reductions from 500
FMVCP and RVP (1990-1996)
Corrections to RACT Rules 305
Corrections to I/M Programs + 200
Total 1,800
In the fifth step, the total required reductions from the
1990 rate-of-progress base year inventory are calculated. The
total reductions comprise the reductions necessary to meet the
15 percent requirement and the expected reductions from the
noncreditable programs (RVP, pre-CAAA FMVCP, RACT rule
corrections, and I/M program corrections). Corrections to RACT
.rules and I/M programs are discussed below. In the above
example, the emissions reductions expected to result from the
corrections to RACT rules are 305 Ib/day, and the emissions
reductions expected to result from corrections to the I/M program
are 200 Ib/day. The total expected reductions by 1996 from the
nonattainment area (i.e., prior to growth) are 1,800 Ib/day
(step 5).
RACT Rule Corrections
Section 4.1 of this document discusses cases where RACT rule
corrections do not directly result in quantifiable emissions
reductions. Any incidental reductions that occur in these
instances may be handled as part of a rule effectiveness
improvement. Corrections to RACT rules that may result in
additional, enforceable, and quantifiable emissions reductions
include situations where either:
• A rule was missing (i.e., a State committed to
develop a rule as part of its 1977 SIP, or post-
1982 SIP, but never carried through on the
commitment prior to the CAAA).
• The limit was wrong.
• A capture system is now required.
Reductions from these types of RACT rule corrections are not
creditable toward the 15 percent VOC emissions reduction
14
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requirement. However, the amount of emissions reductions from
these corrections should be calculated, as they are part of the
total reductions from the 1990 rate-of-progress base year
inventory that are required by the CAAA. Appendix B describes
the methods for estimating the amount of these noncreditable
emissions reductions.
I/M Program Corrections
Corrections to I/M programs are necessary when either:
.(1) the area's I/M program does not meet the reductions achieved
by EPA's minimum requirements, or (2) an area's program does not
meet the standards of its current SIP. The calculation of the
emissions reductions associated with I/M program corrections
requires two MOBILE4.1 runs (or MOBILES when it becomes
available). Appendix C presents the methods for calculating the
emissions reductions from I/M program corrections.
2.2 1996 Target Level of Emissions
The final step is to calculate the 1996 target level of
emissions for planning purposes.
Step 6: Set target level for 1996
To calculate the 1996 target emissions level, the total
reductions from Step 5 are subtracted from the 1990 rate-of-
progress base year inventory for the nonattainment area. The
1996 target level of emissions is 4,000 Ib/day as shown below.
Target Level = Step 2 - Step 5
= 1 990 Rate-of-Progress Base Year
Inventory For Nonattainment Area - Total
Reductions
5,800 Ib/day - 1,800 Ib/day
4,000 Ib/day
Figure 2 provides an overview of the steps followed in
calculating the example 1996 target level of emissions.
It is important to note that although moderate and higher
nonattainment area classifications are required to provide a
rate-of-progress plan describing how a 15 percent VOC emissions -
reduction will be achieved between 1990 and 1996, moderate areas
are not required to show that they have met the 15 percent
emissions reduction requirement. Instead, they are required to
show that they have attained the NAAQS as of November 15, 1996.
Moderate areas must, therefore, plan for and implement a
control strategy that will result in attainment. If, for
example, modeling for the attainment demonstration shows that an
18 percent VOC emissions reduction will be necessary for a
particular moderate area to attain by 1996, then the State should
plan for and include control measures in their SIP submittal to
15
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reach this 18 percent reduction. These States need to track the
post-implementation emissions using the modeled attainment
•percentage rather than the 15 percent rate-of-progress
requirement.
2.3 Requirements of Section 182(b)(1)(A)(ii)
Nonattainment areas can achieve less than the 15 percent
required reductions under the following restrictive
circumstances. The State must demonstrate that the area has a
new source review program equivalent to the requirements in
extreme areas [section 182(e)]/ except that "major source" must
include any source that emits, or has the potential to emit,
5 tons per year (tpy) of VOC or NOX. Additionally, all major
sources of VOC and NOX (down to 5 tpy) in the area must be
required to have RACT-level controls. In light of technological
achievability, the State's plan must also include all mobile and
stationary source control measures that can be feasibly
implemented in the area. In addition, the State must demonstrate
that the area's plan includes the measures that are achieved by
sources in the same source category in nonattainment areas of the
next higher classification. More detailed guidance on this
showing will be provided in forthcoming EPA guidance expected in
the fall of 1992 regarding the development of control strategies
.for the rate-of-progress demonstration plan.
2.4 Emissions Factor Adjustments
Emissions factors, as well as inventory calculation
methodologies, are continually being improved. If emissions
factors or methodologies change significantly, the EPA may advise
the States to correct the base year emissions inventory to
reflect such changes. The release of a revised MOBILE model
(MOBILES.0) is pending. The use of MOBILES.0 is not required for
the SIP submittal due in November 1992. Any emissions values
calculated using MOBILE4.1 will have to be recalculated before
submittal of the final rate-of-progress plan in November 1993.
If other significant changes occur in emissions factors or
methodologies before which time it is impossible for States to
make adjustments to their 15 percent calculations and associated
control strategies, then EPA may require States to make
corrections to the base year emissions inventory, as well as to
the adjusted base year inventory and the 1996 target level of
emissions. Such corrections would be made prior to the submittal
of any subsequent rate-of-progress demonstration.
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3.0 RATE-OF-PROGRESS PLAN ELEMENTS
Required submittals for the rate-of-progress plan will be
staggered to allow additional time for the control strategy
development process. The dates and specific elements that are
required for these submittals are listed below:
November 1992:
• Final 1990 base year inventory.5
• 1990 rate-of-progress base year inventory (limited
to nonattainment area and excluding biogenic
emissions).6
• Initial 1990 adjusted base year inventory.7
• Required 15 percent reductions.7
5States must allow for public review of the base year inventories
if they are to be used in a regulatory exercise such as rate-of-
progress plans, attainment demonstrations, or maintenance plans.
While 1990 base year inventories must be submitted to EPA by
November 15, 1992, EPA will allow the public review process to
occur after this date (because of the length of time generally
required for scheduling and completing the public review
process). If public review is held after the November 15
submittal, then prior to November 15, 1993, and prior to
application in any regulatory activities, the inventory must be
revised to reflect responses to public review comments.
6The rate-of-progress inventory is a subset of the final 1990
base year inventory and should be identified within the base year
inventory documentation. This means that within the base year
inventory submittal, emissions from anthropogenic sources (i.e.,
excluding biogenics) within the nonattainment area (excluding
sources within the 25-mile buffer zone and sources in a model
domain but outside of the nonattainment area) should be
identified. This can be accomplished by summarizing emissions in
the inventory for nonattainment area anthropogenic sources and
.then summarizing emissions for all other sources. Thus, the
rate-of-progress inventory should be submitted as part of the
1990 base year inventory package due by November 15, 1992.
7The EPA stated in an August 7, 1992 memorandum from Mr. J. David
Mobley, Chief, Emission Inventory Branch, to EPA Regional Office
Chiefs, regarding "November 15, 1992, Deliverables for RFP and
Modeling Emission Inventories," that these items (initial 1990
adjusted base year inventory through remaining items under
November 1992) are required by November 15, 1992. If, however, a
State will be submitting a full draft 15 percent rate-of-progress
plan for public review in early 1993 (i.e., no later than March
1993), they may wait and submit the draft plan to EPA at the
beginning of the public review period rather than submitting
these items in November 1992. Please note, however, that for
areas involved in ROM exercises, growth and control factors need
to be submitted to EPA by November 15, 1992.
19
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• Total expected reductions by 1996.7
Target level for 1996.7
• Growth factors for developing projected rate-of-
progress and attainment modeling inventories.7
• CAAA mandated control measures and their
associated control efficiencies.7
May 1993:
• Draft 1996 projected emissions inventory with
controls.
November 1993:
• Fully adopted rate-of-progress plan, including
attainment demonstration for moderate areas not
using the UAM.
Each of the items required for the November 1992 submittal are
described in this section. Subsequent rate-of-progress plan
submittals are discussed briefly in section 5.0 of this document.
Further details on these elements will be provided in the
document entitled, "Growth Factors, Projections, and Control
Strategies," to be issued in the fall of 1992.
