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Nonroad Engine and Vehicle
Emission Study
Report
November 1991
EPA-21A-2001
Certification Division
Office of Mobile Sources
Office of Air & Radiation
U.S. Environmental Protection Agency
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ACKNOWLEDGEMENTS
The Nonroad Engine and Vehicle Emission Study relied extensively on the participation of numerous
organizations both within and outside of the U.S. Environmental Protection Agency. A Technical Review Group
consisting of industry and state-level government representatives was convened to provide a forum for resolving
discrepancies in data used in the analysis. Members of this group are listed in Appendix F. The authors and
editors of this report wish to express their sincere appreciation for the efforts of all participants.
The study also relied on analyses developed by EPA contractors. Under the direction of Mr. Charles T.
Hare, a review of existing data on the emission characteristics of nonroad engines*^ was conducted by the
Southwest Research Institute, which also tested the emissions of several lawn and garden engines that had been
used in the field.* The EPA Project Officer for this contract was Mr. Craig A. Harvey of the Emission Control
Technology Division. The EPA Technical Work Assignment Managers were Mr. Todtf L. Sherwood and Mr.
Kenneth L. Zerafa, both of the Certification Division. Estimates of local area equipment populations and usage
for most nonroad engines and vehicles were developed by Energy and Environmental Analysis, Inc. (EEA) under
the direction of Mr. K.G. Duleep.® An analysis of commercial marine vessel emissions in six nonattainment
areas was developed by Booz • Allen & Hamilton, Inc. (BA&H) under the direction of Ms. Barbara Kuryk.£
The EPA Project Officers for these two contracts were Ms. Celia Shih (EEA) of the Emission Control
Technology Division and Ms. Patricia L. Cox (BA&H) of the Health and Environmental Management Division.
The EPA Technical Work Assignment Manager for the EEA and BA&H analyses was Mr. Kevin A.H. Green of
the Certification Division.
Many members of the Certification Division in Ann Arbor, MI were instrumental in the completion of
tliis study. Ms. Gay MacGregor, Assistant Director, and Mr. John M. German, Project Manager, provided
general and technical oversight, respectively, for the study. Ms. Cheryl F. Adelman provided legal interpretation
and guidance in the area of nonroad equipment classification. Ms. Kathy E. Carter managed the production of
the draft report and accompanying appendices. Mr. Kevin A.H. Green developed estimates of total emissions
from nonroad engines and vehicles for the areas included in the study. Ms. Betsy Lyons McCabe coordinated
revisions and additions to the draft and managed the production of the final report and appendices. Ms. Deanne
R. North and Ms. Sujan V. Srivastava analyzed state estimates of emissions from nonroad sources. Ms. Clare
Ryan coordinated communications inside and outside EPA. With technical guidance from Mr. Michael A.
Sabourin, Project Manager, Mr. Jeffrey T. Prince and Mr. Kenneth L. Zerafa developed a data base of
evaporative and tailpipe emission factors for nonroad engines and vehicles. Ms. Paula Van Lare reviewed
studies of ozone formation and transport and considered their implications for nonroad engines and vehicles. All
of the above staff members are especially appreciative of the typing and production assistance provided by Ms.
Rae Benedetti and by Ms. Janis S. Hagen, a contractor with the Computer Science Corporation, and of the
general assistance from Mr. Donald J. Kachman and Ms. Sherie N. Williams, both student aides in the
Certification Division, and also of the assistance with file sharing and printing provided by the Computer Support
Section.
Ingalls, Melvin N. Nonroad Emission Factors. Southwest Research Institute, San Antonio, TX, February 1991.
'ingalls, Melvin N. Nonroad Emission Factors of Air Toxics, Southwest Research Institute, San Antonio, TX, June 1991.
*Carroll, J.N. Emission Tests of In-Use Small Utility Engines, Report 3426-006. Southwest Research Institure, San Antonio, TX,
September 1991.
Energy and Environmental Analysis, Inc. Methodology to Estimate Nonroad Equipment Populations by Nonattainment Areas,
Arlington, VA, September 1991.
Booz • Allen & Hamilton, Inc. Commercial Marine Vessel Contributions to Emission Inventories. Los Angeles, CA, October 1991.
November 1991
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Table of Contents
Reading and Using the Study Report and Appendixes iv
Executive Summary v
Chapter 1. Overview and Background 1
1.1. The Air Pollution Problem 1
1.2. Congressional Mandate and Scope of Study 3
1.3. Nonroad Equipment Categories Included in the Study 3
1.4. Pollutants Considered in the Study 4
1.5. Geographic Areas Considered in the Study 6
1.6. Public Participation 7
Chapter 2. Methods and Approach 9
2.1. Structure of Emission Inventories 10
2.2. Developing Equipment and Engine Categories 11
2.3. Development of Emission Factors 13
2.4. Development of Activity Levels for Inventory A 15
2.5. Development of Activity Levels for Inventory B 16
2.6. Comparison of Results from October Draft and Final Study 16
2.7. Comparison of Data Used in Inventories A and B 18
2.8. Emissions from Commercial Marine Vessels 39
2.9. Emissions from Other Sources 41
Chapter 3. Results 45
3.1. VOC, NOX, CO, and Paniculate Nonroad Inventories 45
3.2. VOC, NOX, CO, and Paniculate Nonroad Inventories by Categories 51
3.3. National PM, SOX, and Air Toxics Inventories 92
3.4. SIP and CARB Inventory Analysis 94
Chapter 4. Discussion and Analysis of Results 96
4.1. Discussion of Inventory Results 96
4.1.1. Volatile Organic Compounds (VOC) Inventories 96
4.1.2. Nitrogen Oxide (NOX) Inventories 98
4.1.3. Carbon Monoxide (CO) Inventories 99
4.1.4. Paniculate (PM) Inventories 100
4.1.5. National Air Toxics Inventories 101
4.2. Analysis of Inventory Methodologies 104
4.2.1. Data Differences 104
4.2.2. Factors Causing Overestimation or Underestimation 106
4.2.3. Additional Considerations 108
4.3. Analysis of Nonroad Emission Impact 112
Chapter 5. Conclusions 115
References 118
November 1991
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Nonroacl Engine and Vehicle Emission Study
List of Tables
Table ES-01. Equipment Categories Included in Study
Table ES-02. Examples of Emissions from New Nonroad Equipment
Relative to a Typical In-Use Passenger Car
Table ES-03. Pollutants Included in the Study
Table ES-04. Median Contributions of Nonroad Categories to VOC, NOX
and CO Emission Inventories A and B, with New
Engine/In-use Estimate Emission Factors
Table ES-05. Number of Areas in Which Category Contributes at Least 1%
of Total Inventory in the 19 Ozone and 16 CO Nonattainment
Areas Studied
Table 1-01. Equipment Categories Included in Study
Table 1-02. Pollutants Included in Study
Table 1-03. Geographic Areas Included in Study
Table 2-01. Sample CO Emission Inventory
Table 2-02. Nonroad Mobile Source Equipment Categories
Table 2-03. Inventory A and B National Population Estimates
Table 2-04. Inventory A and B Average Rated Horsepower Estimates
Table 2-05. Inventory A and B Typical Operating Load Factor Estimates . . .
