p.1 

OAR Box 1818 

Prepped by Ollie Stewart 

Document Number: 

60) II-F-2 

Docket Number: 

A-87-11 

Printed 11/6/2008 3:12:45 PM Sheet 60 of 79 
P.2 

TE-F-X6ER* 

DRAFT 

Unlttd Starat 

Environm-antil Protaction 

Agtncy 

/4-^-n 

Office ef Air and Radiation 

(ANR-443) 

Waaftington, DC 20460 

FILE COPY 

Air 

Draft Regulatory Impact 

Analysis: Proposed Refueling 

Emission Regulation for 1990 

and Later Model Year 

Gasoline-Fueled Motor 

Vehicles 

Volume II 

Additional Analysis of 

Onboard Controls 

V 
P.3 

• -I 

Draft Regulatory Impact 

Analysis: Proposed Refueling 

Emission Regulation for 1990 

and Later Model Year 

Gasoline-Fueled Motor 

Vehicles 

Volume II 

Additional Analysis of 

Onboard Controls 

OFFICE OF AIR QUALITY PLANNING AND STANDARDS 

AND 

OFFICE OF MOBILE SOURCES 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

Office of A,r and Radiation 

Washington, DC 20480 
P.4 

1.0 INTRODUCTION 

This second volume (Volume II) supplements the first 

volume of the draft Regulatory Impact Analysis in fulfilling 

the objectives of Title 3 - Executive Order 12291 as they apply 

to the proposed onboard rulemaking. It provides a summary of 

the more extensive support analyses of onboard costs and air 

quality benefits that were prepared in the course of developing 

the proposed regulations. Alternatives to the proposed 

regulations are considered in Volume I. 

More specifically, following this introduction (Chapter 

1), Chapter 2 of this volume summarizes the economic impact of 

the proposed rulemaking. It identifies the fixed and variable 

costs to manufacturers for systems development, certification, 

facility modifications, and emission control hardware. It also 

addresses costs to consumers in terms of both first price 

increase for hardware and operating costs or savings. Finally, 

the chapter summarizes aggregate costs of the proposed 

regulations to the nation by year incurred, and the 

socioeconomic impact of the proposed rulemaking. The latter 

category includes a brief discussion of the impacts on the 

financial status of manufacturers and component vendors, 

effects on sales and employment in the automotive and petroleum 

industries, effects on energy usage, balance of trade, and on 

particular segments of the economy. 

Chapter 3 summarizes the air quality benefits of the 

proposed rulemaking. Beginning with a brief characterization 

of refueling emissions potentially controllable by an onboard 

control strategy, the chapter goes on to analyze the effect of 

refueling emissions control on ambient ozone levels in current 

non-attainment areas, i.e. those areas now in violation of the 

National Ambient Air Quality Standards for ozone. The direct 

health effects of ozone have been fully documented in other EPA 

publications and so they are not included in this analysis. 

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REFERENCES FOR CHAPTER 1 

Draft Regulatory Impact Analysis: Proposed Refueling 

Emission Regulations for 1990 and Later Model Year 

Gasoline-Fueled Motor Vehicles, Environmental Protection 

Agency, Office of Air and Radiation, Report tt , 

December [MO],1986. 

1-2 
P.6 

2.0 ECONOMIC IMPACT 

I. Introduction 

This chapter assesses the economic impact of onboard 

control of refueling emissions in terms of the costs to 

manufacturers, costs to the consumer, total cost to the nation 

and the overall socioeconomic impact of the proposed 

regulations. The purpose of this chapter is to summarize and 

assemble into one comprehensive analysis those cost elements 

that have been developed in greater detail than in Volume 1 of 

the draft RIA and other support documents.[1] The reader 

wishing more detail on the various aspects, of the costs of 

onboard control is referred to the appropriate- sections of 

those documents. 

In addition to controlling refueling emissions, properly 

designed and tested onboard control systems also have the 

potential to control excess evaporative emissions. However, 

other approaches to controlling excess evaporative emissions 

are being evaluated separately, so this analysis will focus 

primarily on the costs of refueling emissions control alone. 

Specifically, the costs and credits involved in onboard control 

of refueling emissions described here are incremental to 

vehicle-based excess evaporative control costs. 

This chapter is organized into four sections (1) costs to 

manufacturers, i.e., systems engineering costs, certification 

costs, facility modifications and hardware costs, (2) costs to 

the consumer, including first price increase and operating 

costs or savings, (3) aggregate costs to the nation, by year 

incurred, and (4) socioeconomic impacts of the regulations. 

The latter would include any effects the proposed regulations 

might have on manufacturers' or vendors financial status, 

effects on sales and employment in the automotive and petroleum 

industries, and effects on energy usage, balance of trade, or 

on particular segments of the economy. 

Data from a wide variety of sources were utilized to 

develop the cost estimates summarized in this chapter. The 

primary sources for the hardware cost estimates at the vendor 

level are studies done in 1978 and 1983 by Leroy H. Lindgren. 

[2,3] Retail Price Equivalent (RPE) markups, used to calculate 

costs to the consumer from vendor costs, were developed by an 

EPA contractor.[4] These works have been supplemented where 

appropriate by other EPA contract studies, comments on the 

draft GMS from the automotive and - petroleum industries, 

supplier quotations, trade publications -and previous estimates 

from EPA regulatory support analyses. Most of the estimates of 

vehicle miles traveled (VMT) and fuel consumption data used in 

assessing operating costs were obtained from EPA's MOBILE3 

emission factors and fuel consumption models. Additional 

vehicle usage data came from the Department of Commerce "Truck 

Inventory and Use Survey" (TIUS) and an SAE paper on fuel 

economy done by EPA.[5,6] Vehicle sales estimates are based on 

the Data Resources Incorporated 25-year "Trendlong" 

projections.[7] The dieselization rates applied to these 

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projections to obtain gasoline-fueled vehicle sales estimates 

are from the M0BILE3 model. The heavy- duty gasoline vehicle 

(HDGV) portion of the cost analysis has been updated from that 

found in the Summary and Analysis of Comments to the GMS based 

on the more in-depth analysis contained in an EPA technical 

report.[8] 

In determining costs to the industry, consumers, and 

aggregate costs to the nation, various cost elements must be 

amortized over different periods of time, and in portions of 

the analysis costs must be discounted to reflect the time value 

of money. Systems engineering and certification costs, for 

example, are relatively short term and are likely to be 

incurred and recovered early in the regulation -implementation 

period. These costs will therefore be amortized over a five 

year period 1990-1994, assuming a 1990 implementation date for 

the proposed regulations. The other fixed costs, those for 

modification and construction of testing facilities, are 

longer-term and will be amortized over a ten year period 

1990-1999. Variable costs will be aggregated over the initial 

five-year period to show the highest annual costs and will be 

discounted to reflect the time value of money, where 

necessary. The standard ten percent discount rate will be 

used, and all fixed costs will be amortized at a 10 percent 

interest rate. All costs are expressed in 1986 dollars. 

II. Costs to Manufacturers 

Costs to manufacturers can be divided into two general 

categories, fixed and variable costs. Fixed costs represent 

capital expenditures that must be made before production of 

emission control components can begin. As such, they are 

relatively independent of production volumes. These costs 

include systems engineering costs, certification costs and 

facilities modifications. Variable costs represent the vendor 

cost of the necessary emission control hardware. They are 

directly dependent on production volume and are expressed on a 

per vehicle basis. The fixed costs will be amortized and added 

to variable costs to provide a total unit cost to the 

manufacturer. 

The basic sources for this section are the GMS Summary and 

Analysis of Comments for LDVs and-LDTs, and the HDGV Technical 

Report mentioned previously.[1,8] The latter report contains 

EPA's most recent estimates of HDGV control costs, updated from 

the preliminary estimates found in the GMS Summary and Analysis 

of Comments. For additional detail on both fixed and variable 

costs, the reader is referred to these two documents. 

A. Fixed Costs 

As stated above, the fixed costs involved in onboard 

control of refueling emissions include systems engineering and 

certification costs, and the cost of test facilities 

modifications. These costs can be expected to vary somewhat 

between vehicle classes, however light duty vehicles (LDVs) and 

light duty trucks (LDTs) have the same certification procedures 

and quite similar fuel systems and can therefore be grouped 

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P.8 

together. Heavy duty gasoline vehicles (HDGVs) have similar, 

but larger, systems and different certification procedures. 

Estimating costs for HDGVs requires some different analysis 

than that needed for LDVs and LDTs. 

I. Light Duty Vehicles and Light Duty Trucks 

Systems engineering costs are those incurred in developing 

an onboard system that is integrated with the other related 

vehicle/engine systems. This includes incorporation of the 

onboard system into other vehicle/engine systems (e.g. fuel 

system, packaging) as well as consideration of safety and other 

emission control requirements. In some cases this is a 

straightforward engineering design problem, in o-thers such as 

vehicle safety or emissions control, it involves not only 

design, but also follow-on testing and evaluation. 

At this point EPA has little data on which to base a firm 

estimate of the systems engineering costs. Costs involved 

would generally include engineering design and development, 

procurement and modification of prototype hardware and test 

vehicles, and the actual testing and evaluation of the 

systems. The abovementioned safety testing and evaluation 

would also be included. EPA briefly examined these latter 

costs and concluded that the cost for ensuring compliance with 

the applicable fuel system safety provisions would be about 

$34,000 per body configuration, or approximately $6.9 million 

fleetwide.[9] Since the number of body configurations is 

roughly equal to the projected number of refueling families, 

this cost can easily be included in the total systems 

engineering cost per family. Accordingly, in the Summary and 

Analysis of Comments, EPA estimates a total systems engineering 

cost for LDVs and LDTs (including safety costs) at about 

$146,000 per refueling family (assumed to be similar in number 

to the current evaporative emissions family) . Multiplying by 

the projected number of families (approximately 140 LDV and 65 

LDT) results in an estimated cost of $20.4 million for LDVs and 

$9.5 million for LDTs. Amortizing these costs for five years 

at 10 percent per year and dividing by projected sales during 

the period provides an amortized cost per vehicle of $.49 per 

LDV and $.69 per LDT, including $.12 per vehicle for fuel 

system safety compliance. 

Certification costs include the costs of vehicle buildup, 

mileage accumulation for LDVs and LDTs on durability and 

emission data vehicles, and emissions testing for durability 

and emission data vehicles. The EPA es-timated cost per family 

from the Summary and Analysis of Comments is $181,000 for 

durability vehicles and $28,000 for emission data vehicles. 