3.1 Base Year Inventory
Section 182(a)(1) requires all nonattainment areas to submit
a comprehensive, accurate, and current inventory of actual
emissions from all sources by November 15, 1992. This inventory
is for calendar year 1990 and is identified as the base year
inventory. It includes anthropogenic sources of NOX and carbon
monoxide (CO) emissions, as well as anthropogenic and biogenic
sources of VOC. The base year inventory includes actual VOC,
NOX, and CO emissions for the area on both an annual basis
(except for on-road mobile sources and biogenics) and a typical
weekday basis during the peak ozone season, which is generally
the summer months. All stationary and mobile sources within the
nonattainment area, and stationary sources with emissions of
100 tpy or greater of VOC, NOX, and CO emissions within a 25-mile
wide buffer of the designated nonattainment area, must be
included in the compilation. Including sources within a 25-mile
buffer is necessary to ensure that all sources capable of
affecting air quality within the nonattainment area are
adequately accounted for in modeling demonstrations and strategy
development. For nonattainment areas that will perform
.photochemical grid modeling (e.g., serious and above areas and
multi-State moderate areas), emissions for the entire modeling
domain are required in the base year inventory.
Guidance Documents for Preparing Base. Year Inventory
Guidance documents are available from EPA that specifically
pertain to the calculation and presentation of the 1990 base year
inventory for the purpose of ozone nonattainment area SIP
20
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development. Guidance related to the requirements for the 1990
base year inventory is available in the following document:
• Emission Inventory Requirements for Ozone State
Implementation Plans. (See reference 1.)
Guidance specific to inventorying stationary sources is available
in:
• Procedures for the Preparation of Emission Inventories
for Carbon Monoxide and Precursors..of Ozone. Volume I:
General Guidance for Stationary Sources. (See reference
2.)
For mobile sources the primary guidance documents include:
• Procedures for Emission Inventory Preparation. Volume
IV; Mobile Sources. (See reference 3.)
• User's Guide to MOBTLE4.1. (See reference 4.)
• VMT Forecasting and Tracking Guidance. (See reference
5.)
Guidance specific to inventorying biogenic sources is available
in:
• Personal Computer Version of the Biogenic Emissions
Inventory System (PC-BEIS) And User's Guide. (See
reference 6.)
Other guidance documents related to the 1990 inventory are:
• Procedures for the Preparation of Emission Inventories
for Carbon Monoxide and Precursors of Ozone. Volume
II: Emission Inventory Requirements for Photochemical
Air Quality Simulation Models. (See reference 7.)
• Guidance for the _Preparation of Quality Assurance Plans
for 03/CO SIP Emission Inventories. (See reference 8.)
Quality Review Guidelines for 1990 Base Year Emission
Inventories. (See reference 9.)
• Example Documentation Report for 1990 Base Year Ozone
and Carbon Monoxide State Implementation Plan Emission
Inventories. (See reference 10.)
Guidelines for Estimating and Applying Rule
Effectiveness for Ozone/CO State Implementation Plans.
(See reference 11.)
21
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Documentation Requirements of Base Year Inventory
States must provide their base year inventory information in
both written and computerized formats. Adequate documentation on
the source of the emissions estimates is required in the
submission of the final base year inventory. This documentation
will facilitate the milestone compliance determination and any
necessary emissions estimate recalculations during the
implementation of the SIP. Requirements and guidance for
documentation of the base year inventory are presented in
Emission Inventory Requirements for Ozone State Implementation
Plans (EPA-450/4-91-010) and Example Documentation Report for
1990 Base Year Ozone and Carbon Monoxide State Implementation
Plan Emission Inventories (EPA 450/4-92-007).
The written presentation of emissions inventory information
has to be extensive enough for EPA to reproduce the emissions
inventory elements that are submitted. The EPA's primary concern
is that all inventory elements address the crucial elements
inherent in a good inventory and provide summary data and
documentation that allow the quality of the inventory effort to
be effectively judged. Therefore, the emphasis is on the types
of data that need to be reported and not the specific format in
which they are reported. Inventories not meeting the minimum
data reporting and documentation standards established in these
documents will be deemed unacceptable and returned to the States
for modification before any further technical quality review will
be performed.
Adequate documentation includes all of the information that
is necessary to understand how an emissions estimate was made.
This level of documentation will allow EPA and the States to
determine what the effects would be if some of the data were
revised. For example, to understand the effect of changes in
emissions factors, the State needs to document where the factors
were employed and the supporting data (such as activity data)
that were used in the emissions estimation process.
Some activity data may be revised during the period between
submission of the rate-of-progress plan and the milestone
demonstration (this could include preliminary population data
obtained before the 1990 census data were finalized or VMT
estimates that were later revised using a more sophisticated
model). Therefore, States must document the source of the data
as well as the date or version of the data (and whether the data
are draft or final estimates).
3.2 Additional Rate-of-Progress Plan Elements
Rate-of-progress plan requirements under the CAAA result in
the need to develop two inventories in addition to the base year
inventory: the rate-of-progress base year inventory and the
adjusted base year inventory. The rate-of-progress base year
inventory is an inventory of actual anthropogenic 1990 emissions
for the nonattainment area that is used to track the progress of
22
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the 15 percent reduction plan. The 1990 adjusted base year
inventory, which is also developed for the rate-of-progress plan,
does not contain the expected emissions reductions from the FMVCP
and RVP program from the 1990 rate-of-progress base year
inventory. The required 15 percent reductions are calculated
from this adjusted base year inventory and not the rate-of-
progress base year inventory, thus lowering the States' emissions
reduction burden.
1990 Rate-of-Progress Base Year Inventory
.The 1990 rate-of-progress base year inventory accounts for
the total anthropogenic VOC, CO, and NOX emissions in the
'nonattainment area. The rate-of-progress base year inventory
differs from the 1990 base year inventory in that the rate-of-
progress base year inventory does not include biogenic source
emissions nor emissions from sources located outside of the
nonattainment area, while the base year inventory includes these
emissions (e.g., for point, area, and mobile sources outside of
the nonattainment area but within the UAM domain). States should
document which sources and emissions are located within the
nonattainment area as well as which are located outside of the
nonattainment area. Also, the total biogenic emissions, which
are also removed from the base year inventory, should be listed.
Emissions for anthropogenic sources within the nonattainment area
can be distinguished in the AIRS data set by using the
appropriate retrieval criteria. The rate-of-progress base year
inventory facilitates the calculation of the adjusted base year
inventory.
1990 Adjusted Base Year Inventory
The 1990 adjusted base year inventory is the starting point
for calculating the required 15 percent reductions, and also the
first step in calculating the total expected reductions by 1996
•and the 1996 target level of emissions. The 1990 adjusted base
year inventory does not contain the expected FMVCP (in effect as
of November 15, 1990) and RVP program emissions reductions from
the 1990 rate-of-progress base year inventory. This adjustment
lessens the States' emissions reduction burden, because the
baseline emissions total from which the required 15 percent
reduction is calculated has been lowered.
Documentation of the adjusted base year inventory will take
two distinct forms. The written documentation must include the
expected emissions reductions from the FMVCP and RVP program, as
well as both the actual 1990 motor vehicle emissions using 1990
VMT and MOBILE emissions factors, and the adjusted emissions
using 1990 VMT and the MOBILE emissions factors in calendar year
1996 with the appropriate RVP for the nonattainment area as
mandated by EPA. (See reference 12.) States must provide EPA
with information on how the MOBILE model was run in calculating
the expected emissions reductions from the FMVCP and RVP program.
Section 2.1 of this document provides a description of how the
reductions from these programs are calculated.
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For purposes of the AIRS Area and Mobile Source Subsystem
(AMS) adjusted base year submittal, States must provide the RVP
inputs as required under the CAAA for the nonattainment area, and
run the MOBILE model with a 1996 vehicle mix (the 1990 base year
inventory submittal will contain the actual 1990 motor vehicle
'emissions). Because the calculation of the FMVCP and RVP program
emissions reductions requires two separate runs of the MOBILE
model (see section 2.1 of this document for details), States will
not submit the emissions reductions from these programs directly
into AIRS.
Other requirements for documentation and submittal of the
adjusted base year inventory to AIRS are the same as those for
the 1990 base year inventory. States should realize that there
will be no submittal of an "adjusted" point-source inventory for
AFS because the point-source emissions are not altered in the
calculation of the adjusted inventory from the rate-of-progress
base year inventory. The point-source emissions for both the
rate-of-progress and adjusted base year inventories can,
therefore, be directly retrieved from the 1990 base year
inventory. Stationary area-source emissions are not altered
either. All adjustments apply to mobile source emissions. Base
year and adjusted base year point and stationary emissions are
different because of the different geographic coverage. The AIRS
has a flag to indicate that the emissions are within the
designated nonattainment area boundaries and, therefore, can
separate the point and stationary area-source portions to develop
•portions of these two different inventories.