Table 2-06. Inventory A and B Annual Use Estimates
Table 2-07. Emission Factors
Table 2-08a. Summer and Winter Percentages of Yearly Activity
Table 2-08b. Summer and Winter Percentages of Yearly Activity for
Recreational Marine Equipment
Table 2-08c. Summer and Winter Percentages of Yearly Activity for
Recreational Equipment
Table 2-09. Emissions from Commercial Marine Vessels
Table 2-10. Emissions from Highway Vehicles
Table 2-11. Emissions from Other Area and Point Sources
Table 3-01. Total Nonroad Emissions by Nonattainment Area and
Pollutant (%)
Table 3-02. Air Toxics Emission Inventories
Table 3-03. SIP-Based Inventory Summary
Table 3-04. CARB-Based Inventory Summary
Table 4-01. Equipment Categories Contributing at least 1% of Total
Summertime VOC
Table 4-02. Equipment Categories Contributing at least 1% of Total
Summertime NOX Inventory
Table 4-03. Equipment Categories Contributing at least 1% of Total
Wintertime CO Inventory
Table 4-04. Equipment Categories Contributing at least 1% of Total PM
Inventory
Table 4.05. Summary of Risk Estimates from Motor Vehicle Air Toxics ....
Table 4-06. Risk Estimates for Nonroad Toxic Emissions
Table 4-07. Contribution to Total Inventory
Table 4-08. Comparison of Ozone Precursor Emissions from Various
Vehicles and Equipment
VI
vi
vii
xii
xin
4
5
7
10
12
19
21
23
25
27
37
37
38
40
43
44
46
93
94
95
97
99
100
100
102
103
113
114
November 1991
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Table of Contents
Appendix A.
Appendix B.
Appendix C.
Appendix D.
Appendix E.
Appendix F.
Appendix G.
Appendix H.
Appendix I.
Appendix J.
Appendix K.
Appendix L.
Appendix M.
Appendix N.
Appendix O.
Appendix P.
Appendix Q.
List of Appendixes
Glossary of Acronyms and Terms A-l
Ozone Formation B-l
Ozone and CO Nonattainment and Ak Toxic Risk Estimates C-l
Mobile Source Air Toxics D-l
Manufacturer Association Membership E-l
Technical Review Group Representatives . F-l
Emission Inventories Developed Using SIP and CARB Data G-l
List of Equipment Types H-l
Emission Factor Development H-l
Additional Data Submissions J-l
Adjustments to Data in Developing Inventory A K-l
Regional and Seasonal Adjustments to Inventories L-l
Emission Inventory A M-l
EPA Use of Manufacturer Data In Inventory B N-l
Emission Inventory B O-l
Transport and Nonroad Emissions P-l
Response to Public Comment Q-l
November 1991
ui
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Reading and Using the Study Report and Appendixes
The Nonroad Engine and Vehicle Emission Study has been bound into two volumes -
the report and its appendixes. The report contains five chapters which provide information
on the purpose and goals of the study, the approach, the results, and a discussion and analysis
of those results. Throughout the report, the reader is provided with the basic information
needed to understand what was done to obtain the results presented. More detailed
information has been put into a series of sixteen appendixes, which are bound separately from
the report.
In both the report and the appendixes, the reader will find annotated notes, indicated
by a superscript symbol, at the bottom of the page. These notes are provided where it was
felt some explanatory information might be needed. Reference citations are indicated by a
superscript number. A list of the references cited in the report is located on the last page of
the report. In the appendixes, a list of references can be found at the end of each appendix.
Many acronyms are used in the report. While they are defined when first used, a list
of acronyms and their meanings is also provided in Appendix A. Appendix A also contains a
glossary of some of the terms used in the report.
iv November 1991
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Executive Summary
Congressional Mandate
This study is a response to the Congressional directive** that EPA quantify the
contribution of nonroad sources to ozone and carbon monoxide air pollution and to other
pollutants believed to endanger public health. The Clean Air Act (CAA), as amended, directs
EPA to complete a study of emissions from nonroad engines and vehicles by November 15,
1991. The CAA further requires EPA to regulate emissions from nonroad engines and
vehicles within twelve months after completion of the study if the Agency determines that
these sources are significant contributors to ozone or carbon monoxide (CO) concentrations in
more than one area which has failed to attain the National Ambient Air Quality Standards
(NAAQS) for these pollutants. This report does not constitute EPA's determination of
significance. Any determination EPA makes relative to the significance of nonroad
contributions to air quality will be included as part of any regulations proposed for nonroad
engines and vehicles. Opportunities for public comment on any determination of significance
will be provided through the regulatory process if the Agency proposes nonroad regulations.
Nonroad Engines and Vehicles
The terms "nonroad engines" and "nonroad vehicles" cover a diverse collection of
equipment ranging from small equipment like lawnmowers and chain saws, to recreational
equipment, to farm equipment and construction machinery. EPA considered more than 80
different types of equipment in this report. To ease analysis and reporting EPA has grouped
equipment into 10 equipment categories listed in Table ES-Ol.^
"Section 213(a) of the Clean Air Act, as amended, directs EPA to conduct a study of emissions from nonroad
engines and vehicles and to determine if such emissions cause, or significantly contribute to, air pollution which may
be reasonably anticipated to endanger public health or welfare.
locomotives and aircraft are not included in this study because the CAA provides for them separately.