Although a total recertification would likely be necessary 

because of the refueling regulations, the estimated 10 percent 

of the fleet that normally undergoes certification each year 

regardless of new standards must be deducted to determine the 

net cost of the refueling regulations. Multiplying the cost 

per family by 90 percent of the projected LDV and LDT families 

yields a certification cost of approximately $26 million for 

LDVs and $11 million for LDTs. The amortized cost per vehicle 

is $.61 for LDVs and $.77 for LDTs. 

2-3 
P.9 

Systems engineering and certification efforts will require 

some expansion of and/or improvement to manufacturers' testing 

facilities in order to accommodate the additional testing 

required. " Comments submitted by the Motor Vehicle 

Manufacturers Association (MVMA) contained an estimate of 

$734,000 per manufacturer for additional equipment and testing 

space.[10] Absent any other reasonable estimates of the 

requirements, the Summary and Analysis of Comments uses this 

figure to project the facilities modifications that would be 

required. Although it is unlikely that all 35 LDV/LDT 

manufacturers would incur this entire expenditure, it is 

possible that some larger manufacturers would have to spend 

even more than this amount. To be conservative, then, EPA will 

assume that all manufacturers will make the above"'investment in 

additional facilities, for a total industry cost of 

approximately $26 million. This results in an amortized cost 

per vehicle of approximately $.30. 

2. Heavy Duty Gasoline Vehicles 

Determining manufacturer costs for HDGVs requires a 

slightly different analytical approach from that used for LDVs 

and LDTs, due to the wider range of vehicle sizes and 

applications. For the 1990s and beyond, HDGVs can conveniently 

be divided into three basic groups, classes Ilb/III, VI and 

VII/VIII, based on gross vehicle weight (GVW) rating classes. 

About 80 percent of all HDGVs fall into the class lib weight 

group (i.e., 8,501-10,000 lbs GVW). These are essentially 

heavy LDTs and can benefit directly from the transfer of LDT 

technology. The relatively few (8 percent) class III vehicles 

(10,001-14,000 lbs GVW) that are sold each year, primarily 

Class A motor homes, will also be included in this group. Thus 

class Ilb/III sales represent about 88 percent of all HDGVs 

expected to be sold in 1990 and beyond. The remaining 12 

percent of HDGV sales consist of class VI (19,501-26,000 lbs. 

GVW), and classes VII and VIII (26,001 - 33,000 lbs. GVW and 

all heavier vehicles). About one-half of these vehicles are 

class VI; the remainder are the heavier vehicles, which will be 

grouped together as class VII/VIII HDGVs. 

Systems engineering costs for the Class lib vehicles 

should be the same as for LDTs, i.e., $.69/truck, since they 

are all made by LDT manufacturers and can thus take advantage 

of the LDT work. In fact, some manufacturers may choose to 

certify part or all of their class lib trucks as LDTs. Class 

III HDGVs, which are primarily Class A motor homes, often use 

larger fuel tanks than Class lib vehicles, even though the 

chassis and drivetrains are quite similar. Nevertheless, some 

additional systems engineering work such as • improved purge 

systems may be required to handle the increased emission loads 

associated with the larger fuel tanks. To be conservative, EPA 

estimates that the costs for Class III HDGVs will be the same 

as estimated in the HDGV Technical' Report for larger class VI 

and VII/VIII vehicles, i.e. $2.00 per truck, since essentially 

similar engine technology is used, the refueling emission loads 

are roughly comparable, and the test procedure is the same. A 

weighted average for the entire Ilb/III group would be $0.82. 

2-4 
P.10 

Class VI and VII/VIII HDGV refueling emissions are likely 

to present additional control problems. The emission loads are 

likely to be greater, due to the larger fuel tanks that are 

typically found on these vehicles. Also, most of the heavier 

HDGVs currently have open loop carbureted fuel systems, which 

would have more difficulty with purge control than the 

closed-loop fuel systems with electronic engine controls that 

are more common on LDVs and LDTs and are expected on many class 

Ilb/III vehicles. Some additional purge control systems 

engineering is thus likely to be required for these vehicles. 

Conversely, it should be noted that the current HC and CO 

exhaust emission standards for these vehicles are not as 

stringent as those that apply to the class Ilb/III HDGVs. In 

the HDGV Technical Report, EPA estimates a 'cost^of $2.00 per 

vehicle to cover development of these control systems. On a 

fleet weighted basis, the amortized costs of all HDGV classes 

is $0.96 per vehicle. Equivalent total systems engineering 

costs can be obtained by summing the net present value of the 

$.82 class Ilb/III cost and the $2.00 classes VI and VII/VIII 

cost multiplied by the respective projected sales for the three 

classes for the first five years of the regulation. This would 

equate to a total HDGV systems engineering cost to 

manufacturers of about $1.4 million. 

Control of HDGV refueling emissions would entail 

recertification to the exhaust and evaporative emission 

standards in addition to refueling. Exhaust emission 

recertification would be necessary due to the new requirement 

that evaporative/refueling emission control canister(s) be 

connected to the engine during testing. Evaporative emission 

recertification would be necessary due to the test procedure 

changes and the potential interdependence between the 

evaporative and refueling control systems. 

Exhaust emissions recertification is estimated to cost 

$200,000 per family. This entails both durability assessment 

and three emission data engines. For 1986, HDGV manufacturers 

certified 8 families using 23 emission data engines. Total 

exhaust emission recertification costs including durability 

assessment are estimated at $1.6 million dollars. 

Evaporative emission recertification costs are a bit more 

difficult to estimate since abbreviated certification 

procedures apply to classes lib through VI HDGVs and 

certification is by engineering evaluation for the heavier 

HDGVs. Using the development costs presented in the original 

HDGV RIA, certification costs are estimated at $31,000 per 

evaporative family/system combination. In 1986, 23 

family/system combinations were certified. Using these 

figures, total evaporative emission certification costs are 

estimated at $713,000. 

Even though abbreviated certification procedures have been 

proposed for HDGV refueling, some costs would still be incurred 

for durability assessment and demonstration of system 

performance on emission data vehicles. However, these costs 

2-5 
P.11 

would be incremental to those incurred during system 

development and exhaust and evaporative emission 

recertification. Durability assessment is estimated to cost a 

nominal $50,"000 per manufacturer over those costs incurred for 

exhaust and evaporative recertification, and emission data 

vehicle testing is estimated to cost $9000 per family/system 

combination for testing and mileage accumulation. Assuming 

three primary HDGV manufacturers and the same number of 

refueling and evaporative family/system combinations (i.e. 23) 

the total certification for refueling is estimated to be 

$357,000. 

Summing the estimated costs for exhaust-, evaporative, and 

refueling certification, the total industry cost' is estimated 

at $2.67 million dollars. Assuming these costs are incurred in 

the year prior to the new standard and amortized over vehicles 

sold in the 5 year period 1990-1994, the per vehicle 

certification cost is $2.00. 

The final fixed cost to manufacturers of HDGVs is for 

modification of and improvements to test facilities. It is 

anticipated that the requirements for class lib vehicles will 

be essentially the same as those required for LDTs; the same 

facility may in fact serve both vehicle classes. Class III 

through VI vehicles will also require new or modified 

facilities for certification. Requirements for VII/VIII 

vehicles are not as readily apparent, however, since 

certification for the heavier models would be by engineering 

evaluation, as is the case for current evaporative systems. 

Thus, while the additional facility requirements may be 

minimal, the $.30 per vehicle estimated for LDVs and LDTs is 

also extended to HDGVs. This provides an additional $710,000 

to cover any incidental modifications that may be required for 

HDGV facilities. 

3. Summary 

In summary, the projected manufacturers' fixed costs for 

LDVs, LDTs, and HDGVs are just under $98 million. These costs 

are divided between the various vehicle classes for systems 

engineering, certification and facilities modifications as 

shown in Table 1. Table 1 also shows these fixed costs on an 

amortized per-vehicle basis. 

B. Variable Costs 

Emission control hardware is the primary variable cost to 

the manufacturers. Refueling control" hardware costs for 

individual components are relatively the same for any vehicle 

class/subgroup, but total system costs vary somewhat depending 

on the type of control system, the number of fuel tanks, and 

the vehicle fuel tank capacity. A brief description of the 

onboard control system and a summary of the individual 

component costs is given below. This is followed by a 

discussion of the key factors which can cause the costs to vary 

and a summary of the control system costs used in the analysis. 

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Table l 

Fixed Costs to Manufacturers 

(Millions of Dollars) 

LDV LDT HDGV Total 

Systems Engineering 

Certification 

Facility Mods 

Total 

20.4 

26.0 

17.9 

64.3 

9.5 

11.0 

8.1 

28.6 

1.4 

2.7 

0.'7 

4.8 

31.3 

39.7 

26.7 

97.7 

Amortized Costs per Vehicle 

(Dollars) 

LDV LDT HDGV 

Systems Engineering 0.4 5 

Certification 0.61 

Facility Mods 0.30 

Total 1.36 

0.69 

0.77 

0.30 

1.76 

0.96 

2.00 

0.30 

3.26 
P.13 

As described in the Technological Feasibility portion of 

the GMS, an onboard system is comprised of a number of new 

components and modification of several existing components. 

These are described briefly below: 

1. Fillpipe Seal - Used to prevent gasoline vapor from 

escaping to the atmosphere. Liquid or mechanical seal 

approaches are possible. This analysis assumes all vehicles 

will use liquid seals, except the large HDGVs which may use 

mechanical seals. A pressure relief device may be required for 

mechanical seals. 

2. Fill Limiter - A device inside the tank used" to close the 

refueling vapor line when the tank is full, eventually causing 

actuation of of automatic shut-off on the fuel nozzle. 

3. Vapor Line Closure Valve - A valve used to close the vapor 

line during normal vehicle operation. This is a key component 

in rollover protection. Electronic or mechanical approaches 

are possible. 

4. Liquid/Vapor Separator - Required to decrease the emission 

load to the canister and improve canister durability by 

returning entrained liquid fuel droplets to the fuel tank. 

5. Vapor and Purge Lines - Hoses to route refueling vapor to 

the charcoal canister and purged vapor to the vehicle fuel 

system. Net cost depends on canister location and whether the 

system is integrated or separate from the evaporative control 

systems. 

6. Charcoal Canister - Serves as vapor storage device. Cost 

and size vary with fuel tank size and whether the control 

system is integrated or separate. 

7. Packaging - Hardware or vehicle modifications to 

accommodate canister and other hardware on the vehicle. Costs 

vary depending on vehicle size and type. These costs are 

amortized over five years. 