Required 15 Percent Reductions
The required 15 percent reductions represent the amount of
creditable emissions reductions that must be demonstrated in the
rate-of-progress plan. The amount of these required emissions
reductions is calculated by multiplying the adjusted base year "
inventory by 0.15. The results of the 15 percent emissions
reduction calculation can be documented on a single sheet of
paper as the "required 15 percent reductions."
Total Expected Reductions
In addition to the creditable 15 percent reductions, there
are other emissions reductions that are required under the CAAA.
The "total expected reductions" are the sum of the following:
• 15 percent reductions.
• Expected reductions from the FMVCP (in effect as of
November 15, 1990) and RVP program (1990-1996).
• Reductions from corrections to RACT rules.
• Reductions from corrections to I/M programs.
The expected reductions from the FMVCP and RVP program and any
required corrections to RACT rules and I/M programs, which are
calculated based on the methods described in section 2.1 of this
document, should be documented on paper showing each step,
24
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discussing any assumptions made, and stating the origin of the
numbers used in the calculations.
Target Level for 1996
The target level of emissions for 1996 is the maximum amount
of 1996 anthropogenic emissions within the nonattainment area
that are permitted to occur while complying with the rate-of-
progress requirements. The emissions level is determined by
subtracting the total expected reductions from the 1990 rate-of-
progress base year inventory. The EPA expects the States to
document the target emissions level for 1996 as well as the
calculations made in determining the target. In order to develop
control measures in time to meet the required reductions by 1996,
'States should submit their 1996 target level of emissions to EPA
by November 1992.
The following section provides background on growth factors
and discusses how the growth factors that are required with the
November 1992 SIP submittal should be determined and documented.
Economic Activity and Growth: Determinants and Indicators
Economic activity is a factor influencing the level and form
of anthropogenic pollution. Economic activity levels are
determined by the forces of supply and demand. But emissions are
determined by specific production processes (e.g., xx printing or
yy printing), inputs to those processes (e.g., low solvent versus
...), and the levels of output. With no change in the
utilization of those processes, no additional processes, and no
change in quality or quantity of inputs to those processes, the
relationship of output to emissions seen in the past should be
projected to occur in the future. However, if utilization rates
change, new processes are adopted, or there are input changes,
the relationship between output level and emissions seen in the
past may not be an appropriate assumption for projecting future
• emissions.
Note that growth factors are not included in the
calculations of the 1990 adjusted base year inventory or the 1996
target. Growth factors are needed, however, for the 15 percent
demonstration as part of the rate-of-progress plan that is due on
November 15, 1993 for all moderate and above nonattainment areas.
Growth factors are also needed for the attainment demonstration
that is due on November 15, 1993 for moderate ozone nonattainment
areas using empirical kinetic modeling approach (EKMA), and on
November 15, 1994 for moderate ozone nonattainment areas using
UAM and all serious and above ozone nonattainment areas. States
should include the draft rate-of-progress growth factors in both
computer and written formats to EPA by November 15, 1992. Two
sets of growth factors should be provided. One set is used to
project the growth between 1990 and 1996 for rate-of-progress
plan purposes, and the other set is used to project growth up
through the year of attainment for the attainment demonstration
for modeling purposes. These sets are basically the same for
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moderate areas, which must demonstrate attainment by 1996. The
computer format for the growth factor submittal is presented in
Table 1. Other information that should be included with the list
of growth factors includes: State ID, county ID, zone code (if
the growth factor is to be used for a specific zone within a
county), source category code (either SIC, AFS source
classification code, or AMS source category code), growth factor
reference (e.g., Bureau of Economic Analysis (BEA), plant-
supplied, etc.), and control information discussed below. Any
information not contained in the spreadsheet file (e.g., which
agency submitted the growth information and assumptions made in
preparing the information) should be submitted on paper
accompanying the PC disk).
Well known sources of information and guidance on economic
activity projections include the BEA's Regional Projections to
2040 (see references 13, 14, and 15) and Procedures for Preparing
Emissions Projections (EPA-450/4-91-019). (See reference 16.)
There will be more information forthcoming regarding economic
activity and growth in a separate volume of the rate-of-progress
plan guidance, entitled "Growth Factors, Projections, and Control
Strategies," to be issued in the fall of 1992.
Control Measures/Factors
The CAAA mandated controls and their associated control
efficiencies and rule effectiveness factors for both the rate-of-
progress plan and the attainment demonstration are required in
written and computer diskette (see Table 1) formats by
November 15, 1992. The additional controls required to meet the
15 percent and/or attainment demonstration requirements are
encouraged, but not required for this submittal.
The control measure information consists primarily of a list
of control measures and associated control efficiencies on a
computer diskette file formatted as depicted in Table 1. For
-control measures that will be applied during modeling of
attainment, control information must be reported for the entire
modeling domain, unless measures are specifically limited to the
nonattainment area. Supplied control information for attainment
year strategies will be used as input to the upcoming ROM
exercises to improve consistency between ROM and urban area
modeling results.
Also included should be the rule penetration (percentage of
rule coverage) associated with new area-source control measures
and any expected changes in rule effectiveness for point or area
sources. In addition to the data on spreadsheet, paper
documentation should be provided describing the control measures,
assumptions made, and any further explanation needed for the
information listed on the spreadsheet.
26
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3.3 Attainment Demonstration
States that do not intend to use UAM must submit their
attainment demonstrations as part of the rate-of-progress SIP
revision that is due in November 1993. Moderate areas are
expected to attain the NAAQS for ozone by November 15, 1996.
These moderate areas may either use UAM or EKMA in their modeling
demonstrations. Serious and above areas are required to use UAM
in their modeling demonstrations. Moderate interstate
nonattainment areas are required to use UAM; moderate intrastate
areas have the option of using UAM. Those moderate areas
electing to use EKMA must submit a SIP revision by November 1993
incorporating a modeling demonstration which shows that the
identified control measures will be sufficient to attain the
NAAQS by November 15, 1996. If an area elects to use the UAM for
its modeling demonstration, it may apply for a 1-year extension
(to November 1994) for submitting a SIP revision reflecting an
attainment demonstration. Both UAM and EKMA require emissions
inventories for VOC, NOX, and CO.
28
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4.0 CREDITABILITY OF EMISSIONS REDUCTIONS
This section discusses the creditability of emissions
reductions from selected control programs to the 15 percent VOC
emissions reduction requirement- This presentation is not
intended to be comprehensive in scope; instead, it is included to
'provide preliminary guidance while States begin developing their
control strategies. A future document in this guidance series,
"Growth Factors, Projections, and Control Strategies," will
describe details on emissions reductions creditability for
additional control measures.
States can credit emissions reductions toward the 15 percent
VOC emissions reduction requirement only if the CAAA do not
specify that such emissions reductions are not creditable, and
the reductions meet the following requirements. All emissions
reductions must be real, permanent, and enforceable. States must
keep careful records of all emissions reductions to ensure that
the same reductions are not "double-counted" or, more simply,
used more than one time. In all circumstances, any real
emissions reductions that contribute to attainment of the
standard are creditable in the attainment demonstration.
Section 182(b)(1)(C) and section 182(b)(1)(D) explicitly
disallow certain reductions from counting toward the fulfillment
of the 15 percent reduction in emissions requirement. All real,
permanent, and enforceable post-1990 VOC emissions reductions are
creditable toward the 15 percent requirement except for
•reductions resulting from the following:
1. The FMVCP tailpipe or evaporative standards promulgated
prior to 1990.
2. Federal regulations on RVP (55 FR 23666, June 11,
1990).
3. State regulations required under section 182(a)(2)(A)
submitted to correct deficiencies in existing RACT
rules.
4. State regulations required under section 182(a)(2)(B)
to establish an I/M program or correct deficiencies in
existing I/M programs.
Remember that the noncreditables identified in numbers 1 and 2
above are not contained in the 1990 adjusted base year inventory
that is used to calculate the 15 percent emissions reduction.
The 1990 adjusted base year inventory, in effect, decreases the
target level of emissions (i.e., the total level of emissions
allowed to be produced). Also, these programs cannot be used to
.achieve the 15 percent VOC emissions reductions.
The following paragraphs provide a brief discussion of
programs that are creditable toward the 15 percent emissions
reduction requirement. Also briefly discussed are examples where
29
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reductions are not creditable to the 15 percent reduction
(i.e., RACT rule and I/M fix-ups). Not discussed in this section
are the noncreditable emissions reductions from the FMVCP and RVP
program; section 2.1 of this document discusses these programs
and how the emissions reductions from these programs are
calculated and treated for rate-of-progress purposes.
The programs described here do not constitute an exhaustive
list of all potential creditable programs. Any other new
requirements which generate reductions within a nonattainment
area, such as the marine vessel loading regulations, are
creditable toward the 15 percent.