November 1991
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Nonroad Engine and Vehicle Emission Study
Table ES-01. Equipment Categories Included in Study
Nonroad Equipment Categories
Lawn and Garden Equipment
Airport Service Equipment
Recreational Equipment
Recreational Marine Equipment
Light Commercial Equipment
Industrial Equipment
Construction Equipment
Agricultural Equipment
Logging Equipment
Commercial Marine Vessels
Nonroad engines are not regulated for emissions, and very few nonroad engines
currently use emission control technology. Because of the diversity of nonroad equipment,
characterization of the emissions from nonroad engines is a complex task. A comprehensive
analysis of the air quality benefits potentially available from reducing nonroad engine
emissions has never before been undertaken.
Congress asked EPA to focus on quantifying emissions from unregulated nonroad
sources after 20 years of highway mobile sources regulation and increasingly costly controls
on the automotive industry. As a group, nonroad engines represent the last uncontrolled
mobile source. Potential emission reductions from this source may help resolve local air
quality problems. A comparison between pollution emitted by individual pieces of new
nonroad equipment and pollution emitted by today's typical in-use passenger car illustrates
the logic behind the Congressional mandate.
Table ES-02. Examples of Emissions from New Nonroad Equipment Relative to a
Typical In-Use Passenger Car
1 Hour of Use
1 lawnmower
1 chain saw
1 outboard motor
1 crawler tractor
Pollutant
voc
voc
voc
NOX
Car Miles
50
200
800
900
VI
November 1991
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Executive Summary
State and Industry Participation
EPA's ability to complete this study has been greatly enhanced by contributions of the
nonroad equipment industry and by many state air quality planners. A public workshop was
held April 3-4, 1991, and individual meetings were held with many nonroad manufacturing
groups. An informal group of technical experts, including industry and state representatives,
provided valuable data and technical feedback throughout this study process, hi many cases
the nonroad manufacturers invested resources to provide detailed information to help construct
nonroad emission inventories. On October 30, 1991, EPA held a public meeting on the full
draft of this report.
Study Approach
To estimate the contribution of nonroad sources to air pollution, EPA constructed
national emission inventories of nonroad sources, as well as local inventories for 19 ozone
and 16 carbon monoxide (CO) nonattainment areas. Since it was not possible to construct
inventories for all nonattainment areas within the time allowed for this study, these areas were
selected to represent a spectrum of demographic and geographic characteristics. They also
represent most of the nation's most severe air pollution problems.
Because Congress specified that EPA study the nonroad source contribution to ozone
and CO nonattainment, the study primarily focuses on CO and on the pollutants that
contribute to ozone formation, volatile organic compounds (VOC) and oxides of nitrogen
(NOX). However, the study addresses all the pollutants listed in Table ES-03.
Table ES-03. Pollutants Included in the Study
Pollutants
Volatile Organic Compounds (VOCs) Benzene
Oxides of Nitrogen (NOX) Aldehydes
Carbon Monoxide (CO) 1,3-butadiene
Paniculate Matter (PM) Gasoline Vapors
Sulfur Dioxide (SO2) Nitrosamines
November 1991 vii
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Nonroad Engine and Vehicle Emission Study
Constructing Emission Inventories
Emission inventories are detailed listings of the amount of pollution generated by
different sources in a given area over a specific period of time. In constructing nonroad
inventories, several factors must be estimated: (1) equipment populations in a given
nonattainment area, (2) annual hours of use of each type of equipment adjusted for geographic
region and for the season of interest for each pollutant studied, (3) average rated horsepower
of each type of equipment, (4) typical load factor for each type of equipment, and (5) an
emission factor (EF), or average emissions of each pollutant per unit of use (e.g., g/hp-hr) for
each category of equipment.
Given the number of engine types and equipment included in the study and the limited
amount of data available characterizing emissions from nonroad sources, EPA chose to
construct two sets of inventories. In the first set, EPA constructed inventories that incorporate
commercially and publicly available data so that the method could be repeated by interested
states. The second set of inventories incorporated industry-provided data that might not be
publicly available to states (e.g., confidential sales data to estimate populations), but would
give EPA a valuable cross check for the first set of inventories. This report presents both sets
of inventories:
Inventory A which relies heavily on a commercially available marketing research data
base** and publicly available indices of commercial activity to estimate equipment
populations;
and
Inventory B which incorporates manufacturer-provided data in almost all high usage
categories.
Both inventories use the same emission factors for all pollutants except particulates.
EPA and its contractors, with the assistance of industry, updated nonroad emission factors for
this study using ah1 available test data, including evaporative and refueling (spillage) emission
data. Most of the emission data for nonroad engines are based on tests of new engines. The
limited information EPA does have on in-use nonroad engines shows that in-use emissions
**Power Systems Research maintains a marketing research data base that includes most types of nonroad
equipment.
viii November 1991
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Executive Summary
could be as much as two times higher for some types of equipment than emission estimates
using emission factors based on new engine test data. Consequently, inventories calculated
using new engine emission factors (new engine EFs) will underestimate the contribution of
nonroad engines to air pollution. EPA has developed a second set of emission factors (in-use
EFs) for VOC and CO that includes a gross adjustment for in-use deterioration. Because of
the uncertainty involved in making in-use adjustments, the report presents estimates for both
Inventories A and B with and without the adjustment. In-use adjustments assume very little
deterioration by diesel engines. Hence, category-specific inventories (e.g., Construction
Equipment) for categories dominated by diesel engines show very little difference between the
inventories estimated using new engine EFs and in-use EFs. The estimates using the new
engine EFs should be considered the conservative lower bound of nonroad contribution in
each nonattainment area.
Highlights of Study Results
Results are presented for all nonroad sources and for each equipment category.
Aggregate Nonroad Contributions to Inventories
The results of Inventories A and B are similar. Chart ES-01 shows the median
contributions to total inventories in the 19 ozone and 16 CO nonattainment areas studied. In
general, Inventory B estimates lower emissions than Inventory A.