8. Modifications - Minor modifications will be necessary to 

the fuel tank and vehicle purge system. Fuel tank 

modifications will be needed to accommodate the liquid seal and 

fill limiter. Purge system modifications will be needed to 

efficiently purge the canister while controlling exhaust 

emissions. These costs are amortized over five years of 

production. 

On a per vehicle basis, three other factors may effect the 

total cost of the refueling emission control hardware. These 

include the basic system approach, the number of fuel tanks, 

and the capacity of the fuel tanks. 

Three basic control systems approaches may be used; 

integrated, partially integrated, and separate. The integrated 

system uses one canister to control both evaporative 

2-8 
P.M 

and refueling emissions. The partially integrated system 

collects diurnal evaporative and refueling emissions in one 

canister and. uses a separate canister for capturing hot soak 

emissions, the third approach, the completely separate system, 

captures all evaporative emissions in one canister and all 

refueling emissions in another. 

EPA expects that all fuel injected vehicles will utilize 

fully integrated systems due to the cost advantage and the low 

level of non-fuel tank hot soak emissions. Carbureted vehicles 

may use partially integrated or separate systems due to the 

need to deal with hot soak evaporative emissions. However, EPA 

expects most manufacturers will opt for partially integrated 

systems to take advantage of the available cost savings. 

By 1990, when these regulations are to take affect:, 

current projections are that approximately 88 percent of all 

LDVs and LDTs are expected to be fuel injected and 12 percent 

carbureted. Class Ilb/III HDGV fuel systems are likely to 

follow the same split as LDTs. The majority of the heavier 

HDGVs (Class VI-VIII) are assumed to remain predominantly 

carbureted. Thus 88 percent of LDVs, LDTs and Class Ilb/III 

HDGVs are expected to use integrated systems and the remaining 

12 percent of these vehicles classes are expected to use 

partially integrated systems. Essentially all of the heavier 

HDGVs are assumed to use either partially integrated or 

separate systems. 

On a per vehicle basis, onboard hardware costs also depend 

on whether a vehicle has single or dual fuel tanks. Hardware 

costs for dual fuel tank vehicles are essentially twice those 

of single tanks because each fuel system requires the necessary 

control hardware. Dual tank vehicles could use any of the 

three control system approaches discussed above, and EPA 

assumes that the mix of these control approaches will be the 

same as described above for both single and dual tank 

vehicles. The fractions of dual tank vehicles used in this 

analysis are shown below. These essentially reflect current 

conditions. 

LDV 0% 

LDT 20% 

HDGV: 

Class lib 20% 

Class III 40% 

Class VI 10% 

Class VII 19% 

Class VIII 100% 

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P.15 

While most individual onboard hardware component costs 

will not vary among the vehicle models, the cost of the 

charcoal canister for any given vehicle model will vary 

depending oit the capacity of the fuel tank. The cost of a 

refueling emissions control canister is a function of the 

required control system capacity which in turn depends upon the 

size of the fuel tank. EPA estimated fleet average fuel tank 

sizes for the three vehicle classes/subgroups based on a 

minimum driving range and the fuel economy improvements that 

are expected to occur between 1990 and 2000. The projected 

fuel tank capacities used in calculating canister costs for the 

three vehicle classes/subgroups are shown in Table 2. 

Based on this information regarding 'refueling control 

hardware and those factors which influence total per vehicle 

cost, Tables 3 and 4 present onboard costs for LDVs, LDTs and 

HDGVs. These are manufacturer (vendor level) costs and do not 

reflect manufacturer or dealer markups for overhead and 

profit. For sake of completeness, the amortized fixed costs 

discussed previously are also listed. It should be noted that 

the costs presented in Tables 3 and 4 are incremental to the 

cost of current evaporative emissions systems. 

As can be seen from Tables 3 and 4, costs vary with time 

to reflect both the different amortization periods for fixed 

costs and changing canister sizes due to projected fuel economy 

improvements. Three distinct cost periods can be identified 

for LDVs, and LDTs, and HDGVs: 1990-94, 1995-99, and 2000 and 

beyond. For the sake of brevity, only the total costs are 

shown for the years after 1994 for all vehicle classes. The 

cost differences are based on the following assumptions. For 

all vehicles, systems engineering and certification costs are 

assumed to be fully amortized during the first 5 years, i.e. by 

1994, and are not reflected thereafter. Vehicle modifications 

(i.e. tank and purge system modifications and packaging) costs 

would also disappear after 5 years for LDVs, LDTs and class lib 

HDGVs, as car and truck designs begin to incorporate onboard 

controls from the initial design inception. Class VI - VIII 

HDGVs are assumed to have no packaging costs and so these are 

not reflected in the 1990-94 initial cost estimates. Tank and 

purge system modification costs would also drop out after five 

years for HDGVs, just as they do for LDVs and LDTs. For LDVs, 

LDTs, and HDGVs, facility modifications represent a longer-term 

investment and are assumed to be fully amortized after 10 

years. Therefore they are not included after 1999. 

Projected fuel economy improvements.have been averaged for 

each of the three periods to determine canister size 

requirements for LDVs and LDTs. These are also reflected in 

the decreasing costs for each period.. Fuel economy differences 

are not reflected in long-term HDGV costs, since the projected 

improvements are slight and have a minimal effect on system 

costs. 

2-10 
P.16 

» i 

Table 2 

Projected Fuel Tank Capacity By Vehicle Class 

(Gallons) 

5 Year Period 

Vehicle Class 1990-94 1995-1999 2000 + 

LDV 12 11 10 

LDT 

Single Tank 

Dual Tank 

HDGV 

Ilb/III-Single 

Ilb/III-Dual 

Vl-Single 

VI-Dual 

Vll/VIII-Single 

VII/VIII-Dual 

16 

33 

30 

60/70 

40 

84 

38 

88 

16 

32 

30 

60/70 

40 

84 

38 

88 

15 

29 

30 

60/70 

40 

84 

38 

88 
P.17 

As was mentioned previously, properly designed and tested 

onboard control systems also have the capacity to control the 

excess evaporative emissions caused by the higher volatility of 

commercial fuels. However, these excess evaporative emissions 

could be controlled by increasing the RVP of the fuel used in 

exhaust and evaporative emissions certification testing to the 

in-use level of 11.5 psi, in which case manufacturers would be 

forced to improve their current emission control systems. Thus 

it is appropriate to evaluate onboard refueling control costs 

incremental to excess evaporative emission control costs. 

Calculating the costs of onboard controls incremental to 

improved evaporative systems requires the subtraction of the 

incremental costs of the improved evaporative systems from the 

onboard costs presented in Tables 3 and 4. Thrs is done in 

Table 5 for LDVS, LDTs, HDGVs. The cost of these improved 

systems is taken from EPA's recent study of gasoline volatility 

and vehicle HC emissions. [ 11] For the sake of brevity only a 

single cost is shown for each vehicle class. This cost is a 

weighted average based on the distribution of configurations 

discussed earlier. 

Ill. Costs to the Consumer 

The cost of the proposed regulations to the consumer can 

be divided into two general categories: first price increase 

and operating costs. The first price increase consists of 

hardware costs, amortized manufacturer fixed costs and the 

retail price equivalent (RPE) markups. The RPE reflects the 

various overhead and profit markups that are added to the 

vendor cost of a the onboard system at the manufacturer and 

dealer levels. The second category, operating costs, consists 

of maintenance and in-use inspection costs, if any, plus any 

change in total lifetime fuel costs due to increased or 

decreased fuel consumption rates. Each of these is discussed 

below, followed by an estimate of the net lifetime consumer 

cost. 

A. First Price Increase 

The total first price increase to the consumer consists of 

the manufacturer's cost per vehicle developed in the previous 

section, including amortized fixed costs, multiplied by an RPE 

markup factor of 1.26 for LDVs and LDTs and 1.27 for HDGVs. 

These markup factors represent industry averages and were 

developed by an EPA contractor using available financial data 

for the domestic auto and truck manufacturers and their 

dealers. [4] Data covering a ten year time span were used in 

the determination to dampen the effects x>f the business cycle. 

The markup factor includes corporate overhead and profit plus 

dealer profit and other expenses for interest and sales 

commissions. No dealer overhead is included, since the 

addition of emission control components should not increase the 

dealer's cost for storing or selling his vehicles. Hardware 

costs and amortized costs for certification and facilities 

modifications are marked up using these factors. However, 

2-12 
Table 3 

Manufacturer Costs of Onboard Emission Control Components 

Light Duty Vehicles and Light Duty Trucks 

LDV LDT - Single Tank LDT - Dual Tank 

Category 

1990-94 

Hardware 

Veh. Mods 

Subtotal 

AJIJOI t ;.*..-J 

FlXcU -.'uSt-S 

Integrated 

13.24 

1.07 

14.31 

1.36 

Part Int/Sep 

15.17 

1.97 

17.14 

1.36 

Integrated 

14.58 

1.07 

15.65 

1.76 

Part Int/Sep 

16.54 

1.97 

18.51 

1.76 

Integrated 

32.39 

2.39 

34.78 

2.11 

Part Int/Sep 

34.21 

3.44 

37.65 

2.11 

Total 15.67 18.50 17.41 20.27 36.89 39.76 

Class 

Weighted Avg. 

