EPA-452/R-94-011

STAGE II COMPARABILITY STUDY

FOR THE NORTHEAST

OZONE TRANSPORT REGION

Air Quality Strategies and Standards Division

U.S. Environmental Protection Agency

Office of Air Quality Planning and Standards

Research Triangle Park, North Carolina 27711

January 1995
This report has been reviewed by the Air Quality Strategies and

Standards Division of the Office of Air Quality Planning and

Standards, EPA, and approved for publication. Mention of trade

names or commercial products is not intended to constitute

endorsement or recommendation for use.

Copies of this report are available through the Library Services

Office (MD-35), U.S. Environmental Protection Agency, Research

Triangle Park, NC 27711, or for a fee from National Technical

Information Services, 5285 Port Royal Road, Springfield, VA

22161, (703) 487-4650 or (800) 553-NTIS. The document is also

available on the Technology Transfer Network (TTN) under the

Clean Air Act Amendments Main Menu, Title I, Policy and Guidance.

NOTICE OF ERROR IN EARLIER PRINTING 

After distribution of the first printing of this 

document, it was discovered that there were errors in

Tables 5-2, 5-4, and 5-5. In calculating the comparable

VOC reductions in these tables, the NOx reductions were

inadvertently multiplied by, rather than divided by, the

NOx ratios. These errors have been corrected in this

printing. In addition, the text which summarizes the data

in Section 5.2 (page 45), Section 5.3.3 (page 51), Section

5.4.2 (page 57) and Section 5.4.3 (page 57) has been

revised to reflect the corrected tables. 

ii
TABLE OF CONTENTS

LIST OF TABLES AND FIGURES ................. v

ACRONYMS AND ABBREVIATIONS . . . . . . . . . . . . . . . . vii

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . xi

1.0 INTRODUCTION ..................... 1

1.1 Ground-level Ozone ................ 1

1.2 Clean Air Act Requirements ............ 2

1.3 Study Approach .................. 6

1.4 Organization of Report .............. 8

2.0 COMPARABILITY DETERMINATIONS.............. 9

2.1 Applicability................... 9

2.2 Time Frame for Comparability ........... 9

2.3 Comparable Measure Selection ........... 9

2.4 Conducting an Independent Comparability Analysis . 10

3.0 STAGE II EMISSIONS REDUCTIONS . . . . . . . . . . . . . 11

3.1 Modeling Assumptions . . . . . . . . . . . . . . . 11

3.1.1 Refueling Emissions . . . . . . . . . . . . 11

3.1.2 Stage II Control Assumptions . . . . . . . . 13

3.1.3 Onboard Vapor Recovery Control Assumptions . 15

3.2 Modeling Results . . . . . . . . . . . . . . . . . 16

3.3 Cost-Effectiveness . . . . . . . . . . . . . . . . 16

4.0 CONTROL MEASURES FOR VOLATILE ORGANIC COMPOUNDS . . . . 21

4.1 Motor Vehicle Measures . . . . . . . . . . . . . . 21

4.1.1 Modeling Analyses . . . . . . . . . . . . . 22

 Base Case Controls and VMT Estimates . . . 22

 Enhanced I/M . . . . . . . . . . . . . . . 26

 Reformulated Gasoline . . . . . . . . . . 26

 Combination of Measures . . . . . . . . . 28

4.1.2 Cost-Effectiveness . . . . . . . . . . . . . 31

 Enhanced I/M . . . . . . . . . . . . . . . 31

 Reformulated Gasoline . . . . . . . . . . 31

4.2 Stationary Source VOC Control Measures . . . . . . 32

 More Stringent Controls on Existing Sources 33

5.0 NOx CONTROL MEASURES . . . . . . . . . . . . . . . . . . 37

5.1 NOx Substitution Methodology . . . . . . . . . . . 37

 NOx Substitution Ratios . . . . . . . . . 38

5.2 Motor Vehicle Control Measures . . . . . . . . . . 42

5.3 Utility Control Measures . . . . . . . . . . . . . 45

5.3.1 Modeling Assumptions . . . . . . . . . . . . 48

iii
 Determining NOx RACT and Title IV NOx

 Control Measures . . . . . . . . . . . . 48

5.3.2 NOx RACT to 25 tpy . . . . . . . . . . . . . 50

5.3.3 More Stringent Control for Existing

 Major Sources . . . . . . . . . . . . . . 51

5.4 Non-Utility Point Source Control Measures . . . . . 51

5.4.1 Modeling Assumptions . . . . . . . . . . . . 52

 Determining RACT Level and More

 Stringent Controls . . . . . . . . . . . 52

5.4.2 NOx RACT to 25 tpy Sources . . . . . . . . . 56

5.4.3 More Stringent NOx Control to 100 tpy

 Sources . . . . . . . . . . . . . . . . 57

6.0 CONDUCTING AN INDEPENDENT COMPARABILITY ANALYSIS . . . . 59

6.1 Comparability Demonstrations . . . . . . . . . . . 59

6.2 Determining Stage II Emissions Reductions . . . . . 60

6.3 Determining Emissions Reductions from Alternative

 Measures . . . . . . . . . . . . . . . . . . . . 61

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . 63

APPENDIX A - OZONE NONATTAINMENT CLASSIFICATIONS . . . . . . A-1 

APPENDIX B - VOC EMISSION REDUCTION SUMMARIES

BY SOURCE CATEGORY . . . . . . . . . . . . . . . . . . . B-1

APPENDIX C - NOx EMISSION REDUCTION SUMMARIES

BY SOURCE CATEGORY . . . . . . . . . . . . . . . . . . . C-1

iv
LIST OF TABLES AND FIGURES

Table Page

1-1 Ozone Nonattainment Areas in the Ozone Transport Region 4

3-1 National Gasoline Consumption Projections . . . . . . . 11

3-2 MOBILE5a Model Inputs Summer Season Temperatures and RVPs 12

3-3 Stage II Penetration Rates . . . . . . . . . . . . . . . 13

3-4 Stage II Rule Effectiveness . . . . . . . . . . . . . . 14

3-5 Stage II Vapor Recovery VOC Emission Reductions for

 Projection Year 1999 . . . . . . . . . . . . . . . . . 17

3-6 Cost Effectiveness of Stage II . . . . . . . . . . . . . 19

4-1 Base Case Motor Vehicle Controls . . . . . . . . . . . 23

4-2 Current and Projected Nationwide Vehicle Miles Traveled 24

4-3 Average Speeds by Roadway Classification and

 Vehicle Type . . . . . . . . . . . . . . . . . . . . . 25

4-4 Enhanced I/M Program Modeling Assumptions . . . . . . . 27

4-5 Motor Vehicle Control Measure VOC Reductions -

 Projection Year 1999 . . . . . . . . . . . . . . . . . 29

4-6 Stationary Source Control Measure VOC Emission

 Reductions - Projection Year 1999 . . . . . . . . . . 35

5-1 NOx to VOC Substitution Ratios . . . . . . . . . . . . . 40

5-2 Motor Vehicle NOx Reductions - Projection Year 1999 . . 43

5-3 NOx RACT and More Stringent Control Technologies . . . . 46

5-4 Utility Control Measure Emission Reductions -

 Projection Year 1999 . . . . . . . . . . . . . . . . . 47

5-5 Non-Utility Control Measure Emission Reductions -

 Projection Year 1999 . . . . . . . . . . . . . . . . . 53

A-1 Ozone Nonattainment Classifications . . . . . . . . . A-1

B-1 Stationary Source VOC Control Measure Emission

 Reductions by Source Category - Projection Year 1999 B-1

C-1 Utility Control Measure Emission Reductions

 by Source Category - Projection Year 1999 . . . . . C-1

C-2 Non-Utility Control Measure Emission Reductions

 by Source Category - Projection Year 1999 . . . . C-4

Figure Page

1-1 Northeast Ozone Transport Region Ozone

 Nonattainment Areas ................. 3

v
vi
ACRONYMS AND ABBREVIATIONS

Act 1990 Clean Air Act

AF air-to-fuel (ratio)

BACT best available control technology

BEA Bureau of Economic Analysis

BOOS burners out of service

CMSA consolidated metropolitan statistical area

CO carbon monoxide

CTG control techniques guideline

DOE U.S. Department of Energy

EPA U.S. Environmental Protection Agency

ERCAM emission reduction and cost analysis model

FGR fuel-gas reburning

FIP Federal implementation plan

HPMS highway performance monitoring system

I/M inspection and maintenance

IC internal combustion

IR ignition timing retardation

ISBM independent small business marketer

L-E low emission

LDAR leak detection and repair

LDGT light-duty gasoline truck

LDGV light-duty gasoline vehicle

LEA low excess air

LEV low emission vehicle

LNB low-NOx burner

MSA metropolitan statistical area

NAAQS national ambient air quality standard

NAPAP national acid precipitation assessment program

NGR natural gas reburning

NOx nitrogen oxides

NSCR non-selective catalytic reduction

NSPS new source performance standard

OFA overfire air

OMS Office of Mobile Sources

ORVR onboard refueling vapor recovery

OTR Northeast Ozone Transport Region

PC pulverized coal

RACT reasonably available control technology

ROM Regional oxidant model

RVP Reid vapor pressure

SCR selective catalytic reduction

SEDS State energy data system

SIP State implementation plan

SNCR selective non catalytic reduction

SOCMI synthetic organic chemical manufacturing industry

TCM transportation control measure

tpd tons per day

tpy tons per year

ULNB ultra-low NOx burner

vii
ACRONYMS AND ABBREVIATIONS (continued)

VMT vehicle miles traveled

VOC volatile organic compound

viii
PREFACE

In order to address the problem of interstate ozone air

pollution in the Northeast, section 184 of the Clean Air Act of

1990 (Act) established the Ozone Transport Region (OTR). The OTR

is comprised of 12 Northeastern States and the District of

Columbia. An Ozone Transport Commission (OTC) was also

established, composed of representatives of the 13 OTR

jurisdictions and EPA, to coordinate ozone control efforts in the

OTR. The section 184 provisions contain additional control

requirements which apply throughout the OTR, even in ozone

attainment areas. One of these is the 184(b)(2) requirement for

Stage II vapor recovery (Stage II) or comparable measures. Stage

II control devices at gasoline pumps capture volatile organic

compounds (VOC) emissions from vehicle refueling.

Since passage of the Act, EPA has been working with the OTC

member States to evaluate the ozone problem in the OTR through

the use of the Regional Oxidant Model. The modeling results

indicate that, beyond the basic VOC control programs, additional

nitrogen oxides (NOx) reductions appear to be more effective than

VOC controls, particularly in attainment areas, in helping

control ozone levels in downwind nonattainment areas. Based on

these findings, the OTC has been focusing its efforts on

developing regional NOx control strategies. 

For example, on September 27, 1994, the OTC signed a

Memorandum of Understanding (MOU) to control NOx emissions from

power plants and other large fuel combustion sources. The NOx

MOU will result in substantial NOx reductions throughout the OTR. 

In addition, on February 10, 1994, the OTC recommended that EPA

require the low emission vehicle (LEV) program to reduce motor

vehicle NOx and VOC emissions in the region. The EPA has

recently taken final action to approve this petition. The OTC is

continuing to investigate additional regional NOx control

strategies.

Moreover, on January 24, 1994, EPA promulgated the onboard

refueling vapor recovery (ORVR) rules (at 59 FR 16262, April 6,

1994) which require onboard refueling emissions controls on

passenger cars and light-duty trucks. When fully phased in, the

ORVR rule will control 95 percent of refueling emissions

nationwide from these vehicles. Because onboard controls and

Stage II target the same emissions source, the benefits of Stage

II will steadily decrease as more and more vehicles with onboard

controls enter the fleet. Ultimately, the Stage II program will

become largely a redundant control effort. The authors of the

Act recognized this and released moderate ozone nonattainment

areas from the general Stage II requirement under section

182(b)(3) upon promulgation of the ORVR rule. See section

202(a)(6) of the Act. (However, inasmuch as it will take 10 to

ix
15 years for onboard controls to be fully phased in, early

emissions reductions from Stage II can be beneficial in reducing

air toxics and States may want to implement it for this purpose.)

Considering the significant NOx reductions that the OTR

States have committed to achieve through their regional NOx

control strategies and that, in the long term, onboard controls

will render Stage II largely redundant, EPA is concerned that

emissions reductions from the section 184(b)(2) Stage II

requirement for regional ozone purposes may not justify the cost,

particularly in attainment areas. Therefore, EPA will

immediately begin working with the OTC and affected States to

determine how to best achieve the required ozone benefits in each

affected area.

x
EXECUTIVE SUMMARY

This report was prepared in response to section 184(b)(2) of

the 1990 Clean Air Act (Act) which requires the U.S.

Environmental Protection Agency (EPA) to conduct a study to

identify control measures capable of achieving emissions

reductions comparable to those achievable by Stage II vehicle

refueling controls in the Northeast Ozone Transport Region (OTR). 

Ground-level Ozone

Ground-level ozone has been a pervasive pollution problem in

the United States for several decades. In the upper atmosphere

ozone occurs naturally and forms a protective layer to shield the

earth from the sun's harmful ultraviolet rays. However, in the

lower atmosphere, or at "ground level," man-made ozone can cause

a variety of problems to human health, crops, and trees. Groundlevel ozone is the focus of this report.

Ground-level ozone causes health problems because it damages

lung tissue, reduces lung function, and sensitizes the lungs to

other irritants. Scientific evidence indicates that ambient

levels of ozone not only affect people with impaired respiratory

systems, but healthy adults and children, as well. Each year

ground-level ozone is also responsible for several billion

dollars worth of agricultural crop yield loss. Studies also

indicate that current ambient levels of ozone are responsible for

damage to forests and ecosystems.

Ground-level ozone is particularly difficult to control

because it is not emitted directly into the atmosphere, but

instead is formed by a complex photochemical reaction caused

primarily by volatile organic compounds (VOCs), nitrogen oxides

(NOx), heat, and sunlight. The VOCs are emitted from a variety

of sources, including industrial and chemical processes, and

automobile refueling, among others. The NOx is emitted from the

combustion of fuels from sources such as automobiles, power

plants, and industrial boilers.

One of the major VOC control programs that has been

implemented by many States is controls at gasoline stations to

capture emissions that occur during automobile refueling. These

programs are known as Stage II vapor refueling controls (Stage

II). 

Historically, there has been a major ozone nonattainment

problem in the Northeastern United States. Much of the problem

is due to regional transport of ozone and ozone precursors (VOC

and NOx). To address this problem of interstate ozone air

pollution, section 184(a) of the Act specifically created the

OTR, which is comprised of 12 Northeastern States and the

xi
District of Columbia. Because of concern about the emissions

from attainment areas contributing to violations of the ozone

standard in downwind areas, the Act also requires the OTR States

to adopt Stage II or a comparable measure in attainment areas, as

well as nonattainment areas.

Stage II Comparability Study

The section 184(b)(2) requirement to adopt Stage II or a

comparable measure applies to all attainment and nonattainment

areas in the OTR. However, because States must adopt Stage II in

serious and severe nonattainment areas under a separate

requirement under section 182(b)(3), only moderate and below

nonattainment areas and attainment areas may take advantage of

the flexibility provided in the section 184(b)(2) provision to

adopt a comparable measure instead of Stage II. For this reason,

emissions reductions estimates for various control measures are

only provided for moderate and below nonattainment areas and

attainment portions in the OTR. Because the OTR States of

Connecticut, Massachusetts, and Rhode Island, and the District of

Columbia consolidated metropolitan statistical area (CMSA) are

comprised solely of serious and severe areas, they must adopt

Stage II statewide. Therefore, these States and the District of

Columbia CMSA are not included in this study.