November 1991
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Nonroad Engine and Vehicle Emission Study
Chart ES-01. Comparison of Median Contributions - Inventory A & B
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I-
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o
£}
i_
4-J
C
O
(J
"D
O
c
o
c
(0
13
0)
20
15 -
10 -
VOC/A VOC/B NOx/A NOx/B CO/A
Pol Iutant/ Inventory
tliiiBased on Tests of New Engines
I (Estimated In-Use Effects
CO/B
Under the most conservative assumptions, using the new engine EFs and choosing the
lowest estimate from Inventories A and B combined, minimum contributions by pollutant for
al] cities studied were as follows: 2.9% VOC, 7.6% NOX, and 2.2% CO. It is often useful to
look at the second highest and second lowest values in the range to avoid any "outliers" that
might skew the data. For example, the second lowest contribution of VOC in any
nonattainment area studied was 4.5%, for NOX 9.7%, and for CO 2.3%.
It is also useful to look at the nonattainment area with the second highest contribution
since Congress requires EPA to regulate nonroad engines if it finds that nonroad engines are
significant contributors to pollution in more than one nonattainment area. Chart ES-02 shows,
for VOC, NOX, and CO, the level of contribution in the nonattainment area with the second
highest contribution from nonroad sources.
November 1991
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Executive Summary
Chart ES-02. Percent Contribution from Nonroad Sources in the Nonattainment Area
with the Second Highest Contribution Level
r\
5 40
o
3Q
c
o
'- 20
i->
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O
o
§ 10
L
C
O
C
ra
TJ
CO/B
VOC/A VOC/B NOx/A NOx/B CO/A
Pol Iutant/ Inventory
•aBased on Tests of New Engines
I I Estimated In-Use Effects
Nonroad Contribution to Inventories by Equipment Category
The individual nonroad categories contributing most heavily to the inventories vary by
pollutant. Both Inventory A and B show substantial summertime VOC emissions from
nonroad sources. These emissions are primarily from lawn and garden equipment and from
the recreational marine category. About 1.5% of the lawn and garden contribution to nonroad
VOC inventories is due to evaporative emissions from spilling fuel when refueling equipment.
The nonroad portion of total summertime NOX emissions is estimated to be about the
same, on a percentage basis, as the portion of total VOC emissions from nonroad sources. By
far the largest contributor to nonroad NOX emissions is construction equipment. Inventory A
shows in all areas studied that construction equipment contributions exceed 6% of the total
NOX inventory. Inventory B shows that in 15 of the 19 areas, NOX emissions from
construction equipment exceed 5% of the total inventory. Agricultural, industrial, airport
service, and commercial marine engines are also important contributors of NOX in some areas.
November 1991
XI
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Nonroad Engine and Vehicle Emission Study
Unlike VOC and NOX emissions, no one category dominates the nonroad CO emission
contribution. Light commercial, lawn and garden equipment, industrial, commercial marine,
and recreational equipment categories each contribute a minimum 1.4-2.2% of total
wintertime CO in at least two areas.
Table ES-04 shows the contributions of the different nonroad engine and vehicle
categories to total inventories of VOC, CO, and NOX emissions. The contributions are
expressed in percent of total emissions from all sources. The values given are medians of the
contributions in the various nonattainment areas studied. These are given for both inventories
A and B, using emission factors first based on new engines and second incorporating EPA's
estimate of in-use effects. Finally, the median contribution from all nonroad engines and
vehicles is shown.
Table ES-04. Median Contributions of Nonroad Categories to VOC, NOX and CO
Emission Inventories A and B, with New Engine/In-use Estimate Emission Factors
Source Category
Lawn and Garden
Airport Service
Recreational
Light Commercial
Industrial
Construction
Agricultural
Logging
Recreational Marine
Commercial Marine
Total Nonroad
% Total VOC tpsd
Inv. A
2.6-4.7
0.1-0.1
0.2-0.4
0.6-1.0
0.4-0.5
1.0-1.1
0.2-0.2
0.0-0.0
3.4-4.0
0.1-0.1
9.1-12.6
Inv. B
2.4-4.1
0.1-0.1
0.2-0.3
0.6-1.1
0.4-0.4
0.8-0.8
0.2-0.2
0.0-0.0
2.2-2.5
0.1-0.1
7.4-10.3
% Total NOX tpsd
Inv. A
0.2
1.1
0.0
0.2
1.7
9.7
1.6
0.0
0.3
0.7
17.3
Inv. B
0.2
1.2
0.0
0.2
1.3
8.4
1.7
0.01
0.2
1.0
14.5
% Total CO tpwd
Inv. A
0.6-1.1
0.2-0.2
0.4-0.8
2.0-3.6
1.3-1.5
0.5-0.6
0.1-0.1
0.0-0.0
0.1-0.1
0.1-0.1
5.9-9.4
Inv. B
0.5-0.9
0.2-0.2
0.4-0.7
2.0-3.7
1.1-1.4
0.4-0.5
0.1-0.1
0.0-0.0
0.1-0.1
0.1-0.1
5.2-8.5
Relative Contributions of Nonroad and Other Emission Sources
One of the difficulties in improving air quality is that a multitude of small sources
contribute to air pollution. In fact, many of what are considered "large" sources are actually
groups of smaller sources (e.g., motor vehicles are categorized into light-duty vehicles,
XII
November 1991
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Executive Summary
light-duty trucks, heavy-duty vehicles). Most large sources, like motor vehicles, have
substantially reduced emissions because of regulatory requirements over the past two decades.
Because many of the technologically and economically feasible reductions available from
large sources have already been realized, a number of emission control programs recently
mandated by Congress are aimed at achieving marginal inventory reductions. These
reductions are relatively small compared to past reductions taken from an uncontrolled
baseline. Since marginal reductions tend to be costly, the EPA has begun to focus on
controlling many small sources of pollution. Because nonroad engines are uncontrolled, it is
reasonable to expect that introduction of controls on sources emitting 1% of the total
inventory would at least achieve benefits in the range of many other control programs now
mandated by Congress in the CAA.
Table ES-05 shows, using the new engine EFs, the number of nonattainment areas in
Inventories A and B in which specific nonroad categories contribute at least 1% of total
inventory. Many of these areas exceed the 1% contribution by a wide margin.