1990-94 

1995-99 

2000 + 

LDV 

16.01 

14.00 

12.87 

LDT-ST 

17.75 

15.51 

14.29 

LDT-DT 

37.23 

33.82 

32.08 

All LDT 

21.65 

19.17 

17.85 
Table 4 

Manufacturer Costs of Onboard Emission Control Components 

Heavy Duty Gasoline Vehicles 

Category 

1990-94 

Hardware 

Veh. Mods 

Subtotal 

Amortized 

Fixed Costs 

CL. Ilb/III 

Single Tank 

22.39 

1.03 

23.42 

3.16 

HDGV 

Dual Tank 

51.12 

2.17 

53.29 

3.29 

CL. VI HDGV 

Single Tank Dual Tank 

31.63 

.72 

32.35 

4.88 

67.26 

1.44 

68.70 

4.88 

CL. VII/VIII 

Single Tank 

30.48 

.72 

31.20 

4.88 

HDGV 

Dual Tank 

64.77 

1.44 

66.21 

4.88 

Total 26.58 56.58 37.23 73.58 36.08 71.09 

Class 

Weighted Avg: 

1990-94 

1995-99 

2000 + 

lib/' 

33 

29 

28 

[II 

.18 

.15 

.77 

VI 

40.86 

35.49 

35.21 

VII/VIII 

43.78 

38.32 

38.18 

All HDGV 

34.27 

30.08 

29.78 
P.20 

Table 5 

Onboard Hardware Costs to Manufacturers 

(Incremental to Costs for Control of 

Excess Evaporative Emissions) 

LDV LDT HDGV 

1990-94 Hardware cost1 

Less: excess evap. cost 

Incremental cost2 

1995-99 Hardware cost1 

Less: excess evap cost 

Incremental cost2 

2000 + Hardware cost1 

Less: excess evap cost 

Incremental cost2 

$16.01 

-2.29 

13.72 

14.00 

-1.51 

12.49 

12.87 

-1.51 

$21 

-3 

'18 

19 

-1 

17 

17 

-1 

65 

02 

6.h 

17 

98 

19 

85 

.98 

$34.27 

-3.28 

30.99 

30.08 

-2.70 

27.38 

29.78 

2.70 

11.36 15.8 7 27.08 

1 Incremental to cost of current evaporative control systems. 

2 Incremental to cost of improved evaporative control systems 

capable of controlling excess evaporative emissions. 
P.21 

using the markup methodology developed by Lindgren for EPA, 

systems engineering costs are essentially R&D and are not 

subject to RPE markups, but rather are added to the total cost 

after the RPE markup has been applied. Table 6 shows the first 

price increase to the consumer when onboard costs are evaluated 

incremental to excess evaporative emission control costs. 

B. Operating Costs 

As discussed in the GMS analysis, an onboard system should 

not require any additional maintenance over the current 

evaporative emission control system. Also, no in-use 

inspections of onboard systems are likely, . since evaporative 

systems are generally not inspected in currenf'programs and 

tampering rates are relatively low. Therefore, no increases in 

operating costs related to onboard system maintenance or in-use 

inspections are expected. 

However, some change in lifetime operating costs are 

expected as a result of the positive fuel consumption benefit 

realized from the fuel recovery credits. Fuel recovery credits 

accompany both the recovery of refueling and excess evaporative 

emissions, but this analysis will address only the refueling 

emissions which are captured by the onboard system. As was 

mentioned previously, a properly designed and tested onboard 

system would also have the capacity to control excess 

evaporative emissions, but alternative strategies for 

controlling excess evaporative emissions may reduce or totally 

eliminate the excess evaporative credit. 

The lifetime change in fuel consumption resulting from the 

recovery of refueling emissions actually is the difference of 

two effects: the gross recovery credit less the effect of the 

weight penalty associated with the onboard system. The gross 

recovery credit is determined by calculating the gasoline 

equivalent of the total mass of refueling vapors captured, then 

multiplying this figure by the presumed vapor combustion 

efficiency. This recovery credit must then be reduced by the 

fuel economy penalty resulting from the slight weight increase 

associated with the onboard system. The weight penalty was 

determined using the estimated weight of an onboard system 

together with a weight/fuel consumption sensitivity factor. 

Using this approach, the net change in fuel consumption in 

each year of the vehicle life was determined and then 

multiplied by the value of a gallon of gasoline ($0.98) to get 

the monetary value of the recovery credit. These values were 

then discounted at 10 percent to the first year of the 

vehicle's life to get a monetary value in the same terms as the 

RPE. 

This analysis was conducted for the six vehicle 

classes/subgroups being evaluated here for the three time 

periods mentioned earlier for the hardware, ie. 1990-1994, 

1995-1999, and 2000 and beyond. The results of the analysis 

are shown in Table 6. 

2-14 
Table 6 

Costs to the Consumer' 

Onboard Refueling Emissions Control 

Costs: 1990-94: 

First Price Increase: 

Refueling FPI 

Less: 

Refueling Credits 

Net cost to consumer 

LDV 

17.17 

(4.24) 

$12.93 

LDT 

18.39 

(6.50) 

$11.89 

Dual Tank 

LDT 

42.82 

(3.35) 

$39.47 

Class lib/ Class Class VII/ 

III HDGV VI HDGV VIII HDGV 

37.84 47.01 50.90 

(11.48) (16.43) (21.75) 

$26.36 $30.58 $29.15 

Costs: 1995-1999: 

Refueling FPI 

Less: 

Refueling Credits 

Net cost to consumer 

Costs: 2000 & Beyond: 

Total FPI Refueling F 

Less: 

Refueling Credits 

Net cost to consumer 

15.71 

(3.85) 

$11.86 

PI 14.29 

(3.53) 

$10.76 

17.01 

(6.31) 

$10.70 

15.47 

(5.93) 

$9.54 

40.08 

(3.22) 

$36.86 

37.89 

(3.09) 

$34.80 

33.03 

(10.87) 

$22.16 

32.65 

(10.75) 

$21.90 

41.46 

(16.13) 

$25.33 

41.08 

(15.74) 

$25.34 

45.24 

(21.15) 

24.09 

44.86 

(20.67) 

$24.19 

1 Minor differences between the costs presented in this table and those presented' in 

the GMS S & A of Comments or the HDGV Technical Report are due to rounding. 

Costs are incremental to excess evaporative emissions control costs. > 
P.23 

C. Net Consumer Costs 

The net lifetime consumer costs for onboard control are 

shown in Table 6. In this table the costs associated with the 

first price increase are partially offset by the net present 

value of the recovery credits. Net costs are shown for the six 

vehicle class/subgroups and the three time periods mentioned 

previously. 

IV. Aggregate Costs to the Nation 

Aggregate costs to the nation include the fixed costs to 

manufacturers for systems engineering, certification and 

facility modifications, plus the cost to -the ^consumer for 

hardware, less the fuel recovery credits. In calculating these 

costs, the net amounts from Table 6, adjusted to remove the 

amortized fixed costs, were multiplied by the projected sales 

shown in Table 7. The 1988-94 aggregate costs are shown in 

Table 8 (undiscounted) and Table 9 (discounted) by the year 

they are expected to be incurred. A total discounted cost is 

also shown for each vehicle class, representing a lump sum 

payment as of the year the standards are effective. Costs are 

shown for LDVs, LDTs, HDGVs and a total for all three classes. 

All costs before the year the standard takes effect (1990) are 

for systems engineering, certification, and facility 

modifications; all costs for 1990 and subsequent years are for 

hardware costs, less fuel recovery credits. It is assumed that 

all systems engineering and facility modifications costs will 

be incurred in 1988 while all certification costs will be 

incurred in 1989. All of the costs shown in Table 9 are 

discounted at 10 percent per year to 1990, the first model year 

of the standard. As shown in the table, the total discounted 

cost to the nation for the proposed refueling regulations (in 

1986 dollars) is about $909 million. 

IV. Socioeconomic Impact 

The socioeconomic effects of the proposed regulations 

include any impact they may have on manufacturers' cash flow, 

sales and employment, energy usage, balance of trade, and on 

particular groups of individuals or segments of the economy. 

The overall impact of the proposed regulations on 

manufacturers' cash flow is expected to be minor. Hardware 

costs are recouped by the manufacturers during the year they 

are incurred. With current computerized inventory control 

systems, manufacturers are not expected to be required to 

maintain large, expensive parts inventories during the course 

of the manufacturing year, so the only significant negative 

impact on manufacturers' cash flow would come from the fixed 

costs, i.e. systems engineering, certification and facilities 

modifications. Although these costs would eventually be 

recovered, they would likely be incurred during the two years 

prior to the effective model year of the regulations, when 

there would be no directly offsetting revenues received. 

Assuming that all of the fixed costs would be incurred in the 

2-16 
P.24 

Table 7 

-Projected Gasoline-fueled Vehicle Sales 

(Millions of Vehicles) 

1990-2000 

Year LDV1 LDT1 HDGV' 

1990 

1991 

1992 

1993 

1994 

1995 

1996 

1997 

1998 

1999 

2000 + 

11.2 

11.2 

11.2 

11.1 

11.0 

10.8 

10.9 

11.0 

11.0 

11.0 

11.0 

3.71 

3.68 

3.64 

3.56 

3.47 

3.35 

3.40 

3.43 

3.45 

3.46 

3.48 

0.384 

0.381 

0.379 

0.381 

0.383 

0.384 

0.385 

0.388 

0.392 

0.396 

0.400 

1 Based on DRI "Trendlong" Projections, 

Fall, 1984 Long Term Review, Data Resources, Inc., 1984 

2 See Reference 11. 
P.25 

Table 8 

Aggregate Incremental Costs 

of Onboard Refueling Controls 

(Millions of Dollars1) 

Undiscounted 

Calendar Year LDGVs LDGTs 

17.6 0 

11.0 0 

57.0 0 

56.5 5 

55.9 5 

54.7 0 

53.3 5 

Rounded to the nearest 0.05 million. 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

38.30 

26.00 

126.90 

126.90 

126.90 

125.75 

124.65 

HDGVs 

2.10 

2.70 

8.80 

8.70 

8.65 

8.75 

8.75 

Total Costs 

58.00 

39.70 

-i92.70 

192.15 

191.50 

189.20 

186.75 
P.26 

Table 9 

Aggregate Incremental Costs 

of Onboard Refueling Controls 

(Millions of Dollars1) 

Discounted 1990 

Calendar Year LDGVs LDGTs 

1988 

1989 

1990 

1991 

1992 

1993 

1994 

Total 

46.35 

28.60 

126.90 

115.35 

104.85 

94.50 

85.10 

601.65 

21.30 

12.10 

57.00 

51.40 

46.25 

41.10 

36.45 

265.60 

HDGVs 

2.55 

3.00 

8.80 

7.90 

7.15 

6.55 

6.00 

41.95 

Total Costs 

70.20 

43.70 

192.70 

174.65 

158.25 

142.15 

127.55 

909.20 

Rounded to the nearest 0.05 million. 
two years prior to the effective date of the standards, the 

average cost per year would be less than $50 million. This 

represents less than one-half of one percent of the cash outlay 

made by the domestic industry during 1980 and 1981 for 

modernization and downsizing.[13] 

The effect of these regulations on sales and employment is 

also expected to be minimal. The first price increase to 

consumers is only 0.1 to 0.2 percent of the average cost of a 

new vehicle for LDVs, LDTs and HDGVs. By contrast, the annual 

price increases for new vehicles have been many times these 

percentages in recent years, even in times of very low 

inflation. The impact of such increases on consumer demand for 

vehicles is commonly expressed in terms of the price elasticity 

of demand, ie. the reduction in sales corresponding to an 

increase in price. EPA has determined a price elasticity ,of 

demand of -1.0 for LDVs & LDTs and -0.9 to -0.5 (average of 

-0.7) for HDGVs.[1,11] The resulting decrease in demand would 

thus be -.1 to -.2 percent for LDVs, LDTs and HDGVs. However, 

a real question arises as to whether it is appropriate to apply 

this price/demand model to such small price increases. Tnus, 

although it is conceivable that consumer demand, and 

consequently sales, could be affected slightly, it is highly 

unlikely and not measurable. Accordingly, the impact on 

employment in the auto industry should also be minimal. In 

fact, some additional employment in the manufacture of onboard 

control hardware is likely. This employment would occur in the 

traditional auto industry but would also extend to suppliers of 

activated carbon, vapor lines, and other components. 