Only measures not already prescribed in the Act may be

considered as potential comparable measures. Under EPA's

interpretation of section 184(b)(2), such prescribed measures or

measures already required under the State's implementation plan

prior to 1990 may not be substituted for Stage II. For example,

onboard refueling vapor recovery controls cannot be considered as

a comparable measure because they are required of all areas by a

Federal rule. However, control measures that are used to meet

rate-of-progress requirements or to reach attainment, but are not

otherwise required by the Act, may be used to meet the section

184(b)(2) requirement.

The emissions reductions estimates for Stage II and

alternative measures are given for future year 1999. This year

corresponds to the attainment date for serious ozone areas. This

year was selected as the timeframe for comparability because it

is the first statutory attainment date and milestone year that

would occur following full phase-in of a Stage II program, if a

State chose to adopt Stage II rather than a comparable measure. 

The Act provides for a 2-year phase-in schedule for Stage II,

with an optional third year to phase-in independent small

business marketers.

To provide flexibility to the States, this report does not

specify a list of comparable measures from which each area must

select. Rather, emission reduction estimates are provided for a

variety of measures that a State can examine for a strategy

xii
comparable to Stage II. The emission reduction estimates for the

alternative measures are given for nonattainment and attainment

areas on an area-by-area basis. A State may select comparable

measures for each individual affected area or may determine

comparability on an aggregate basis for affected areas in the

State. 

Some alternative measures may not be comparable alone, but

in combination with other measures may achieve comparable

emissions reductions to Stage II. The State may choose to adopt

a single measure or a number of control measures whose emissions

reductions equal or exceed Stage II reductions. As single

measures, reformulated gasoline, enhanced inspection and

maintenance programs (in areas where they are not already

required), and more stringent stationary source NOx controls show

comparability for a number of areas. (States should be aware

that there are significant legal and technical issues regarding

whether and how reformulated gasoline programs can be applied in

attainment areas and nonclassifiable nonattainment areas. The

EPA is currently exploring these issues.)

States may substitute NOx emissions reductions for VOC

reductions according to the methodology given in this document. 

If a particular measure provides both VOC and NOx reductions,

these may be added together to yield a total emissions reduction

estimate for the measure. 

States have the option of conducting an independent

comparability analysis to re-examine measures covered in this

report using up-to-date, State-specific information or to

evaluate control measures not included in this report. 

Within one year of completion of the study, States must

adopt and submit as a State implementation plan (SIP) revision

either Stage II or a comparable measure. States are encouraged

to rely on the information presented in this study report as

guidance in determining which measures may be considered

comparable to Stage II for their areas. The EPA believes this is

what Congress intended by requiring EPA to issue this study. 

However, because this study report did not go through notice-andcomment rulemaking, it is not EPA's final action on the question

of which measures are comparable to Stage II. The EPA will

entertain comments on the study findings for a specific area in

the context of rulemaking on a SIP submittal intended to satisfy

the Act requirement for Stage II or a comparable measure.

xiii
xiv
1.0 INTRODUCTION

This document was prepared in response to section 184(b)(2)

of the 1990 Clean Air Act (Act) which requires the U.S.

Environmental Protection Agency (EPA) to conduct a study to

identify control measures capable of achieving emissions

reductions comparable to those achievable by Stage II vehicle

refueling controls (Stage II) in the Northeast Ozone Transport

Region (OTR).

1.1 Ground-level Ozone

Ground-level ozone has been a pervasive pollution problem in

the United States for several decades. In the upper atmosphere,

or stratosphere, ozone occurs naturally and forms a protective

layer to shield the earth from the sun's harmful ultraviolet

rays. However, in the lower atmosphere, or at "ground level,"

man-made ozone can cause a variety of problems to human health,

crops, and trees. 

Ground-level ozone causes health problems because it damages

lung tissue, reduces lung function, and sensitizes the lungs to

other irritants. Scientific evidence indicates that ambient

levels of ozone not only affect people with impaired respiratory

systems, such as asthmatics, but healthy adults and children, as

well. Exposure to ozone for six to seven hours at relatively low

concentrations has been found to significantly reduce lung

function in normal, healthy people during periods of moderate

exercise. This decrease in lung function is often accompanied by

such symptoms as chest pain, coughing, nausea, and pulmonary

congestion.

Though not as well established in humans, animal studies

have demonstrated that repeated exposure to ozone for many months

can produce permanent structural damage in the lungs and

accelerate the rate of lung function loss, as well as the aging

of lungs. Each year ground-level ozone is also responsible for

several billion dollars worth of agricultural crop yield loss. 

It also causes noticeable foliar damage in many crops and species

of trees. Studies also indicate that current ambient levels of

ozone are responsible for damage to forests and ecosystems.

Ground-level ozone is particularly difficult to control

because it is not emitted directly into the atmosphere, but

instead is formed by a complex photochemical reaction caused

primarily by volatile organic compounds (VOCs), nitrogen oxides

(NOx), heat, and sunlight. The VOCs are emitted from a variety

of sources, including automobile exhaust, industrial and chemical

processes, evaporating gasoline vapors, and automobile refueling,

among others. The NOx is emitted from the combustion of fuels

1
from sources such as automobiles, power plants, and industrial

boilers.

One of the major VOC control programs that has been

implemented by many States is Stage II controls at gasoline

stations to capture emissions that occur during automobile

refueling. (Controls put into place to capture VOC emissions

that occur earlier in the gasoline marketing chain, during

loading/unloading gasoline from bulk terminals, are known as

Stage I controls.)

By 1990, there were 98 areas in the country that did not

meet the EPA-established national ambient air quality standard

for ozone. About 140 million Americans lived in these areas. 

Many of these areas were in the Northeastern United States. That

same year the U.S. Congress passed new amendments to the Clean

Air Act. The amended Act requires a broad array of programs to

further reduce emissions of VOCs, NOx, and other pollutants from

the automobile, petroleum, chemical, steel, utility, and pulp and

paper industries, as well as a wide variety of other large and

small sources. 

1.2 Clean Air Act Requirements

Historically, there has been a major ozone nonattainment

problem in the Northeastern United States. Much of the problem

is due to regional transport of ozone and ozone precursors (VOC

and NOx). To address this problem of interstate ozone air

pollution, section 184(a) of the Act specifically created the

OTR, which is comprised of the entire States of Connecticut,

Delaware, Maine, Maryland, Massachusetts, New Hampshire, New

Jersey, New York, Pennsylvania, Rhode Island, and Vermont, and

the District of Columbia consolidated metropolitan statistical

area (CMSA), which includes a portion of Virginia.

Figure 1-1 provides a map of the OTR showing the designated

attainment and nonattainment areas. The Act established five

classifications of ozone nonattainment areas. In ascending order

of severity of the air pollution problem, these are: marginal,

moderate, serious, severe, and extreme. In addition, there are

three types of nonclassifiable ozone nonattainment areas: 

submarginal, transitional, and incomplete/no data. (See Appendix

A for the definitions of the ozone nonattainment area types.) 

The OTR ozone areas are listed by classification in Table 1-1. 

Within the OTR, there are no extreme, submarginal, or

transitional areas.

The Act requires specific control requirements according to

the designation and classification of each area. Section 184

also provides for a specific set of additional requirements for

the OTR designed to address the regional transport problem. 

2
MAP

3
Table 1-1. Ozone Nonattainment Areas in the Ozone Transport Region

Severe-17

New York-N New Jer-Long Is, NY-NJ-CT

Severe-15

Baltimore, MD Philadelphia-Wilm-Trent, PA-NJ-DE-MD

Serious

Boston-Lawrence-Worcester (E.MA), MA-NH Providence (All RI), RI

Greater Connecticut Springfield (Western MA), MA

Portsmouth-Dover-Rochester, NH Washington, DC-MD-VA

Moderate

Atlantic City, NJ Portland, ME

Knox & Lincoln Cos, ME Poughkeepsie, NY

Lewiston-Auburn, ME Reading, PA

Pittsburgh-Beaver Valley, PA

Marginal

Albany-Schenectady-Troy, NY Johnstown, PA

Allentown-Bethlehem-Easton, PA-NJ Kent and Queen Anne's Cos, MD

Altoona, PA Lancaster, PA

Buffalo-Niagara Falls, NY Manchester, NH

Erie, PA Scranton-Wilkes-Barre, PA

Essex Co (Whiteface Mtn), NY Sussex Co, DE

Hancock & Waldo Cos, ME York, PA

Harrisburg-Lebanon-Carlisle, PA Youngstown-Warren-Sharon, OH-PA*

Jefferson Co, NY

Incomplete/No Data

Franklin Co (part), ME Juniata Co, PA

Oxford Co (part), ME Lawrence Co, PA

Somerset Co (part), ME Northumberland Co, PA

Belknap Co, NH Pike Co, PA

Cheshire Co, NH Schuylkill Co, PA

Sullivan Co, NH Snyder Co, PA

Crawford Co, PA Susquehanna, Co, PA

Franklin Co, PA Warren Co, PA

Greene Co, PA Wayne Co, PA

*Only the Pennsylvania counties of this nonattainment area are in the OTR.

4
These additional requirements include control measures for

attainment areas as well as nonattainment areas. 

For the OTR, there are two requirements related to Stage II

vehicle refueling controls. One is the section

182(b)(3)requirement that all moderate and above nonattainment

areas must adopt Stage II vehicle refueling controls. However,

pursuant to section 202(a)(6), moderate areas were released from

this requirement when EPA promulgated onboard vapor recovery

rules. (See reference 1.)

The second is the section 184(b)(2) requirement that all

areas in the OTR must adopt Stage II or alternative measures

capable of achieving comparable emissions reductions, as

identified in this study. Because States that contain serious

and above nonattainment areas must implement Stage II programs

under the first requirement above, even after promulgation of the

onboard regulations, they cannot take advantage of the

flexibility provided by section 184(b)(2) to adopt a comparable

measure instead. Therefore, this document only evaluates

alternative measures for moderate and below nonattainment areas

and attainment portions of the OTR. Affected States have within

1 year of the completion of this study to adopt and submit as a

State implementation plan (SIP) revision either Stage II or a

comparable measure.

Section 182(b)(3) of the Act sets forth the general

requirements for Stage II gasoline vapor recovery programs as

follows:

(3) GASOLINE VAPOR RECOVERY.

(A) GENERAL RULE - Not later than 2 years after the

date of the enactment of the Clean Air Act Amendments of

1990, the State shall submit a revision to the applicable

implementation plan to require all owners or operators of

gasoline dispensing systems to install and operate, by the

date prescribed under subparagraph (B), a system for

gasoline vapor recovery of emissions from the fueling of

motor vehicles. The Administrator shall issue guidance as

appropriate as to the effectiveness of such system. This

subparagraph shall apply only to facilities which sell more

than 10,000 gallons of gasoline per month (50,000 gallons

per month in the case of an independent small business

marketer of gasoline as defined in section 324).

(B) EFFECTIVE DATE - The date required under

subparagraph (A) shall be -

(i) 6 months after the adoption date, in the

case of gasoline dispensing facilities for which

construction commenced after the date of the enactment of

the Clean Air Act Amendments of 1990;

5
(ii) one year after the adoption date, in the

case of gasoline dispensing facilities which dispense at

least 100,000 gallons of gasoline per month, based on

average monthly sales for the 2-year period before the

adoption date; or

(iii) 2 years after the adoption date, in the case

of all other gasoline dispensing facilities.

Any gasoline dispensing facility described under both clause

(i) and clause (ii) shall meet the requirements of clause

(i).

(C) REFERENCE TO TERMS - For purposes of this

paragraph, any reference to the term "adoption date" shall

be considered a reference to the date of adoption by the

State of requirements for the installation and operation of

a system for gasoline vapor recovery of emissions from the

fueling of motor vehicles.

Section 182(b)(3)(A) requires Stage II vapor recovery on all

gasoline dispensing facilities that dispense more than 10,000

gallons of gasoline per month or 50,000 gallons of gasoline per

month for independent small business marketers (ISBM's). 

In addition to the 2-year phase-in schedule of section

182(b)(3)(B), States can also opt for a 3-year phase-in period

for ISBM's. 

1.3 Study Approach

The major objectives of this study are to:

! assess the emission reductions associated with the

implementation of Stage II vapor recovery in the study

areas, and

! analyze the emission reductions associated with

alternative control measures that may be selected as a

control strategy comparable to Stage II.

A secondary objective is to examine the costs of the control

measures analyzed to assist the States in their decisions of

whether to adopt Stage II or comparable measures. 

The Emission Reduction and Cost Analysis Model for VOC

(ERCAM-VOC) was selected as the primary modeling tool in the

study analysis. This model was used throughout the debate

leading to the passage of the 1990 Clean Air Act Amendments to

analyze the costs and emission reductions associated with the

alternative measures aimed at controlling VOC.

6
The ERCAM-VOC was created to analyze the national impacts of

VOC controls; thus, many of the modeling techniques reflect the

needs for analyzing this large domain. Since the study only

addresses certain areas in the OTR, improvements in the modeling

methods were implemented for the Stage II and motor vehicle

components of the model. State-specific emission factor

(MOBILE5a) modeling was performed for these sectors. The

specific modeling techniques are discussed in more detail in

Chapters 3 and 4 of this report.

The EPA promulgated regulations for onboard vapor recovery

on January 24, 1994. In recognition of this, the Stage II

emission reduction benefit analysis assumes onboard vapor

recovery rules are promulgated in 1994 with a phase-in of onboard

controls beginning in model year 1998.

The base year emissions for the study area are from the

Interim 1990 Inventory. This data source was chosen because it

covers the entire geographical region studied under this

analysis. While SIP emissions inventory data may be available

for some areas, States are required to submit 1990 emission

inventories only for their nonattainment areas (data may also be

available for surrounding counties for modeling purposes) and the

inventories are not currently finalized. It is acknowledged that

State-submitted data may differ from the inventory data used in

this analysis.

The Interim Inventory point source emissions are projected

from the 1985 National Acid Precipitation Assessment Program

(NAPAP) Inventory. State point source inventories are expected

to be higher because the 1985 NAPAP Point Source Inventory

generally did not include sources in the 25 to 100 ton per year

range. However, the inventory may contain sources of nitrogen

oxides (NOx) within this size range if the source is a major

emitter of another criteria pollutant. While the effects of

applying reasonably available control technology (RACT) to

sources at this level are examined in this report, the effects

are expected to be underestimated due to the limitations of the

inventory.

Control measures were selected for analysis based on the

availability of data on control effectiveness, coverage of

emissions in the inventory, effectiveness in less urbanized

areas, and availability of modeling approaches for assessing the

emission reductions. Only measures not already prescribed in the

Act were considered because, under EPA's interpretation of

section 184(b)(2), such prescribed measures and measures already

required under the State's implementation plan prior to 1990 may

not be substituted for Stage II. Control measures that are used

to meet rate-of-progress requirements or to reach attainment, but

are not otherwise required by the Act, may be used to meet the

section 184(b)(2) requirement.

7
Initially, a comprehensive list of alternative control

measures was developed and each was examined with respect to the

criteria above. The list was then narrowed, based on the

criteria discussed above, to include the following measures:

! enhanced inspection and maintenance (I/M),

! reformulated gasoline program,

! more stringent control on existing VOC stationary

sources,

! RACT to 25 tpy NOx stationary sources, and

! more stringent control of existing NOx stationary

sources.