Table ES-05. Number of Areas in Which Category Contributes at Least 1% of Total
Inventory in the 19 Ozone and 16 CO Nonattainment Areas Studied
Nonroad Category
Lawn and Garden
Recreational Marine
Commercial Marine
Recreational Equipment
Light Commercial Equipment
Construction Equipment
Agricultural Equipment
Airport Service Equipment
Industrial Equipment
Number of Areas > 1%
Inventory A/B
VOC
19-18
17-17
1-1
2-0
2-2
11-5
1-1
0
0
NOX
0-0
2-1
10-9
0
0
19-19
12-13
12-12
13-13
CO
5-3
0
2-2
3-2
15-15
3-0
0
0
12-10
November 1991
xui
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Nonroad Engine and Vehicle Emission Study
Charts ES-03 through ES-08 show VOC, NOX, and CO emission inventories for
nonattainment areas typical of those included in the study.§§ For comparison, the national
emission inventories are also shown.
The nonroad portion of each chart is based on the average between Inventories A and
B with and without adjustments for increased in-use emissions. The key at the bottom of
each page lists the other sources included in the charts.
The nonroad contribution to the summertime VOC inventory for the New York
CMSA/NECMA is greater than the combined contribution from all highway vehicles except
light-duty gasoline vehicles. For the Philadelphia CMSA, the nonroad summertime NOX
contribution is larger than that from all heavy-duty highway vehicles. The nonroad
contribution to the wintertime CO inventory for the Denver CMSA is greater than the
combined contribution from all other sources except highway vehicles.
Nationally, the nonroad summertime VOC and NOX contributions are greater than
those from any other single source categories except solvent evaporation (VOC) and electrical
generation (NOX). The national nonroad CO contribution is greater than the combined
contributions from all highway mobile sources except light-duty vehicles.
55 For each pollutant, the area shown is that for which the nonroad portion of the inventory was nearest to the
median value for the different areas included in the study.
xiv November 1991
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Executive Summary
Chart ES-03. National Summertime VOC Inventory
Nonrood C19 6*0
A1 C3. 19O
HOGV C1
C1B 7*0
HDDV CO.2X3
LOT C 6 . 7*3
Other C21.2*3
A3 C6.8SO
Chart ES-04. New York CMSA/NECMA Summertime VOC Inventory
LDGT C4
Nonroad C 10. 290
HDGV C 1 • 29O
LDGV C31
All Other Sources C52.
DSLV C 0 . 83O
Highway Mobile Sources
LDGV - light-duty gasoline vehicles
LDV - light-duty vehicles
LDGT - light-duty gasoline trucks
LDT - light-duty trucks
HDGV - heavy-duty gasoline vehicles
HDDV - heavy-duty diesel vehicles
DSLV - diesel vehicles
Area and Point Sources
Al - petroleum refining
A2 - solvent evaporation
A3 - petroleum product storage/transfer
A4 - electrical generation
A5 - industrial combustion
A6 - industrial processes
A7 - residential fuel use
November 1991
xv
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Nonroad Engine and Vehicle Emission Study
Chart ES-05. National Summertime NOX Inventory
Nonroad C15 1SQ
HDDV £11.2*0
HDGV £1 3*0
LDV
A4 C32 2*0
LOT £4.9»0
/ Other £7 4*0
A6 £2 6*0
A5 £13 8*0
Chart ES-06. Philadelphia CMSA Summertime NOX Inventory
HDDV £9 0*0 HDGV £1 5*0
Nonroad £12 .3X3 X' \\ II \ LDV C18
LOT C3.
All Other Sources C.55.2JO
Highway Mobile Sources
LDGV - light-duty gasoline vehicles
LDV - light-duty vehicles
LDGT - light-duty gasoline trucks
LOT - light-duty trucks
HDGV - heavy-duty gasoline vehicles
HDDV - heavy-duty diesel vehicles
DSLV - diesel vehicles
Area and Point Sources
AI - petroleum refining
A2 - solvent evaporation
A3 - petroleum product storage/transfer
A4 - electrical generation
A5 - industrial combustion
A6 - industrial processes
A7 - residential fuel use
xvi
November 1991
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Executive Summary
Chart ES-07. National Wintertime CO Inventory"
LOT C10. 2X5
HDGV C5.05O
HDDV CO-9*O
Nonroo
A 7 C20
LDV C26. 0*T>
Other C 23 • 2*0
Chart ES-08. Denver CMSA Wintertime CO Inventory
LDV £57.0X1
HDDV CO. 7*0
LOT C 23. 5SQ
Nonroad C6 9*0
HDGV C5.BSQ
Highway Mobile Sources
LDGV - light-duty gasoline vehicles
LDV - light-duty vehicles
LDGT - light-duty gasoline tracks
LDT - light-duty tracks
HDGV - heavy-duty gasoline vehicles
HDDV - heavy-duty diesel vehicles
DSLV - diesel vehicles
Area and Point Sources
Al - petroleum refining
A2 - solvent evaporation
A3 - petroleum product storage/transfer
A4 - electrical generation
A5 - industrial combustion
A6 - industrial processes
A7 - residential fuel use
Corrections for wintertime increases in CO emission factors were not made for either nonroad sources or
highway vehicles due to limitations in national-level data.
November 1991
xvu
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Nonroad Engine and Vehicle Emission Study
Because nonroad sources are among the few remaining uncontrolled sources of
pollution, their emissions appear large in comparison to the emissions from sources that are
already subject to substantial emission control requirements. For example, the CAA requires
extreme ozone nonattainment areas to employ Reasonably Available Control Technology
(RACT) on all stationary sources with VOC or NOX emissions above 10 tons per year (tpy).
Annual operation of only 10 crawler tractors or 24 agricultural tractors will produce 10 tpy of
NOX. Typical annual operation of only 74-142 boats with outboard motors or 730-1,630
chain saws will emit 10 tpy of VOC" In contrast, it takes 700 new, current-technology
passenger cars driving an average of 13.000 miles each in a year (a total of more than 9
million miles) to produce 10 tpy of VOC.
Areas of Further Study
In the process of constructing the study, EPA identified a number of areas where
estimates were developed using limited data or were not developed at all because of lack of
data altogether. While existing nonroad emission factors estimate tailpipe emissions from
relatively new engines, more work needs to be done to quantify the effects of in-use
deterioration, crankcase and evaporative emissions, toxic and paniculate emissions, and
emissions under cold start conditions. Because these emissions are not totally captured by the
emission factors used in this study, the inventories presented in the study, particularly those
calculated using the new engine emission factors, are likely to be conservative estimates of
the nonroad contribution to air pollution.