Onboard controls could result in a slight decrease in the 

demand for gasoline, due to the fuel recovery credits. 

However, the savings involved are small in comparison to the 

projected gains in fuel economy during the period in question 

without the credits, or to the normal fluctuations in consumer 

demand due to other factors. A slight reduction in demand for 

gasoline could in turn result in a slight decrease in the 

demand for imported oil and perhaps an improvement in the 

nation's balance of trade, but this would likely be offset by 

the price increase on imported vehicles. Any effect on 

employment in the petroleum industry would also be negligible. 

In conclusion, the overall socioeconomic impact of these 

regulations is expected to be minimal. Barring a significant 

recession in the late 1980'S auto and truck manufacturers are 

expected to have no trouble underwriting the capital investment 

required. Vehicles sales should not be impacted measurably, 

and employment in the automotive and related industries may 

increase slightly. These regulations are not expected to have 

any net effect on the balance of trade. 

2-18 
REFERENCES FOR CHAPTER 2.0 

1. "Draft Regulatory Impact Analysis: Proposed 

Refueling Emission Regulations for 1990 and after Model Year 

Gasoline-Fueled Motor Vehicles, Volume 1, Analysis of Gasoline 

Marketing Regulatory Strategies, U.S. EPA, OAR, [MO] 1987. 

2. "Evaluation of Air Pollution Regulatory Strategies 

for Gasoline Marketing Industry," EPA-450/3-84-012a, U.S. EPA, 

OAR, July, 1984. 

3. "Cost Estimations for Emission Control-Related 

Components/Systerns and Cost Methodology Description," Leroy H. 

Lindgren, Rath and Strong for U.S. EPA, 1978.' .., ••*— 

4. Draft "Manufacturing Cost and Retail price 

Equivalent of Onboard Vapor Recovery System for Gasoline 

Filling Vapors," Leroy H. Lindgren for API, 1983. 

5. "Update of EPA's Motor Vehicle Emission Control 

Equipment Retail Price Equivalent (RPE) Calculation Formula", 

Jack Faucett Associates for U. S. EPA, 1985. 

6. "1977 Census of Transportation, Truck Inventory and 

Use Survey", U.S. Department of Commerce, Bureau of the Census, 

1980. 

7. "Light Duty Automotive Fuel Economy...Trends Thru 

1985", Murrell et. al., SAE Technical Paper Series K850550, 

1985. 

8. "U.S. Long Term Review, Fall 1984", Data Resources, 

Inc., 1984. 

9. "Feasibility, Cost and Cost Effectiveness of Onboard 

Vapor Control For Heavy-Duty Gasoline Vehicles," Holbert and 

Laing, U. S. EPA, OAR, OMS, 1986. 

10. Memorandum "Cost of Crash Testing to Assure Fuel 

System Integrity for Onboard Systems," Johnson to the Record, 

EPA, OAR, OMS, August, 1986. 

11. Comments of the Motor Vehicles Manufacturers 

Association of the U.S., Inc. on EPA Report "Evaluation of Air 

Pollution Regulatory Strategies for Gasoline Marketing 

Industry," MVMA, Public Docket A-84-07, I-H-127, 1984. 

12. "Study of Gasoline Volatility and Hydrocarbon 

Emissions from Motor Vehicles," U. S. EPA, OAR, OMS, 1985. 

13. "Regulatory Support Document, Revised Gaseous 

Emission Regulations for 1985 and Later Model Year HD Engines," 

U. S. EPA, OAR, OMS, 1983. 

14. "Draft Regulatory Impact Analysis and Oxides of 

Nitrogen Pollutant-Specific Study," U. S. EPA, OAR, OMS, 1984. 

2-19 
P.29 

3.0 ENVIRONMENTAL IMPACT: Ozone Air Quality 

I. Introduction 

This chapter evaluates the effects on ambient air quality 

associated with implementing a 0.10 gram per gallon (g/gal) 

refueling emission standard for 1990 and later model year 

light-duty vehicles, light-duty trucks, and heavy-duty vehicles 

that use gasoline fuel. The following section serves as the 

background for the remainder of the chapter. It includes a 

brief characterization of the emissions associated with the 

refueling process, a discussion of those emissions which are 

potentially controllable with onboard control technology, and 

the interaction between refueling emission jcontrols and 

concurrent reductions in excess evaporative emissions from 

motor vehicles. The last section evaluates the relative effect 

of controlling refueling and excess evaporative emissions on 

ambient ozone levels in selected urban areas currently in 

violation of the National Ambient Air Quality Standard (NAAQS) 

for this pollutant. The actual adverse effects of ozone on man 

and the environment will not be described in this section, 

since these effects have been fully documented elsewhere.[1,2] 

In general, this chapter has a relatively narrow focus. 

The ambient air quality analyses contained herein have a much 

more limited range than the emission inventory analyses 

presented in Volume l of the draft Regulatory Impact Analysis 

(draft RIA). The analyses of this chapter examine only those 

non-California urban areas that were in non-attainment status 

for the ozone standard on the basis of 1983 design values. A 

detailed evaluation of various national emission reduction 

scenarios is contained in the first volume of the draft RIA, 

and is not repeated here. Also, this chapter does not address 

the carcinogenic potential of gasoline vapors. Again, this 

topic is thoroughly discussed in the first volume of the draft 

RIA. Readers wishing to obtain further information on the 

aforementioned subjects should see the appropriate sections of 

this document. 

II. General Description of the Emissions Associated with 

Refueling and the Use of Onboard Controls 

A. Refueling Emissions 

Gasoline vapors are composed of various hydrocarbon (HC) 

compounds. During the vehicle refueling process, these vapors 

are emitted from a variety of sources.. The majority of the 

refueling emissions (i.e., about' 90 percent) are HC vapors 

displaced from the vehicle's fuel tank by the incoming 

gasoline. The mass of vapor which escapes per unit of gasoline 

dispensed, or the emission factor, is dependent on several 

variables, including: (D the temperature of the dispensed 

3-1 
P.30 

fuel, (2) the difference between the temperature of the 

dispensed fuel and the fuel tank, and (3) the volatility of the 

fuel.[3] These highly concentrated vapors are emitted from the 

vehicle's fillneck directly into the breathing zone of the 

person performing the refueling operation. 

In addition to displacement losses from the vehicle tank, 

there are two secondary sources of emissions associated with 

refueling. The first is spillage, due to "splash back" from 

the fill pipe or the escape of some liquid from the dispensing 

nozzle when withdrawn from the fill pipe. The second is the 

escape of vapor from the vent of the service station's 

underground tank following refueling. As fuel is pumped into 

the vehicle's fuel tank, ambient air is drawn into the service 

station's tank through its tank vent. This "fresh" air causes 

fuel in the tank to evaporate until an equilibrium 

concentration is reestablished between the vapor and the 

liquid. As this process takes place, the total volume of the 

ingested air in the underground tank increases somewhat, and 

the excess volume is emitted from the vent in the form of HC 

emissions. These latter two sources each account for about 5 

percent of the total emissions associated with the refueling 

process, as described in the first volume of the draft RIA. 

The total refueling emission factor is expressed as the 

mass of HC emitted per gallon of dispensed fuel (g/gal), and 

varies from region to region due to differences in temperatures 

and fuel volatility. As an example, using national average 

temperature values and national average estimates of future 

volatility levels based on historic trends, the total emission 

factor for all three sources is 6.6 g/gal.[3] 

B. Emissions Potentially Controllable by Onboard 

Technology 

Onboard controls function during a refueling operation by 

sealing the vehicle's fillneck and then routing the displaced 

vapors to a storage canister, where the HC molecules are 

adsorbed onto the surface of activated charcoal. When the 

vehicle's engine is started, fresh air is drawn through the 

canister to purge the HC molecules from the charcoal. The 

resulting vapor is transferred to the fuel metering system and 

subsequently burned in the engine. Tests have shown that 

properly designed and operating onboard systems are capable of 

controlling about 99 percent of the displacement vapors.[4] 

(The control effectiveness value was revised upward from the 97 

percent used in the gas marketing study based on more recent 

test data.) Of those emissions not captured, nearly all escape 

from the fillneck (i.e., 95 percent). The remainder (i.e., 5 

percent appear to be emitted from the canister, which typically 

is located in the engine compartment. 

3-2 
P.31 

Onboard control technology will also have the effect of 

eliminating one of the two secondary sources of emissions 

associated with refueling mentioned previously, that of "splash 

back." These emissions, which result from the spillage and 

subsequent evaporation of liquid gasoline, should be 

significantly reduced through the design of the proposed test 

procedure. The primary cause of fuel spillage is dispensing of 

the fuel at too rapid a rate, relative to what the vehicle 

fillneck is able to accept. The proposed test procedure 

specifies a maximum fuel dispensing rate of 10 gallons per 

minute. The draft regulations accompanying today's proposal 

specify this same maximum fuel flow rate as an in-use standard, 

as well as being part of the test procedure. Since, to be able 

to meet the proposed standard, no fuel spillage can be 

tolerated during certification testing of the onboard system, 

EPA believes that spillage due to high fueling rate will be 

eliminated through fuel flow rate restrictions and-standardized 

design of fuel delivery nozzles. Of course, spillage from such 

causes as nozzle malfunctions will not be affected by the new 

procedures. The other secondary source of refueling-related 

emissions, emptying losses from service stations' underground 

storage tanks, will not be affected by onboard control 

technology. 

The overall in-use efficiency of capturing displacement 

vapors will be somewhat less than 99 percent, due to the 

effects of tampering on some vehicles. Tampering is primarily 

expected to take the form of removal or disconnection of the 

canister. In such instances, the displacement losses revert to 

the uncontrolled level, but are re-oriented spatially. With 

tampered systems, the majority of the vapors would be emitted 

at the location of the missing or disconnected canister, rather 

than from the fillneck into the breathing zone of the person 

dispensing, the fuel. 

