VOLUME III: CHAPTER 11

GASOLINE MARKETING (STAGE I AND

STAGE II)

Revised Final

January 2001

Prepared by:

Eastern Research Group, Inc.

Prepared for:

Area Sources Committee

Emission Inventory Improvement Program
DISCLAIMER

As the Environmental Protection Agency has indicated in Emission Inventory Improvement

Program (EIIP) documents, the choice of methods to be used to estimate emissions depends on

how the estimates will be used and the degree of accuracy required. Methods using site-specific

data are preferred over other methods. These documents are non-binding guidance and not rules. 

EPA, the States, and others retain the discretion to employ or to require other approaches that

meet the requirements of the applicable statutory or regulatory requirements in individual

circumstances.
ACKNOWLEDGEMENT

This document was prepared for the Area Sources Committee of the Emission Inventory

Improvement Program and for Charles Mann of the Air Pollution Prevention and Control

Division, U.S. Environmental Protection Agency. Members of the Area Sources Committee

contributing to the preparation of this document are:

Kristin Abraham, West Virginia Department of Environmental Protection

Kwame Agyei, Puget Sound Air Pollution Control Agency

Ray Bishop, Oklahoma Department of Environmental Quality

Dan Brisko, New York State Department of Environmental Conservation

Orlando Cabrera-Rivera, Wisconsin Department of Natural Resources

Andy Delao, California Air Resources Board

Laurel Driver, Emission Factor and Inventory Group, U.S. Environmental Protection Agency

Mark Eastburn, Delaware Department of Natural Resources

Charles Mann, Air Pollution Prevention and Control Division, U.S. Environmental Protection Agency

Sally Otterson, Washington Department of Ecology

Kenneth Santlal, Massachusetts Department of Environmental Protection

Walter Simms, Maryland Department of the Environment

Jack Sipple, Delaware Department of Natural Resources and Environmental Control

Karla Smith-Hardison, Texas Natural Resources Conservation Commission

Angel Thompson, South Carolina Department of Health and Environmental Control

Lee Tooly, Emission Factor and Inventory Group, U.S. Environmental Protection Agency
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EIIP Volume III v

CONTENTS

Section Page

1 Introduction ....................................................... 11.1-1

2 Source Category Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2-1

2.1 Category Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2-1

2.2 Process Description and Emission Sources . . . . . . . . . . . . . . . . . . . . . . . . . 11.2-1

2.3 Factors Influencing Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2-3

2.4 Control Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2-3

3 Overview of Available Methods ....................................... 11.3-1

3.1 Emission Estimation Methodologies .............................. 11.3-1

3.2 Available Methodologies ....................................... 11.3-1

3.1.1 Emission Factors ....................................... 11.3-2

3.1.2 Activity Levels ......................................... 11.3-3

3.1.3 Special Emission Calculation Issues ........................ 11.3-8

3.1.4 Methodology Summaries ................................. 11.3-8

3.3 Data Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3-8

3.3.1 Data Elements ......................................... 11.3-8

3.3.2 Adjustments to Emissions Estimates ....................... 11.3-11

3.3.3 Point Source Corrections ................................ 11.3-11

3.3.4 Application of Controls ................................. 11.3-11

3.3.5 Spatial Allocation...................................... 11.3-12

3.3.6 Temporal Resolution ................................... 11.3-12

3.4 Projecting Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3-13

4 Preferred Methods for Estimating Emissions ............................. 11.4-1

4.1. Gasoline Trucks in Transit ...................................... 11.4-1

4.2 Fuel Delivery to Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4-2

4.3 Vehicle Refueling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4-2

4.4 Storage Tank Breathing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4-3

5 Alternative Methods for Estimating Emissions ............................ 11.5-1

5.1 Alternative Method 1 .......................................... 11.5-1

5.1.1 Gasoline Trucks in Transit ................................ 11.5-1

5.1.2 Fuel Delivery to Outlets .................................. 11.5-2

5.1.3 Vehicle Refueling ...................................... 11.5-2

5.1.4 Storage Tank Breathing .................................. 11.5-3
CONTENTS (CONTINUED)

Section Page

vi EIIP Volume III

5.2. Alternative Method 2 .......................................... 11.5-3

5.2.1 Gasoline Trucks in Transit ................................ 11.5-3

5.2.2 Fuel Delivery to Outlets .................................. 11.5-3

5.2.3 Vehicle Refueling ...................................... 11.5-4

5.2.4 Storage Tank Breathing .................................. 11.5-4

6 Quality Assurance/Quality Control ..................................... 11.6-1

6.1 Emission Estimate Quality Indicators ............................. 11.6-1

6.1.1 Data Attribute Rating System (DARS) Scores ................ 11.6-1

6.1.2 Sources of Uncertainty ................................... 11.6-8

7 Data Coding Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.7-1

7.1 Necessary Data Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.7-1

8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.8-1
EIIP Volume III vii

FIGURES AND TABLES

Figure Page

11.2-1 Gasoline Marketing Operations and Emission Sources ................... 11.2-2

Table Page

11.3-1 VOC Emission Factors for Gasoline Marketing Activities ................ 11.3-2

11.3-2 HAP Percent of VOC Emissions .................................... 11.3-2

11.3-3 Preferred and Alternate Methods for Estimating Emissions from Gasoline

 Distribution Subcategories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3-5

11.3-4 Data Elements Needed for Each Method ............................. 11.3-10

11.3-5 Daily and Hourly Allocation of Gasoline Distribution System

 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3-13

11.6-1 Preferred Method DARS Scores: Tank Trucks in Transit; Local Gasoline 

Sales, Adjustment Factor from Highway Weigh Station Data . . . . . . . . . . . . . . 11.6-2

11.6-2 Alternative Method 1 DARS Scores: Tank Trucks in Transit; Local Gasoline 

Sales, Default Adjustment Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.6-2

11.6-3 Alternative Method 2 DARS Scores: Tank Trucks in Transit; Scaled 

State-Level Gasoline Sales, Default Adjustment Factor . . . . . . . . . . . . . . . . . . 11.6-3

11.6-4 Preferred Method DARS Scores: Fuel Delivery to Outlets; Local Gasoline 

Sales, Filling Method from Survey ................................... 11.6-3

11.6-5 Alternative Method 1 DARS Scores: Fuel Delivery to Outlets; Scaled 

State-Level Gasoline Sales, Filling Method from Survey ................. 11.6-4

11.6-6 Alternative Method 2 DARS Scores: Fuel Delivery to Outlets; Scaled 

State-Level Gasoline Sales, Filling Method from Trade Groups ............ 11.6-4

11.6-7 Preferred Method DARS Scores: Vehicle Refueling; Local Gasoline Sales, 

Filling Method from Regulators .................................... 11.6-5
viii EIIP Volume III

FIGURES AND TABLES (CONTINUED)

Table Page

11.6-8 Alternative Method 1 DARS Scores: Vehicle Refueling; Scaled State-Level 

Gasoline Sales, Filling Method from Survey .......................... 11.6-5

11.6-9 Alternative Method 2 DARS Scores: Vehicle Refueling; Gasoline Use from 

VMT, Filling Method from Survey .................................. 11.6-6

11.6-10 Preferred Method DARS Scores: Storage Tank Breathing; Local Gasoline 

Sales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.6-6

11.6-11 Alternative Method 1 DARS Scores: Storage Tank Breathing; Scaled 

State- Level Gasoline Sales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.6-11

11.7-1 Area and Mobile Source Category Codes For Gasoline Marketing .......... 11.7-2
EIIP Volume III 11.1-1

1

INTRODUCTION

This chapter is one of a series of documents developed to provide cost-effective, reliable and

consistent approaches to estimating emissions for area source inventories. Multiple methods are

provided in the chapters to accommodate needs of state agencies with different levels of

available resources and skills; and different levels of needs for accuracy and reliability of their

estimates. More information about the EIIP program can be found in Volume 1 of the EIIP

series, Introduction and Use of EIIP Guidance for Emissions Inventory Development.