These control measures are evaluated in Chapters 4 and 5. States

also have the option to evaluate other control measures.

1.4 Organization of Report

The information in this report provides the basis for State

selection and adoption of control measures comparable to Stage

II.

Chapter 2 discusses how the information presented in this

report is to be used by States in making a comparability

determination.

Chapter 3 discusses the methods used to model Stage II

emission reductions and presents the emissions reductions

estimates on an area-by-area basis.

Chapter 4 evaluates mobile and stationary VOC control

measures as potential comparable measures. The modeling

assumptions used for each control measure are described.

Chapter 5 evaluates mobile and stationary source NOx control

measures as potential comparable measures. The chapter provides

a NOx substitution method for determining what level of NOx

emissions reductions is comparable to the VOC emissions

reductions from Stage II.

Chapter 6 describes a method by which States can conduct an

independent comparability analysis to re-examine measures covered

in this report using up-to-date, State-specific information or to

evaluate control measures not included in the report.

8
2.0 COMPARABILITY DETERMINATIONS

2.1 Applicability

The section 184(b)(2) requirement to adopt Stage II or a

comparable measure applies to all attainment and nonattainment

areas in the OTR. However, because States must adopt Stage II in

serious and severe nonattainment areas under a separate

requirement under section 182(b)(3), only moderate and below

nonattainment areas and attainment areas may take advantage of

the flexibility provided in the section 184(b)(2) provision to

adopt a comparable measure instead of Stage II. For this reason,

emissions reductions estimates for various control measures are

only provided for moderate and below nonattainment areas and

attainment portions in the OTR. Because the OTR States of

Connecticut, Massachusetts, and Rhode Island, and the District of

Columbia CMSA are comprised solely of serious and severe areas,

they must adopt Stage II statewide. Therefore, these States and

the District of Columbia CMSA are not included in this study.

2.2 Time Frame for Comparability

In the following chapters, emissions reductions for Stage II

and alternative measures are given for the future year 1999. 

This year corresponds to the attainment date for serious ozone

areas. This year was selected because it is the first statutory

attainment date that would occur following full phase-in of a

Stage II program, if a State chose to adopt Stage II rather than

a comparable measure. The Act provides for a 2-year phase-in

schedule for Stage II, with an optional third year to phase-in

ISBM's. For marginal and below nonattainment areas and

attainment areas, the emissions reductions achieved from

application of this requirement are clearly intended to assist in

the attainment of downwind areas of higher classifications rather

than for attainment in the controlled area. (Marginal areas were

required to be in attainment by November 15, 1993.) For moderate

areas, the emissions reductions may also help bring the local

area into attainment.

2.3 Comparable Measure Selection

Only measures not already prescribed in the Act may be

considered as potential comparable measures. Under EPA's

interpretation of section 184(b)(2), such prescribed measures or

measures already required under the State's implementation plan

prior to 1990 may not be substituted for Stage II. For example,

onboard refueling vapor recovery (ORVR) controls cannot be

considered as a comparable measure because they are required of

all areas by a Federal rule. However, control measures that are

used to meet rate-of-progress requirements or to reach

9
attainment, but are not otherwise required by the Act, may be

used to meet the section 184(b)(2) requirement.

To provide flexibility to the States, this report does not

specify a list of comparable measures from which each area must

select. Rather, emission reduction and cost information are

provided for a variety of measures that the State can examine for

a strategy comparable to Stage II for a particular area. Stage

II emissions reductions are contained in Chapter 3. These

emissions reductions estimates establish the level of emissions

reductions that an alternative control measure must achieve or

exceed to be comparable. Emissions reductions estimates for

alternative VOC and NOx control measures are given in Chapters 4

and 5, respectively.

Some alternative measures may not be comparable alone, but

in combination with other measures may achieve comparable

emissions reductions to Stage II. The State may choose to adopt

a single measure or a number of control measures whose emissions

reductions equal or exceed Stage II reductions. In addition,

States may substitute NOx emissions reductions for VOC reductions

according to the methodology given in Chapter 5.0. If a

particular measure provides both VOC and NOx reductions, these

may be added together to yield a total emissions reduction

estimate for the measure.

 Emissions reduction estimates for the alternative VOC and

NOx control measures are given for nonattainment and attainment

areas on an area-by-area basis. A State may select comparable

measures for each individual affected area or may determine

comparability on an aggregate basis for affected areas in the

State. In the second case, if the sum of the projected emissions

reductions from the selected alternative measure in applicable

areas equals or exceeds the sum of the projected Stage II

reductions for the same areas, the alternative measure would be

considered comparable.

2.4 Conducting an Independent Comparability Analysis

States have the option of conducting an independent analysis

to re-examine measures covered in this report using up-to-date,

State-specific information or to evaluate control measures not

included in this report. The methodology for the analysis is

provided in Chapter 6.0.

10
3.0 STAGE II EMISSION REDUCTIONS

This chapter describes the emission projection methodology

and modeling assumptions used to estimate VOC emission reductions

from Stage II vapor recovery controls. Results of the modeling

analyses are provided on an area-by-area basis for the year 1999. 

The emissions reductions estimated for Stage II establish the

level of emissions reductions that an alternative control

strategy must meet to be considered a comparable measure.

3.1 MODELING ASSUMPTIONS

3.1.1 Refueling Emissions

Base year vehicle refueling emissions are estimated from

gasoline consumption (by county) and State-specific MOBILE5a

emission factors. (See reference 2.) Gasoline consumption

estimates are based on the Interim 1990 Inventory. (See

reference 3.) The Interim Inventory gasoline consumption

estimates were projected from the 1985 NAPAP Inventory (see

reference 4) based on State-level historical estimates of motor

vehicle gasoline consumption from the U.S. Department of Energy

(DOE) State Energy Data System (SEDS). (See reference 5.) The

emission estimates presented in this analysis parallel those in

the Interim Inventory with the exception that State-specific

emission factors, rather than a national average emission factor,

were used to estimate emissions. 

Vehicle refueling emission projections are calculated by

applying growth factors to the gasoline consumption estimates and

multiplying this by the State-specific MOBILE5a refueling

emission factor (in grams per gallon) for the projection year. 

National projections of gasoline usage from the MOBILE4.1 Fuel

Consumption Model (see reference 6) were used to estimate growth

for each area. The national estimates of gasoline consumption

and corresponding annual (compounded) growth rates are shown in

Table 3-1.

Table 3-1. National Gasoline Consumption Projections

Projection Year

Gasoline Usage

(million gallons)

Equivalent Annual

Growth (% per year)

1990 94,585 -

1999 105,221 1.2 (1990-1999)

State-specific refueling emission factors are used to

account for differences in temperature and gasoline Reid vapor

pressure (RVP). Summer (ozone) season temperatures and RVPs were

11
used to calculate ozone season daily emissions. Table 3-2

presents the minimum and maximum temperatures, as well as the

1990 RVP, the phase II RVP, and the projection year RVP used as

model inputs for each State. For areas with a 9.0 phase II

limit, the projection year RVP is the phase II RVP minus a 0.3

psi default compliance safety margin. For areas with a phase II

limit of 7.8 psi, no safety margin is applied. This is in

accordance with EPA's Office of Mobile Sources (OMS) guidance on

the selection of RVPs for modeling purposes. (See reference 7.) 

The MOBILE5a emission factor accounts for refueling vapor

displacement and spillage losses. Underground tank breathing

losses were estimated using AP-42 emission factors. (See

reference 8.) These calculations are consistent with the

methodologies recommended in the mobile source inventory

guidance.

Table 3-2. MOBILE5a Model Inputs

Summer Season Temperatures and RVPs

State

Minimum

Temperaturea

(

o

F)

Maximum

Temperaturea

(

o

F)

RVP

(1990)b

RVP

(Phase II

Limit)c

RVP

(Projection

Year)

Delaware 64 84 8.4 9.0 8.7

Maine 55 76 8.3 9.0 8.7

Maryland 65 85 8.3 7.8 7.8

New Hampshire 54 80 8.3 9.0 8.7

New Jersey 62 82 8.4 9.0 8.7

New York 61 81 8.3 9.0 8.7

Pennsylvania 62 83 8.6 9.0 8.7

Vermont 56 78 8.3 9.0 8.7

SOURCES: aSee reference 9.

b

See reference 10.

c

See reference 11.

3.1.2 Stage II Control Assumptions

The Act and the General Preamble for the Implementation of

Title I of the Clean Air Act Amendments of 1990 (Title I General

Preamble) (see reference 12) include the following specifications

for Stage II vapor recovery programs:

C Stage II must be applied to facilities that sell more

than 10,000 gallons of gasoline per month (50,000

12
gallons per month for ISBM's). States are not

precluded from adopting lower source size cutoffs

(section 182(b)(3)).

C States should prescribe the use of Stage II systems

that are certified to achieve at least 95 percent

control of VOCs and that are properly installed and

operated (General Preamble).

For modeling purposes, the control program requirements 

should be translated into a control device efficiency, a rule

penetration (fraction of sources affected), and rule

effectiveness (to account for equipment malfunctions and

noncompliance). These three variables are combined to form an

overall effectiveness for Stage II, which is input to MOBILE5a.

Because the Title I General Preamble specifies that the

systems should be tested or certified at 95 percent reduction of

VOC (for properly installed and operated systems), a 95 percent

control device efficiency was used for the modeling analysis.

The penetration rate depends on the size cutoffs implemented

by the area. The national average percentage of consumption

excluded at various size cutoffs and corresponding penetration

rates are shown in Table 3-3. (See reference 13.)

Table 3-3. Stage II Penetration Rates

Exemption Scenario

Percentage

of Consumption

Excluded (%)

Penetration 

Rate (%)

< 2,000 gal/month 2.4 97.6

<10,000 gal/month 2.8 97.2

<10,000 gal/month &

 ISBM's < 50,000 gal/month

10.0 90.0

The consumption estimates in Table 3-3 are based on a study

of metropolitan area service station size distributions. This

represents the best survey information to date and was used to

determine overall effectiveness of Stage II. However, size

distribution varies from area to area, and rural areas may tend

to have a greater population of ISBM's.

The Act-mandated cutoffs of 10,000 gallons per month for

gasoline dispensing facilities, or 50,000 per month in the case

13
of ISBM's, were used in the modeling, with a penetration rate of

90 percent. If States opt to establish programs with a single

size cutoff of 10,000 gallons per month, this would increase the

emissions reductions from Stage II.

Rule effectiveness discounts the control device efficiency

to account for noncompliance, equipment malfunctions, improper

installation and maintenance, and improper use of the equipment. 

Table 3-4 shows the in-use efficiency and corresponding rule

effectiveness values at various inspection levels. (See

reference 13.)

The certification efficiency is the control device

efficiency standard that Stage II vapor recovery systems are

required to achieve. This is the baseline for measuring rule

effectiveness. The Stage II Technical Guidance Document (see

reference 13) notes that these in-use efficiency calculations do

not account for misinstallation of underground vapor piping. 

Nevertheless, this represents the best available data on Stage II

rule effectiveness.

Table 3-4. Stage II Rule Effectiveness

Inspection Frequency

In-Use

Efficiency (%)

Rule

Effectiveness (%)

Certification 95 ----

Semi-Annual 92 96.8

Annual 86 90.5

Minimal 62 65.3

The Enforcement Guidance for Stage II Vehicle Refueling

Control Programs (see reference 14) sets minimal standards for

compliance inspections at gasoline dispensing facilities. This

guidance specifies that a minimum of one compliance inspection

should be conducted at each facility every year. Therefore, this

analysis assumed annual inspections and used the corresponding

rule effectiveness value from Table 3-4. Combining the control

device efficiency (95 percent), rule penetration (90 percent),

and rule effectiveness (90.5 percent) yields an overall

effectiveness of 77 percent for Stage II. This was input to the

MOBILE5a model to estimate projection year emission factors.

The emission factor for breathing losses with Stage II

controls was calculated as a 77 percent reduction from

uncontrolled levels, or 0.23 lbs VOC per 1,000 gallons of fuel.

14
3.1.3 Onboard Refueling Vapor Recovery Control Assumptions 

Section 202 of the Act requires implementation of ORVR

systems beginning with the fourth model year after the rules are

promulgated. The ORVR rules were promulgated on January 24,

1994; therefore, the controls are required to be installed

beginning with model year 1998 vehicles.

The ORVR rules require ORVR systems to be installed on 40

percent of light-duty gasoline vehicles (LDGV) in 1998, 80

percent in 1999, and 100 percent thereafter. Because MOBILE5a

does not model this type of phase-in for ORVR controls (MOBILE5a

only accepts a start year of input and assumes that all new

vehicles in that model year install ORVR controls), a start date

of model year 1999 was assumed in this analysis for LDGV. The

effect of modeling ORVR control requirements with full

implementation in the second model year rather than as phased-in

over 3 years will tend to slightly underestimate the benefits of

ORVR controls in 1999. This is because the sum of 40 percent of

model 1998 LDGVs and 80 percent of model year 1999 LDGVs is

greater than 100 percent of the new model cars in 1999. Slightly

underestimating the reductions from ORVR controls, in turn, will

cause reductions from Stage II to be slightly overestimated.

The ORVR rules also require a similar phase-in for controls

on light-duty gasoline trucks (LDGT) beginning in 2001 for

vehicles with a gross weight rating of 0-6,000 lbs, and in 2004

for vehicles with a gross weight rating of 6,001-8,500. Because

emission reductions from controls on these vehicles begin after

1999, they do not affect the Stage II comparability analyses. 

However, in the future, as more and more vehicles with ORVR

controls enter the fleet, the benefits of Stage II (incremental

to ORVR) will decrease.

MOBILE5a applies a 96 percent reduction (from uncontrolled

levels) to the refueling emissions from cars with ORVR controls. 

ORVR controls do not reduce breathing losses.

Because ORVR controls are mandated by the Act for all areas,

ORVR controls have been applied first in the modeling simulations

and will be attributed with controlling the refueling emissions

in cases where redundancy occurs.

3.2 MODELING RESULTS

The emission reductions attributable to Stage II vapor

recovery were calculated for each area by comparing the

projection year with the uncontrolled baseline. As discussed

above, emission reductions from Stage II are estimated assuming

ORVR controls are installed. The results are presented in Table

3-5 for projection year 1999.

15
In general, emission reductions from Stage II are highest in

larger and/or more urbanized areas. Urban areas exhibit a higher

population density and thus higher gasoline usage. This

increases the baseline vehicle refueling emissions from which

emission reductions are measured. In many States, the area

designated "Attainment Counties" in Table 3-5 shows the highest

emission reduction simply because this division encompasses more

counties than the individual nonattainment areas.

3.3 COST EFFECTIVENESS

The Stage II Technical Guidance Document (see reference 13)

provides cost-effectiveness estimates for Stage II at various

size cutoffs. Annual inspections are assumed in deriving these

cost effectiveness values, which is consistent with the

requirements of the Act and the modeling assumptions used in this

analysis. Cost effectiveness may vary from area to area

depending on the distribution of service station sizes and single

versus multiproduct dispensers. The cost-effectiveness values

shown in Table 3-6 are based on a nationwide survey of service

stations that were classified into model plants. The costeffectiveness estimates assume an equal distribution between

single and multiproduct dispensers. Costs per ton are higher for

multiproduct than for single-product dispensers.

At the Act-mandated size cutoffs of 10,000 and 50,000 for

non-ISBM's and ISBM's, respectively, the average cost

effectiveness is estimated to be $930 per ton.