An issue that is intimately associated with the 

implementation of an onboard refueling standard is the 

interaction between the requisite control technology and the 

elimination of excess evaporative emissions from motor 

vehicles. Evaporative emissions are primarily a combination of 

breathing losses from the vehicle's fuel tank, due to diurnal 

temperature changes, and losses from the carburetor bowl, fuel 

lines, and fuel tank that occur as the result of residual heat 

from the engine and exhaust system after the engine is turned 

off. Presently, gasoline-fueled vehicles must be certified to 

certain evaporative emission standards prior to mass production 

and sale. The control technology used to reduce evaporative 

emissions to the required levels is .similar in design and 

function to that described above for onboard refueling hardware 

(i.e., carbon canisters). However, data from EPA's emission 

factor program indicate that many in-Use vehicles fail to 

comply with the applicable standards. The principle cause of 

3-3 
P.32 

these failures is that in-use fuel typically has a higher 

volatility than the fuel specified for certification testing. 

The increased amounts of evaporative HC caused by higher in-use 

volatilities cannot be adsorbed by current charcoal canister 

systems. These additional HC vapors escape into the atmosphere 

as excess evaporative emissions. 

The Agency is presently considering a variety of 

strategies aimed at assuring in-use compliance with evaporative 

emission standards. While no decision has been made, one 

alternative is to make relatively simple changes to the current 

evaporative emission test procedures and to increase the 

volatility of certification fuel to be more representative of 

in-use levels (i.e., certification fuel volatility equals 

in-use fuel volatility). These revisions basically would 

result in larger canisters and different purge rates. Since 

onboard technology includes a larger charcoal canister than is 

necessary to control evaporative emissions, even assuming t'he 

revision of test fuel volatility, and because refueling 

normally would not coincide with the occurrence of evaporative 

emissions, it is possible to control excess evaporative losses 

by integrating the requisite controls with the refueling 

control system at little additional cost. In order to 

illustrate the effects of such a program, the analyses 

presented in the remainder of this chapter will include a 

scenario that combines the control of refueling emissions plus 

excess evaporative emissions, in addition to a scenario that 

evaluates only the control of refueling emissions. 

Ill. Air Quality Analysis 

The NAAQS for ozone requires that the fourth highest daily 

maximum one-hour measured concentration not exceed 0.12 parts 

per million (ppm) in any three-year period. On the basis of 

ozone air quality monitoring data collected in 1982, 1983, and 

1984, which are the most recent complete data available, there 

are 73 urban areas in violation of this standard.[5] Twelve of 

these 73 non-attainment areas are located in California. As 

already discussed. Stage II vapor recovery systems are 

currently being used in nearly all of California, and it is 

unclear whether these systems will continue to be used or if 

they will be discontinued in favor of onboard controls. 

Because of this uncertainty, only the 61 non-California urban 

areas listed "" in Table 1 are included in the air quality 

analysis. This simplifies the analysis without affecting the 

resulting conclusions. 

Preliminary air quality analyses in support of this 

chapter were performed using 1982 as the base year. (As is 

explained further in the section on air quality methodology, 

base year data required as input for EKMA include emission 

inventories and design values, a measure of ambient ozone 

3-4 
P.33 

concentrations.) With 1982 as the base year, EPA found 47 nonCalifornia urban areas (standard metropolitan statistical areas 

(SMSAs), or groupings of SMSAs into metropolitan areas) to have 

design values of 0.13 parts per million (ppm) or greater, thus 

indicating ozone non-attainment status. Seven California 

areas, all of them urban, also met this criterion. EPA 

includes all non-California urban areas with design values of 

0.13 ppm or greater in its modeling of future ozone air quality. 

The analyses presented in the remainder of this chapter 

have been updated to use 1983 as the base year. In addition to 

more recent base-year emission inventories, this means that the 

design values used are based on ozone air quality monitoring 

data collected in 1982, 1983, and 1984. (The 1982 design 

values are based on 1981, 1982, and 1983 monitoring, data.) 

There is another significant difference in the air quality 

analysis using 1983 as the base year, relative to previous 

analyses. This refinement involves the use of different sets 

of design values for the determination of non-attainment status 

and for input data to EKMA. This is discussed in more detail 

in Section III.A.6. of this chapter. 

Applying the same test as was used in the preliminary 

analyses to the newer design values, EPA found that the number 

of urban areas in non-attainment status had increased from 54 ^'-* 

(47 non-California) in 1982, to 73 (61 non-California) in 1983. 

This increase in the number of urban ozone non-attainment areas 

between 1982 and 1983 indicates the need for further reductions 

in emissions of ozone precursors. Ozone air quality modeling 

in recent years, using design values from the early 1980s, has 

consistently projected steady improvements in ambient ozone 

concentrations and a parallel decrease in the number of 

non-attainment areas. The most recent design values, based on 

1982-84 air quality monitoring data, suggest that this 

projected "improvement trend" is not occurring. This situation 

has widespread implications for EPA's ozone compliance 

strategies and post-1987 policies, most of which are beyond the 

scope of discussion in this chapter.* 

The Administrator announced EPA's new four-phase ozone 

compliance strategy in a speech to the Air Pollution 

Control Association's June 1986 annual meeting. The basic 

four phases are: (1) improve the effectiveness of existing 

regulations and programs; (2) adopt additional national 

policies and control measures; (3) demonstration of 

attainment of the ozone NAAQS; and.(4) sustained Progress 

Programs (for those areas unable to .attain and demonstrate 

compliance with the ambient air quality standard despite 

implementation of the first three phases). Onboard 

control of vehicle refueling emissions, as a national 

control measure, is one component of Phase II of this 

strategy. 

3-5 
Table 1 

61 Non-California Urban Ozone Non-Attainment 

Areas and Associated Design Values (ppm) 

P.34 

Area 

EPA Region l 

Boston Metropolitan Area 

Greater Metropolitan Connecticut 

New Bedford, MA 

Portland, ME 

Portsmouth-Dover-Rochester, NH-ME 

Providence, RI 

Springfield, MA 

Worcester, MA 

82-84 

DVs 

0.19 

0.23 

0 . Vf 

0.15 

0.13 

0. 16 

0. 19 

EKMA 

DVs 

0.18 

0.18 

0.19 

0.10 

0.09 

0.15 

0.17 

0. 14 0. 12 

EPA Region 2 

Atlantic City, NJ 

New York Metropolitan Area 

Vineland-Mi1lvi1le-Bridgeton, NJ 

EPA Region 3 

Allentown-Bethlehem, PA 

Baltimore, MD 

Erie, PA 

Harrisburg-Lebanon-Carlisle, PA 

Lancaster, PA 

Philadelphia Metropolitan Area 

Pittsburgh, PA 

Reading, PA 

Richmond-Petersburg, VA 

Scranton-wilkes Barre, PA 

Washington, DC-MD-VA 

York, PA 

EPA Region 4 

Atlanta, GA 

Birmingham, AL 

Charlotte-Gastonia-Rock Hill, NC-SC 

Chattanooga, TN-GA 

Huntington-Ashiand, WV-KY-OH 

Louisville, KY-IN 

Memphis, TN-AR-MS 

Miami-Hialeah, FL 

Nashville,. TN 

Tampa-St. Petersb* .eanwater, FL 

0.19 

0.23 

0.14 

0. 15 

0 . 17 

0 . 13 

0. 13 

0. 14 

0. 18 

0. 14 

0. 13 

0. 14 

0. 13 

0 . 16 

0. 13 

0.15 

0.24 

0.14 

0 . 14 

0. 17 

0. 13 

0. 13 

0.09 

0.20 

0. 14 

0. 13 

0. 14 

0.13 

0. 17 

0. 13 

0 . 17 

0 . 15 

0. 13 

0 . 13 

0 . 14 

0 . 15 

0. 13 

0. 13 

0. 13 

0. 13 

0. 17 

0. 15 

0. 13 

0. 13 

0. 14 

0. 15 

0. 13 

0. 13 

0. 13 

0. 13 
Table 1 (cont'd) 

P.35 

Area 

82-84 

DVs 

EPA Region 5 

Akron, OH 

Canton, OH 

Chicago Metropolitan Area 

Cincinnati Metropolitan Area 

Cleveland, OH 

Dayton-Springfield, OH 

Detroit, MI 

Grand Rapids, MI 

Indianapolis, IN 

Milwaukee Metropolitan Area 

Muskegon, MI 

EPA Region 6 

Baton Rouge, LA 

Beaumont-Port Arthur, TX 

Brazoria, TX 

Dallas-Fort Worth Metropolitan Area 

El Paso, TX 

Galveston-Texas City, TX 

Houston, TX 

Lake Charles, LA 

Longview-Marshall, TX 

New Orleans, LA 

San Antonio, TX 

Tulsa, OK 

EKMA 

DVs 

0 

0 

0 

0 

0 

0 

0 

0 

0 

13 

13 

20 

15 

14 

13-

14 

13 

13 

17 

14 

17 

21 

14 

16 

17 

17 

25 

15 

15 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

13 

13 

25 

17 

14 

13 

14 

13 

13 

17 

14 

0.15 

0. 14 

0.13 

0 

0 

0 

0 

0 

0 

0 

0 

0. 15 

0. 15 

0. 14 

0. 13 

17 

21 

14 

16 

17 

17 

25 

15 

EPA Region 7 

Kansas City, MO-KS 

St. Louis, MO-IL 

EPA Region 8 

Denver Metropolitan Area 

Salt Lake City-Ogden, UT 

EPA Region 9 

Phoenix, AZ 

0.14 

0.17 

0. 14 

0.15 

0. 15 

0 . 14 

0. 17 

0. 14 

0. 15 

0. 15 
One issue raised by this information, however, concerns 

the validity of EPA's usual assumptions concerning the rate of 

implementation and the efficiency of "reasonably available 

control technology" (RACT) on stationary sources of ozone 

precursor emissions, in the form of volatile organic compounds 

(VOC). This is discussed at greater length in sections 

III.A.6. and 7., below. 

A, Air Quality Methodology 

Future ambient ozone concentrations in specific urban 

areas are estimated using the Empirical Kinetic Modeling 

Approach (EKMA). This model utilizes a series of ozone 

isopleths depicting downwind ozone concentrations as a function 

of initial non-methane hydrocarbon (NMHC) an.d oxides of 

nitrogen (NOx) concentrations, the differences between 

initialand subsequent NMHC and NOx emission inventories, 

meteorological conditions, and reactivity of the precursor mix, 

in addition to concentrations of ozone and precursors 

transported from upwind areas. It should be noted, however, 

that EKMA as used by EPA is a nationwide-average model. In 

other words, the only city-specific information used as input 

data for the model are the base-year ambient ozone 

concentrations (design values) and the emission inventories 

from which future concentrations are projected, and the 

NMHC:NOx ratios. Meteorological conditions and other input 

data are held constant for all the urban areas modeled. 