Throughout this chapter and other EIIP area source methods chapters, we stress that area source

categories should be prioritized by the inventory planners so that resources can be spent on the

source categories that are the largest emitters, most likely to be subject to regulations or are

already subject to regulations, or require special effort because of some policy reason. 

Prioritization is particularly important for area source inventories, because in some cases, a

difficult to characterize source category may contribute very little to overall emissions and

attempting a high quality estimate for that source category may not be cost effective.

EIIP chapters are written for the state and local air pollution agencies, with their input and

review. EIIP is a response to EPA’s understanding that state and local agency personnel have

more knowledge about their inventory area’s activities, processes, emissions, and availability of

information; and require flexible inventory methods to best use their sometimes limited

resources. These EIIP area source chapters are written as a set of options presented to inventory

professionals capable of using their own experience and judgement to apply the method that best

fits their overall needs and constraints.

This chapter describes the procedures and recommended approaches for estimating emissions

from gasoline tank trucks in transit and at retail gasoline marketing outlets. Section 2 of this

chapter contains a general description of the gasoline distribution industry category and an

overview of available control technologies. Section 3 provides an overview of available

emission estimation methods. Section 4 presents the preferred method for estimating emissions,

and Section 5 presents the alternative emission estimation techniques. Quality assurance issues

and emission estimate quality indicators for the methods presented in this chapter are discussed

in Section 6. Data coding procedures are discussed in Section 7. Section 8 contains references

used for this chapter.
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2

SOURCE CATEGORY DESCRIPTION

2.1 CATEGORY DESCRIPTION

Motor gasoline is produced by domestic petroleum refineries or in some cases imported to the

United States, and then transported through a distribution network to customers. The distribution

network is a complex system that includes many wholesale and retail outlets. The network

includes a variety of storage and transfer facilities. Gasoline may be transported by tanker ships

and barges, through pipelines, or by rail tank cars or tank trucks. This chapter covers most of

those sections of the distribution network where evaporative emissions are usually considered to

be area sources. Stage I and Stage II emissions (occurring during the transfer of gasoline from

tank trucks to storage tanks at service stations, and subsequent transfer to the vehicle gasoline

tank, respectively) are covered, as well as emissions from delivery trucks in transit, gasoline

station storage tanks, and spillage. Additional information about this category can be found in

AP-42 (Section 4.4) (EPA, 1995), and the AIRS Area and Mobile Source Category Codes

(EPA, 2000).

Figure 11.2-1 shows a typical path by which gasoline may be transported from producer to

consumer. This path includes operations that are not addressed in this chapter. Marine vessel

loading and unloading operations are covered in Chapter 12. Bulk terminals and gasoline bulk

plants, which are intermediate distribution points between refineries and outlets, are usually

inventoried as point sources. Loading and unloading of railroad tank cars and pipeline

transmission losses could be significant area source categories in some areas, but have not been

included in this chapter.

2.2 PROCESS DESCRIPTION AND EMISSION SOURCES

The area sources of evaporative VOC emissions from the distribution of gasoline that are

covered in this chapter include the following:

 Trucks in transit: evaporation of gasoline vapor (1) from loaded tank trucks

during transportation of gasoline from the bulk plant/terminal to the service

station or other dispensing outlet, and (2) from empty tank trucks returning from

service stations to bulk plant/terminals.
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Figure 11.2-1

Gasoline Marketing Operations and Emission Sources
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 Stage I: displacement of gasoline vapors from the storage tanks during the

transfer of gasoline from tank trucks to storage tanks at the service station

 Stage II: displacement of gasoline vapors from vehicle gasoline tanks during

vehicle refueling. This category also may include spillage of gasoline (and

subsequent evaporation) during either delivery activity above. This loss includes

prefill and postfill nozzle drip and spitback and overflow from the filler pipe of

the vehicle's fuel tank during filling.

 Storage tank working losses: evaporation of gasoline vapors from the storage

tank and from the lines going to the pumps during transfer of gasoline.

Service stations (Standard Industrial Classification code 5541) traditionally have been the

primary retail distributors for gasoline. Gasoline can be purchased from other types of

businesses, such as auto repair garages, parking garages, and convenience stores. Gasoline may

also be distributed to vehicles through various nonretail outlets, such as government motor pools

and other vehicle fleet servicing operations. Gasoline is stored in underground and aboveground

storage tanks at service stations and other dispensing facilities. Evaporative emissions occur

during tank filling and vehicle refueling.

2.3 FACTORS INFLUENCING EMISSIONS

VOC emissions from gasoline marketing activities are influenced by several factors. Fuel

volatility (measured as Reid vapor pressure, or RVP) affects the evaporation rate of gasoline. 

The technology for loading tank trucks and tanks (splash loading, submerged loading, vapor

balance, etc.) affects the release of displacement emissions. Tank characteristics (color and

design) affect working losses from aboveground storage tanks.

2.4 CONTROL TECHNIQUES

Emissions from underground tank filling operations at service stations (Stage I emissions) can be

reduced by the use of a vapor balance system, which consists of a hose that returns gasoline

vapors displaced from the underground tanks during filling back to the tank truck, as well as

measures to ensure tightness of the truck. The control efficiency of the balance system can range

from 93 to 100 percent (EPA, 1995). Emissions from vehicle refueling (Stage II emissions) also

can be reduced by a vapor balance system. During refueling, the vapors displaced from the

vehicle fuel tanks are returned to the underground tanks through the use of a special nozzle

(EPA, 1995). Stage I controls have been implemented in some areas, both attainment and

nonattainment. Stage II controls are currently not widely implemented, but are required in some

ozone nonattainment areas as defined by the 1990 Clean Air Act (CAA) (EPA, 1991).
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Emissions  Emission Factor × Activity Level (11.3-1)

3

OVERVIEW OF AVAILABLE METHODS

3.1 EMISSION ESTIMATION METHODOLOGIES

The following activities of the gasoline distribution industry are generally area sources of air

pollution: (1) gasoline trucks in transit; (2) fuel delivery to outlets (Stage I); (3) vehicle refueling

(Stage II); and (4) storage tank breathing. The emissions estimation methodologies for the

subcategories of gasoline distribution identified in Section 2 have a common, simple form:

The methodologies for adjusting the emission factors and activity levels vary somewhat among

the subcategories. Accordingly, methodologies for developing emission factors and activity

levels are presented separately for each subcategory.

3.2 AVAILABLE METHODOLOGIES

Selection of the appropriate estimation method depends on the relative significance of emissions

from this source in the inventory area and the data quality objectives (DQOs) of the inventory

plan. Refer to EIIP Volume VI, Quality Assurance Procedures, Sections 2.1 and 2.4 for

discussions of inventory categories and DQOs.