16
Table 3-5. Stage II Vapor Recovery VOC Emission Reductions

Projection Year 1999

Ozone Area

Stage II Reduction

(tpd)

Delaware

Sussex County 0.58

Maine

Hancock & Waldo Counties 0.23

Knox & Lincoln Counties 0.29

Lewiston-Auburn 1.14

Portland 2.11

Franklin County 0.13

Oxford County 0.22

Somerset County 0.18

Attainment Counties 1.44

Maryland

Kent & Queen Anne's Counties 0.29

Attainment Counties 2.74

New Hampshire

Manchester 2.13

Belknap County 0.25

Chesire County 0.17

Sullivan County 0.15

Attainment Counties 0.78

New Jersey

Allentown-Bethlehem-Easton 0.78

Atlantic City 3.37

New York

Albany-Schenectady-Troy 3.84

Buffalo-Niagara Falls 4.39

Essex County 0.14

Jefferson County 0.40

Poughkeepsie 0.99

Attainment Counties 15.32

Pennsylvania

Allentown-Bethlehem-Easton 2.12

Altoona 0.45

Erie 1.54

17
Table 3-5 (continued)

Ozone Area

Stage II Reduction

(tpd)

Harrisburg-Lebanon-Carlisle 3.18

Johnstown 0.88

Lancaster 1.19

Pittsburgh-Beaver Valley 10.95

Reading 1.16

Scranton-Wilkes-Barre 2.51

York 1.38

Youngstown-Warren-Sharon 0.49

Crawford County 0.34

Franklin County 0.35

Greene County 0.14

Juniata County 0.07

Lawrence County 0.53

Northumberland County 0.28

Pike County 0.08

Schuylkill County 0.36

Snyder County 0.08

Susquehanna County 0.16

Warren County 0.17

Wayne County 0.22

Attainment Counties 4.35

Vermont

Attainment Counties 2.64

18
Table 3-6. Cost-Effectiveness of Stage II

Exemption Scenario

Cost-Effectiveness

($/ton)

No exemptions 1,230

< 2,000 gal/month 1,130

< 10,000 gal/month 1,000

< 10,000 gal/month & ISBM's < 50,000 gal/month 930

SOURCE: See reference 13.

19
20
4.0 CONTROL MEASURES FOR VOLATILE ORGANIC COMPOUNDS

This chapter presents the results of the analysis of a

variety of VOC control measures. Section 4.1 examines motor

vehicle control measures and Section 4.2 examines stationary

source measures. Emission reduction estimates provided for these

measures should be compared with the emission reduction estimates

for Stage II in Chapter 3.0 to determine whether a measure or

combination of measures achieves comparable reductions to Stage

II. Some of the measures also reduce NOx emissions (see Chapter

5). In determining comparability to Stage II emissions

reductions, the VOC and NOx emissions reductions from an

alternative measure may be combined according to the methodology

provided in Section 6.1.

4.1 MOTOR VEHICLE MEASURES

The motor vehicle measures analyzed in the study that

provide VOC emission reductions are: (1) enhanced I/M programs

and (2) reformulated gasoline. Some areas (metropolitan

statistical areas (MSA's) of 100,000 population or greater) are

already required by the Act to implement enhanced I/M. For these

areas, enhanced I/M cannot be considered as a comparable measure.

The following measures were considered but not included in

the final study:

! Clean fuel fleets were evaluated in a preliminary

scoping study and the resulting emission benefits were

low. Programs targeting vehicle fleets show higher

benefits in more urban areas. The affected areas in

this study, in large part, are the less urbanized

portions of the States. This measure was therefore not

examined in the final study.

! Transportation control measures (TCM's) are also not

included in the analysis. TCM's are, by nature, area

specific and usually developed as a package of

measures. It is beyond the scope of this study to

develop potential TCM programs for each area. In

addition, TCM's are generally most effective in

urbanized areas. States wishing to consider TCM's

instead of Stage II may conduct an independent analysis

of the measures using the procedures provided in

Chapter 6.

! The California low emission vehicle (LEV) program is

also not included in this study. On February 10, 1994,

the OTC submitted a recommendation to EPA that EPA

require the LEV program throughout the OTR. Under this

recommendation, the LEV program is scheduled to begin

21
in model year 1999. Because the emissions reductions

benefits from this program rely on fleet turnover, only

limited reductions will be achieved in the first model

year due to the limited number of vehicles in the fleet

that will be meeting the standard.

! Accelerated vehicle scrappage results in higher fleet

turnover and speeds up the benefits of programs such as

the Tier 1 tailpipe standards if people replace their

scrapped vehicles with new cars. Because of the

uncertainty in benefits, this measure was not included

in the final study.

4.1.1 Modeling Analyses

Base Case Controls and VMT Estimates

The base case motor vehicle projections include all of the

mandatory control requirements of the Act. This includes

enhanced I/M in MSA's with a population of 100,000 or more for

all areas in the OTR, and basic I/M for moderate areas not

required to implement enhanced I/M. In the case of enhanced I/M,

the Act only mandates that the program apply to the urbanized

portions of the MSA. Under the base case modeling scenario, no

judgement was made as to whether specific counties would be

exempt based on this provision; the enhanced I/M controls were

applied to the entire MSA. The base case motor vehicle controls

are summarized in Table 4-1.

Highway vehicle emissions are projected by combining

estimated vehicle miles traveled (VMT) with MOBILE5a (see

reference 2) emission factors. Base year VMT estimates are from

the Interim 1990 Inventory. (See reference 3.) The VMT

estimates were retained by county, vehicle type, and roadway

classification. Ozone season daily VMT was estimated from annual

VMT by applying seasonal and daily temporal allocation factors. 

(See reference 15.) Projection year VMT was calculated using

national VMT growth from the MOBILE4.1 Fuel Consumption Model

(see reference 16), which was scaled to each area based on

expected population growth. Table 4-2 shows the national VMT

projections and corresponding annual growth rates.

State-specific MOBILE5a emission factors were applied to the

VMT estimates to calculate emissions. The ozone season

temperatures and RVP's used in the modeling are the same values

used for the vehicle refueling projections, as shown in Table

3-2. Each vehicle type/roadway classification was matched to an

average speed used in the MOBILE5a modeling. The correspondence

between roadway classifications and speeds is shown in Table 4-3.

22
Table 4-1. Base Case Motor Vehicle Controls

Attainment, Marginal, and Moderate Areas in the OTR

Program Description

RVP Phase II RVP minus a 0.3 psi margin of safety. 

For areas with a 7.8 psi limit, no safety margin is

applied.

Tailpipe Standards Federal Tier I standards are required nationally. 

Tier II standards are optional (the Act mandates a

study investigating the need for the standards)

and were not modeled.

Evaporative Test Procedure The new Federal evaporative test procedure

applies to all vehicles certified outside California.

I/M Enhanced I/M was applied in MSA's with a

population of 100,000 or more. Basic I/M was

applied in moderate areas unless enhanced I/M is

required.

23
Table 4-2. Current and Projected Nationwide Vehicle Miles Traveled

Vehicle Miles Traveled

(billions)

Equivalent Annual

Growth Rate

(percent per year)

1990 1999 1990-1990

LDGV 1,169.22 1,361.35 1.7

LDGT 444.19 617.03 3.7

HDGV 55.70 72.02 2.9

Diesel 130.45 174.38 3.3

 Total 1,799.56 2,224.78 2.4

NOTES: LDGV = light-duty gasoline vehicle

LDGT = light-duty gasoline truck

HDGV = heavy-duty gasoline vehicle

SOURCE: EPA, 1991f.

24
Table 4-3. Average Speeds by Roadway Classification and Vehicle Type

(mph)

Rural Urban

Interstate

Principal

Arterial

Minor

Arterial

Major

Collector

Minor

Collector Local Interstate

Other Freeways

& Expressways

Principal

Arterial

LDV 60 45 40 35 30 30 45 45 20 LDT 55 45 40 35 30 30 45 45 20 HDV 40 35 30 25 25 25 35 35 15 

NOTES: LDV = light-duty vehicle

LDT = light-duty truckHDV = heavy-duty vehicle

SOURCE: Derived from the Highway Performance Monitoring System Impact Model.
Enhanced I/M

Enhanced I/M modeling parameters are described in Table 4-4. 

These are based on each area meeting I/M performance standard

requirements from the Inspection/Maintenance Program

Requirements; Final Rule. (See reference 17.) States may vary

the I/M program parameters (e.g., biennial versus annual,

stringency of cutpoints, waiver rates) as long as the resulting

emission benefits are equivalent to those of the model program.

In fact, the guidance suggests a biennial program, which is

generally more cost effective than an annual program. Emission

reductions for enhanced I/M are measured incremental to Act

requirements. In areas where basic I/M is required, the

reductions for enhanced I/M are measured incremental to this

baseline. This analysis assumes that all counties within MSAs of

population greater than 100,000 implement enhanced I/M under

baseline Act requirements. The Act requires enhanced I/M only

within the urbanized portions of these areas. Thus, Act

requirements may be overstated in this analysis. Benefits from

extending enhanced I/M to non-urbanized portions of nonattainment

areas or MSAs may be substituted for Stage II reductions.

Enhanced I/M shows comparable reductions in all areas where

this measure not already required under the Act. 

Reformulated Gasoline

Section 211(k) of the Act requires EPA to promulgate

regulations establishing requirements for reformulated gasoline

for conventional vehicles in the nine worst ozone nonattainment

areas. This provision also allows other areas classified as

marginal, moderate, serious, and severe to opt into the Federal

reformulated gasoline program at the request of the Governor of

the State. The final rules were published on February 16, 1994. 

(See reference 18.) The reformulated gasoline program will be

implemented in two phases. Phase I begins on January 1, 1995 and

will achieve a 15 to 17 percent reduction in both VOC emissions

and toxic emissions from motor vehicles. Phase II begins on

January 1, 2000 and will achieve a 25 to 29 percent VOC

reduction, a 20 to 22 percent reduction in toxics emissions, and

a 5 to 7 percent reduction in NOx emissions.

Reformulated gasoline was modeled according to the Federal

program requirements using the MOBILE5a reformulated gasoline

routines. This simply involved setting an input flag within the

MOBILE5a input file. The model then calculated the projection

year emission factors using Phase I or Phase II reformulated gas,

depending on the projection year. The reformulated gasoline

program will be in Phase I in 1999, the year selected for

comparability demonstration. Therefore, only the emissions

26
Table 4-4. Enhanced I/M Program Modeling Assumptions

I/M Program:

 Start year:

 Pre-1981 MYR stringency rate:

 Model years covered:

 Waiver rate (pre-1981):

 Waiver rate (1981 and newer):

 Compliance rate:

 Inspection type:

 Inspection frequency:

 Vehicle types covered:

 Test Type:

1996

20%

1986 - 2020

3%

3%

96%

Centralized

Annual

LDGV, LDGT 1 & 2

1968 - 1985 MY

2500/Idle

1986 - 2020 MY

Transient

Cutpoints (g/mile):

0.80 HC

20.0 CO

2.0 NOx

Anti-tampering Program:

 Start year:

 Model years covered:

 Vehicle types covered:

 Inspection type:

 Inspection frequency:

 Compliance rate:

 Tampering inspections performed:

1996

1984 - 2020

LDGV, LDGT 1 & 2

Centralized

Annual

96%

Catalyst, Fuel inlet

restrictor

Evaporative System Pressure Test:

 Start year:

 Model years covered:

 Vehicle types covered:

 Inspection type:

 Inspection frequency:

 Compliance rate:

1996

1983-2020

LDGV, LDGT 1 & 2

Centralized

Annual

96%

Functional Purge Test:

 Start year:

 Model years covered:

 Vehicle types covered:

 Inspection type:

 Inspection frequency:

 Compliance rate:

1996

1986 - 2020

LDGV, LDGT 1 & 2

Centralized

Annual

96%

27
reductions attributable to Phase I were evaluated for possible

comparability to Stage II reductions.

Table 4-5 includes data on emissions reductions from

reformulated gasoline in all areas affected by the Stage II or

comparable measure requirement. However, States should be aware

that there are significant outstanding legal and technical issues

regarding whether and how reformulated gasoline programs may be

applied in attainment and incomplete data nonattainment areas. 

The EPA is currently exploring these issues. States should

contact the EPA Office of Mobile Sources for further information.

The emission reductions achieved by reformulated gasoline

depend on the mix of emission control measures already in place. 

Reformulated gasoline standards include a further reduction in

gasoline RVP. Therefore, a lower RVP in the baseline lessens the

effectiveness of reformulated gasoline. To a smaller degree, the

impacts of reformulated gasoline are also dependent on whether

the area is subject to an enhanced I/M program in the baseline.

The majority of areas will achieve comparable reductions

with reformulated gasoline. Exceptions in 1999 include the two

areas in New Jersey; Portland, ME; Manchester, NH; Albany and

Buffalo, NY; and Erie, Harrisburg, and Pittsburgh, PA. The

common characteristic of these areas is that all require enhanced

I/M under the Act that reduces the baseline from which

reformulated gasoline reductions are measured.

Because opting into the Federal reformulated gasoline

program is a voluntary action, the program may be selected as a

comparable measure in marginal and moderate areas if it is shown

to achieve emissions reductions equal to or greater than Stage

II. However, section 184(b)(2) requires that either Stage II or

the comparable measure be reflected in the SIP. Therefore, the

opt-in letter from the Governor would need to undergo the SIP

rulemaking process.

Combination of Measures

Enhanced I/M and reformulated gasoline programs were

combined to estimate the overall benefit of the two measures. 

The benefits of motor vehicle measures are not additive because

the controls may be affecting the same emission component (i.e.,

exhaust, evaporative loss, resting loss, or running loss). 

Separate MOBILE5a runs were therefore completed combining the

measures and emissions projected using the resulting emission

factors.