References 6 and 7 contain additional information on the use of 

EKMA. 

The initial, or base-year, emission inventories used in 

the model are based on the information contained in EPA's 

National Emissions Data System (NEDS), which is compiled by the 

Agency's Office of Air Quality Planning and Standards (OAQPS). 

The NEDS inventory includes emissions from both stationary and 

mobile sources. The most recent emissions compilation is for 

calendar year 1983, and is referred to as the 1983 base-year 

inventory. Stationary source inventories for any future year 

are computed by the model using anticipated growth and 

retirement rates, along with estimates of emission control 

efficiency. Similarly, future inventories are constructed for 

mobile sources using the emission factor ratios (base-to-future 

years) and annual compound VMT growth rates for each vehicle 

class, derived from EPA's MOBILE3 Emission Factor Model and 

M0BILE3 Fuel Consumption Model, respectively. 

The specific stationary source estimates and assumptions 

used in the model for this analysis are the same as those that 

were used in EPA's recent report on in-use fuel volatility and 

evaporative emissions (hereafter referred to as the volatility 

study).[8] Because these model inputs are fully described in 

that document, they are not repeated here. The volatility 

study also evaluated baseline and excess evaporative control 

3-8 
scenarios that are identical to those considered in this 

chapter. Rather than repeat the detailed discussion of the 

mobile source inputs for these scenarios, only a few of the key 

features of that analysis, along with the basic inputs used to 

model the onboard control scenario evaluated here, are 

described below. 

1. Fuel Volatility 

Under the baseline scenario, the Reid vapor pressure (RVP) 

of in-use fuel is the maximum summertime value (11.5 pounds per 

square inch) recommended by the American Society for Testing 

and Materials (ASTM) in "Class C" areas, which include most 

areas of the country with significant ozone air guality 

problems. [8] This value was chosen because' nearly all ozone 

NAAQS violations in these locations occur during the summertime 

and, based on current fuel volatility trends, it is expected 

that this RVP level will be reached by the time onboard 

controls enter the marketplace. (In fact, this level is 

already being exceeded in some areas, at least at times.) The 

RVP of the certification fuel for the baseline scenario is the 

currently specified value of 9.0 psi. Under the control 

scenarios, the RVP of in-use fuel is again 11.5 psi. However, 

the RVP of certification fuel is assumed to be revised to equal 

that of in-use fuel. 

2. Fuel Temperatures 

The mass of gasoline vapors displaced from the vehicle's 

fuel tank is highly dependent on the temperature of the 

dispensed fuel, as well as the temperature of the fuel already 

in the tank. As mentioned with regard to fuel volatility, most 

ozone violations occur during the summer months. Therefore, 

national average summertime temperatures for the two 

fuel-related temperature parameters are appropriate when 

modeling ozone air quality. These values are 88.2°F and 

78.8°F for fuel tank and dispensed fuel, respectively.[3] 

3. Refueling Emission Factors 

The refueling emission factor is composed of three parts: 

vehicle fuel tank displacement losses, spillage, and service 

station tank emptying losses. The amount of displacement 

vapors which escape from an uncontrolled vehicle during the 

refueling event are found by using the RVP and temperatures 

just described, along with the equation developed in an EPA 

technical report that relates these parameters to displacement 

losses:[3] 

Displacement losses = 

-5.909 - 0.0949(AT) + 0.884(TD) + 0.485(RVP) 

-5.909 - 0.0949(+9.4) + 0.884(78.8) + 0.485(11.5) 

3-9 
Where: 

TD = temperature of the dispensed fuel (°F), 

AT = TT - TD = difference between the temperature of 

fuel already in the vehicle tank (TT) and dispensed 

fuel, and 

RVP = Reid Vapor Pressure of the dispensed fuel (psi). 

The resulting value for the displacement losses component of 

the refueling emission factor is 5.7 g/gal. 

As discussed in greater detail in reference [3], data on 

the frequency and magnitude of spillage losses are both scarce 

and widely variable. EPA has chosen to .use 0.3 g/gal to 

represent the spillage portion of the refueling enrission factor 

and 0.4 g/gal to represent the emptying losses. These values 

are taken from Volume 1 of the draft RIA. Summing these three 

components yields the uncontrolled refueling emission factor bf 

6.4 g/gal. 

For vehicles equipped with onboard controls, two emission 

factors are used in the analysis, depending on whether the 

system is properly operating or has been tampered with. Tests 

of properly operating (non-tampered) systems have shown the 

capability to control 99 percent of the displacement losses.[4] 

As noted earlier EPA expects that implementing onboard controls 

will also serve to reduce spillage losses. However, since the 

amount of spillage which will be controlled is unclear at this 

time, EPA has taken the more conservative position of assuming 

no reduction in spillage. Therefore, adding the spillage and 

emptying losses, the resulting non-tampered emission factor is 

0.8 g/gal. 

Since there are no externally visible changes to a vehicle 

equipped with an onboard control system, the rate of tampering 

with such systems is assumed to be no more frequent than that 

occurring with current evaporative controls, and will take only 

the forms of removal or disconnection of the storage canister. 

When this occurs, emissions would revert to their uncontrolled 

level (i.e., 6.4 g/gal). MOBILE3 accounts for the effects of 

tampering by utilizing this uncontrolled emission factor with 

appropriate tampering rates (see below). 

It should be noted that the uncontrolled emission factor 

used to examine ambient ozone air quality differs slightly from 

that used to evaluate other health effects (i.e., 6.4 versus 

6.6 g/gal).- This is the result of using different volatility 

and temperature data to estimate displacement losses for the 

two analyses. As mentioned above, ozone violations are 

primarily a summer problem, so the emission factor for the air 

qu'ality analysis is based on national summertime average 

values. In contrast, the emission factor for the health 

effects analysis was derived using national annual average 

3-10 
P.39 

values since, unlike ozone violations, these phenomena are not 

restricted to certain areas of the country or to a specific 

season. Since fuel volatility and fuel temperatures vary over 

the course of the year, the two resulting emission factors are 

not equal. •" In any event, it should be noted that the 

difference in the emission factors is only about 3 percent. 

4. Tampering Rates 

In the onboard control scenario, the tampering rates used 

in M0BILE3 for removal and disconnection of the evaporative 

emissions storage canister are also used to reflect refueling 

canister tampering. It should be noted that the tampering 

rates contained in the original MOBILE3 were revised in the 

volatility study to reflect later informatiori froiiu EPA's in-use 

surveillance programs.[8] The inclusion of these 1985 survey 

data had the effect of slightly increasing the tampering rates, 

relative to the original MOBILE3 tampering rates. These new 

rates, which vary as a function of vehicle mileage, have been 

used in this analysis. The tampering rates used in this 

analysis for LDVs and LDTs, respectively, are about 2.5 and 6 

percent at 50,000 miles, and about 6 and 9 percent at 100,000 

miles.[8] 

It should also be noted here that with the use of a liquid 

seal, which EPA anticipates will be the dominant approach, the 

vehicle fillneck is no different with than without an onboard 

control system. In fact, the incorporation of onboard 

technology with the liquid seal should be virtually transparent 

to the vehicle owner/operator, thus presenting no real 

incentive to tamper. Thus, it is assumed that whatever 

tampering will occur as a result of the implementation of 

onboard controls will be limited only to the removal or 

disconnection of the canister, as noted above. This would not 

be the case with Stage II control systems, or with onboard 

control systems using mechanical fillneck seals. 

5. Inspection and Maintenance Program 

The exhaust emission factors used in the air quality 

analysis assume the existence of Inspection and Maintenance 

Programs (I/M) in each of the non-attainment areas throughout 

the projection period. This assumption has the effect of 

slightly lowering the average emission factors assigned to 

those vehicles subject to I/M. This assumption was made in 

consideration of the fact that most of the high-population 

areas among the 61 non-California urban, areas modeled either 

have I/M programs in effect already, .or have such programs 

scheduled to go into effect in the near, future. In addition, 

I/M programs are a fundamental component of the Agency's 

recently announced four-phase ozone, compliance strategy (see 

the introduction to this section). 

3-11 
P.40 

6. Design Values and Base Year Inventories 

As was noted in the introduction to this section, the 

inventory projections and air quality analyses in this chapter 

use 1983 as the base year. The 1983 design values are based on 

air quality monitoring data recorded in 1982, 1983, and 1984. 

These design values, which are shown in Table l under the 

heading "82-84 DVs," are the basis for determining which urban 

areas are in non-attainment status for the ozone NAAQS. These 

values are significantly different, in terms of the number of 

non-attainment areas, than the 1982 design values that have 

been used in previous EPA studies. Where the 1982 design 

values indicated 47 non-California urban non-attainment areas, 

the 1983 design values show 61 such areas. (The number of 

non-attainment areas within California, which are> not included 

in the analyses of this chapter for reasons already discussed, 

increased from 7 to 12 on the same basis.) Some of the 

implications of this increase are discussed in the next section. 

As was briefly noted earlier in this chapter, two 

different types of design values have been used as part of this 

analysis. Those design values discussed in the immediately 

preceding paragraphs and used in the determination of nonattainment status are based on the 1982, 1983, and 1984 

monitoring data without modification. In other words, the 

values shown in Table 1 under the heading "82-84 DVs" represent 

the fourth highest one-hour ambient ozone concentrations 

measured in the three years of monitoring data examined. 

Previous ozone air quality analyses have used similarily 

defined values as a necessary input for EKMA. In this 

application, the value is interpreted as the ambient ozone 

concentration in the base year. However, the air quality 

analyses for this chapter include a refinement which leads to 

the development of a second set of "design values" being used 

to represent the base year ambient concentrations. These 

values are also shown in Table 1, under the heading "EKMA DVs." 

This second set of design values reflect modifications 

that attempt to take into account the transport of ozone. This 

is accomplished by a computer program known as MASH (Multiple 

Airshed) . MASH uses wind directions and the times that ozone 

exceedances (i.e., one-hour concentrations in excess of the 

0.12 ppm NAAQS) occur to determine whether an exceedance is 

predominantly the result of emissions originating in the local 

area, or of emissions originating in a nearby major 

metropolitan area upwind. It then assigns the measured ozone 

levels to either the upwind metropolitan, area or the local area 

as a function of selected criteria.[5] In regions where ozone 

transport is significant (e.g., the northeastern part of the 

country), this process tends to lower the design values in 

smaller cities or SMSAs and to raise the design values in the 

larger metropolitan areas. These MASH-processed design values 

3-12 
P.41 

are intended for use in ozone air guality modeling, and are not 

appropriately used in determining attainmeht/non-attainment 

status. 