Methods for estimating emissions from the gasoline marketing system generally involve

employing an emission factor (provided by EPA or generated with EPA's MOBILE model)

relating emissions to the volume of gasoline distributed. Gasoline distribution within the study

area may be determined by area-specific tax records or survey data. Unfortunately, gasoline sales

tax data are not always available at the county or city level, and performing a valid survey may

not be feasible due to resource limitations. Alternately, state-level gasoline sales may be

allocated to the study area based on economic data (dollars of total sales, available in U.S.

Bureau of the Census publications).

Emission factors for gasoline trucks in transit, fuel delivery to outlets, and storage tank breathing

are all provided by EPA. No methodologies have been identified to replace the use of these

emission factors. Emission factors for vehicle refueling should be developed through the use of
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EPA's MOBILE model. This software uses local data (e.g., temperature, fuel volatility) to

generate a custom VOC emission factor.

In selecting preferred methodologies identified for gasoline marketing subcategories, preference

has been given to methodologies that maximize use of survey data or other data collected or

reported at the county or city level.

3.1.1 EMISSION FACTORS

Gasoline Trucks in Transit

EPA has published emission factors for gasoline tank trucks in transit. The emission factors are

included in Table 11.3-1.

TABLE 11.3-1

VOC EMISSION FACTORS FOR GASOLINE MARKETING ACTIVITIESa

Emission Source

mg/Liter

Throughput

lb/1000 gal

Throughput

Gasoline Tank Trucks in Transit

Vapor-filled Tank Trucksb 6.5 0.055

Gas-filled Tank Trucksc 0.5 0.005

Filling Underground Tank (Stage I)

Submerged Filling 880 7.3

Splash Filling 1,380 11.5

Balanced Submerged Filling 40 0.3

Underground Tank Breathing and Emptyingd 120 1.0

a Source: AP-42 Tables 5.2-5, 5.2-7.

b Midpoint of typical range provided in AP-42. Under extreme conditions, the upper end of

the range is 0.37 lb/1000 gal (44.0 mg/L). c Midpoint of typical range provided in AP-42. Under extreme conditions, the upper end of

the range is 0.08 lb/1000 gal (9.0 mg/L).

d Includes any vapor less between tank and gas pump.
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EIIP Volume III 11.3-3

Emission factors can be supplemented by using the HAP speciation profiles provided in the NTI

area source category, Gasoline Distribution Stage II. The NTI documentation provides profiles

that can be applied to the VOC estimates for baseline, reformulated, and winter-oxygenated

gasolines. The reformulated and winter-oxygenated gasolines are then subdivided depending on

the additive contents, which include methyl tertiary butyl ether (MTBE) or ethanol. Table 11.3-2

displays the HAP speciation profiles that should be applied to the VOC emissions.

TABLE 11.3-2

HAP PERCENT OF VOC EMISSIONS

HAP

Gasoline Type

Baseline

Reformulated Winter-Oxygenated

w/ MTBE w/ Ethanol w/ MTBE w/ Ethanol

2,2,4-Trimethylpentane 0.8 0.7 0.7 0.7 0.7

Benzene 0.9 0.4 0.4 0.7 0.7

Ethylbenzene 0.1 0.1 0.1 0.1 0.1

Hexane 1.6 1.4 1.4 1.4 1.4

MTBE 0 8.7 0 11.9 0

POM as 16-PAH 0.05 0.05 0.05 0.05 0.05

Toluene 1.3 1.1 1.1 1.1 1.1

Xylene 0.5 0.4 0.4 0.4 0.4

Source: EPA, 1999

Fuel Delivery to Outlets

EPA has published emission factors for filling underground storage tanks (Stage I). The

emission factors are included in Table 11.3-1.

Vehicle Refueling

EPA recommends that the MOBILE model be used to generate refueling (Stage II) emission

factors for highway vehicle emission inventories (EPA, 1992b). The model, designed to support

the evaluation of air pollution from gasoline- and diesel-fueled vehicles, generates emission
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factors for tailpipe emissions and refueling activities. A detailed discussion of using this model

is available from EPA (EPA, 1994).

The MOBILE model allows the user to select whether refueling emission factors are presented in

grams per gallon (g/gal) of dispensed fuel or in grams per mile (g/mi). The preferred approach is

to use the g/gal refueling emission factor that reflects any applicable Stage II controls, then

multiply the emission factor by total gasoline sales (TGD). Using the g/gal emission factor will

capture refueling emissions from gasoline purchased in the study area but consumed outside the

study area. Conversely, the g/mi emission factor will assign to the study area emissions for

vehicles refueled outside the study area but driven within the study area. It should be noted that

MOBILE makes use of improved predictive equations to calculate refueling emission factors,

including sensitivity to temperature and Reid vapor pressure (RVP), and these have not yet been

incorporated into published AP-42 factors for refueling. Additionally, the user may provide

information on local Stage II emission controls to develop an emission factor for controlled

emissions.

Refueling emissions have two mechanisms of introducing emissions to the environment: (1)

vapor displacement from the vehicle fuel tank during refilling; and (2) gasoline spillage during

refueling. The MOBILE user may request either a single emission factor that combines the two

mechanisms or separate emission factors for displacement and spillage. Because both

mechanisms should be taken into account when estimating refueling emissions, the preferred

approach is to request the combined emission factor.

Storage Tank Breathing

EPA has published emission factors for storage tank breathing. The emission factors are

included in Table 11.3-1.

3.1.2 ACTIVITY LEVELS

All of the preferred methodologies discussed in this document use total gasoline distribution as

activity levels. The most useful source of existing data for estimating total gasoline distributed

(TGD) in the inventory area is any existing collection of highway fuel sales data. The preferred

approach to estimating TGD is to use these data. If available, these data should be collected,

assessed, and processed to ensure that only highway vehicle gasoline dispensed in the area of

concern is included in the total to be used as TGD. According to a recent EPA study, only

10 states actually collect and publish this type of data: Alabama, Arizona, Florida, Hawaii,

Mississippi, Nevada, New Mexico, New York, Washington and, Wyoming. Most of the states

with significant nonattainment problems are absent from this list. In addition, the reliability of

these statistics as measures of gasoline distributed at the county level is unknown; significant

errors in allocation may occur if statistics are based on locations of distributors and not all of this
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 1 Highway Statistics. U.S. Department of Transportation. Federal Highway

Administration, Washington, D.C. (Annual publication. Check USDOT/FHWA Web site

for latest version, http://www.fhwa.dot.gov).

 2 Census of Retail Trade: Geographic Area Series. Bureau of the Census, U.S. Department

of Commerce, Washington, D.C. (Available on hard copy by contracting the Census

Bureau at 1-800-541-8345 or see the Census Bureau Web site, http://www.census.gov. 

Alternatively, check http://sasquatch.kerr.orst.edu/econ-stateis.html.

EIIP Volume III 11.3-5

fuel supply remains in the area of concern, or if substantial quantities of fuel come from

distributors outside the area.

Where adequate data are not routinely collected, the only other alternatives for developing

county-level data are (1) to collect sales tax data from the state taxing agency, if these data are

available at sufficient disaggregation, or (2) to generate original data by collecting gasoline sales

data from fuel distributors and retailers. State taxing agencies typically cannot provide the level

of geographic detail necessary for inventory application; fuel taxes are usually collected from

distributors rather than retailers, and these data are often considered proprietary information. 