The estimated emission reductions for each of the motor

vehicle measures, as well as the combination of the measures, are

shown in Table 4-5. The same areas that show comparable benefits 

28
Table 4-5. Motor Vehicle Control Measure VOC Reductions

Projection Year 1999

VOC Reduction (tpd)

Ozone Area

Enhanced

I/M

Reformulated

Gasoline

Enhanced

+

Reform

Delaware

Sussex County 3.10 1.25 3.79

Maine

Hancock & Waldo Counties 1.73 0.62 2.06

Knox & Lincoln Counties 1.49 0.53 1.77

Lewiston-Auburn 4.26 1.54 5.08

Portland NA* 1.76 NA*

Franklin County 0.72 0.26 0.86

Oxford County 1.20 0.43 1.43

Somerset County 1.02 0.37 1.22

Attainment Counties 6.61 2.38 7.87

Maryland

Kent & Queen Anne's Counties 1.18 0.47 1.43

Attainment Counties 7.22 3.84 9.70

New Hampshire

Manchester NA 2.00 NA

Belknap County 1.00 0.39 1.21

Chesire County 1.45 0.57 1.76

Sullivan County 0.78 0.30 0.95

Attainment Counties 3.14 1.23 3.83

New Jersey

Allentown-Bethlehem-Easton NA 0.40 NA

Atlantic City NA 1.42 NA

New York

Albany-Schenectady-Troy NA 3.50 NA

Buffalo-Niagara Falls NA 4.13 NA

Essex County 0.75 0.29 0.91

Jefferson County 1.63 0.63 1.97

Poughkeepsie NA 1.28 NA

Attainment Counties 30.97 21.08 46.65

*NA = not applicable, enhanced I/M is already required by the Act in this area. All counties within the area were

assumed to apply enhanced I/M under the Act. If certain counties are exempt (i.e., not urbanized), then reductions in

these counties would be creditable for substitution.Pennsylvania

Allentown-Bethlehem-Easton NA 2.08 NA

Altoona NA 0.50 NA

Erie NA 0.89 NA

Harrisburg-Lebanon-Carlisle NA 2.56 NA

Johnstown NA 1.02 NA

Lancaster NA 1.60 NA

Pittsburgh-Beaver Valley NA 9.87 NA

Reading NA 1.23 NA

Scranton-Wilkes-Barre NA 2.59 NA

29
Table 4-5 (continued)

VOC Reduction (tpd)

Ozone Area

Enhanced

I/M

Reformulated

Gasoline

Enhanced

+

Reform

York NA 1.78 NA

Youngstown-Warren-Sharon NA 0.51 NA

Crawford County 1.78 0.70 2.17

Franklin County 2.25 0.89 2.75

Greene County 0.87 0.34 1.06

Juniata County 0.43 0.17 0.53

Lawrence County 1.95 0.77 2.38

Northumberland County 1.76 0.70 2.14

Pike County 0.41 0.16 0.50

Schuylkill County 2.86 1.13 3.49

Snyder County 0.70 0.28 0.86

Susquehanna County 0.85 0.34 1.04

Warren County 0.95 0.38 1.16

Wayne County 0.74 0.29 0.91

Attainment Counties 15.98 7.28 20.45

Vermont

Attainment Counties 9.17 4.18 11.78

*NA = not applicable, enhanced I/M is already required by the Act in this area. All counties within the area were

assumed to apply enhanced I/M under the Act. If certain counties are exempt (i.e., not urbanized), then reductions in

these counties would be creditable for substitution.

30
with enhanced I/M alone also show comparable benefits with

enhanced I/M and reformulated gasoline combined.

4.1.2 Cost Effectiveness

Enhanced I/M

The EPA has developed estimates of inspection and repair

costs for enhanced I/M programs. (See reference 19.) A biennial

enhanced I/M program that would satisfy the requirements of EPA's

final rule has an estimated net annual cost of $5.4 million per

year per million vehicles. If all program costs are allocated to

VOC reductions, the biennial enhanced I/M program has an annual

cost-effectiveness of $880 per ton of VOC. If program costs are

allocated among the three criteria pollutants reduced by enhanced

I/M -- NOx, carbon monoxide (CO), and VOC -- the cost per ton of

VOC reduced is estimated to be $500 for a biennial enhanced I/M

program. Although EPA's performance standards are based on an

annual program, most areas required to implement enhanced I/M are

expected to implement biennial programs that have been shown to

be more cost effective. It should be noted that EPA's estimates

of inspection and repair costs are based on programs implemented

in urbanized areas. Costs for rural areas may be higher because

fewer cars would be serviced by each inspection station. 

Inconvenience to vehicle owners in rural areas may also be higher

than in urban areas because distances to inspection stations may

be greater in less populated areas.

Reformulated Gasoline

The final rule for reformulated gasoline estimates an

incremental cost of approximately 3 to 5 cents per gallon for

Phase I reformulated gasoline above the cost of conventional

gasoline. 

The cost per ton of VOC reduced varies from State to State

based on the estimated emission benefit. The cost has generally

been estimated to be less than $5,000 per ton. Emission benefits

depend on the baseline from which reductions are measured. Areas

with enhanced I/M programs and lower RVP values in the baseline

show lower benefits attributable to reformulated gasoline. The

costs of producing Phase I reformulated gasoline result from the

required addition of oxygenates to gasoline, RVP reductions, and

refinery processing changes. 

4.2 STATIONARY SOURCE VOC CONTROL MEASURES

The stationary source measures analyzed by the study are

more stringent controls on existing sources for several selected

source categories.

31
The following measures were considered but not included in

the final study:

! Control of industrial adhesives was considered as a

potential measure. The 1990 Interim Inventory emission

estimates for industrial adhesives are based on a

national material balance. Resulting emissions are

higher than any previous estimates and are considered

uncertain. Because of this uncertainty, this measure

is not included in the final study, but may be

independently analyzed by the States.

! RACT to smaller sources was also considered as a

potential measure. RACT to 50 tpy is already required

for VOC sources in the OTR (severe areas are required

to install RACT on 25 tpy and greater sources). The

Interim Inventory point source data base is based on

the 1985 NAPAP inventory, which has a major stationary

source size cutoff of 100 tpy for VOC. Because the

inventory does not cover the smaller sources and

because the fraction of area source emissions in the 25

or 10 to 50 tpy range is unknown, this measure cannot

be adequately assessed.

! Increased offsets were also considered. This measure

could include extending offsets to smaller sources or

increasing the offset ratio. Benefits are difficult to

quantify because growth cannot be accurately allocated

between major new sources and modifications (subject to

offsets) and increases in activity or operating rates

(not subject to offsets unless a permit modification is

triggered).

! Emissions from the application of pesticides can be

reduced through reformulation, reduced use of

fumigants, and increases in application efficiency. 

Reformulation of pesticides is a lengthy and relatively

expensive process since the reformulated product must

undergo testing and be permitted for use. This measure

is being considered in California and other areas. The

California Federal Implementation Plan (FIP) calls for

a study of pesticide formulations leading to the

establishment of standards to reduce overall emissions

in the range of 20 to 40 percent. Because of the

uncertainty in potential benefits and costs, this

measure was not further analyzed.

32
More Stringent Controls on Existing Sources

Stationary source VOC control measures were analyzed using

ERCAM-VOC. Base year emissions are from the 1990 Interim

Inventory. Emissions are projected to future years using

State/2-digit SIC earnings growth and population projections.

The Act requires RACT for major sources (those emitting

50 tpy VOC) in the OTR. To represent a more stringent set of

controls than RACT, best available control technology (BACT) or

new source performance standard (NSPS) level controls were

applied to existing major (point) sources, or controls were

applied to area source emitters that would be expected to be

below the source size cutoff for RACT. The controls applied are

based on the set of existing control measures in ERCAM-VOC. It

is likely that there are additional source categories to which

additional controls could be applied; however, these controls may

vary significantly by area, so no attempt has been made to

identify new control techniques.

More stringent controls were applied to five source

categories as follows:

SOCMI fugitives -- Synthetic organic chemical manufacturing

industry (SOCMI) fugitives are controlled through improved

equipment and leak detection and repair (LDAR) programs. 

The baseline (RACT) control level assumed for this area

source category is 37 percent. A more stringent program was

applied at a 56 percent VOC emission reduction under the

more stringent control on existing sources scenario. The

estimated cost effectiveness is $200 per ton from

uncontrolled levels. The estimated incremental (incremental

to RACT level control) cost effectiveness is $375 per ton.

Petroleum refinery fugitives -- Petroleum refinery fugitive

(equipment leak) emissions are controlled through equipment

(e.g., seals) and maintenance (e.g., leak detection and

repair (LDAR)). A 69 percent control level was applied to

represent RACT. A control level of 93 percent was applied

under the more stringent control scenario. The higher level

of control can be achieved through more frequent inspections

for leaks and more sophisticated equipment, such as double

mechanical seals or seals with a buffer or barrier fluid. 

The estimated cost effectiveness is $2,030 per ton from

uncontrolled levels. The estimated incremental cost

effectiveness is $8,200 per ton reduced.

Pharmaceutical manufacturing -- Baseline controls for this

area source category (which includes mainly fugitive

emissions) include an LDAR program at an estimated control

level of 37 percent. A more stringent LDAR program and

improved equipment are applied to achieve a 56 percent

33
reduction in the more stringent control scenario. The

estimated cost is $340 per ton from uncontrolled levels. 

The incremental cost is estimated to be $480 per ton.

Bakeries -- No controls are applied to this area source

category in the baseline (emission levels are assumed to be

below the major source size cutoff). An 80 percent control

level, representing afterburners, is applied in the more

stringent control case. Cost effectiveness is estimated to

be $1,275 per ton reduced.

Small drycleaners -- No controls are applied to this area

source category in the baseline scenario. A 70 percent

control, representing recovery dryers, is applied in the

more stringent control scenario. This includes small

commercial drycleaners using both petroleum solvent and

perchloroethylene. Approximately half of the emissions in

this category are from perchloroethylene drycleaning. 

Reductions from these operations are included here but may

not be creditable, since it has been proposed that

perchloroethylene be exempted as a VOC. Cost effectiveness

is estimated to be $200 per ton reduced.

Emission reductions attributable to more stringent controls

on existing stationary sources from the RACT-level or

uncontrolled baseline are shown in Table 4-6. These emissions

estimates represent the total emissions reductions if the

existing sources for the five source categories listed above are

controlled to the more stringent level. Applying these VOC

stationary source control measures does not provide comparable

benefits for any area. A detailed summary by source category is

given in Appendix B.

34
Table 4-6. Stationary Source Control Measure VOC Emission Reductions

Projection Year 1999 

VOC Reduction (tpd)

Ozone Area

More Stringent

Existing Source Controls

Delaware

Sussex County 0.17

Maine

Hancock & Waldo Counties 0.05

Knox & Lincoln Counties 0.03

Lewiston-Auburn 0.56

Portland 0.79

Franklin County 0.00

Oxford County 0.01

Somerset County 0.01

Attainment Counties 0.25

Maryland

Kent & Queen Anne's Counties 0.07

Attainment Counties 0.52

New Hampshire

Manchester 1.05

Belknap County 0.03

Chesire County 0.09

Sullivan County 0.00

Attainment Counties 0.10

New Jersey

Allentown-Bethlehem-Easton 0.09

Atlantic City 0.36

New York

Albany-Schenectady-Troy 1.07

Buffalo-Niagara Falls 1.82

Essex County 0.00

Jefferson County 0.07

Poughkeepsie 0.14

Attainment Counties 5.19

Pennsylvania

Allentown-Bethlehem-Easton 0.69

Altoona 0.19

Erie 0.30

Harrisburg-Lebanon-Carlisle 0.66

35
Table 4-6 (continued)

VOC Reduction (tpd)

Ozone Area

More Stringent

Existing Source Controls

Johnstown 0.12

Lancaster 0.63

Pittsburgh-Beaver Valley 3.48

Reading 0.79

Scranton-Wilkes-Barre 0.61

York 0.72

Youngstown-Warren-Sharon 0.16

Crawford County 0.22

Franklin County 0.04

Greene County 0.02

Juniata County 0.00

Lawrence County 0.02

Northumberland County 0.17

Pike County 0.02

Schuylkill County 0.05

Snyder County 0.02

Susquehanna County 0.00

Warren County 0.02

Wayne County 0.01

Attainment Counties 0.81

Vermont

Attainment Counties 0.77

36
5.0 NOx CONTROL MEASURES

Under EPA's interpretation of section 184(b)(2), States have

the option of adopting comparable NOx control measures instead of

Stage II. Section 5.1 provides the method for determining what

level of NOx emission reductions is comparable to Stage II VOC

emissions reductions for a particular area and therefore can be

substituted. NOx may not be substituted for VOC in areas where a

waiver under section 182(f) of the Act from some or all NOx

requirements has been obtained because such a waiver indicates

that NOx reductions are either excess and not necessary for

attainment, or NOx reductions are otherwise not beneficial.

The NOx control measures evaluated in the study have been

divided into three categories: motor vehicle, utility point

source, and non-utility point source. The emissions reduction

estimates for these categories are provided in sections 5.2, 5.3,

and 5.4, respectively. Calculations of the VOC equivalency for

the NOx emissions reductions, according to the methodology in

section 5.1, are provided. If a measure controls both NOx and

VOC emissions (see Chapter 3 for VOC emissions reductions

estimates), the emissions reductions may be combined to yield a

total emissions reduction estimate for the measure. 

5.1 NOx SUBSTITUTION METHODOLOGY

To determine whether a NOx control measure achieves

comparable emissions reductions to Stage II, the NOx reductions

for the measure and Stage II VOC reductions are compared on the

basis of percentage reductions of the respective NOx and VOC base

year anthropogenic emission inventories (rather than on a tonper-ton basis). For example, a 10 percent reduction in the NOx

inventory would be considered comparable to a 10 percent

reduction in the VOC inventory. (By this method, the ton-per-ton

equivalency will vary by area according to the ratio of the VOC

and NOx emissions inventories.)

Comparability determinations for NOx control measures are

illustrated by the following example. 

Example A. Consider an area with a 1990 base year VOC emissions

inventory of 500 tons per day (tpd) and a NOx emissions inventory

of 400 tpd. Stage II, more stringent controls on coal-fired

boilers, and enhanced I/M (which controls both VOC and NOx) are

analyzed below for projection year 1999.

Assume Stage II control yields a 2 percent reduction from

the 1990 VOC base year emissions inventory (10 tpd reduction

divided by 500 tpd total). Therefore, to be comparable, a NOx

control measure must achieve a reduction of 2 percent or more in 

37
Example A

VOC Reduction NOx Reduction

Control Measure tpd % tpd %

Stage II 10 2 -- --

More Stringent Controls on Coal-Fired Utilities 0 0 9 2.3

Enhanced I/M

7 1.4 1.5 0.4

emissions from the 1990 NOx base year emissions inventory (8 tpd

or more reduction from 400 tpd total). More stringent control

for NOx on coal-fired utilities would be considered comparable

where this measure yields a reduction of 2.3 percent from base

year emission levels (9 tpd NOx reduction divided by 400 tpd NOx

total). Enhanced I/M reduces both VOC and NOx emissions. 

Therefore, the VOC reductions and the NOx reductions may be

summed for this measure. Enhanced I/M would not be considered

comparable because the sum of the percent NOx and VOC emissions

reductions is only 1.8 percent: 1.4 percent for VOC (7 tpd VOC

reduction divided by 500 tpd VOC total) and 0.4 percent for NOx

(1.5 tpd NOx reduction divided by 400 tpd NOx total).

NOx Substitution Ratios

The calculations for comparing emissions reductions using

the percent of inventory method can be simplified by deriving the

NOx substitution ratio for an area. The NOx substitution ratio

is simply the NOx inventory divided by the VOC inventory. In

Example A, the NOx substitution ratio would be 0.8 (400 tpd NOx

divided by 500 tpd VOC). Thus, 0.8 tpd NOx is comparable to 1

tpd VOC for that area. The NOx substitution ratio will vary area

by area according to the relative amounts of VOC and NOx

emissions.

The NOx emissions reductions estimated for an alternative

measure can be divided by the NOx substitution ratio to convert

the NOx emissions to comparable VOC reductions. The VOC

reductions can then be compared on a ton-for-ton basis with the

Stage II VOC reductions. This is illustrated by the following

example. 

Example B. This example uses the same scenario described in

Example A. The 1990 NOx inventory is 400 tpd and the 1990 VOC

inventory is 500 tpd. Dividing the NOx inventory by the VOC

inventory produces a NOx substitution ratio of 0.8. In the table

below, the NOx emissions reductions have been divided by the NOx

substitution ratio to produce the VOC equivalent reductions for

the measures.

Example B

38
Control Measure

VOC

Reduction

(tpd)

NOx

Reduction

(tpd)

Comparable VOC

Reduction (tpd)

Stage II 10 -- --

More Stringent Controls on Coal-Fired

Utilities

0 9 11.3

Enhanced I/M 7 1.5 1.9

Stage II achieves a VOC reduction of 10 tpd. More stringent

NOx control on coal-fired utilities is comparable because it

achieves NOx emissions reductions comparable to 11.3 tpd

reduction in VOC. Enhanced I/M is not comparable because it

achieves only an 8.9 tpd reduction in VOC emissions (7 tpd VOC +

1.9 tpd in VOC comparable emissions).