*** These numbers indicate the range between data used to develop A and B national inventories.
xviii November 1991
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Chapter 1. Overview and Background
The cornerstone of the Clean Ak Act (CAA) is the effort to attain and maintain
National Ambient Ak Quality Standards (NAAQS).1 w Prior to the enactment of the
1990 CAA Amendments (CAAA), efforts to achieve and maintain ak quality standards
focused on regulation of emissions from on-highway, area, and stationary sources. As a result
of these efforts, significant progress has been made in reducing such emissions. However,
due to the growth in ak pollution sources, many ak quality regions have failed to attain the
NAAQS, particularly those for ozone and carbon monoxide (CO).
The CAAA contain numerous provisions that are intended to remedy these continuing
ak quality problems, through the application of new controls on currently regulated mobile
and stationary sources of emissions and the promulgation of regulations for new sources. As
part of the effort to identify and control unregulated sources of ak pollution, the CAAA dkect
the U.S. Envkonmental Protection Agency (EPA) to study contributions to ak quality from
nonroad engines*** and nonroad vehicles^ (other than locomotives or engines used in
locomotives).^ This study is the result of that dkective.
1.1. The Air Pollution Problem
The CAA requires the EPA to set ak quality standards for common and widespread
pollutants after preparing "criteria documents" summarizing scientific knowledge on thek
health effects. Currently, six "criteria" pollutants are regulated by primary and secondary
nt Reference citations are indicated by a superscripted number. A list of citations can be found at the end of
the report.
*** Section 216(10) of the CAA, as amended, defines "nonroad engine" as an internal combustion engine
(including the fuel system) that is not used in a motor vehicle or a vehicle used solely for competition, or that is not
subject to standards promulgated under section 111 (new stationary sources) or section 202 (motor vehicles) of the
CAA. As defined in section 216(2) of the CAA, "motor vehicle" means any self-propelled vehicle designed for
transporting persons or property on a street or highway.
898 Section 216(11) of the CAA, as amended, defines "nonroad vehicle" as a vehicle that is powered by a
nonroad engine and that is not a motor vehicle or a vehicle used solely for competition.
t££ Emissions from locomotives and new engines used in locomotives are being addressed in a separate study,
as required under section 213(aX5) of the CAA, as amended.
November 1991
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Nonroad Engine and Vehicle Emission Study
NAAQS.**** As of 1989, over one-half of the population of the United States was still
exposed to levels of these pollutants which were considered unhealthful by EPA.
Based on ak quality data from 1988-1989, more than 33 million people resided in the
41 areas that failed to meet the NAAQQS for CO.2 An area is considered to have failed to
attain the NAAQS for CO if it exceeds 9 parts per million (ppm) two or more times in a two
year period. Carbon monoxide, formed as a result of the incomplete combustion of fuel, is
emitted during the combustion process.
In contrast to CO, ozone is formed in the atmosphere as a result of a complex series
of chemical reactions between oxides of nitrogen (NOX) and volatile organic compounds
(VOCs). hi most urban nonattainment areas, both NOX and VOCs must be substantially
reduced to bring the area into attainment of the ozone standard. Further, since airborne ozone
and NOX, and possibly VOCs, can be transported from one area to another, attainment of the
ozone standard in some areas may require control of NOX and VOC emissions in upwind
regions.
An area is in nonattainment for ozone if it exceeds 0.12 ppm more than three times in
a three year period. In 1987-1989, 96 U.S. cities exceeded the standard for ozone. Of these
cities, nine were classified as "severely" polluted, experiencing peak ozone levels that
exceeded the standard by 50 percent or more. Based on 1989 ak quality data, over 66
million people lived in counties not meeting the ozone standard.3 Appendix B contains a
description of ozone formation and a bibliography of the literature on ozone. A list of carbon
monoxide and ozone nonattainment areas can be found in Appendix C.
As with CO and ozone, many areas are in nonattainment for paniculate matter (PM).
At the time the CAAA were enacted, 73 areas failed to meet the NAAQS for PM. Over 28
million people lived in areas not meeting the paniculate standard in 1989.4 *^
In addition to problems associated with nonattainment of the NAAQS, EPA is
concerned with the health risks associated with ak toxics. Most ak toxics are hydrocarbon
compounds capable of causing adverse health effects. Benzene, formaldehyde, and 1,3-
*"* NAAQS have been established for paniculate matter (PM), sulfur dioxide (SO2), carbon monoxide (CO),
nitrogen dioxide (NO2), ozone, and lead.
tw The estimate for paniculate matter is considered a lower bound estimate, because the PM10 monitoring
network is still evolving.
November 1991
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Overview and Background
butadiene are emitted by motor vehicles and are considered to be human or probable human
carcinogens. Some air toxics, such as benzene, are components of gasoline and can be
emitted as unburned fuel or as fuel that evaporates. Other air toxics, such as formaldehyde,
which results from the same reactions that form ozone, and 1,3-butadiene, are not present in
fuel, but are by-products of incomplete combustion. A summary of cancer risk estimates
associated with motor vehicle pollutants of most concern can be found in Appendix C.
1.2. Congressional Mandate and Scope of Study
Section 213(a) of the CAA, as amended, directs EPA to conduct a study of emissions
from nonroad engines and vehicles and to determine if such emissions cause, or significantly
contribute to, air pollution which may reasonably be anticipated to endanger public health or
welfare. Within 12 months after the completion of the study, the Administrator of EPA must
determine whether the emissions of CO, NOX, and VOCs from such new or existing engines
or vehicles are significant contributors to ozone or CO concentrations in more than one area
which has failed to attain the NAAQS for ozone or CO. If an affirmative determination is
made, the Administrator is required to promulgate regulations containing standards applicable
to emissions from those classes or categories of new nonroad engines and vehicles which in
the Administrator's judgment cause, or contribute to, such air pollution.
This study is the result of the directive in section 213(a) that EPA conduct a study of
nonroad emissions. The study quantifies, through the use of nonroad equipment emission
inventories, the contributions of nonroad sources to air quality problems. The study does not
make a determination of the significance of emissions from nonroad sources. Such a
determination will be included as part of any regulations promulgated for nonroad engines
and vehicles.