Any tax-based estimates should be cross-checked with data from associations of service station

owners, distributors, and other local sources. The large number of retailers and ongoing changes

in retailer locations and ownership can make an original survey costly and difficult, although a

small area might find this a reasonable approach. Scaling survey results to account for outlets

not surveyed and/or nonresponders is also problematic; however, this could be accomplished

using employment data for SIC Code 5541 or data on the total numbers of outlets in the area. 

One advantage of this approach is that information on the amount of gasoline distributed under

different types of emission control scenarios can be directly estimated.

Another alternative for estimating gasoline consumption is to use data from various national

publications. The Federal Highway Administration (FHWA) annually publishes Highway

Statistics, which contains gasoline consumption data for each state.1 Countywide estimates can

be made by apportioning these statewide totals by the percentage of state gasoline station sales

occurring within each county. Countywide service station gasoline sales data (dollars of sales,

not gasoline volume) are available from the Bureau of the Census's Census of Retail Trade.

2

(Note: Data in the Census of Retail Trade are usually too old to use directly in estimating

countywide sales; however, they are useful in allocating other data to the county level.) Other

apportioning variables, such as registered vehicles or vehicle miles traveled (VMT), can be used

if the local agency feels that their use results in more accurate distributions of state totals to the

county level. Even if the agency uses local sales data in the area source inventory, this approach

should be used as a cross-check of the local consumption estimates. One distinct advantage of

using data in Highway Statistics is that sales are tabulated by month which facilitates a seasonal

adjustment of the gasoline station emission totals.
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GTA  TGD TGT

TGD (11.3-2)

Another method of estimating gasoline sales is to use VMT data available from the ongoing

transportation planning process. This alternative is not generally recommended for several

reasons. First, it requires local information on both the percentage of VMT attributable to diesel

versus gasoline fuel and the average miles-per-gallon fuel efficiency of the gasoline-powered

motor fleet. None of these data may be available locally, and using nationwide averages may

introduce errors in certain applications. Moreover, highway travel will not account for all

gasoline sold at various off-highway applications. For these reasons, fuel sales is the preferred

method for determining fuel use.

Note: Using state or local air pollution permit files for inventorying gasoline dispensing outlets

is not likely to be an effective alternative. Permit information is not usually collected because of

the large number of stations and because each station's emissions are much lower than traditional

point source cutoff levels. Registration systems are being attempted in some states where major

retail chains are required to compile and submit service station lists. Such a detailed approach is

not usually warranted when gasoline distribution data will yield adequate emissions estimates.

Gasoline Trucks in Transit

The activity level for estimating emissions from gasoline trucks in transit is fuel transported

through the study area. In order of preference, the available methods for estimating fuel

throughput include: (1) obtaining (if available) existing gasoline sales data for the study area;

and (2) apportioning state gasoline sales data to the study area level using surrogate allocation

variables such as gasoline sales, vehicle registration, or economic activity data.

Gasoline distributed in an inventory area may be transported once (from bulk terminals outside

the study area to retail outlets) or twice (distribution to gasoline bulk plants, then subsequent

distribution to retail outlets). Recent industry trends favor more direct delivery to outlets,

bypassing bulk plants.

The following equation can be used to develop an adjusted gasoline transportation activity factor

for trucks in transit to account for gasoline transported twice within the inventory region:

where:

GTA = Gasoline transportation adjustment factor

TGD = Total gasoline dispensed in the inventory region (1,000 gallons)

TGT = Amount of gasoline transported twice within the inventory region

(1,000 gallons)
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TTE  (TGD × LEF × GTA) (TGD × UEF × GTA)

2000 (11.3-3)

A default value of 1.25 for GTA can be used if the information needed to calculate GTA is not

available. This default value is based on an estimated overall historical national ratio of bulk

plant throughput to total gasoline consumption and should be used only as a last resort since it

will not reflect temporal or regional variations from this national historical average. 

Depending on the location of nearby gasoline terminals and routes used to deliver product to

remote bulk plants or outlets, there may be some inventory areas with heavy tank truck traffic on

local interstates consisting of gasoline being transported through the area but not loaded or

unloaded locally. There are currently no adjustment factors for this specific type of activity. 

However, it may be possible to obtain data on this type of traffic from weigh stations on

interstate highways and add this throughput to the estimate of TGD in the area to obtain an

upper-limit estimate for total emissions for trucks in transit including transport through the area

(assuming that the factors for full and empty trucks are appropriate in this case). Inventory

preparers may want to make a gross estimate of the contribution to overall emissions that these

trucks may make before investing significant resources in this effort. (Typical round-trip

emissions for each truck are probably less than 1 pound of VOCs.)

Total gasoline tank truck emissions (TTE) in the inventory region can be estimated with the

following equation:

where:

TTE = Total gasoline emissions from tank trucks in transit (tons)

LEF = Loaded tank truck in-transit emission factor from Table 11.3-1 (pounds

per 1,000 gallons)

UEF = Unloaded tank truck in-transit emission factor from Table 11.3-1 (pounds

per 1,000 gallons)

Fuel Delivery to Outlets

In order to use the emission factors for fuel delivery to outlets included in Table 11.3-1, it may be

necessary to make estimates of the amounts of fuel delivered by each delivery technology

(submerged filling, splash filling, balanced submerged filling). The first step is to determine

what rules are in place for Stage I tank filling. If a rule requires a certain type of control or filling

method, then the inventory preparer need only determine a rule penetration factor. Otherwise,

estimates of or surrogates for the volumes of fuel delivered via each filling method are required. 

Potential methodologies for making these estimates include:
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.3-8 EIIP Volume III

Ai  Fi × TGD (11.3-4)

Method 1 - Obtain estimates of gasoline delivery volumes: Obtain data on throughput of area

gasoline outlets from state/local regulators or industry and trade groups (the national Petroleum

Marketing Association, located in Arlington, Virginia, or state/local associations of gasoline

dealers and repair shops). This is the preferred method.

Method 2 - Use estimated fractions of service stations using each filling method: Obtain the

number of gasoline outlets that use each of the three types of tank filling methods from state and

local regulators or industry and trade groups. Distribute gasoline delivery volumes according to

these results.

Method 3 - Survey of outlets by filling method: Perform a survey of all or a representative

sample of gasoline dispensing outlets in the inventory region to determine the type of tank filling

method. Distribute gasoline delivery volumes according to these results. A survey design must

ensure that the sample selected is representative. It is likely that smaller stations may use

different controls or filling methods than larger ones. A sample should be stratified to ensure

that all types of outlets are included. The survey needs to collect gasoline throughput data and

other data that may be used to scale survey results to study area totals. Potential surrogates may

be number of employees, number of pumps, or storage tank capacities.

The activity levels for each of the three fuel delivery technologies is then calculated as follows:

where:

Ai = Adjusted activity rate for fill type I (1,000 gallons)

Fi = Fraction of area total for fill type I (based on either throughput or number of

stations)

TGD = Total gasoline dispensed in the inventory region (1,000 gallons)

I = 1-3 representing the three filling methods

Vehicle Refueling 

The activity factor for vehicle refueling can be either the total amount of gasoline distributed in

the area or vehicle miles of travel (VMT). The preferred approach is to use estimates of local

gasoline sales if these data are available.