In data tables in this chapter, all of the NOx emissions

reductions estimates for the measures evaluated have been

converted into comparable VOC equivalent reductions for ease in

comparing the reductions to the applicable Stage II VOC emissions

reductions. The ratios for determining equivalent VOC reductions

are shown in Table 5-1.

The method for substituting NOx for the Stage II or

comparable measure requirement is based, in part, on the NOx

Substitution Guidance (see reference 20) developed for States to

use to meet post-1996 emission reduction requirements under

section 182(c)(2)(B) of the Act. Section 182(c)(2) requires each

serious and above ozone nonattainment area to submit a SIP

revision by November 15, 1994, which describes how the area will

achieve an actual VOC emissions reduction of 3 percent per year,

averaged over consecutive 3-year periods beginning November 15,

1996 until the area's attainment date. Substitution of NOx

emissions reductions is permitted if certain conditions are met.

Central to both substitution procedures is that NOx and VOC

emissions reductions are compared on a percentage of the base

year inventory basis rather than on a ton-per-ton basis. 

However, there are some significant differences. The two NOx

substitution methods differ in regard to applicability and the

approvability criteria for the substitution. The post-1996 NOx

substitution guidance applies only to serious and above ozone

nonattainment areas. The approvable degree of NOx substitution

in the rate-of-progress plans is linked to an area's attainment

demonstration. NOx emissions reductions must be shown to be

necessary for attainment and be included in the area's SIP

control strategy before they may be substituted for VOC emissions

reductions in the rate-of-progress plans.

39
Table 5-1. NOx to VOC Substitution Ratios - Percent of Inventory Method

Ozone Area

1990 VOC

(tpd)

1990 NOx

(tpd)

NOx to

VOC Ratio

Delaware

Sussex County 173.3 67.8 0.4

Maine

Hancock & Waldo Counties 14.5 13.6 0.9

Knox & Lincoln Counties 11.3 10.6 0.9

Lewiston-Auburn 39.4 26.4 0.7

Portland 79.7 69.1 0.9

Franklin County 5.7 9.2 1.6

Oxford County 11.9 9.6 0.8

Somerset County 9.8 10.3 1.0

Attainment Counties 66.6 56.7 0.9

Maryland

Kent & Queen Anne's Counties 11.4 9.8 0.9

Attainment Counties 128.7 116.1 0.9

New Hampshire

Manchester 82.4 102.2 1.2

Belknap County 8.5 6.7 0.8

Chesire County 12.4 9.2 0.7

Sullivan County 6.4 4.9 0.8

Attainment Counties 27.1 24.4 0.9

New Jersey

Allentown-Bethlehem-Easton 21.6 22.1 1.0

Atlantic City 52.6 70.0 1.3

New York

Albany-Schenectady-Troy 196.2 135.6 0.7

Buffalo-Niagara Falls 226.7 237.1 1.0

Essex County 6.5 7.4 1.1

Jefferson County 17.0 13.4 0.8

Poughkeepsie 53.1 32.8 0.6

Attainment County 937.8 719.4 0.8

Pennsylvania

Allentown-Bethlehem-Easton 102.2 116.0 1.1

Altoona 22.1 19.7 0.9

Erie 184.3 45.1 0.2

Harrisburg-Lebanon-Carlisle 106.8 80.3 0.8

Johnstown 42.2 33.9 0.8

Lancaster 83.2 62.2 0.7

Pittsburgh-Beaver Valley 441.0 658.2 1.5

Reading 64.3 58.3 0.9

Scranton-Wilkes-Barre 131.3 91.2 0.7

York 82.4 133.7 1.6

40
Table 5-1 (continued)

Ozone Area

1990 VOC

(tpd)

1990 NOx

(tpd)

NOx to

VOC Ratio

Youngstown-Warren-Sharon 22.6 20.0 0.9

Crawford County 26.0 18.9 0.7

Franklin County 22.7 16.1 0.7

Greene County 7.4 115.2 15.6

Juniata County 4.4 3.3 0.8

Lawrence County 17.6 39.9 2.3

Northumberland County 18.4 12.5 0.7

Pike County 12.5 3.3 0.3

Schuylkill County 28.2 19.5 0.7

Snyder County 7.2 37.7 5.3

Susquehanna County 56.4 6.2 0.1

Warren County 16.6 16.2 1.0

Wayne County 7.0 5.3 0.8

Attainment Counties 215.6 543.2 2.5

Vermont

Attainment Counties 110.5 77.9 0.7

NOTE: Base year anthropogenic emissions are taken from the 1990 Interim Inventory. (See reference 3.)

41
In contrast, the Stage II Comparability Study NOx

substitution guidance applies to moderate, marginal, and

incomplete data ozone nonattainment areas and attainment 

portions of the OTR.1 Most of these areas are already at ornear

attainment and are not required to submit attainment

demonstrations. Therefore, approvability of the degree of NOx

substitution for the purposes of this requirement cannot be

related to attainment demonstrations.

Instead, EPA believes any mix of VOC and NOx emissions

reductions is permissible to meet the comparability requirement. 

This is supported by the findings of the National Academy of

Science report Rethinking the Ozone Problem in Urban and Regional

Air Pollution (see reference 21) and the results of Regional

Oxidant Model (ROM) simulations, which suggest that substantial

reductions of both NOx and VOC emissions will be needed to bring

the OTR into attainment.

5.2 MOTOR VEHICLE CONTROL MEASURES

The enhanced I/M program was evaluated as a potential

comparable NOx control measure for motor vehicles. This control

measure was also evaluated for VOC emissions reductions in

Chapter 4. The program parameters are described in that chapter. 

The projection methodology and the modeling assumptions used to

examine this measure for NOx control are identical to those used

for the VOC analysis. These are described in detail in Chapter

4. Also provided in Chapter 4 are the cost estimates for

implementing this measure. Federal reformulated gas was analyzed

as a motor vehicle control measure for VOC, but it is not

included in this section because the Act only requires that Phase

I reformulated gasoline not increase NOx emissions. Phase II

reformulated gasoline will reduce NOx emissions; however, Phase

II reformulated gasoline does not begin until the year 2000. 

Other motor vehicle measures were considered, as discussed in

Chapter 4, but not included in the final study.

The estimated NOx reductions from enhanced I/M are shown in

Table 5-2. No benefit is shown for areas where enhanced I/M

programs are already required. For the purposes of making a

comparability determination, an area can only take credit for

emissions reductions from control measures that are in excess of

control measures prescribed under the Act. As discussed in

Section 5.1, the NOx and VOC emissions reductions may be combined

 1Technically, the section 184(b)(2) requirement to adopt Stage II or a

comparable measure, and thus the related NOx substitution guidance, applies to

all areas in the OTR, including serious and severe areas. However, as

discussed in Chapter 2.0, because States with serious and severe areas must

adopt Stage II under section 182(b)(3), they cannot take advantage of the

option to adopt a comparable measure.

42
Table 5-2. Motor Vehicle NOx Reductions - Projection Year 1999

Enhanced I/M

Ozone Area

NOx

(tpd)

Comparable VOC

(tpd)

Delaware

 Sussex County 1.81 4.53

Maine

 Hancock & Waldo Counties 1.13 1.26

 Knox & Lincoln Counties 0.98 1.09

 Lewiston-Auburn 2.33 3.33

 Portland NA* NA

 Franklin County 0.48 0.30

 Oxford County 0.78 0.98

 Somerset County 0.65 0.65

 Attainment Counties 3.94 4.38

Maryland

 Kent & Queen Anne's Counties 0.83 0.92

 Attainment Counties 4.90 5.44

New Hampshire 

 Manchester NA NA

 Belknap County 0.62 0.78

 Chesire County 0.89 1.27

 Sullivan County 0.46 0.58

 Attainment Counties 1.99 2.21

New Jersey

 Allentown-Bethlehem-Easton NA NA

 Atlantic City NA NA

New York

 Albany-Schenectady-Troy NA NA

 Buffalo-Niagara Falls NA NA

 Essex County 0.48 0.44

 Jefferson County 0.96 1.20

 Poughkeepsie NA NA

 Attainment Counties 18.19 22.74

*NA = not applicable; enhanced I/M is mandated by the Act for these areas.Pennsylvania

 Allentown-Bethlehem-Easton NA NA

 Altoona NA NA

 Erie NA NA

 Harrisburg-Lebanon-Carlisle NA NA

 Johnstown NA NA

 Lancaster NA NA

 Pittsburgh-Beaver Valley NA NA

43
Table 5-2 (continued)

Enhanced I/M

Ozone Area

NOx

(tpd)

Comparable VOC

(tpd)

 Reading NA NA

 Scranton-Wilkes-Barre NA NA

 York NA NA

 Youngstown-Warren-Sharon NA NA

 Crawford County 0.95 1.36

 Franklin County 1.20 1.71

 Greene County 0.47 0.03

 Juniata County 0.24 0.30

 Lawrence County 1.00 0.43

 Northumberland County 0.89 1.27

 Pike County 0.23 0.77

 Schuylkill County 1.46 2.09

 Snyder County 0.38 0.07

 Susquehanna County 0.47 4.70

 Warren County 0.51 0.51

 Wayne County 0.40 0.50

 Attainment Counties 8.52 3.41

Vermont

 Attainment Counties 5.76 8.23

*NA = not applicable; enhanced I/M is mandated by the Act for these areas.

44
to determine comparability to Stage II VOC reductions. As shown

in Chapter 4, areas where enhanced I/M is applicable show

comparable benefits with the VOC reductions alone. Examining the

NOx benefits alone shows comparable benefits in all applicable

areas except Greene, Lawrence, Snyder, and the attainment

counties in Pennsylvania. These latter areas all have NOx to VOC

ratios greater than 2.

5.3 UTILITY CONTROL MEASURES

Utility boilers are affected by both Title I and Title IV of

the Act. Under Title I, utility units are subject to NOx RACT

requirements for major stationary sources (100 tpy or greater in

the OTR). Through Title IV, many utility units will be subject

to NOx emission limits.

The NOx control measures examined for utility boilers are

lowering the NOx RACT source size cutoff from 100 tpy to 25 tpy,

and requiring more stringent controls for existing major sources

(i.e., 100 tpy or greater sources). Table 5-3 shows the control

technologies selected to represent RACT and the more stringent

control for utility as well as non-utility point sources (see

section 5.4 for the analysis of the latter source category).

The 1990 Interim Inventory was used as the basis for

evaluating control measures for fossil-fuel steam utility units. 

The utility component of the inventory includes all plants of at

least 10 megawatts and that have at least one operating boiler. 

An electric plant is a station containing prime movers, electric

generators, and auxiliary equipment for converting mechanical,

chemical, and/or fission energy into electric energy. The

Interim Inventory utility data base contains fossil-fuel fired

boilers only. Electric utilities include facilities which

produce electricity primarily for use by the public.

NOx reductions expected to be achieved through these

controls are shown in Table 5-4. The emissions reductions broken

down by boiler type are given in Table C-1 in Appendix C. Areas

not appearing on these tables do not have existing utility units

and therefore have no emissions from utility boilers. Areas

appearing on the results tables all have utility boilers;

however, the resulting emission reductions are sometimes (often

for RACT) zero. This indicates that the control measures applied

do not result in emission reductions in excess of existing levels

and Act requirements. Therefore, the controls could not be

considered as potential comparable measures.

45
Table 5-3. NOx RACT and More Stringent Control Technologies

Source Category RACT Control

Percent

Control

Cost

 ($/ton)

More Stringent

Control

Utility Boilers - PC Wall Fired LNB 45 305 SCR Utility Boilers - PC Tangential LNB 29 880 SCR Utility Boilers - Oil/Gas Wall Fired BOOS + FGR 39 645 SCR Utility Boilers - Oil/Gas Tangential BOOS + FGR 42 940 SCR Utility Boilers - Cyclone NGR 53 650 NGR Industrial Boilers - PC LNB 50 1,350 SCR Industrial Boilers - Stoker SNCR 55 1,800 SNCR Industrial Boilers - Residual Oil LNB 50 620 SCR Industrial Boilers - Distillate Oil LNB 50 1,180 SCR Industrial Boilers - Natural Gas LNB 50 770 SCR IC Engines - Natural Gas AF + IR 30 551 L - E IC Engines - Oil IR 25 518 SCR Gas Turbines - Natural Gas LNB 84 236 SCR + Steam Injection Gas Turbines - Oil Water Injection 70 1,166 SCR + Water Injection Process Heaters - Natural Gas ULNB 75 532 LNB + SCR Process Heaters - Distillate Oil ULNB 74 735 LNB + SCR Process Heaters - Residual Oil ULNB 73 442 LNB + SCR Adipic Acid Manufacturing Plants Thermal Reduction 81 459 Thermal Reduction Nitric Acid Manufacturing Plants Extended Absorption 95 173 NSCR 

Abbreviations: LNB = low NOx burner AF = air-to-fuel (ratio)

LEA = low excess air IR = ignition timing retardBOOS = burners out of service ULNB = ultra-low NOx burner

FGR = flue gas reburning SCR = selective catalytic reductionNGR = natural gas reburning L-E = low emissionSNCR = selective non-catalytic reduction IC = internal combustion

NSCR = non-selective catalytic reduction
Table 5-4. Utility Control Measure Emission Reductions

Projection Year 1999

RACT to 25 tpy**

More Stringent Control

to 100 tpy**

Ozone Area*

NOx

(tpd)

Comparable

VOC

NOx

(tpd)

Comparable

VOC

Delaware

 Sussex County 0.00 0.00 21.40 53.50

Maine

 Knox & Lincoln Counties 0.00 0.00 0.03 0.03

 Portland 0.00 0.00 5.08 5.64

 Attainment Counties 0.00 0.00 0.00 0.00

Maryland

 Attainment Counties 0.00 0.00 5.27 5.86

New Hampshire

 Manchester 0.00 0.00 0.00 0.00

New Jersey

 Atlantic City 0.00 0.00 1.09 0.84

New York

 Albany-Schenectady-Troy 0.00 0.00 8.37 11.96

 Buffalo-Niagara Falls 0.00 0.00 43.67 43.67

 Attainment Counties 0.00 0.00 57.18 71.48

Pennsylvania

 Allentown-Bethlehem-Easton 0.00 0.00 25.82 23.47

 Altoona 0.00 0.00 0.00 0.00

 Erie 0.00 0.00 3.92 19.60

 Lancaster 0.00 0.00 0.00 0.00

 Pittsburgh-Beaver Valley 0.00 0.00 183.73 122.49

 Reading 0.00 0.00 6.14 6.82

 Scranton-Wilkes-Barre 0.00 0.00 0.00 0.00

 York 0.00 0.00 45.67 28.54

 Greene County 0.00 0.00 45.94 2.94

 Lawrence County 0.00 0.00 11.28 4.90

 Snyder County 0.00 0.00 14.79 2.79

 Warren County 0.00 0.00 0.00 0.00

 Attainment Counties 0.00 0.00 179.39 71.76

Vermont

 Attainment Counties 0.00 0.00 0.00 0.00

NOTES: *Areas not appearing on the table do not have existing utility boilers and therefore have zero

emissions.