4.1 RACT Programs
Emissions reductions resulting from required corrections to
VOC RACT rules ("RACT fix-ups") are not creditable toward the
required 15 percent VOC emissions reduction; any future
reductions resulting from measures not associated with the
•required corrections would be creditable. For example, RACT rule
corrections involving revision to applicability thresholds and
emissions limits, or additions of missing regulations that were
required preenactment are not creditable toward the 15 percent
VOC emissions reduction requirements (or offsets). If the State
revises the emissions limit or changes the applicability
threshold beyond the level required in EPA guidance (see
reference 17), and these modifications result in further
emissions reductions, these additional reductions are creditable.
In this case, the State would need to differentiate, through
documentation submitted in the rate-of-progress plan, between
emissions reductions that occurred through a correction to the
RACT rule and the additional reductions that resulted from
extension of the rule to sources of a lower threshold than
recommended in EPA's model RACT rule guidance.
RACT Fix-Ups
Section 182(b) (1) (D) (iii) specifies that emissions
reductions generated from corrections to RACT rules (RACT fix-
ups) required under section 182(a)(2)(A) are not creditable
toward meeting the rate-of-progress requirements. These
.corrections can be described in two ways: (1) where the emissions
reductions from the corrections are difficult to attribute
directly to the fix-up (any emissions reductions associated with
these types of corrections may generally be considered rule
effectiveness improvements), and (2) where the resultant decrease
in emissions is more clearly attributable to RACT fix-ups.
In the first case, emissions reductions associated with such
fix-ups are difficult to sort-out from those achieved from rule
effectiveness and, therefore, EPA believes that it is appropriate
to allow such corrections, in combination with improved
compliance programs that result in additional, quantifiable, and
enforceable emissions reductions, to count towards meeting the
rate-of-progress requirements as part of a rule effectiveness
30
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improvement effort. For example, RACT rule corrections that add
the appropriate recordkeeping requirements or test methods do not
directly result in additional emissions reductions. However, the
resulting RACT rules are more enforceable, and the corrections
make determining compliance an easier task. The EPA believes
that in such situations, credit is given to the States for
improving the compliance programs, not for correcting the RACT
rules, although the RACT fix-up program was essential to creating
more enforceable rules.
In the second case, however, corrections do result in
additional, enforceable, and quantifiable emissions reductions.
These corrections, which are not creditable toward the 15 percent
requirement, include situations where:
• A rule was missing (i.e., a State committed to
develop a rule as part of its 1977 SIP, or post-
1982 SIP, but never carried through on the
commitment prior to the CAAA).
• The limit was wrong.
• A capture system is now required to ensure meeting
the RACT limit.
Appendix B provides example emissions reduction calculations
for each of these three examples. These examples are not
intended to be fully inclusive. States should evaluate all RACT
rule corrections to determine if such corrections result in real,
enforceable, and permanent emissions reductions. If so, such
reductions must be quantified and considered noncreditable in the
•SIP development process.
RACT Catch-Ups
*
Emissions reductions resulting from RACT catch-ups are
creditable. One example of a RACT catch-up occurs when applying
the RACT rules to the newly designated portions of a preenactment
nonattainment area not previously subject to the rules. For
example, if an area is extended to include three counties that
were not previously part of the nonattainment area, application
of RACT rules to sources in those counties will result in
creditable emissions reductions.14 However, States that employed
s_tatewide RACT rule implementation .to avoid the new source
preconstruction monitoring requirements will not necessarily
receive credit. Such States will only receive credit for the
emissions reductions resulting from the enhancement of RACT rule
requirements brought about by the CAAA, extending beyond RACT
rule requirements already on the books, and implemented after the
1990 base year.
14In addition, if the counties were not part of an existing I/M
.program, extension of the I/M program to the counties will result
in creditable reductions.
31
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Reductions achieved through rules adopted pursuant to any
new control technique guideline (CTG) are creditable only to the
extent that the reductions were not required by a SIP or Federal
implementation plan developed under the pre-amended Act. For
example, if a non-CTG rule in a SIP prior to enactment (or
required to be included in such a SIP) required an
81 percent reduction in VOC emissions and a new CTG for the same
source category recommends a 90 percent reduction, to the extent
that a specific source achieves the 90 percent reduction, only up
to 9 percent would be creditable. In addition, if a State was
required to adopt a RACT rule for a particular source under the
pre-amended Act but failed to do so, adoption of a rule for that
source would be considered part of the RACT fix-ups. Therefore,
any reductions achieved by such a rule would not be creditable.
4.2 Inspection and Maintenance Programs
The I/M Section of the Emission Planning and Strategies
Division of the EPA's Office of Mobile Sources has published a
draft technical support document that discusses I/M program
performance standards for VOC emissions. (See reference 18.)
Emissions reductions that result from corrections to I/M programs
that failed to meet this performance standard, or from
corrections to programs that failed to meet a more stringent
standard previously included in the SIP, are not creditable
toward the 15 percent emissions reduction requirement. Any other
improvements in I/M programs required by the CAAA (such as
enhanced I/M) or any improvements that a State chooses to make in
a new SIP are creditable. In the case where a State has both
made corrections to its SIP according to the EPA's minimum
performance standard, and included additional provisions that go
beyond that standard, the State will model two I/M programs in
the MOBILE model to calculate the creditable reductions; one
representing the program up to the EPA's minimum standard, and
the other with the State's full I/M program. The difference
between the two programs' emissions reductions represents the
portion of the total emissions reduction that is creditable '
toward the 15 percent emissions reduction requirement. Appendix
•C provides details on calculating the emissions reductions from
I/M program corrections.
4.3 Preenactment Banked Emissions Reduction Credits
If the State has an emissions credit bank that meets the
EPA's requirements under an earlier policy statement (see
reference 19), the State is allowed to use its preenactment
banked emissions reduction credits to facilitate the location of
new sources in nonattainment areas during the 1990-1996 period.
However, because these reduction credits represent emissions that
are not included in the 1990 base year inventory, any additional
emissions that result from the use of banked credits must be
treated as growth in order to ensure that the 15 percent VOC
emissions reduction requirement is achieved. Also, it is
important to note that the use of preenactment banked emissions
32
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credits must be in accordance with the offset ratios prescribed
in the CAAA (e.g., 1.3 to 1 in severe areas.)
Figure 3 presents an example of the use of preenactment
banked emissions credits during the 1990-1996 period. In this
example, a new 30 tpy source of VOC emissions wishes to locate in
a severe nonattainment area, and the State allows the source to
use available preenactment banked emissions credits. Because the
source wants to locate in a severe nonattainment area, 39 tpy of
VOC emissions must be removed from the bank (i.e., 30 tpy x 1.3 =
39 tpy). Although the bank has been reduced by 39 tpy, there has
been a 30 tpy increase in emissions in the^nonattainment area due
to the new source. To assure that new source growth will not
.interfere with the 15 percent VOC emissions reduction requirement
when preenactment banked credits are used, existing sources must
eventually, by time of reconciliation, reduce their emissions at
least as much as the emissions growth.
Bank
39 tpy in bank
New Source
Allowed to emit
+ 30 tpy
9 tpy from offset
ratio of 1.3 to 1
for severe area
Existing Sources
-15 tpy -15 tpy
Must be offset by 30 tpy emission reductions
Figure 3. Example of use of
preenactment banked emissions
credits.
33
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4.4 Maximum Achievable Control Technology (MACT) Standards
General Requirements
Many of the 189 hazardous air pollutants listed under
section 112(b)(1) of the Act are VOC's. Any emissions reductions
of a hazardous VOC resulting from the application of a MACT
standard is creditable toward the 15 percent VOC emissions
reduction requirement for ozone nonattainment areas. Any
incidental emissions reduction of a non-hazardous VOC -resulting
from the application of a MACT standard is also creditable toward
the 15 percent VOC emissions reduction requirement. It is
important to note that some sources will be subject to both MACT
standards and RACT rules. Because only the more stringent of the
two standards will apply in these cases, States should be aware
that double counting of the VOC emissions reductions from these
two programs is not permitted.
States should recognize that reductions resulting from MACT
standards must occur prior to November 15, 1996, to be creditable
.toward the 15 percent VOC emissions reduction requirements. Most
MACT standards will not be promulgated until after the post-1996
emissions reduction requirements take effect. Guidance regarding
the creditability of MACT reductions toward the post-1996
reduction requirements is presently under development within EPA.
Section 112(d)(1) of the CAAA requires the promulgation of
regulations establishing emissions standards for categories and
subcategories of major sources and area sources of the 189
hazardous air pollutants. The emissions standard for a
particular hazardous air pollutant emitted from a new or existing
source must be based on the maximum degree of reduction that the
Administrator determines is achievable through the application of
emissions control technologies. The determination of MACT
considers the cost of achieving such emissions reductions and any
non-air quality health and environmental impacts and energy
requirements.