 Obtain information on the amount of gasoline dispensed in the inventory region

(TGD) using the methods described previously in this section. Use the best

locally available estimate of TGD as the activity factor for vehicle refueling.
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.3-9

 If no local sources of information are available for estimating TGD, the agency

may wish to use VMT as an alternative. Estimates of VMT should be obtained

from the local transportation or planning agency who is responsible for preparing

the highway vehicle emissions inventory. The disadvantage of using VMT is that

it is a measure of vehicle activity in the area not a measure of the fuel dispensed in

the inventory area. VMT produced by vehicles simply passing through the area,

that did not refuel in the inventory region would tend to overstate the vehicle

refueling activity level.

Storage Tank Breathing

The activity level for estimating emissions from storage tank breathing is total gallons delivered

(TGD) in the inventory area. The methodology for estimating TGD for vehicle refueling is also

recommended for this subcategory.

3.1.3 SPECIAL EMISSION CALCULATION ISSUES

Estimation of month-specific emissions from gasoline distribution can be based on activity

apportionment factors developed from monthly state fuel use statistics available in Highway

Statistics. Projections for fuel use can also be based on historic fuel use and vehicle miles

traveled data from Highway Statistics, historic records from the sources from which current year

area fuel usage was obtained, and/or area-specific VMT from Highway Performance Monitoring

System (HPMS) (from Federal Highway Administration, Washington, DC) or local

transportation agencies.

3.1.4 METHODOLOGY SUMMARIES

The methodologies proposed in this document are summarized in Table 11.3-3 below. 

Preferred and alternate methodologies are presented for each of the subcategories.

3.3 DATA NEEDS

3.3.1 DATA ELEMENTS

The data elements needed to calculate emission estimates for the gasoline distribution system

depend on the methodology used for data collection. Each methodology requires some measure

of activity (or surrogate for activity) and an emission factor. The data elements needed for each

emission estimation technique are presented in Table 11.3-4.
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.3-10 EIIP Volume III

TABLE 11.3-3

PREFERRED AND ALTERNATE METHODS FOR ESTIMATING EMISSIONS 

FROM GASOLINE DISTRIBUTION SUBCATEGORIES

Sub-category Method Description

Gasoline

Trucks in

Transit

Preferred Method - Use

detail or survey data

Emission Factors - from Table 3-1.

Activity Level - Obtain fuel sales from tax records or survey data. 

Develop adjustment factor based on survey or highway-weigh

station data.

Alternate Method 1 - Use

combination of default

and detailed data

Emission Factor - from Table 3-1.

Activity Level - Same as preferred method, substituting default

 GTA.

Alternate Method 2 - Use

default GTA and

allocated fuel sales data

Emission Factor - from Table 3-1.

Activity Level - Same as preferred method, substituting default

 GTA, allocate state fuel sales to study area based on gasoline 

station sales.

Fuel Delivery

to Outlets

Preferred Method - Use

detail or survey data

Emission Factor - from Table 3-1.

Activity Level - Obtain fuel sales from tax records or survey data. 

 Use survey data to determine filling technologies.

Alternate Method 1 - Use

allocated fuel sales data,

survey filling data

Emission Factor - from Table 3-1.

Activity Level - Same as preferred method, using allocated fuel 

sales estimates instead of actual data. Use survey data to determine

filling technologies' usage.

Alternate Method 2 - Use

allocated fuel sales data,

local knowledge of filling

technology

Emission Factor - from Table 3-1.

Activity Level - Same as preferred method, using allocated fuel

sales estimates instead of actual data. Use trade association or local

knowledge to determine filling technologies' usage.

Vehicle

Refuel-ing

Preferred Method - Use

 MOBILE emission

factor and detail or

survey data

Emission Factor - use MOBILE emission factor.

Activity Level - Obtain fuel sales from tax records or survey data. 

Alternate Method 1 - Use

 MOBILE emission

factor, allocated fuel sales 

Emission Factor - use MOBILE emission factor.

Activity Level - use allocated fuel sales estimates instead of actual

data.

Alternate Method 2 - Use

 MOBILE emission

factor, vehicle miles

traveled (VMT) data

Emission Factor - use MOBILE emission factor to get emission 

factor in dimensions grams per mile traveled.

Activity Level - Get VMT data from highway planners.

Storage Tank

Breath-ing

Preferred Method - Use

 EPA emission factor and

detail or survey data

Emission Factor - see Table 3-1.

Activity Level - Obtain fuel sales from tax records or survey data. 

Alternate Method 1 - Use

EPA emission factor,

allocated fuel sales

Emission Factor - see Table 3-1.

Activity Level - Use allocated fuel sales estimates instead of actual

data.
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.3-11

TABLE 11.3-4

DATA ELEMENTS NEEDED FOR EACH METHOD

Subcategory Data Element

Preferred

Method

Alternate

 Method 1

Alternate

 Method 2

Gasoline Trucks in Transit County-level fuel sales

tax/survey data

X X

Highway/weigh-station

data

X

State fuel sales X

Gasoline station sales X

Fuel Delivery to Outlets County-level fuel sales

tax/survey data

X

Filling technology survey

data

X X

Filling technology

summary from local/state

regulators or trade groups

X

State fuel sales X X

Gasoline station sales X X

Vehicle Refueling MOBILE model inputs

(see Reference 8)

X XX

County-level fuel sales

tax/survey data

X

State fuel sales X

Gasoline station sales X

VMT data X

Tank Breathing County-level fuel sales

Tax/survey data

X

State fuel sales X

Gasoline station sales X
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.3-12 EIIP Volume III

3.3.2 ADJUSTMENTS TO EMISSIONS ESTIMATES

Adjustments applied to annual emissions estimates include point source corrections, applications

of controls, spatial allocation, and temporal resolution. The type of adjustment is dependent on

the type of inventory required. The data needs for point source emission estimate adjustments

are dependent in part on the methodology used. Data needs for the adjustments listed below are

as follows:

 Point source corrections point source emissions or point source employment

for inventory area for the specific SIC

 Application of controls control efficiency, rule effectiveness, rule

penetration

 Spatial allocation employment, population, facility location, zoning or

business districts location

 Temporal resolution seasonal throughput, operating days per week,

operating hours per day 

3.3.3 POINT SOURCE CORRECTIONS

If the preferred method is used to estimate area source emissions from this category, the point

source correction is performed as part of the method itself. If Alternate Method 1 is used, the

point source corrections can be performed by one of the following: (1) subtract point source

emissions from calculated total emissions, or (2) subtract point source employment in the

specific SIC from total employment in that SIC and calculate area source emissions using the

remaining employment in the SIC. If Alternate Method 2 is used, the point source corrections

are performed by subtracting point source emissions from calculated total emissions.

3.3.4 APPLICATION OF CONTROLS

Section 3.8 of Procedures for the Preparation of Emission Inventories for Carbon Monoxide and

Precursors of Ozone, Volume I, (EPA, 1991) provides guidance for determining and applying

rule effectiveness (RE) for a source category. In addition, the EPA document Procedures for

Estimating and Applying Rule Effectiveness in Post-1987 Base Year Emission Inventories for

Ozone and Carbon Monoxide State Implementation Plans (EPA, 1989) provides more detailed

information on RE.
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.3-13

CAEA  (EFA )(Q)[1  (CE)(RP)(RE)] (11.3-5)

CAEA  (UAEA )[1  (CE)(RP)(RE)]

Controlled area source emissions may be calculated with either of the following equations:

or

where: CAEA = controlled area source emissions of pollutant A

EFA = emission factor for pollutant A

Q = activity factor for category

CE = control efficiency/100

RP = rule penetration/100

RE = rule effectiveness/100

UAEA = uncontrolled area source emissions of pollutant A

3.3.5 SPATIAL ALLOCATION

If the emissions estimates are developed using a per employee factor, the spatial allocation of

emissions can be performed according to facility location (if known) as with the point source

inventory, or with local employment data. The agency should be aware that since location of

gasoline marketing does not necessarily mirror location of population within a county, using

population to spatially allocate emissions might be misleading. The inventorying agency will

need to evaluate options for allocating county emissions, such as zoning information, actual

location data identified from surveys, industry publications, etc.