1.3. Nonroad Equipment Categories Included in the Study
EPA considered over 80 different types of equipment in this analysis. To ease
analysis and reporting and to assist the disaggregation of national or state equipment
populations to the local level, EPA grouped the equipment types into the 10 equipment
November 1991
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Nonroad Engine and Vehicle Emission Study
categories listed in Table 1-01. Additional information on these equipment types and
equipment categories can be found in Chapter 2. It should be noted that these categories
were developed only for use in this study and are not intended to represent potential
regulatory categories. Aircraft and locomotives were not included in this study.****
Table 1-01. Equipment Categories Included in Study
Categories
Lawn and Garden Equipment
Airport Service Equipment
Recreational Equipment
Recreational Marine Equipment
Light Commercial Equipment
Industrial Equipment
Construction Equipment
Agricultural Equipment
Logging Equipment
Commercial Marine Vessels
1.4. Pollutants Considered in the Study
Although numerous pollutants have the potential to meet the criteria set forth in the
C AAA for inclusion in the study, EPA chose to limit the number of pollutants examined in
this study to those listed in Table 1-02.
****Aircraft are already regulated under a separate subpart of the Clean Air Act and, hence, are not classified as
nonroad engines or vehicles. Locomotives were specifically excluded from inclusion by Congress in the CAAA.
November 1991
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Overview and Background
Table 1-02. Pollutants Included in Study
Pollutants
Volatile Organic Compounds (VOCs)
Oxides of Nitrogen (NOX)
Carbon Monoxide (CO)
Paniculate Matter (PM)
Sulfur Dioxide (SO2)
Benzene
Aldehydes
1,3-butadiene
Gasoline Vapors
Nitrosamines
Section 213(a) of the CAA, as amended, requires that VOCs, CO, and NOX be
included in the nonroad study. Of the three other NAAQS criteria pollutants (PM, SO2 and
lead), EPA chose to include PM and SO2, since both are currently regulated for on-highway
sources and have been identified as contributing to air quality conditions that are dangerous to
public health or welfare. The last criteria pollutant, lead, although highly toxic, was not
included in the study because the CAAA prohibit the production of motor vehicle engines and
nonroad engines that require leaded gasoline after model year 1992.
Nonroad sources also emit other pollutants commonly referred to as air toxics, which
include carcinogens, mutagens, and reproductive toxins. Currently, little information exists
regarding air toxic emissions from nonroad engines and vehicles or the health effects of such
emissions. Moreover, none of these pollutants from on-highway sources have been regulated
on the basis of carcinogenicity.
EPA's authority to include air toxics in this study is derived from section 213(a)(4) of
the CAA. In determining which air toxics to examine, EPA considered three sources of
information: compounds suggested by contractors which show the greatest cancer incidences
and other risks,5 pollutants to be included in EPA's CAA-mandated study of mobile
source-related air toxics, and those pollutants emitted from nonroad sources which are found
in Title in of the CAA. After reviewing the availability of data and the cancer risk
November 1991
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Nonroad Engine and Vehicle Emission Study
incidences, EPA chose to address the following air toxics in this study: benzene; aldehydes;
1,3-butadiene; gasoline vapors; and nitrosamines. Appendix D contains a listing of the air
toxics considered in this study.
1.5. Geographic Areas Considered in the Study
In determining which geographic areas to include in the study, EPA decided to focus
on the 24 areas, listed in Table 1-03, which failed to attain the NAAQS for either ozone, CO,
or both. Nineteen of the areas were evaluated for VOCs and NOX, and 16 areas for CO. A
primary reason for selecting these areas is the severity of their local air quality problems.
EPA also believes these areas are representative of other urban areas with air pollution
problems due to their diverse geographic and demographic characteristics.
Table 1-03. Geographic Areas Included in Study
Nonattainment Areas
Atlanta, GA MSA
Baltimore, MD MSA
Baton Rouge, LA MSA
Boston-Lawrence-Salem-Lowell-Brockton, MA NECMA
Chicago-Gary-Lake County IL-IN-WI CMSA
Cleveland-Akron-Lorain, OH CMSA
Denver-Boulder, CO CMSA
El Paso, TX MSA
Hartford-New Britain-Middletown-Bristol, CT NECMA
Houston-Galveston-Brazoria, TX CMSA
Miami-Fort Lauderdale, FL CMSA
Milwaukee-Racine, WI CMSA
Minneapolis-St. Paul, MN-WI MSA
New York-Northern NJ-Long Island, NY-NJ-
CT CMSA/NECMA9S§8
Philadelphia- Wilmington-Trenton, PA-NJ-DE-
MDCMSA
Provo-Orem, UT MSA
St. Louis, MO-IL MSA
San Diego, CA Air Basin£f££
San Joaquin, CA Air Basin
Seattle-Tacoma, WA CMSA
South Coast, CA Air Basin
Spokane, WA MSA
Springfield, MA NECMA
Washington, DC-MD-VA MSA
8585 Consolidated Metropolitan Statistical Area (CMSA) and North East County Metropolitan Statistical Area
(NECMA) definitions are given in State and County Metropolitan Area Data Book. U.S. Bureau of the Census, 1986.
"" California air basins are defined for the purposes of this study as in the 1990 version of the 1987 emission
inventory prepared by the California Air Resources Board (CARB) for the State of California.
November 1991
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Overview and Background
1.6. Public Participation
EPA recognizes that involvement by the manufacturing and environmental
communities is essential in ensuring the effective implementation and enforcement of any
policies and regulations which may be developed. Therefore, throughout the nonroad engine
and vehicle study process, EPA actively solicited information and comment from interested
parties. The information supplied by these parties enabled EPA to use the best available data
in developing estimates of the contribution of nonroad engines to air quality problems.
A public workshop was held on April 3-4, 1991, with over 200 persons in attendance.
The purpose of the workshop was to discuss the nonroad engine and vehicle study and the
Agency's regulatory process. Presentations were made by EPA, state agency representatives,
and industry representatives. EPA requested that manufacturers submit population
inventory and emission data for the nonroad equipment to be considered in the study. In
addition, a briefing for environmental groups on general air quality issues held in Washington,
D.C., on May 14, 1991, included a presentation on the nonroad study.