Early Reductions Program
As a temporary alternative to complying with an applicable
MACT standard, an existing source may elect to comply with the
early reduction requirements of section 112(i)(5). By electing
'to achieve early reductions, an existing source may, under
certain conditions, meet an alternative emissions limit in lieu
of meeting an otherwise applicable MACT standard. The
alternative emissions limit expires 6 years after the otherwise
applicable MACT standard compliance date, at which time the
source must comply with the MACT requirement. Except as follows,
to obtain the MACT compliance extension the reduction must be
achieved before the otherwise applicable MACT standard is first
proposed. A source may also obtain an extension if it commits to
make the 90 percent reduction prior to proposal of the MACT
standard and actually achieves the 90 percent reduction prior to
January 1, 1994.
34
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The early reduction program requires a source to achieve
hazardous air pollutant emissions reductions of at least 90
percent (at least 95 percent in the case of particulates). The
emissions reduction must be determined from a comparison of the
actual post-control emissions with the actual and verifiable
•emissions in a base year not earlier than 1987. A base year of
1985 or 1986 can be used by a source if its emissions data are
based on information received by the Administrator prior to
November 15, 1990, pursuant to an information request issued
under section 114 of the Act.
Hazardous VOC emissions reductions under the early reduction
program are creditable toward the 15 percent VOC emissions
reduction requirements to the extent that reductions were taken
after the 1990 base year inventory applicable to the 15 percent
VOC emissions reduction requirements. Because a source can
credit reductions that took place prior to 1990 toward the early
reduction program, the entire 90 percent early reduction may not
be creditable toward the rate-of-progress requirement.
States should be aware that EPA is developing a policy
regarding potential conflicts between the early reduction program
and the RACT requirements. (See reference 20.) The interaction
between the early reduction program and RACT requirements causes
concern because the prospect of applying RACT requirements to
sources that already made early reductions would effectively
limit the attractiveness of, and therefore participation in, the
.early reductions program. Additionally, States should also be
aware that early reductions must be taken prior to November 15,
1996, to be credited toward the 15 percent VOC emissions
reduction requirements. Guidance regarding the creditability of
section 112(i)(5) early reductions toward the post-1996 reduction
requirements is presently under development within EPA. Readers
interested in further details regarding the section 112(i)(5)
early reductions program are referred to the proposed regulations
published in the Federal Register. (See reference 21.) Final
rules are anticipated by early 1993.
4.5 Rule Effectiveness Improvements
Many States with preexisting nonattainment areas have
already adopted rules defining RACT for most of the larger
sources, including non-CTG categories. In such cases, there is
.considerable concern about what additional measures are needed to
meet the 15 percent VOC emissions reduction requirement. One
method of achieving creditable reductions from stationary sources
in such areas is to improve the implementation of existing
regulations. This is referred to as rule effectiveness
improvement. These improvements are subject to the same
creditability constraints as are the other emissions
35
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reductions.15 Rule effectiveness improvements must reflect real
emissions reductions resulting from specific implementation
program improvements. Actual emissions reductions must result
from improving rule effectiveness; simply calculating a higher
rule effectiveness using a different methodology is not
creditable.
Rule effectiveness improvements must be documented at a
minimum by conducting a post-implementation (after the
implementation of rule effectiveness improvement programs)
source-specific emissions study. Two methods are available for
calculating creditable rule effectiveness improvements; both
•require that a post-implementation Stationary Source Compliance
Division (SSCD) protocol study be conducted. The first method
involves pre- and post-rule effectiveness improvement
implementation studies as delineated by SSCD. For example, if
the rule effectiveness increases from 50 to 75 percent, the
emissions reductions associated with this improvement would be
creditable. The second approvable method uses the EPA default
value of 80 percent for the pre-rule effectiveness improvement
rule effectiveness value. Thus, if the results of a SSCD
protocol study show 85 percent rule effectiveness after
implementation, the increase in emissions reductions associated
with the improvement from 80 to 85 percent would be creditable
toward the 15 percent rate-of-progress requirement. Additional
discussion of rule effectiveness, including provisions for the
calculation and use of category-specific rule effectiveness
factors, is available in Guidelines for Estimating and Applying
Rule Effectiveness for Ozone/CO State Implementation Plans. (See
reference 22.) The document "Growth Factors, Projections, and
Control Strategies," to be released in the fall of 1992, will
provide a list of control measures that involve rule
effectiveness improvements. Future guidance is under development
for the quantification of rule effectiveness improvements. The
EPA plans to issue the quantification guidance by late fall of
1992.
15For example, some RACT rule corrections that result in improved
rule effectiveness may be creditable; a discussion of this
appears in section 4.1 of this document.
36
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5.0 PREVIEW OF THE DEVELOPMENT OF EMISSIONS PROJECTIONS, CONTROL
STRATEGY, AND 1996 MILESTONE COMPLIANCE DEMONSTRATION
This document focuses on the development and submittal of
the elements of the rate-of-progress plan due by November 15,
1992. While EPA review of this submittal is underway, States
should undertake the calculation of emissions projections for the
year 1996 and the development of full control strategies. These
elements of the rate-of-progress plan will be due in draft form
to EPA by May 15, 1993. The fully adopted rate-of-progress plan
is then due by November 15, 1993. A separate guidance document
is being developed by EPA on these other elements of the rate-of-
progress plan, which will include hypothetical nonattainment area
examples in describing the development of the required elements
for these submittals. This guidance is expected to be available
in the fall of 1992.
The first milestone demonstration must illustrate that the
area has reached the 1996 target level of emissions as defined in
•the 15 percent VOC emissions reduction demonstration plan.
Actual annual and typical ozone season weekday emissions for
point sources should be listed by facility. Area and off-highway
source emissions for each county by source category should also
be listed. Finally, the highway vehicle emissions should be
listed. Once the emissions from all of the known anthropogenic
sources are listed, the total emissions for the nonattainment
area should be computed and compared to the 1996 target.
Section 182(a)(3)(A) requires the States to submit periodic
inventories starting the third year after submission of the base
year inventory required by section 182(a)(1) and every 3 years
thereafter until the area is redesignated to attainment. The EPA
recommends that States synchronize their schedules for developing
the periodic inventories so that the second periodic inventory
(which would be due no later than November 15, 1998) is submitted
by February 13, 1997 and addresses emissions in 1996. By
accelerating preparation and submittal of the 1996 periodic
inventory, the milestone demonstration that is due for serious
and above areas by February 13, 1997 can be based on this
periodic inventory. If similarly accelerated, future periodic
inventories would then also coincide with subsequent milestone
.demonstrations. The periodic inventory is to be based on actual
emissions and will cover VOC, NOX, and CO emissions sources.
Like the base year inventory, the periodic inventory is to be
determined using typical peak ozone season weekday emissions.
The specific reporting requirements for the 15 percent VOC
emissions reduction milestone demonstration will be addressed in
an EPA regulation to be promulgated in the summer of 1993. This
regulation will address summary data needs as well as detailed
reporting requirements. The rule will also address consequences
of submitting an inadequate demonstration (in terms of
documentation) as well as consequences of failure to demonstrate
the 15 percent VOC emissions reduction.
37
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REFERENCES
1. Emission Inventory Requirements for Ozone State
Implementation Plans, EPA-450/4-91-010, U.S. Environmental
Protection Agency, Office of Air Quality Planning and
Standards, Research Triangle Park, NC. March 1991.
2. Procedures for the Preparation of Emission Inventories for
Carbon Monoxide and Precursors of Ozone. Volume I: General
Guidance for Stationary Sources, EPA-450/4-91-016, U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC. May
1991 .
3. Procedures for Emission Inventory Preparation, Volume IV:
Mobile Sources, EPA -450/4-81-026d (Revised), U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC. July
1992.
4. User's Guide to MOBILE4.1 (Mobile Source Emission Factor
Model), EPA-AA-TEB-91-01, U.S. Environmental Protection
Agency, Office of Mobile Sources, Ann Arbor, MI. July 1991.
5. Vehicle Miles Traveled Forecasting and Tracking Guidance,
U.S. Environmental Protection Agency, Office of Mobile
Sources, Ann Arbor, MI. March 1992.
6. Personal Computer Version of the Bioqenic Emissions
Inventory System (PC-BEIS) And User's Guide, EPA-450/4-91-
017, U.S. Environmental Protection Agency, Research Triangle
Park, NC. July 1991.
. 7. Procedures for the Preparation _of Emissions Inventories for
Carbon Monoxide and Precursors of Ozone. Volume II:
Emission Inventory Requirements for Photochemical Air
Quality Simulation Models. EPA-450/4-91-014, U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC. May
1991 .