3.3.6 TEMPORAL RESOLUTION

Seasonal Apportioning

Because emissions from these subcategories are generally directly proportional to fuel sales and

fuel sales have well-documented seasonal trends, annual gasoline distribution emissions should

be apportioned monthly based on fuel sales data. Fuel sales tax revenues are usually available

from state departments of revenue and should be used to allocate emissions.

Daily/Hourly Resolution

As with all issues, the inventory agency should use local data if available. If no data are

available, inventory agencies may use the Table 11.3-5 as default values:
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.3-14 EIIP Volume III

TABLE 11.3-5

DAILY AND HOURLY ALLOCATION OF 

GASOLINE DISTRIBUTION SYSTEM EMISSIONS

Subcategory

Daily Allocation

(days per week)

Hourly Allocation

(hours per day)

Trucks in Transit 6 24

Fuel Delivery to Outlets 6 24

Vehicle Refueling 7 24

Storage Tank Breathing 7 24

3.4 PROJECTING EMISSIONS

The type of surrogate used to project emissions is dependent on the methodology used to develop

the initial emissions estimate. In “growing” the emissions estimate, the inventorying agency

should use the same activity parameter as was used to develop the initial estimate. For example,

if a per gallon factor was used to develop the initial estimate, growth in gasoline sales should be

used to develop the projected emissions estimate.

The EIIP Projections Committee has developed a series of guidance documents containing

information on options for forecasting future emissions. You can refer to these documents at

http://www.epa.gov/ttn/chief/eiip/project.htm.
EIIP Volume III 11.4-1

GTA  TGD TGT

TGD (11.4-1)

TTE  (TGD × LEF × GTA) (TGD × UEF × GTA)

2000 (11.4-2)

4

PREFERRED METHODS FOR

ESTIMATING EMISSIONS

The following procedures should be used for estimating emissions from the gasoline distribution

subcategories. See Section 3 for additional guidance for the application of these methods.

4.1 GASOLINE TRUCKS IN TRANSIT

(1) Consult state gasoline sales tax records or data collected through a survey of fuel

distributors and retailers to determine the gasoline consumption in the study area.

(2) Obtain highway weigh-station data to estimate the amount of fuel transported through the

area. Calculate GTA, the factor accounting for twice-transported fuel:

where:

GTA = Gasoline transportation adjustment factor

TGD = Total gasoline dispensed in the inventory region (1,000 gallons)

TGT = Amount of gasoline transported twice within the inventory region

(1,000 gallons)

(3) Calculate emissions:

where:

TTE = Total gasoline emissions from tank trucks in transit (tons)

LEF = Loaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)

UEF = Unloaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.4-2 EIIP Volume III

4.2 FUEL DELIVERY TO OUTLETS

(1) Consult gasoline sales tax records or survey data to determine the gasoline consumption

in the study area.

(2) Use survey data to determine penetration of each filling technology.

(3) Multiply total fuel sales in the study area by the fraction of stations using each filling

technology to estimate the fuel dispensed by each technology.

(4) Use technology-specific emission factors to estimate emissions from submerged filling,

splash filling, and vapor-balanced submerged filling activities.

(5) Sum emissions from each technology to estimate total emissions.

4.3 VEHICLE REFUELING

(1) Consult gasoline sales tax records or survey data to determine the total amount of

gasoline dispensed in the study area.

(2) From the local control agency or survey data, determine the level of local Stage II

refueling controls.

(3) Run the MOBILE model to determine the emission rate on a mass per volume throughput

(grams per gallon, converted to pounds per gallon) basis. (In MOBILE5b, this is

accomplished by setting HCFLAG = 3). Based on the results of step 2, determine

whether Stage II refueling controls need to be considered. If local stage II controls are in

place, enter the appropriate data in the MOBILE one-time data section per MOBILE

model requirements (EPA, 1994). (In MOBILE5b, set RLFLAG = 1 if there are no local

Stage II controls, or set RLFLAG = 2 to calculate an emission factor that includes local

Stage II controls. Note that MOBILE5b will factor in the effects of the national on-board

vapor recovery system requirements for either value of RLFLAG.) MOBILE6 is due for

release in 2000. The reader should check the OTAQ Website for updated information on

MOBILE6 (www.epa.gov/oms/m6.htm).

(4) Multiply the emission factor (lb/gallon of fuel) times the estimated gasoline volume

(gallons of gasoline) to estimate emissions from vehicle refueling.
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.4-3

4.4 STORAGE TANK BREATHING

(1) Consult gasoline sales tax records or survey data to determine the gasoline consumption

in the study area.

(2) Multiply gasoline sales (gallons) times the emission factor to estimate emissions from

storage tank breathing.
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.4-4 EIIP Volume III

This page is intentionally left blank.
EIIP Volume III 11.5-1

TTE  (TGD × LEF × GTA) (TGD × UEF × GTA)

2000 (11.5-1)

5

ALTERNATIVE METHODS FOR

ESTIMATING EMISSIONS

Frequently, local county-level sales tax data for gasoline sales or other local data needed to adjust

these values are not available. Also, the collection of local gasoline sales data through surveys of

distributors and retailers may be impractical or too expensive. Under these circumstances, use of

one of the following alternative methods is appropriate.

5.1 ALTERNATIVE METHOD 1

5.1.1 GASOLINE TRUCKS IN TRANSIT

This method is the same as the preferred method, except that a default factor is used to estimate

the adjustment factor for gasoline transported twice in the inventory area.

(1) Consult gasoline sales tax records or survey data to determine the gasoline consumption

in the study area.

(2) Use 1.25, a national default rate, as GTA (gasoline transportation adjustment factor).

(3) Calculate emissions:

where:

TTE = Total gasoline emissions from tank trucks in transit (tons)

LEF = Loaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)

UEF = Unloaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.5-2 EIIP Volume III

5.1.2 FUEL DELIVERY TO OUTLETS

This method apportions state-level data to counties instead of using local sales tax or survey data.

(1) Assume that gasoline consumption is proportional to gasoline station sales, reported in

the Bureau of the Census's Census of Retail Trade. Allocate state gasoline consumption

data from Highway Statistics to the study area according to the dollar sales figures

reported in the Census of Retail Trade.

(2) Use survey data to determine penetration of each filling technology.

(3) Multiply total fuel sales in the study area by the fraction of stations using each filling

technology to estimate the fuel dispensed by each technology.

(4) Use technology-specific emission factors to estimate emissions from submerged filling,

splash filling, and vapor-balanced submerged filling activities.

(5) Sum emissions from each technology to estimate total emissions.