**Zeros under RACT or more stringent control indicate that there are no additional reductions (above

the Act requirements) for this measure. RACT to 25 tpy shows no reductions because utility boilers in

these areas all emit at levels greater than the major source size cutoff.

47
5.3.1 Modeling Assumptions

Ozone season daily emissions for utility boilers were

estimated from annual emissions using seasonal and daily temporal

allocation factors developed for the 1985 NAPAP Inventory. (See

reference 15.) Temporal allocation factors were used because

operational data (seasonal throughput, weeks per year, days per

week) were not available for utilities in the Interim Inventory. 

The temporal factors are State- and SCC (boiler type)-specific. 

The typical weekday factor was used in conjunction with the

summer seasonal allocation factor to estimate ozone season daily

emissions.

Growth in emissions from existing sources occurs through

increased capacity utilization. Capacity utilization refers to

the actual power generation provided annually by a unit compared

with the potential output if the unit operated 24 hours per day

for 365 days per year. Growth in capacity utilization is a

function of fuel type, unit age, and State growth projections. 

Projected capacity utilization for 1999 was estimated using

average capacity utilization factors, which were determined for

each boiler-fuel type with data from the Interim Inventory years

1987 through 1991. Where limited data were available, State

averages for each boiler-fuel type were used as the projected

capacity utilization. Additional power generation demands not

met by existing units would require new unit construction.

Growth estimates indicate that additional units will be

needed in many areas; however, since these new units will be

subject to new source review requirements, these units will

already be required to operate at the more stringent control

levels modeled in this analysis.

Determining NOx RACT and Title IV NOx Control Measures

In order to determine the emissions reductions attributable

to additional NOx control measures, first a baseline scenario was

developed that included NOx controls to represent NOx RACT

applied to major stationary sources (100 tpy or greater) (as

required by the Act) and NOx control measures to meet the acid

deposition provisions of Title IV. 

Title IV NOx standards are 0.45 lb/MMBtu for tangentially

fired coal boilers and 0.5 lb/MMBtu for dry bottom wall-fired

coal boilers. The Title IV standard assumed for the remaining

coal-fired boilers is 1.0 lb/MMBtu. Phase I units are subject to

Title IV standards in 1996. Phase I units include the 260

dirtiest SO2 emitting units. In addition to being classified as

Phase I, the units must operate at least 50 percent on coal (on a

Btu basis) to be subject to the Title IV NOx standard. All units

are required to comply with Title IV NOx limits under Phase II

48
beginning in 2002. Again, the units must operate at least 50

percent on coal.

The Nitrogen Oxides Supplement to the General Preamble for

the Implementation of Title I of the Clean Air Act Amendments of

1990 (NOx General Preamble) (see reference 22) specifies NOx RACT

limits of 0.2 lb/MMBtu for tangentially fired oil and gas boilers

and 0.3 lb/MMBtu for wall-fired oil and gas boilers. The NOx

RACT limits for coal-fired boilers are equivalent to the Title IV

acid deposition limits.

Controls modeled to meet RACT and Title IV standards are

described below. Selection of the particular controls was based

on a recent EPA report that evaluated NOx controls for existing

utility boilers in the NESCAUM region. (See reference 19.) One

control technique was chosen for each fuel/firing type of utility

boiler in the Interim Inventory. The selected control is applied

to all boilers with current NOx emission rates that are more than

10 percent above the Title IV standard. Boilers emitting within

10 percent of the standard were assumed to be able to make minor

combustion modifications to achieve the standard.

Coal Fired, Dry Bottom, Wall -- If the boiler does not meet

the Title IV standard or is required to install RACT, low

NOx burner (LNB) was applied. LNB is estimated to achieve a

45 percent reduction in emissions. Based on the utility

boilers in the OTR, this is sufficient for most to achieve

the necessary reductions. Overfire air (OFA), with a

control efficiency of 21 percent, will not achieve the

reductions necessary to meet Title IV requirements.

Coal Fired, Tangential -- LNB was also applied to

tangentially fired coal boilers. The estimated reduction is

29 percent. This proved to be sufficient to bring all

boilers into compliance with the Title IV standard.

Coal, Cyclone -- Natural gas reburning (NGR) was applied to

cyclone boilers at a 53 percent reduction. NGR is the only

control technique applicable to cyclone boilers based on the

EPA/NESCAUM study.

Oil, Wall -- Burners out of service (BOOS) plus (+) fuel gas

reburning (FGR) was applied to wall-fired residual and

distillate oil utility boilers not meeting the RACT standard

(being within 10 percent of the standard). While FGR alone

will achieve the necessary reductions in some cases, BOOS +

FGR is more cost effective. LNB is as effective in reducing

NOx, but is more costly than BOOS + FGR. BOOS + FGR

provides a 39 percent reduction in emissions. All

distillate oil boilers are already below the expected RACT

limit (0.3 lb/MMBtu).

49
Oil, Tangential -- BOOS + FGR (at 42 percent control) was

modeled to bring tangential boilers into compliance with

RACT requirements. LNB (at 33 percent control) is

sufficient for most boilers, but is more costly than BOOS +

FGR. All distillate oil boilers are already below the RACT

limit (0.2 lb/MMBtu).

Oil, Cyclone -- NGR (at a 53 percent reduction) is the only

control technique available for application to cyclone

boilers. According to the EPA/NESCAUM report, this

technique is not well demonstrated and will probably not be

commercially available. The Title I General Preamble does

not include specific RACT limits for cyclone boilers.

Gas, Wall -- BOOS + FGR (at a 39 percent reduction) was

estimated to achieve the necessary reductions for wall-fired

natural gas units. This brings most units into compliance. 

Other controls that achieve necessary reductions for all

units are more costly, therefore BOOS + FGR is modeled based

on the assumption that other minor modifications in

operation will probably bring the boilers into compliance

with the standard.

Gas, Tangential -- BOOS is estimated to achieve the

necessary reductions to meet RACT limits for gas-fired

tangential utility boilers. The estimated efficiency used

for modeling is 25 percent.

Gas, Cyclone -- NGR was applied at a 53 percent reduction. 

This is the only control technique available for cyclone

boilers based on the EPA/NESCAUM report. Again, this

technique is not well demonstrated. Specific RACT limits

for cyclone boilers are not included in the Title I General

Preamble.

5.3.2 NOx RACT to 25 tpy

The controls modeled as RACT for the 100 tpy and above

sources were also considered to be RACT for sources emitting 25

to 100 tpy under this scenario. Table 5-3 lists the RACT-level

controls along with cost estimates for implementing the controls. 

RACT was applied to all boilers emitting above 25 tpy, rather

than the 100 tpy RACT cutoff mandated for the OTR.

As shown in Table 5-4, lowering the RACT cutoff does not

result in any incremental NOx benefits beyond those achieved

through Act-required measures. One reason for this is that

utility units tend to be above the 100 tpy RACT cutoff. In

addition, utilities may also be subject to Title IV limits. 

Lastly, the utility data base from the 1990 Interim Inventory was

developed from fossil-fuel use data for plants of 10 MW or

50
greater. It is difficult to quantify the potential NOx emissions

from smaller units because emissions depend on the fuel type, the

boiler configuration, and the hours operated. Smaller units,

however, tend to operate on oil or gas, which is less polluting

than coal. The State inventories may include these smaller

plants; however, the effect of extending RACT to these units is

expected to be small. Because it is likely the smaller plants

will operate on oil or gas, most will emit less than 50 tpy and

many will be below the 25 tpy cutoff to which RACT was extended

in this analysis.

5.3.3 More Stringent Control for Existing Major Sources 

Selective catalytic reduction (SCR) was applied to all

existing 100 tpy or greater utility boilers (except stokers and

cyclones) under the more stringent control scenario. The

estimated control efficiencies are shown in Table 5-3. NGR was

applied to cyclone boilers, equivalent to what was assumed in

modeling RACT-level controls. NGR is the only control technique

applicable to cyclone boilers based on recent studies.

The emission reductions for applying more stringent controls

on utility boilers vary significantly from area to area as shown

in Table 5-4. The level of reductions achieved depends on the

magnitude of emissions in the baseline (i.e., the number and size

of boilers in each area) and the baseline emission level (lbs NOx

per MMBtu). Gas- and oil-fired units emit less to begin with, so

corresponding reductions are lower. In areas where no reductions

are observed, the units are either below the 100 tpy cutoff

modeled or units are expected to be retired (and may be replaced

by new units). Comparing these reductions to the Stage II

reductions in Table 3-5 shows that more stringent controls on

utility boilers would result in comparable reductions in most

areas with existing utility units. Exceptions include those

where very low incremental reductions are shown, including Knox

and Lincoln Counties in Maine, and Atlantic City, New Jersey. 

5.4 NON-UTILITY POINT SOURCE CONTROL MEASURES

Non-utility point sources examined in this analysis include

industrial boilers, internal combustion engines, stationary gas

turbines, process heaters, and acid manufacturing plants. As

with the utility point source category, the alternative measures

analyzed for non-utility point sources were lowering the NOx RACT

source size cutoff from 100 tpy to 25 tpy and requiring more

stringent control for existing 100 tpy or greater sources.

51
5.4.1 Modeling Assumptions

Emissions were projected to future years by applying Bureau

of Economic Analysis (BEA) earnings-based growth factors by twodigit SIC and State to the base year emission estimates. (See

reference 23.) Ozone season daily emissions were calculated from

the annual emissions by source category using operational data

from the Interim Inventory. Default values of 52 operational

weeks per year, 7 operational days per week, and a summer

percentage throughput of 25 percent were used in cases where data

were not available for ozone season calculations. The equations

used to estimate ozone season daily emissions were as follows:

Ozone Season Weeks = Max (13, (Summer Throughput Percentage * Weeks per Year))

Ozone Season Daily Emissions = (NOx Emissions * Summer Throughput Percentage)

 (Ozone Season Weeks * Days per Week)

The results of the control analysis are presented in Table 5-5. 

Detailed summaries by source category are provided in Appendix C.

Determining RACT Level and More Stringent Controls

NOx RACT and more stringent control strategies and

associated control costs are shown in Table 5-3 and described

below. Control measure information for non-utility point sources

was taken from the various EPA Alternative Control Technology

Documents as cited under each source category described below. 

NOx RACT to 100 tpy sources is required under Title I of the Act. 

The controls specified as RACT were applied to each individual

source if it qualified as a major source and if the existing

control level was lower than the RACT level.

1. Industrial Boilers

Pulverized Coal -- LNB was assumed as the RACT method of

control for pulverized coal (PC)-fired industrial boilers. 

This control is expected to provide a NOx reduction of 45

percent at an average cost per ton of $1,350. SCR was

chosen as the more stringent control at an estimated 79

percent reduction in emissions $6,600 per ton reduced. (See

reference 24.)

Stokers -- Because limited data were available on control

techniques for stokers, the RACT and more stringent level of

control were assumed to be the same. Selective noncatalytic reduction (SNCR) was the selected control

technique, with a NOx reduction of 55 percent and average

default cost of $1,800 per ton. (See reference 24.)

Residual Oil, Distillate Oil, and Natural Gas -- RACT and

more stringent control techniques for each of the three oil 

52
Table 5-5. Non-Utility Control Measure Emission Reductions

Projection Year 1999

RACT to 25 tpy**

More Stringent Control

to 100 tpy**

Ozone Area*

NOx

(tpd)

Comparable

VOC

NOx

(tpd)

Comparable

VOC

Delaware

 Sussex County 0.38 0.95 1.05 2.63

Maine

 Hancock & Waldo Counties 0.45 0.50 0.26 0.29

 Knox & Lincoln Counties 0.16 0.18 0.00 0.00

 Lewiston-Auburn 0.30 0.43 0.00 0.00

 Portland 0.31 0.34 0.49 0.54

 Franklin County 0.00 0.00 0.84 0.53

 Oxford County 0.00 0.00 0.23 0.29

 Somerset County 0.34 0.34 0.17 0.17

 Attainment Counties 1.07 1.19 1.77 1.97

Maryland

 Kent & Queen Anne's Counties 0.00 0.00 0.00 0.00

 Attainment Counties 1.83 2.03 2.09 2.32

New Hampshire

 Manchester 0.10 0.08 0.00 0.00

 Chesire County 0.00 0.00 0.00 0.00

 Attainment Counties 0.25 0.28 0.63 0.70

New Jersey

 Allentown-Bethlehem-Easton 0.33 0.33 3.29 3.29

 Atlantic City 0.29 0.22 0.00 0.00

New York

 Albany-Schenectady-Troy 1.80 2.57 0.94 1.34

 Buffalo-Niagara Falls 1.44 1.44 1.27 1.27

 Essex County 0.00 0.00 0.44 0.40

 Jefferson County 0.30 0.38 0.21 0.26

 Poughkeepsie 0.76 1.27 0.00 0.00

 Attainment Counties 4.19 5.24 8.22 10.28

Pennsylvania

 Allentown-Bethlehem-Easton 0.17 0.15 0.00 0.00

 Altoona 0.34 0.38 0.00 0.00

 Erie 0.11 0.55 0.40 2.00

 Harrisburg-Lebanon-Carlisle 0.44 0.55 0.00 0.00

 Johnstown 0.81 1.01 0.03 0.04

 Lancaster 0.20 0.29 1.32 1.89

 Pittsburgh-Beaver Valley 3.40 2.27 7.92 5.28

 Reading 1.05 1.17 0.00 0.00

 Scranton-Wilkes-Barre 0.79 1.13 1.21 1.73

 York 0.43 0.27 1.51 0.94

53
Table 5-5 (continued)

RACT to 25 tpy**

More Stringent Control

to 100 tpy**

Ozone Area*

NOx

(tpd)

Comparable

VOC

NOx

(tpd)

Comparable

VOC

 Youngstown-Warren-Sharon 0.56 0.62 1.20 1.33

 Crawford County 0.00 0.00 0.30 0.43

 Franklin County 0.07 0.10 0.00 0.00

 Greene County 0.00 0.00 0.00 0.00

 Lawrence County 0.00 0.00 0.00 0.00

 Northumberland County 0.22 0.31 0.00 0.00

 Pike County 0.07 0.23 0.00 0.00

 Schuylkill County 0.07 0.10 0.00 0.00

 Warren County 0.79 0.79 0.00 0.00

 Attainment Counties 5.18 2.07 6.53 2.61

Vermont

 Attainment Counties 0.13 0.19 0.00 0.00

NOTES: *Areas not appearing in the table do not have non-utility point source NOx emitters.

**Zeros indicate that additional reductions (above the Act) would not be achieved through the selected control

measures.

54
and gas-fired boiler types were assumed to be the same. 

RACT control via LNB provides NOx reductions of 50 percent,

while SCR control (more stringent) reduces emissions by 80

percent for all sources. Costs per ton for these RACT

controls average $620 for residual oil, $1,180 for

distillate oil, and $770 for natural gas. Estimated average

costs for SCR are $2,450 per ton reduced for residual oil,

$3,950 for distillate oil, and $3,000 for boilers fired with

natural gas. (See reference 24.)

2. Internal Combustion Engines

Natural Gas -- The RACT-level control technique chosen for

natural gas-fired internal combustion (IC) engines is an AF

ratio combustion modification coupled with an IR

modification expected to provide an emissions reduction of

30 percent at an average cost of $551 per ton reduced. Low

emission (L-E) combustion designs provide an emission

reduction of 80 percent for the more stringent control

technique at an average of $618 per ton reduced. (See

reference 25.)