8. Guidance for the Preparation of Quality Assurance Plans for
0,/CO SIP Emission Inventories, EPA-450/4-88-023, U.S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC.
December 1988.
9. Quality Review Guidelines for 1990 Base Year Emission
Inventories. EPA-450/4-91-022, U.S. Environmental Protection
Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC. July 1992.
10. Example Documentation Report for 1990 Base Year Ozone and
Carbon Monoxide State Implementation Plan Emission
Inventories, EPA-450/4-92-007, U.S. Environmental Protection
39
-------
Agency, Office of Air Quality Planning and Standards,
Research Triangle'Park, NC. March 1992.
11. Guidelines for Estimating and Applying Rule Effectiveness
For Ozone/CO State Implementation Plans, Draft Report,
Prepared by Alliance Technologies Corporation, Prepared for
U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Ozone and Carbon Monoxide Branch,
Research Triangle Park, NC. April 1992 (final report
forthcoming).
12. 55 FR 23666, "Volatility Regulations for Gasoline and
Alcohol Blends Sold in Calendar Years 1992 and Beyond," June
11, 1990.
13. BEA Regional Projections to 2040, Volume I: States, U.S.
Department of Commerce, Bureau of Economic Analysis,
Washington, D.C., U.S. Government Printing Office. October
1990.
14. BEA Regional Prelections to 2040, Volume II: Metropolitan
Statistical Areas, U.S. Department of Commerce/ Bureau of
Economic Analysis, Washington, D.C., U.S. Government
Printing Office. October 1990.
15. BEA Regional Projections to 2040, Volume III: BEA Economic
Areas, U.S. Department of Commerce, Bureau of Economic
Analysis, Washington, D.C., U.S. Government Printing Office.
October 1990.
16. Procedures for Preparing Emissions Projections, EPA-450/4-
91-019, U.S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Research Triangle Park, NC.
July 1991.
17. Model Volatile Organic Compound Rules for Reasonable
Available Control Technology: Planning for Ozone
Nonattainment Pursuant to Title I of the Clean Air Act
(Staff Working Document), U.S. Environmental Protection
Agency, Office of Air Quality and Planning Standards,
Research Triangle Park, NC. June 1992.
18. I/M Costs, Benefits, and Impacts Analysis, U.S.
Environmental Protection Agency, Office of Mobile Sources,
Ann Arbor, MI. February 1992.
19. 51 FR 233 "Emissions Trading Policy Statement; General
Principles for Creation, Banking and Use of Emission
Reduction Credits; Final Policy Statement and Technical
Issues Document." December 4, 1986.
20. "Early Reductions Program/Title I Interface," Memorandum
from John S. Seitz, U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Research
Triangle Park, NC. December 20, 1991.
40
-------
21. 56 FR 27338. "National Emission Standards for Hazardous Air
Pollutants for Source Categories; Proposed Regulations
Governing Compliance Extensions for Early Reductions of
Hazardous Air Pollutants." June 13, 1991.
22. Reference 11.
41
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APPENDIX A: DEFINITION OF TERMS
This appendix provides the specific definitions of EPA terms
as they are used in this guidance. Different EPA programs
sometimes use different definitions of the same term (e.g., major
source). This appendix notes where conflicts occur in the
definition of a term used in this guidance. These definitions
are presented for the purposes of this guidance document only;
the reader is advised to refer to specific regulations, policies,
and sections of the Act to obtain complete definitions for the
program or title of interest.
Area Source Any stationary or non-road source that is too small
and/or too numerous to be included in the stationary point-source
emissions inventories.
Attainment Demonstration Moderate and above ozone nonattainment
'areas must demonstrate that the reductions specified in the
revised SIP will result in modeled air quality for the
nonattainment area that achieves attainment by the applicable
attainment date. This requirement can be met through the
application of an EPA-approved model and EPA-approved modeling
techniques described in the current version of the Guidance on
Air Quality Models16 (EPA-450/2-78-027R), which is currently
under revision. Two models are suggested: the UAM or EKMA. The
EPA requires the submittal of attainment demonstrations employing
UAM for serious and above areas and multi-State moderate areas as
part of the SIP revision due by November 15, 1994. Attainment
demonstrations based on EKMA for moderate nonattainment areas
within a single state (intrastate moderate areas) must be
submitted as part of the SIP revision due by November 15, 1993,
unless the State chooses to use UAM, in which case the
demonstration must be submitted as part of the SIP revision due
by November 15, 1994. The use of EKMA is described in Guideline
for Use of City-Specific EKMA in Preparing Ozone SIP/s (EPA-
450/4-80-027) as well as the aforementioned guideline that is
under revision. This document, and the appropriate Regional
Office, should be consulted before an analysis is conducted with
this modeling approach. The use of UAM is described in Guideline
• for Regulatory Application of the .Urban Airshed Model (EPA-450/4-
91-013) .1V
16Guidance on Air Quality Models (Revised), EPA-450/2-78-027R,
July 1986 (currently under revision).
17Guideline for .Regulatory Application of the Urban Airshed
Model, EPA-450/4-91-013, U.S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Research Triangle
Park, NC.
A-1
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Attainment Determination The EPA must determine within 6 months
after the applicable attainment date whether an area has attained
'the NAAQS for ozone. The attainment dates are as follows:
• Marginal areas — November 15, 1993.
• Moderate areas — November 15, 1996.
• Serious areas — November 15, 1999.
• Severe areas — November 15, 2005 (severe areas
with a 1986-1988 ozone design value
of 0.190 up to, but not including
0.280 parts per million have until
November 15, 2007).
• Extreme areas — November 15, 2010.
In making the attainment determination, EPA will use the most
recently available, quality-assured air quality data covering the
3-year period preceding the attainment date. For ozone, the
average number of exceedances per year after adjustment for
missing data are used to determine whether the area has attained.
Basic Inspection and Maintenance (I/M) Programs requiring the
inspection of vehicles including, but not limited to, measurement
of tailpipe emissions, and mandating that vehicles with tailpipe
emissions higher than the program cutpoints be repaired to pass a
'tailpipe emissions retest. Basic I/M programs must be at least
as stringent as the requirements set out in section 182(a) (2) (B) .
Maior Stationary Source The CAAA have multiple definitions for
major stationary sources depending upon the nonattainment
classification and the pollutant. Section 302 of the CAAA
defines a major stationary source as one that directly emits, or
has the potential to emit, 100 tpy or more of any air pollutant.
As exceptions to this rule, major stationary source emissions
thresholds, as defined in Part D of Title I of the CAAA, are
listed in Table A-1 for both VOC and NOV sources.
A.
Milestone Compliance Demonstration For serious and above
classified nonattainment areas, demonstrating achievement of the
15 percent VOC emissions reduction over the 1990-1996 period, or
demonstrating subsequent 3 percent VOC emissions reductions per
year averaged over each consecutive 3-year period from November
15, 1996 until the attainment date. Section 182(g)(2) requires
that within 90 days of the date on which an applicable milestone
occurs (not including an attainment date on which a milestone
occurs in cases where the standard has been attained), States
with nonattainment areas must submit a demonstration that the
•milestone has been met (e.g., the 15 percent VOC emissions
reduction is demonstrated by February 13, 1997). The EPA expects
to release regulations pertaining to the requirements of the
milestone demonstration in the Summer of 1993.
1990 Adjusted Base Year Inventory Section 182(b)(1)(B) and (D)
describes the inventory (hereafter referred to as the adjusted
base year inventory) from which moderate and above ozone
nonattainment areas must achieve a 15 percent reduction in VOC
A-2
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TABLE A-1. MAJOR SOURCE THRESHOLDS AND MINIMUM EMISSIONS OFFSET
RATIO REQUIREMENTS FOR OZONE NONATTAINMENT AREA CLASSIFICATIONS
Ozone Nonattainment Area
Extreme
Severe
Serious
Moderate
Moderate, in an ozone
transport region
Marginal
voc
(tpy)
10
25
50
100
50
100
NOX
(tpy)
10
25
50
100
100
100
Minimum
Emissions
Offset Ratio
Required
1.5 to 118
1.3 to I13
1.2 to 1
1.15 to 1
1.15 to 1
1.1 to 1
Marginal, in an ozone
transport region
All other nonattainment areas,
outside of an ozone
transport region19
All other nonattainment areas,
in an ozone transport region19
Attainment, in an ozone
transport region
50
100
100
50
100
100
100
100
1.15 to 1
>1.0 to 1
1.15 to 1
1.15 to 1
18The minimum ratio is reduced to 1.2 to 1 if the applicable
State implementation plan requires all major sources of VOC and
NOX emissions to use best available control technology.