5.1.3 VEHICLE REFUELING

(1) Allocate state gasoline consumption from Highway Statistics to the study area. Assume

that gasoline consumption is proportional to gasoline station sales, reported in the Bureau

of the Census's Census of Retail Trade.

(2) From the local control agency or survey data, determine the level of local Stage II

refueling controls.

(3) Run the MOBILE model to determine the emission rate on a mass per volume throughput

(grams per gallon, converted to pounds per gallon) basis. (In MOBILE5b, this is

accomplished by setting HCFLAG = 3). Based on the results of Step 2, determine

whether Stage II refueling controls need to be considered. If local Stage II controls are in

place, enter the appropriate data in the MOBILE one-time data section per MOBILE

model requirements (EPA, 1994). (In MOBILE5b, set RLFLAG = 1 if there are no local

Stage II controls, or set RLFLAG = 2 to calculate an emission factor that includes local

Stage II controls. Note that MOBILE5b will factor in the effects of the national on-board

vapor recovery system requirements for either value of RLFLAG.) MOBILE6 is due for

release in 2000. The reader should check the OTAQ Website for updated information on

MOBILE6 (www.epa.gov/oms/m6.htm).
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.5-3

TTE  (TGD × LEF × GTA) (TGD × UEF × GTA)

2000 (11.5-2)

(4) Multiply the emission factor (lb/gallon of fuel) times the estimated gasoline volume

(gallons of gasoline) to estimate emissions from vehicle refueling.

5.1.4 STORAGE TANK BREATHING

(1) Allocate state gasoline consumption from Highway Statistics to the study area. Assume

that gasoline consumption is proportional to gasoline station sales, reported in the Bureau

of the Census's Census of Retail Trade.

(2) Multiply gasoline sales (gallons) times the Table 11.3-1 emission factor to estimate

emissions from storage tank breathing.

5.2 ALTERNATIVE METHOD 2

5.2.1 GASOLINE TRUCKS IN TRANSIT

(1) Allocate state gasoline consumption from Highway Statistics to the study area. Assume

that gasoline consumption is proportional to gasoline station sales, reported in the Bureau

of the Census's Census of Retail Trade.

(2) Use 1.25, a national default rate, as GTA.

(3) Calculate emissions:

where:

TTE = Total gasoline emissions from tank trucks in transit (tons)

LEF = Loaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)

UEF = Unloaded tank truck in-transit emission factor from Table 11.3-1

(pounds per 1,000 gallons)

5.2.2 FUEL DELIVERY TO OUTLETS

(1) Allocate state gasoline consumption from Highway Statistics to the study area. Assume

that gasoline consumption is proportional to gasoline station sales, reported in the Bureau

of the Census's Census of Retail Trade.
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.5-4 EIIP Volume III

(2) Use advice of local trade groups, industry representatives, or regulators to determine

penetration of each filling technology.

(3) Multiply total fuel sales in the study area by the fraction of stations using each filling

technology to estimate the fuel dispensed by each technology.

(4) Use technology-specific emission factors to estimate emissions from submerged filling,

splash filling, and vapor-balanced submerged filling activities.

(5) Sum emissions from each technology to estimate total emissions.

5.2.3 VEHICLE REFUELING

(1) Consult state or local transportation planners to obtain VMT data for the study area.

(2) From the local control agency or survey data, determine the level of local Stage II

refueling controls.

(3) Run the MOBILE model to determine the emission rate on a mass per vehicle-mile

(grams per vehicle mile traveled, converted to pounds per mile) basis. (In MOBILE5b,

this is accomplished by setting HCFLAG = 2). Based on the results of Step 2, determine

whether Stage II refueling controls need to be considered. If local Stage II controls are in

place, enter the appropriate data in the MOBILE one-time data section per MOBILE

model requirements (EPA, 1994). (In MOBILE5b, set RLFLAG = 1 if there are no local

Stage II controls, or set RLFLAG = 2 to calculate an emission factor that includes local

Stage II controls. Note that MOBILE5b will factor in the effects of the national on-board

vapor recovery system requirements for either value of RLFLAG.)MOBILE6 is due for

release in 2000. The reader should check the OTAQ Website for updated information on

MOBILE6 (www.epa.gov/oms/m6.htm).

(4) Multiply the emission factor times the VMT estimates to estimate emissions from vehicle

refueling.

5.2.4 STORAGE TANK BREATHING

Only one alternate methodology is provided for this category.
EIIP Volume III 11.6-1

6

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CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.6-2 EIIP Volume III

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TABLE 11.6-1

PREFERRED METHOD DARS SCORES: TANK TRUCKS IN TRANSIT;

LOCAL GASOLINE SALES, ADJUSTMENT FACTOR

FROM HIGHWAY WEIGH-STATION DATA



	
 
 		 		

7
 ,5 ,12,6 ,4+2,1-

..			 ,1 ,42,8 ,+42,-,

.	 

	 ,5 ,52! ,462,5,

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	 ,8 ,52,9 ,-82,4,

 	. ,1- ,1,2,9, ,-52,8!
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.6-3

TABLE 11.6-2

ALTERNATIVE METHOD 1 DARS SCORES: TANK TRUCKS IN TRANSIT;

LOCAL GASOLINE SALES, DEFAULT ADJUSTMENT FACTOR



	
 
 		 		

7
 ,5 ,12,6 ,4+2,1-

..			 ,1 ,52,6 ,4+2,84

.	 

	 ,5 ,82,9 ,-52,8-

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	 ,8 ,82,1 ,+12,-,

 	. ,1- ,862,56 ,-52,8,

TABLE 11.6-3

ALTERNATIVE METHOD 2 DARS SCORES: TANK TRUCKS IN TRANSIT;

SCALED STATE-LEVEL GASOLINE SALES, DEFAULT ADJUSTMENT FACTOR



	
 
 		 		

7
 ,5 ,1 ,4+

..			 ,1 ,5 ,4+

.	 

	 ,5 ,8 ,-5

) 

	 ,8 ,8 ,+1

 	. ,1- ,86 ,-5
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.6-4 EIIP Volume III

TABLE 11.6-4

PREFERRED METHOD DARS SCORES: FUEL DELIVERY TO OUTLETS;

LOCAL GASOLINE SALES, FILLING METHOD FROM SURVEY



	
 
 		 		

7
 ,5 ,42,8 ,+62,-9

..			 ,5 ,42,8 ,+42,-+

.	 

	 ,5 ,52! ,462,5,

) 

	 ,8 ,52,9 ,-82,4,

 	. ,18 ,842,5, ,-42,48

TABLE 11.6-5

ALTERNATIVE METHOD 1 DARS SCORES: FUEL DELIVERY TO OUTLETS;

SCALED STATE-LEVEL GASOLINE SALES, FILLING METHOD FROM SURVEY



	
 
 		 		

7
 ,5 ,4 ,+6

..			 ,5 ,4 ,+4

.	 

	 ,5 ,1 ,4+

) 

	 ,8 ,5 ,-8

 	. ,18 ,8+ ,--
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.6-5

TABLE 11.6-6

ALTERNATIVE METHOD 2 DARS SCORES: FUEL DELIVERY TO OUTLETS;

SCALED STATE-LEVEL GASOLINE SALES, FILLING METHOD FROM TRADE GROUPS



	
 
 		 		

7
 ,5 ,4 ,+6

..			 ,5 ,4 ,+6

.	 