It should also be noted that there is relatively little 

difference in the two sets of design values, with the "82-84 DV" 

and "EKMA DV" being equal for 46 of the 61 areas modeled. Of 

the 15 areas where the application of the MASH program led to a 

change in the design value, the value used for input to EKMA is 

lower than the unmodified value in 10 of the areas and higher 

in five of them. The areas with differences between the two 

values are concentrated in the Northeast and along the central 

East Coast (EPA Regions 1, 2, and 3), where many of the SMSAs 

and metropolitan areas are contiguous. The greatest increase 

in design value resulting from the MASH program o-ecurs for the 

Chicago Metropolitan Area. The increase of 0.05 ppm represents 

a 25 percent increase over the unmodified value, reflecting the 

fact that much of the ozone-precursor emission inventory 

generated in this area is transported downwind before it is 

photochemically converted to ozone. 

In addition to the design values, EKMA also requires a 

detailed inventory of pollutant emissions in the base year by 

source category. For ozone air guality modeling, NMHC 

inventories and NMHC:NOx ratios are required. As noted above, 

the inventories are developed as part of the National Emission 

Data System (NEDS). 

To model air quality in a given future projection year, a 

number of assumptions must be made about control technology, 

control efficiency, and growth rates. For example, modeling 

the air quality impact of the proposed refueling emission 

standard involves the calculation of emission factors for 

refueling emissions from all gasoline-fueled mobile sources 

(light-duty vehicles and trucks and heavy-duty vehicles), both 

with and without onboard refueling controls. By holding other 

parameters constant in both cases (i.e., growth rates, exhaust 

emission standards, stationary source control efficiences and 

growth rates), the effect of the proposed refueling emission 

standard on ozone air quality can be projected. 

7. Stationary Source RACT and the FMVCP 

The modeling of future NMHC inventories and ambient ozone 

concentrations involves looking at emissions from both mobile 

and stationary sources. For mobile sources, the key inputs 

include the emission factors (as calculated by MOBILE3) and 

vehicle miles travelled (VMT) growth, rates. The emission 

factors for each vehicle/engine class -vary by model year, 

reflecting the impact of the Federal Motor Vehicle Control 

Program (FMVCP), under which increasingly stringent exhaust and 

evaporative emission standards have been established. 

3-13 
P.42 

EPA has developed an extensive data base on the in-use 

performance of mobile source emission control technology. 

Based on this information, the Agency has a high degree of 

confidence in the emissions reductions projected to result from 

standards established under the FMVCP. Even when coupled with 

projected VMT growth, the FMVCP gains net reductions in the 

mobile source portion of future NMHC inventories into the 1990s. 

In the case of stationary sources, the two main inputs 

required for modeling future emissions are growth rates and 

control efficiencies. Stationary source NMHC emissions are 

divided into six major categories in EPA's models.[8,9] For 

some stationary sources, EPA has defined "reasonably available 

control technologies" (RACT) and issued control technology 

guidelines (CTGs). RACT-based emission controls, for those 

categories covered by CTGs, are required to be included as part 

of each state's plan for attaining the NAAQS for ozone. 

Previous EPA modeling results have always indicated 

decreasing emission inventories and improving air guality at 

least through the mid and late 1980s. Nonetheless, the most 

recent ambient ozone monitoring data indicate that the 

projected improvements indeed may not be occurring. It is 

widely accepted that the mobile source portion of the inventory 

will continue to decline as a result of fleet turnover, with an 

increasing fraction of the national fleet being comprised of 

vehicles subject to the stringent emission standards taking 

effect in the early and mid 1980s. Since the FMVCP continues 

to yield emission reductions, but monitoring data suggest the 

ozone air guality situation is deteriorating, the assumptions 

used in previous EPA analyses concerning the efficiency and 

timing of stationary source RACT control appear to have been 

overly optimistic. EPA is currently attempting to assemble an 

accurate data base on in-use RACT control efficiencies. That 

task will not be completed, however, in time for inclusion in 

this analysis. 

The Agency knows that some RACT-based emission reductions 

had already occurred as of the base year; what is not known is 

what fraction of sources subject to RACT actually were 

controlled. Nor is it known, because of various practical 

constraints on the application of RACT controls, what fraction 

of the sources subject to RACT can actually be expected to be 

controlled in'the near future. Without this information, the 

amount of additional RACT-based control still available is also 

uncertain. EPA is attempting to resolve these questions as 

part of the abovementioned review of RACT controls. Until EPA 

has better data available on the actual rate of implementation 

and control efficiency of stationary source RACT, the 

"baseline" scenario for this analysis assumes no RACT-based 

stationary source emission reductions are assumed to occur 

after the base year. 

3-14 
P.43 

B. Ambient Air Quality Results 

Tables 2 and 3 present the results of the EKMA-based air 

quality projections for the 61 urban areas currently in nonattainment of the ozone NAAQS. The information in Table 2 is 

also presented graphically in Figure 1. Two measures of air 

quality in various calendar years are shown: total NMHC 

emissions- and the number of non-attainment areas. Each table 

displays the model's output for the scenarios analyzed: 

baseline (FMCVP only), control of excess evaporative emissions 

only, and control of both refueling and excess evaporative 

emissions. A comparison of the results for the three scenarios 

indicates the incremental effects of implementing control of 

excess evaporative emissions and then refueling controls. 

Before discussing the results for the control scenarios,, 

it is interesting to briefly examine the projections for the 

baseline scenario in each table. Generally, the results Tor 

this scenario show significant improvements occur primarily in 

response to the stationary and motor vehicle emission standards 

which already have been promulgated. However, Table 3 shows 

that a significant number of violations and non-attainment 

areas continue to exist throughout the projection period. It 

also appears that by about the mid to late 1990s, the trend 

toward decreasing ambient ozone levels will be reversed, and 

air quality will worsen steadily thereafter. The continued 

number of non-attainment areas, in addition to the projected 

deterioration in air quality, indicates the need for additional 

HC reductions to help attain and maintain the NAAQS for ozone 

across the nation. 

Regarding the effects of the control scenarios, Table 2 

shows that as onboard-equipped vehicles comprise an increasing 

percentage of the motor vehicle fleet over time, reductions in 

the non-methane hydrocarbon inventory due solely to refueling 

controls change from 105,000 tons (about 1.5 percent) in 1995, 

to 179,000 tons (about 2.1 percent) in 2010. If reductions in 

excess evaporative emissions are also included, the reductions 

are approximately double those amounts. 

Based on the air quality modeling results presented above, 

and in Tables 2 and 3 and Figure 1, it appears that the 

implementation of onboard refueling standards for gasolinefueled LDVs, LDTs, and HDVs can provide significant long-term 

benefits in helping to achieve and maintain the ozone NAAQS. 

3-15 
Table 2 

P.44 

Total Non-Methane Hydrocarbon Emissions 

for 61 Urban Areas (xlOOO Tons) 

Scenario 

Baseline (FMVCP only) 

Excess Evap Control2 

Refueling & Excess 

Evap Control 

1990 

6961 

(14.2)1 

6958 

(14.2) 

6931 

(14.6) 

1995 

6926 

(14.6) 

6823 ' 

(15.9) 

6718 

(17.2) 

2000 

7256 

(10.5) 

7,0,74 

(12.8) 

6928 

(14.6) 

2010 

8420 

(+3.8) 

8160 

(+0.1) 

7981 

(1.6) 

Figures in parentheses represent the percent change 

(decrease, unless otherwise noted), relative to the 1983 

base-year inventory of 8,111.6 tons for the 61 areas. 

No control of refueling. 
>-

a: 

o 

Z c 

o 

II 

< 

o 

8.5 

ngure l 

TOTAL IH C INVENTORIES FOR 

61 URBAN NON-ATTAINMENT AREAS 

1983 1990 1995 2000 2010 

D BASE 

YEAR 

EX EVAP EVAP&REF 

I 
P.46 

Table 3 

Estimated Number of Non-California 

Urban Ozone Non-Attainment Areas 

Scenario 

Baseline (FMVCP only) 

Excess Evap Control2 

Refueling & Excess 

Evap Control 

1990 

47 

47 

46 

1995 

46 

44 

40 

2000 

48 

47 

44 

2010 

55l 

53 

51 

Only the 61 non-California areas listed in Table 3 were 

modeled. Additional areas are likely to be in 

non-attainment in 2010 under the "Baseline (FMVCP only)" 

scenario. 

No control of refueling. 
REFERENCES FOR CHAPTER 3 

P.47 

1. "Air Quality Criteria for Ozone and Other 

Photochemical Oxidants," U.S. EPA, ORD, April 1978, 

EPA-600/8-78-004. 

2. "Air Quality Criteria for Ozone and Other 

Photochemical Oxidants," U.S. EPA, ORD, July 1984, 

EPA-600/8-84-020A. 

-,V 

3. "Refueling Emissions from Uncontrolled Vehicles," 

Dale S. Rothman and Robert Johnson, U.S. EPA, OMS, ECTD, 

EPA-AA-SDSB-85-6, July 1985. 

4. American Petroleum Institute unpublished test data. 

Presented to EPA Office of Mobile Sources on June 18, 1985 and 

August 7, 1985. 

5. "1982-84 Ozone Design Values for Regulatory Impact 

Analyses," Memorandum from Richard G. Rhoads, Director of 

Monitoring and Data Analysis Division, to Charles Gray, 

Director of Emission Control Technology Division, June 16, 1986. 

6. "Uses, Limitations and Technical Basis of Procedures 

for Quantifying Relationships Between Photochemical Oxidants 

and Precursors," U.S. EPA, OAQPS, EPA-450/2-77-021a, November 

1977. 

12 

<, '22 

fte~< 

/S^o'd7. "Guidelines for Use of City-Specific EKMA in y>,c A 

Preparing Ozone SIPs," U.S. EPA, OAQPS, EPA-450/4-80-027, March I- /u "' 

1981. 

8. "Study of Gasoline Volatility and Hydrocarbon 

Emissions from Motor Vehicles", U.S. EPA, OMS, November 1985, 

EPA-AA-SDSB-85-5. A 

3-19