19The other nonattainment areas are submarginal, transitional,
and incomplete/no data.
A-3
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emissions by 1996. This inventory is equal to "the total amount
of actual VOC or NOX emissions from all anthropogenic (man-made)
sources in the area during the calendar year of enactment,"
excluding the emissions that would be eliminated by FMVCP
regulations promulgated by January 1, 1990, and RVP regulations
(55 FR 23666, June 11, 1990), which require specific maximum RVP
levels for gasoline in particular nonattainment areas during the
peak ozone season. The 1990 rate-of-progress base year inventory
(defined below) removes biogenic emissions and emissions from
sources listed in the base year inventory that are located
outside of the nonattainment area. The adjusted base year
•inventory removes the emissions reductions from the FMVCP and RVP
program from the 1990 rate-of-progress base year inventory. The
adjusted base year inventory, which is due by November 15, 1992,
is used to calculate the required 15 percent reductions.
Adjusted Base Year Emissions Inventory = Base Year Emissions
Inventory, minus the following:
• Biogenic source emissions.
• Emissions from sources outside of the nonattainment
area boundary.
• Emissions reductions from the FMVCP.
• Emissions reductions from the RVP rules.20
1990 Base Year Inventory The 1990 base year inventory is an
inventory of actual annual and typical weekday peak ozone season
emissions that States use in calculating their adjusted and
projected inventories, and in developing their control strategy.
The base year inventory comprises emissions for the area during
the peak ozone season, which is generally the summer months. It
includes anthropogenic sources of NOX and CO emissions, and both
anthropogenic and biogenic sources of VOC emissions. Also
.included in the inventory are emissions from all stationary point
sources and area sources as well as highway and nonhighway mobile
sources located within the nonattainment area, and stationary
sources with emissions of 100 tpy or greater' of VOC, NOX, and CO
emissions within a 25-mile wide buffer zone of the designated
nonattainment area. The base year inventory contains off-shore
sources located within the nonattainment area boundaries and off-
shore stationary sources with emissions of 100 tpy or greater of
VOC, NOX, or CO emissions within the 25-mile wide buffer area.
For nonattainment areas that will perform photochemical grid
modeling (e.g., serious and above areas and multi-State moderate
areas), emissions for the entire modeling domain, which is
usually larger than the nonattainment area because ozone is an
area-wide problem, are required in the modeling inventory. This
modeling inventory could be submitted with the base year
inventory, or the modeling inventory submittal could be in a
separate package. It is important to note that the 1990 base
20See figures 1 and 2 in section 2.0 of this document for a
further description of the relationship of the adjusted base year
inventory to the 1990 rate-of-progress base year inventory.
A-4
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year inventory serves as the starting point for all other
inventories.
1990 Rate-of-Progress Base Year Inventory An accounting of all
anthropogenic VOC, CO, and NOX emissions in the nonattainment
area. This emissions inventory is calculated by removing
biogenic emissions and the emissions from sources that are
located outside of the nonattainment area from the base year
'inventory. This inventory is used in developing the adjusted
base year inventory. It is also used as the basis from which to
calculate the 1996 target level of emissions.
1996 Target Level of Emissions The 1996 target level of
emissions is the maximum amount of ozone season VOC emissions
that can been emitted by an ozone nonattainment area in 1996 for
that nonattainment area to be in compliance with the 15 percent
rate-of-progress requirements. It is calculated by first taking
15 percent of the adjusted base year inventory emissions. This
emissions value is then added to the expected emissions
reductions due to the FMVCP and RVP program, and from corrections
to any deficient RACT rules and I/M programs. The summation of
the 15 percent, the expected reductions from deficient I/M and
RACT programs, and reductions from the FMVCP and RVP program are
then subtracted from the 1990 rate-of-progress base year
inventory to arrive at the 1996 target level of emissions. This
target is used by States to design their 15 percent VOC emissions
reduction control strategies. The projected control strategy
inventory used in the rate-of-progress plan must be at or below
the 1996 target level of emissions to demonstrate that the 15
percent VOC emissions reduction will be accomplished.
1996 Target Level of Emissions = Rate-of-Progress Base Year
Inventory, minus the following:
• 15 percent of the adjusted base year inventory
emissions.
• Emissions reductions from corrections to any deficient
RACT rules.
• Emissions reductions from corrections to deficient I/M
programs.
• Emissions reductions from the pre-1990 FMVCP.
• Emissions reductions from RVP rules.
Peak Ozone Season The contiguous 3-month period of the year
during which the highest ozone exceedance days have occurred over
the 3 to 4 years prior to the 1990 base year. Most ozone
nonattainment areas have a peak ozone season lasting from June
through August.
Offset Ratios For the purpose of satisfying the emissions offset
reduction requirements of section 173(a)(1)(A), the emissions
offset ratio is defined as the ratio of total actual emissions
.reductions of VOC (and NOX unless exempted under section 182[f])
obtained as offsets from existing sources to total allowable
emissions increases of such pollutant from the new source. (See
A-5
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Table A-1 for a list of offset ratios by nonattainment area.)
Additional information on offsets will be provided in forthcoming
guidance regarding the interaction of the 15 percent VOC
emissions reduction requirements of Title I with the emissions
reduction requirements of other Titles (i.e./ New Source Review,
Title II reductions, etc.).
Point Source Any stationary source that has the potential to
emit more than some specified threshold level of a pollutant or
is identified as an individual source in a State's emissions
inventory. For base year SIP inventory purposes, point sources
are defined as sources emitting 10 tpy or more of VOC emissions
or 100 tpy or more of NOX or CO emissions.
'Post-1996 Rate-of-Progress Plan The portion of the SIP revision
due by November 15, 1994, which describes how serious and above
areas plan to achieve the post-1996, 3 percent per year VOC
emissions reductions averaged over each consecutive 3-year period
from November 15, 1996 until the attainment date. This SIP
revision also includes the attainment'demonstration for moderate
interstate nonattainment areas and serious and above
nonattainment areas.
RACT "Catch-ups" The application of RACT for all applicable
sources as listed in section 182(b)(2), regardless of what was
previously required. Each moderate and above ozone nonattainment
area (as well as attainment areas within the ozone transport
region) are subject to the RACT "catch-up" requirement of section
182(b)(2). The new law requires any of the above areas that had
not previously adopted RACT consistent with all of the CTG's to
"catch-up" and apply RACT to all sources covered by a
preenactment or post-enactment CTG document. Many of these areas
were not previously required to apply RACT to sources covered by
Group III CTG's (CTG's published after September 198,2). In
addition, areas previously considered rural nonattainment, which
had to apply RACT only to certain major sources in certain CTG
•categories under prior policy, will have to revise their SIP's to
apply RACT to all sources, including nonmajor sources, that are
covered by any CTG. The RACT "catch-up" provision also requires
these nonattainment areas to adopt RACT rules for all major
sources not covered by a CTG. Additional information on the RACT
"catch-up" program will be provided in forthcoming guidance
regarding the interaction of RACT rules with emissions
inventories.
RACT "Fix-ups" Corrections States are required to make under
section 182(a)(2)(1) to their current RACT rules to make up for
deficiencies (e.g., improper exemptions) in pre-amendment plans.
Under RACT "fix-ups", States are required to have RACT rules that
comply with section 172(b) of the pre-1990 Act, as interpreted by
EPA's pre-amendment guidance. Since the RACT "fix-up" provisions
refer to RACT as required by pre-amended section 172(b), only
areas subject to pre-amended section 172(b) need to meet the RACT
"fix-up" requirement. Therefore, for nonattainment areas that
will be expanded to contain regions that were designated
A-6
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'attainment prior to enactment, the RACT corrections are only for
the original nonattainment. area. The RACT "fix-up" provision
essentially codifies EPA's SIP calls, issued in May 1988 and
November 1989 (as announced in the Federal Register on September
7, 1988 [53 FR 34500] and July 30, 1990 [55 FR 30973]). The RACT
fix-ups were due on May 15, 1991. Between May 24 and June 24,
1991, EPA's Regional offices mailed letters to several Governors
and air agency officials concerning the progress of the States in
meeting RACT "fix-up" requirements and listing the outstanding
deficiencies that still had not been corrected. Additional
information on the RACT "fix-up" program will be provided in
forthcoming guidance regarding the interaction of RACT rules with
emissions inventories.
Rate-of-Progress Plan The portion of the SIP revision due by
November 15, 1993, that describes how moderate and above ozone
nonattainment areas plan to achieve the 15 percent VOC emissions
reduction. All moderate intrastate areas that choose to utilize
the EKMA in their attainment demonstration, are also required to
include their attainment demonstration in this SIP revision.