	 ,5 ,1 ,4+

) 

	 ,8 ,5 ,-8

 	. ,18 ,84 ,-4

TABLE 11.6-7

PREFERRED METHOD DARS SCORES: VEHICLE REFUELING;

LOCAL GASOLINE SALES, FILLING METHOD FROM REGULATORS



	
 
 		 		

7
 ,9 ,42,5 ,-+2,81

..			 ,9 ,12,9 ,492,14

.	 

	 ! ,52! ,5,2!,,

) 

	 ,6 ,52,9 ,1-2,5+

 	. ,99 ,1,2,9- ,8-2,5-
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.6-6 EIIP Volume III

TABLE 11.6-8

ALTERNATIVE METHOD 1 DARS SCORES: VEHICLE REFUELING;

SCALED STATE-LEVEL GASOLINE SALES, FILLING METHOD FROM SURVEY



	
 
 		 		

7
 ,5 ,4 ,+9

..			 ,9 ,1 ,49

.	 

	 ! ,1 ,1,

) 

	 ,6 ,5 ,1-

 	. ,98 ,89 ,8,

TABLE 11.6-9

ALTERNATIVE METHOD 2 DARS SCORES: VEHICLE REFUELING;

GASOLINE USE FROM VMT, FILLING METHOD FROM SURVEY



	
 
 		 		

7
 ,5 ,4 ,+9

..			 ,9 ,4 ,-+

.	 

	 ! ,5 ,5,

) 

	 ,6 ,5 ,1-

 	. ,98 ,88 ,49
1/31/01 CHAPTER 11 - GASOLINE MARKETING

(STAGE I AND STAGE II)

EIIP Volume III 11.6-7

TABLE 11.6-10

PREFERRED METHOD DARS SCORES: STORAGE TANK BREATHING;

LOCAL GASOLINE SALES



	
 
 		 		

7
 ,5 ,12,6 ,4+2,1-

..			 ,5 ,52,6 ,462,1-

.	 

	 ,5 ,52! ,462,5,

) 

	 ,8 ,52,9 ,-82,4,

 	. ,18 ,192,6, ,442,86

TABLE 11.6-11

ALTERNATIVE METHOD 1 DARS SCORES: STORAGE TANK BREATHING;

SCALED STATE-LEVEL GASOLINE SALES



	
 
 		 		

7
 ,5 ,1 ,4+

..			 ,5 ,5 ,46

.	 

	 ,5 ,1 ,4+

) 

	 ,8 ,5 ,-8

 	. ,18 ,18 ,4+
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.6-8 EIIP Volume III

		
	
	
		


	

		
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CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.6-10 EIIP Volume III

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EIIP Volume III 11.7-1

7

DATA CODING PROCEDURES

The inventory preparer should check the EPA website (http://www.epa.gov/ttn/chief/) for the

latest information (codes) available to characterize emission estimates from gasoline marketing. 

A complete list of Source Classification Codes (SCC) can be retrieved at 

http://www.epa.gov/ttn/chief/codes/. Table 11.7-1 lists the applicable SCCs for gasoline

marketing. 

Available codes and process definitions influence and help guide the preparation of emission

estimates for this category. Data transfer formats should be taken into account when an

inventory preparer plans for data collection, calculation, and inventory presentation. Consistent

categorization and coding will result in greater continuity between emission inventories for use in

regional and national scale analyses. 



	

	

If the category emissions data will be transferred to EPA for incorporation into the national

criteria and toxics air pollutant inventory, specific data transfer formats are acceptable. The

acceptable data transfer format(s) are described and available for download at

http://www.epa.gov/ttn/chief/net/. The acceptable data transfer formats contain the data elements

necessary to complete the data set for use in regional or national air quality and human exposure

modeling. The inventory preparer should review the area source portion of the acceptable file

format(s) to understand the necessary data elements. The EPA describes its use and processing

of the data for purposes of completing the national inventory, in its Data Incorporation Plan, also

located at http://www.epa.gov/ttn/chief/net/.
CHAPTER 11 - GASOLINE MARKETING 1/31/01

(STAGE I AND STAGE II)

11.7-2 EIIP Volume III

TABLE 11.7-1

AREA AND MOBILE SOURCE CATEGORY CODES 

FOR GASOLINE MARKETING

Process Description Source Category

Codes

Petroleum Product Transit: Truck - Gasoline 25-01-030-120

Petroleum Product: Underground Tank Filling-Submerged 25-01-060-051

Storage - Gasoline Service Stations: Underground Tank Filling-Splash 25-01-060-052

Storage - Gasoline Service Stations: Underground Tank Filling-Balanced Submerged 25-01-060-053

Storage - Gasoline Service Stations: Vehicle Fueling-Uncontrolled Displacement Loss 25-01-060-101

Storage - Gasoline Service Stations: Vehicle Fueling-Controlled Displacement Loss 25-01-060-102

Storage - Gasoline Service Stations: Vehicle Fueling-Spillage 25-01-060-103

Storage - Gasoline Service Stations: Underground Tank-Breathing and Emptying 25-01-060-201

Storage - Gasoline Service Stations: Total All Processes 25-01-060-000
EIIP Volume III 11.8-1

8

REFERENCES

EPA, 2000. AIRS Area and Mobile Source Category Codes. U.S. Environmental Protection

Agency, Office of Air Quality Planning and Standards (OAQPS), Research Triangle Park, North

Carolina. (www.epa.gov/ttn/chief/scccodes.html)

EPA 1999. SPECIATE database, version 3.1. U.S. Environmental Protection Agency, Office of

Air Quality Planning and Standards (OAQPS), Research Triangle Park, North Carolina.

(http://www.epa.gov/ttn/chief/software.html#speciate)

EPA. 1995. Compilation of Air Pollution Emission Factors - Volume 1: Stationary Point and

Area Sources. Fifth Edition, Supplements A-F, AP-42. U.S. Environmental Protection Agency,

Research Triangle Park, North Carolina. (www.epa.gov/ttn/chief/ap42.html)

EPA. 1994. User's Guide to MOBILEXX (Current version covers MOBILE5b; however,

MOBILE6 is due for release by early 2001). U.S. Environmental Protection Agency, Office of

Mobile Sources, Ann Arbor, Michigan. 

EPA, 1992a. AIRS Area and Mobile Source Category Codes. U.S. Environmental Protection

Agency, Office of Air Quality Planning and Standards (OAQPS), Research Triangle Park, North

Carolina. 

EPA. 1992b. Procedures for Emission Inventory Preparation-Volume IV: Mobile Sources. 

EPA-450/4-81-026d (Revised). U.S. Environmental Protection Agency, Office of Mobile

Sources, Ann Arbor, Michigan and Office of Air Quality Planning and Standards, Research

Triangle Park, North Carolina. 1992.

EPA. 1991. Procedures for the Preparation of Emissions Inventories for Carbon Monoxide and

Precursors of Ozone. Volume 1: General Guidance for Stationary Sources. EPA-450/4-91-016. 

(NTIS PB92-112168). U.S. Environmental Protection Agency, Office of Air Quality Planning

and Standards, Research Triangle Park, North Carolina.

EPA. 1989. Procedures for Estimating and Applying Rule Effectiveness in Post-1987 Base Year

Emission Inventories for Ozone and Carbon Monoxide State Implementation Plans. U.S.

Environmental Protection Agency, Research Triangle Park, North Carolina.
CHAPTER 11 - GASOLINE MARKETING 1/31/01

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