Oil -- The ignition timing retardation (IR) method of

emissions control was used in determining RACT reductions

for oil fired IC engines. The associated NOx reduction is

25 percent and costs an average of $518 per ton of NOx

reduced. SCR (more stringent control) is estimated to

reduce NOx emissions by 80 percent, costing an average of

$1,540 per ton of NOx reduced. (See reference 25.)

3. Gas Turbines

Natural Gas -- A LNB control method was chosen to reflect

RACT-level controls for natural gas-fired turbines with an

average default cost per ton of $236 and an emissions

reduction of 84 percent. SCR control in addition to a steam

injection system is estimated to reduce emissions by up to

95 percent, while costing $5,581 per ton of NOx reduced. 

(See reference 26.)

Oil -- RACT control was chosen to be a water injection

system that reduces NOx emissions by 70 percent from

uncontrolled rates. This control technique costs an average

of $1,166 per ton of NOx reduced. The water injection

system, coupled with SCR, was selected as the more stringent

control option and is estimated to reduce emissions by 94

percent, costing an average of $2,835 per ton reduced. (See

reference 26.)

55
4. Process Heaters

Natural Gas -- ULNB was utilized to reduce NOx emissions by

75 percent in the natural gas-fired process heaters. These

reductions cost an average of $532 per ton NOx reduced. A

combination of LNB and SCR controls reduced emissions by 88

percent, costing $3,905 per ton reduced. (See reference

27.)

Distillate Oil -- ULNB was chosen for RACT control, reducing

emissions by 74 percent, but with a slightly higher cost

than with gas-firing, at $735 per ton reduced. The more

stringent control option was estimated as the LNB + SCR

combination, reducing NOx emissions by 92 percent and

costing an average of $6,340 per ton reduced in distillate

oil fired heaters. (See reference 27.)

Residual Oil -- The ULNB and LNB + SCR methods of control

were again chosen to represent RACT and the more stringent

control option for residual oil-fired process heaters, with

emissions reductions of 73 percent and 91 percent, and

average NOx control costs of $442 and $3,820 per ton,

respectively. (See reference 27.)

5. Acid Manufacturing Plants

Adipic Acid -- Both the RACT and more stringent control

methods assumed were thermal reduction control in adipic

acid manufacturing plants. Very little data were available

for these plants, but reductions of 81 percent were reported

at an average cost of $460 per ton. (See reference 28.)

Nitric Acid -- A method of extended absorption was chosen

for RACT control in the nitric acid manufacturing plants. 

This method reduces NOx emissions by 95 percent and costs an

average of $173 per ton reduced compared with the 98 percent

reduction and $600 per ton reduced listed for the more

stringent control technique of NSCR. (See reference 28.)

5.4.2 NOx RACT to 25 tpy Sources

The incremental effect of applying RACT to 25 tpy sources

was examined by comparing this scenario with the baseline (the

Act) scenario. The results of this analysis are shown in Table

5-5 for projection year 1999. Because the point source inventory

does not provide complete coverage of sources below 50 tpy for

NOx (sources less than 50 tpy would only appear if they are

considered major for one of the other criteria pollutants), the

effect of applying NOx RACT to 25 tpy is expected to be

underestimated. The magnitude of the emission reductions vary by

56
area depending on the mix of sources in the individual areas. 

Comparing the reductions with the Stage II reductions in 

Table 3-5 shows comparable reductions for NOx RACT to 25 tpy in

Sussex County in Delaware, Hancock/Waldo and Somerset counties in

Maine, Poughkeepsie in New York, Johnstown, Reading, YoungstownWarren-Sharon, Northumberland County, Pike County, and Warren

County in Pennsylvania. For some areas, such as Sussex County in

Delaware and Poughkeepsie in New York, the low NOx to VOC ratio

contributes to the comparability.

5.4.3 More Stringent NOx Control to 100 tpy Sources

The incremental effects of applying more stringent controls

on NOx sources was examined by applying the control levels

discussed above and comparing this scenario with the baseline

control (the Act) scenario. These results are also shown in

Table 5-5. The reductions achieved depend on the mix of sources

within the area. Several areas show reductions comparable to

Stage II for more stringent NOx controls. Areas that do not 

show comparable reductions are those where reductions are zero

(either no sources are above 100 tpy or more stringent control

options are not available for the types of sources in the area), 

areas with high NOx to VOC substitution ratios, such as the

attainment counties in Pennsylvania, and other areas where the

NOx reductions are low due to the mix of sources. Detailed

results by source category are provided in Appendix C.

57
58
6.0 CONDUCTING AN INDEPENDENT COMPARABILITY ANALYSIS

States have the option of conducting an independent

comparability analysis to re-examine measures covered in this

report using up-to-date, State-specific information or to

evaluate control measures not included in this report. This

chapter describes the method that States may use for the

analysis. Included are procedures for determining the emission

reductions achieved by Stage II controls and the emission

reductions associated with alternative measures the State is

considering to adopt as comparable to Stage II. 

6.1 COMPARABILITY DEMONSTRATIONS

To be comparable, the emissions reductions achievable

through the alternative measures must equal or exceed those

achievable by Stage II at projection year 1999. As discussed in

Chapter 2, States have some flexibility with regard to certain

aspects of their comparability determination. These items are

summarized below. 

C Both single measures and combinations of measures may

be considered as potential comparable measures.

C States may adopt comparable NOx control measures

instead of Stage II.

C VOC and NOx emissions reductions from an alternative

measure may be summed (in the manner described in

Chapter 5).

C Measures may be shown to be comparable on an individual

ozone area basis or on an aggregate basis for affected

areas in the State.

Consistent data sets should be used to demonstrate

comparability. If the State elects to use its own 1990 base year

inventory instead of the 1990 Interim Inventory to project

emissions reductions for comparable measures, then to maintain

consistency, the entire demonstration should be made using the

State's inventory. Likewise, if the State uses its own inventory

to estimate reductions due to Stage II vapor recovery, then the

emission reductions associated with comparable measures should

also be estimated using the State inventory. 

States may wish to substitute their own growth or control

information for the data used in this analysis. The EPA

recognizes that complete State inventories may not be available

for all areas covered under this study. States may therefore use

the Interim Inventory as the basis for demonstrating

comparability of measures, substituting State-specific growth or

59
control assumptions. The Interim Inventory may also be used to

demonstrate the comparability of other measures not examined in

this study.

The States will have the responsibility to adequately

document the following: 1) the 1990 base year inventory for all

source categories affected by control measures used to

demonstrate comparability; 2) the growth factors used to project

emissions to 1999; 3) control measure assumptions for the

baseline (including Act-required measures) projection and the

control strategy (potential comparable measures) projection;

4) information on how the MOBILE5 model was run; 5) the expected

emissions reductions for Stage II and the comparable measures;

and 6) the equivalency of NOx reductions to VOC reductions (if

NOx control measures are used).

6.2 DETERMINING STAGE II EMISSIONS REDUCTIONS

In a State's own comparability analysis, the Stage II

emission reduction estimates may be taken directly from this

report or the State may utilize its own data to estimate VOC

emissions reductions attributable to Stage II. If a State

chooses to use its own data, the following information and

documentation should be provided:

C Base year (1990) vehicle refueling emissions and

emission calculations -- States should follow SIP

emission inventory guidance and follow EPA-approved

methods for calculating base year emissions. The

recommended method is to apply MOBILE5a emission

factors (in grams per gallon) to estimated gasoline

consumption. Alternatively, VMT-based emission factors

may be used. If the State uses the Interim Inventory

as the basis for projections, documentation is limited

to simply stating so.

C Growth factors (and documentation if factors other than

BEA or E-GAS are used) for projecting activity to 1999. 

If BEA or E-GAS (EPA-recommended sources) are used,

documentation is limited to simply stating this;

otherwise, documentation should be sufficient for EPA

to duplicate calculations and make a judgment as to the

acceptability of the growth factors.

C MOBILE5a emission factors and input files for the 1999

baseline scenario that includes mandatory controls but

not Stage II -- Mandatory controls affecting refueling

emissions include phase II RVP and ORVR controls

(discussed below).

C MOBILE5a emission factors and input files for the 1999

scenario, with Stage II.

60
C 1999 projection year refueling emissions without Stage

II.

C 1999 projection year refueling emissions after Stage II

controls are applied.

C Stage II emission reduction estimates for the

projection year.

Emission reductions for Stage II should be measured from a

future year baseline which includes the effects of ORVR. ORVR

controls should be modeled beginning in model year 1999 for LDGV

(because MOBILE5a does not model phase-in for ORVR).

6.3 DETERMINING EMISSIONS REDUCTIONS FROM ALTERNATIVE MEASURES

As stated previously, States may re-examine measures covered

in this report or evaluate measures not covered by this report. 

In either case, the State should clearly define the particular

measure(s) and document the methods used to estimate emissions

reductions from implementation of the measures. At a minimum, 

the following information should be submitted:

C Base year emissions and calculations for the source

category(s) affected -- States should follow EPA

guidance on the development of SIP inventories when

preparing base year emission estimates. Alternatively,

the State may use the Interim Inventory for the base

year emissions. The data selected should be consistent

with the emissions data used to estimate Stage II

emissions reductions.

C Growth factors for projecting emissions to 1999. If

BEA or E-GAS (EPA-recommended sources) are used,

documentation is limited to simply stating this;

otherwise, documentation should be sufficient for EPA

to duplicate calculations and make a judgment as to the

acceptability of the growth factors.

C Control assumptions for the baseline controls,

including the emission factors, control efficiency,

rule effectiveness, and rule penetration for each

source category. Documentation of MOBILE5a input

should be provided if motor vehicle measures are

included.

C Control assumptions for the control strategy

(comparable measure) projection, including the emission

factor, control efficiency, rule effectiveness, and

rule penetration for each source category. 

61
Documentation of MOBILE5a input should be provided if

motor vehicle measures are included.

C 1999 projection year emissions by source category under

the mandatory Act requirements.

C 1999 projection year emissions by source category after

application of comparable measures.

C Estimated emissions reductions for comparable measures

calculated using the two projections above.

C Calculation of VOC comparable emissions if a NOx

control measure is being substituted for Stage II. The

method for substituting NOx for VOC is given in Chapter

5 of this report. If the State uses its own inventory

data, then complete VOC and NOx inventories should be

provided in order to show equivalency of NOx measures

on a percent of inventory basis.

62
REFERENCES

1. 59 FR 16262 "Control of Air Pollution From New Motor

Vehicles and New Motor Vehicle Engines; Refueling Emission

Regulations for Light-Duty Vehicles and Light-Duty Trucks,"

Final Rule, Federal Register. April 6, 1994.

2. "Users Guide to MOBILE5a," Chapter 2, U.S. Environmental

Protection Agency, Office of Mobile Sources, Ann Arbor, MI. 

March 1993.

3. "Regional Interim Emission Inventories (1987-1991) -

Volume 1: Development & Methodologies," Prepared by E.H.

Pechan & Associates, Inc., Prepared for U.S. Environmental

Protection Agency, Source Receptor Analysis Branch. May

1993.

4. "The 1985 NAPAP Emissions Inventory (Version 2); Development

of the Annual Data and Modeler's Tapes," EPA-600/7-89-012a,

U.S. Environmental Protection Agency, Air and Energy

Engineering Research Laboratory, Research Triangle Park, NC. 

November 1989.

5. "State Energy Data Report -- Consumption Estimates 1960-

1989," DOE/EIA-0214(89), U.S. Department of Energy, Energy

Information Administration, Washington, DC. May 1992.

6. "MOBILE4.1 Fuel Consumption Model," Chapter 3, U.S.

Environmental Protection Agency, Ann Arbor, MI. January

1989.

7. "Procedures for Emission Inventory Preparation - Volume IV: 

Mobile Sources," EPA-450/4-81-026d (Revised), U.S.

Environmental Protection Agency. 1992.

8. "Supplement D to Compilation of Air Pollutant Emission

Factors, Volume I: Stationary Point and Area Sources," AP42, U.S. Environmental Protection Agency. September 1991.

9. "Climatology of the United States," No. 81, U.S. National

Oceanic and Atmospheric Administration. September 1982.

10. "Motor Gasoline Survey," Motor Vehicle Manufacturers

Association. 1987-1991.

11. 55 FR 112 Table of RVP limits, pg. 23667, Federal Register,

U.S. Environmental Protection Agency. June 11, 1990.

12. 57 FR 13498 "General Preamble for the Implementation of

Title I of the Clean Air Act Amendments of 1990," Federal

Register. April 16, 1992.

63
REFERENCES (continued)

13. "Technical Guidance -- Stage II Vapor Recovery Systems for

Control of Vehicle Refueling Emissions at Gasoline

Dispensing Facilities," Vol. 1, EPA-450/3-91-022a, U.S.

Environmental Protection Agency, Office of Air Quality

Planning and Standards, Research Triangle Park, NC. 

November 1991.

14. "Enforcement Guidance for Stage II Vehicle Refueling

Programs," U.S. Environmental Protection Agency, Office of

Air and Radiation. December 1991.

15. "The 1985 NAPAP Emissions Inventory: Development of

Temporal Allocation Factors," EPA-600/7-89-010d, U.S.

Environmental Protection Agency, Air and Energy Engineering

Research Laboratory, Research Triangle Park, NC. April

1990.

16. "Growth Factors from Draft MOBILE4 Fuel Consumption Model,"

memorandum to J. Wilson, E.H. Pechan & Associates, Inc., M.

Wolcott, Office of Mobile Sources, U.S. Environmental

Protection Agency. April 29, 1991.

17. 57 FR 52950 "Inspection/Maintenance Program Requirements,"

Final Rule, Federal Register, U.S. Environmental Protection

Agency. November 5, 1992.

18. 59 FR 7716 "Regulation of Fuels and Fuel Additives: 

Standards for Reformulated and Conventional Gasoline," Final

Rule, Federal Register. February 16, 1994.

19. "I/M Costs, Benefits, and Impacts Analysis," (Draft), U.S.

Environmental Protection Agency. February 1992.

20. "NOx Substitution Guidance," U.S. Environmental Protection

Agency. December 1993.

21. "Rethinking the Ozone Problem in Urban and Regional Air

Pollution," National Research Council, National Academy

Press, Washington, DC. 1991.

22. 57 FR 55620 "State Implementation Plans; Nitrogen Oxides

Supplement to the General Preamble for the Implementation of

Title I of the Clean Air Act Amendment of 1990," Federal

Register. November 25, 1992.

23. "1990 BEA Regional Projections to 2040: Volume 1: States,"

U.S. Department of Commerce, Bureau of Economic Analysis,

Washington, DC. June 1990.

64
REFERENCES (continued)

24. "Alternative Control Techniques Document - NOx Emissions

from Industrial/Commercial/Institutional Boilers," draft

chapters, U.S. Environmental Protection Agency. July 1993.

25. "Alternative Control Techniques Document -- NOx Emissions

from Stationary Reciprocating Internal Combustion Engines,"

EPA-453/R-93-032, U.S. Environmental Protection Agency. 

1993.

26. "Alternative Control Techniques Document -- NOx Emissions

from Stationary Gas Turbines," EPA-453/R-93-007, U.S.

Environmental Protection Agency. 1993.

27. "Alternative Control Techniques Document -- NOx Emissions

from Process Heaters," EPA-453/R-93-015, U.S. Environmental

Protection Agency. 1993.

28. "Alternative Control Techniques Document -- Nitric and

Adipic Acid Manufacturing Plants," EPA-450/3-91-026, U.S.

Environmental Protection Agency. 1993.

65