Rule Effectiveness (RE) For stationary sources, a measure of the
•extent to which a regulatory program achieves emissions
reductions. An RE of 100 percent reflects a regulatory program
achieving all the emissions reductions that could be achieved by
full compliance with the applicable regulations at all sources at
all times. However, regulations typically are not 100 percent
effective due to limitations of control techniques or
shortcomings in the implementation and enforcement process. The
EPA allows the use of three different methods for determining RE:
an 80 percent default value; results from EPA Questionnaires; or
results from a Stationary Source Compliance Division (SSCD)
study.
Volatile Organic Compound Any compound of carbon, excluding CO,
carbon dioxide, carbonic acid, metallic carbides or carbonates,
and ammonium carbonate, which participates in atmospheric
photochemical reactions. This includes any organic compound
other than those EPA has determined to have negligible
photochemical reactivity.21
2157 Federal Register 3945, February 3, 1992.
A-7
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APPENDIX B:
CALCULATION OF EMISSIONS REDUCTIONS FROM RACT RULE CORRECTIONS
Section 4.1 of this document discusses cases where RACT rule
corrections do not directly result in quantifiable emissions
reductions. Any incidental reductions that occur in these cases
'may be handled as part of a rule effectiveness improvement.
Corrections to RACT rules that may result in additional,
enforceable, and quantifiable emissions reductions include
situations where:
• A rule was missing (i.e., a State committed to
develop a rule as part of its 1977 SIP, or post-
1982 SIP, but never carried through on the
commitment prior to the CAAA).
• The limit was wrong.
• A -capture system is now required to ensure meeting
a RACT limit.
For the case where a rule was missing, the State should first
calculate the uncontrolled emissions in 1990 and multiply the
1990 uncontrolled emissions by the appropriate growth factor.
Next, the State must evaluate the expected emissions reduction in
1996 by calculating 1996 emissions (including growth and
controls) and subtracting this number from 1990 emissions. This
total expected emissions reduction should be added to the total
reductions in step 5 in the example in section 2.1 of this
document. These reductions are not creditable toward the 15
•percent VOC emissions reduction requirement.
For the second case, the State should first evaluate the
pound (Ib) VOC/gallon (gal) solids for each limit.
1990 limit = 3.5 Ib VOC/gal coating
1) 1990 Ib VOC/gal solids =
3.5 Ib VOC x 1 gal coating = 0.476 gal VOC
gal coating 7.36 Ib VOC gal coating
2) Calculate solids in 1 gal coating:
1 - 0.476 = 0.524 gal solids
3) Calculate gallons of coating needed to get gallon of solids:
1 gal coating = 1.908 gal coating
0.524 gal solids gal solids
4) Convert 3.5 Ib/gal coating to Ib VOC/gal solids:
3.5 Ib VOC x 1.908 gal coating = 6.678 Ib VOC
gal coating gal solids gal solids
The 1996 limit will be 2.9 Ib/gal.
Similarly, convert 2.9 Ib VOC/gal coating to Ib VOC/gal
solids.
B-1
-------
5) 2.9 Ib VOC x 1 gal VOC = 0.394 gal VOC
gal coating 7.36 Ib VOC gal coating
6) Volume of solids in 1 gal coating:
1 - 0.394 = 0.606 gal solids
7) Calculate gallons of coating needed to get 1 gallon of solids;
1 gal coating = 1.650 gal coating
0.606 gal solids gal solids
8) Convert 2.9 Ib VOC gal coating to Ib VOC/gal solids:
2.9 Ib VOC x 1.650 gal coating = 4.785 Ib VOC
gal coating ' gal solids gal solids
The facility uses 100 gal solids in 1990
day
9) Compare 1990 and 1996 Emissions:
1990 = 6.678 Ibs VOC x 100 gal solids = 667.8 Ibs VOC
gal solids day day
1996 = 4.785 Ib VOC x 100 gal solids x growth factor(1.2)
gal solids day
= 574.2 Ib VOC
day
1990 Emissions - 1996 Emissions = 667.8 - 574.2 =93.6 Ib VOC
day
Therefore, 93.6 Ib VOC/day are noncreditable.
For the third case where a capture system is required,
expected emissions reductions should be calculated in the
following way. First, uncontrolled emissions should be
determined.
1990 Paper Coaters:
• 80 percent of emissions coming out of the oven and
vented to an incinerator of 98 percent demonstrated
destruction efficiency.
• 20 percent of emissions are fugitive from
uncontrolled flash-off area.
Total uncontrolled emissions in 1990 =
1,000 Ib/day if total is uncontrolled, however,
when system is controlled, 80 percent of this
is captured, and 98 percent of captured
emissions are destroyed.
B-2
-------
So, emissions from the incinerator after control are
1,000 Ib/day x (1-(0.80)) x (1-(0.98)) =
(1,000 Ib/day) x (0.20) x (0.02) = 4 Ib/day
controlled. Total Emissions from incinerator +
fugitives = 4 Ib/day + (1,000 Ib/day x (0.20))
= 204 Ib/day
1996 Emissions:
New State rule now requires permanent total enclosure,
so the controlled emissions are:
1,000 Ib day (1.0) (0.02) = 20 Ib/day
Noncreditable Emissions Reductions =
1990 Emissions - 1996 Emissions = 204 Ib/day - 20 Ib/day
184 Ib/day
The preceding examples are not intended to be fully
inclusive. States should evaluate all RACT rule corrections to
.determine if such measures result in real, enforceable, and
permanent emissions reductions. If so, such reductions must be
quantified and considered in the SIP development process when
preparing the 1996 target level of emissions. If a State is
unclear on how to calculate such reductions, then the State
should consult with the Regional Office and Headquarters for
guidance.
B-3
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APPENDIX C:
CALCULATION OP EMISSIONS REDUCTIONS PROM I/M PROGRAM CORRECTIONS
Corrections to I/M programs occur when either (1) the area's
I/M program does not meet the reductions achieved by EPA's
minimum requirements, or (2) an area's program does not meet the
standards of their current SIP. I/M program corrections are
calculated by modeling two separate I/M programs in MOBILE4.1:
the area's current I/M program, and the stricter of: the I/M
program described in the area's SIP, or the minimum I/M program
as specified by EPA. MOBILE4.1 (or MOBILES with the flag set to
turn off new CAAA measures) should be run for calendar year 1996
using I/M input that describes the program before and after
corrections are made. The difference between the resulting
emissions factors is then multiplied by 1990 VMT to get the
emissions reduction associated with the I/M program correction.
In case 1, the motor vehicle emissions factor is calculated
for 1996 with the area's current program and with EPA's model
program. In each case, the MOBILE model is run with the pre-CAAA
FMVCP and phase II RVP. No additional CAAA requirements are
modeled. Sample MOBILE4.1 inputs for EPA's model program are
shown in Table C-l.
TABLE C-l. INSPECTION AND MAINTENANCE (I/M) PROGRAM INPUTS
I/M Program Characteristics Input
Start year (January 1) 1983
Pre-1981 model stringency rate 20%
First model year covered 1968
Last model year covered 2020
Waiver rate (pre-1981) 0%
Waiver rate (1981 and newer) 6%
Compliance rate 100%
Inspection type Centralized
Inspection frequency Annual
Vehicle types covered LDGV
The difference in motor vehicle emissions with the current
program and the model program is the I/M program correction.
This correction should only be calculated for areas within the
nonattainment area which were required to have an I/M program
under the Act.
C-l
-------
The following describes an example I/M program correction
calculation. It is important for States t° realize that these
reductions are not creditable toward the 15 percent VOC emissions
reduction requirement.
SAMPLE I/M CORRECTION CALCULATION:22
1990 VMT: 101.6 million miles per day
1996 MOBILE4.1 emissions factor with area's current program:
1.291 grams/mile
1996 MOBILE4.1 emissions factor with EPA's minimum model program:
1.248 grams/mile
Calculate motor vehicle emissions:
current program:
101.6 x 106 miles x 1 .291 grams = 288,911 Ibs/day
day mile
model program:
101.6 x 106 miles x 1.248 grams = 279,288 Ibs/day
day mile
Calculate I/M correction:
I/M correction = Emissions with current I/M -
Emissions with model I/M
288,911 - 279,288
= 9,623 Ib/day of noncreditable emissions.
In case 2, motor vehicle emissions are calculated with the
area's current program as implemented and with the program
required under the area's SIP. Again, MOBILE4.1 input files
.should model the FMVCP and phase II RVP but no additional CAAA
controls. The difference between these two estimates is the I/M
correction.
22This calculation uses total VMT and a total speed/vehicle type
weighted emissions factor. Alternatively, VMT and emissions
factors by vehicle type/roadway class could be used to calculate
total emissions under the current program and EPA's model
program.
C-2
-------
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