Following the public workshop, EPA held individual meetings with a number of
manufacturers and manufacturer groups, including: Outdoor Power and Equipment Institute
(OPEI), Industrial Truck Association (ITA), Engine Manufacturers Association (EMA), the
Equipment Manufacturers Institute (EMI), Portable Power Equipment Manufacturers
Association (PPEMA), John Deere Company, National Marine Manufacturers Association
(NMMA), Manufacturers of Emission Controls Association (MECA), Ford Motor Company,
Ford/New Holland, and Tecumseh Products Company. At these meetings, manufacturers
provided EPA with up-to-date information which assisted EPA in the development of the
inventories in the study. Association descriptions and membership lists are in Appendix E.
An informal external technical review group, composed of representatives from a
variety of manufacturer associations and state agencies, was convened by EPA to provide
technical review and feedback throughout the development of the study. The review group
provided informal feedback on the nonroad population inventory methodology, emission
factors, and per-source usage rates for the study. A complete list of the Technical Review
Group members is included in Appendix F.
Presentation materials and other comments are available for public review in Docket #A-91-24.
November 1991
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Nonroad Engine and Vehicle Emission Study
EPA published a draft of this report for public review in October 1991, and held a
public meeting on the nonroad study on October 30, 1991. This report reflects EPA's
consideration of comments received on the draft report. A discussion of EPA's response to
public comments is found in Appendix Q.
November 1991
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Chapter 2. Methods and Approach
The goal of the EPA Nonroad Engine and Vehicle Emission Study was to develop an
inventory of nonroad engine and vehicle emissions within the Congressionally mandated time
period. To achieve this goal, EPA used the limited data that was available. Where feasible,
these data were updated or new data were developed.
In developing emission inventories for nonroad engines, EPA found that comparisons
between existing data were not always direct or easy. One of the biggest challenges was to
find a way to present, compare, and analyze data from a variety of sources. Given the
number of types of engines and equipment included in the study, and the amount of data
available that characterized emissions from nonroad sources, EPA chose to construct two sets
of inventories, both of which are presented in this report.
In the first set of inventories (Inventory A), EPA incorporated commercially and
publicly available data so that the method of inventory construction could be repeated by
interested states. The second set of inventories (Inventory B) incorporated industry-provided
data that might not be publicly available to states (e.g., confidential sales data to estimate
populations) but which provided EPA with a means of validating the first set of inventories.
A discussion of the methodology and data used for both inventories is presented later in this
chapter. Each inventory is based, at least in part, on specific data sources:
Inventory A relies primarily on data provided by contractor
studies; in particular, on population and per-source usage rate
data derived from recent work contracted by EPA for this study.
For most categories of equipment, populations are drawn from a
commercially available market research data base. Inventory A
also includes some data supplied by states and manufacturers.
Inventory B incorporates population and per-source usage rate
data supplied to EPA by manufacturers and manufacturer
associations. For most categories, population estimates were
supplied by the manufacturers or are derived from confidential
sales data provided by manufacturers. Where gaps existed, data
from Inventory A were used, so that a complete inventory could
be developed.
November 1991
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Nonroad Engine and ^Vehicle Emission Study
The study also considers a third set of inventories, Inventory C, which is based on
data developed by individual states for their 1987 State Implementation Plans (SIPs).1tttt
At the time the study was initiated, SIPs provided the most comprehensive source of nonroad
engine and vehicle emission data. Each SIP contains a state-developed inventory which
considered population and per-source usage rate estimates. However, two factors restricted
the ability of EPA to utilize this inventory as a basis of comparison with Inventories A and B.
First, the SIPs considered a limited number of nonroad equipment types. Second, a
substantial amount of new data on nonroad sources was developed after the states constructed
their 1987 draft inventories. Nevertheless, the SIPs still constitute a valuable point of
reference. Further discussion of this inventory is found in Appendix G.
2.1. Structure of Emission Inventories
Emission inventories are detailed listings of the amount of pollution generated by
different sources in an area during a specific period of tune and are used to account for the
various sources of differen! air pollutants. For example, a CO emission inventory might
appear as shown in Table 2-01.
Table 2-01. Sample CO Emission Inventory.
Source
Light-Duty Highway Vehicles
Other Highway Vehicles
Nonroad Mobile Sources
Other Area and Point Sources
Total (All Sources)
1987 tpy*
400
200
300
100
1000
tons per year
tint Tjtie i of the CAA requires states to develop plans to demonstrate how they intend to meet the NAAQS.
10
November 1991
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Methods and Approach
In developing emission inventories for nonroad engines and vehicles, EPA used the
following formula to calculate emissions from most nonroad sources*****:
Mt = N x MRS x HP x IF x EFl
where:
M, = mass of emissions of ith pollutant during inventory period
N = source population (units)
HRS = annual hours of use
HP = average rated horsepower
LF = typical load factor
EF, = average emissions of itb pollutant per unit of use (e.g., grams per horsepower-
hour)
For this study, the product of the annual hours of use, the average rated horsepower,
and the load factor is referred to as the per-source usage rate. The product of the population
and the per-source usage rate is referred to as the activity level. Nonroad engine emissions
are expressed as tons per year (tpy), except when emissions are adjusted for seasonal usage
patterns to reflect tons per summer day (tpsd) or tons per winter day (tpwd).
2.2. Developing Equipment and Engine Categories
The development of an emission inventory requires the estimation of activity levels,
which is facilitated by the use of categories that group together types of equipment, such as
tractors, balers, harvesters, and other types of agricultural equipment, which have common
function and use characteristics. Emission factors, on the other hand, are generally best
developed for different types of engines, such as diesel, gasoline, 4-stroke, and 2-stroke, used
within an equipment type. Consequently, EPA estimated activity levels by equipment type,
while applying emission factors appropriate to corresponding engine types.
EPA developed the ten equipment categories listed in Table 2-02. The primary
purpose of equipment categories is to simplify the distribution of equipment populations and
annual usage to the local nonattainment area level. Over 80 different types of equipment
were considered in this analysis, many of which are highly specialized and have low sales
*****Note that EPA used grams/hour emission factors for most recreational equipment and grams/gallon of fuel
for recreational and commercial marine equipment.
November 1991 11
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Nonroad EnRJne and Vehicle Emission Study
volumes. EPA recognizes that many of the 80 equipment types, such as chain saws,
generator sets, forklifts, and crawler tractors, are used in more than one industry or
application (e.g., farming, construction, general industry or recreation) and that, consequently,
the ten equipment categories are not mutually exclusive with respect to equipment type.
Nevertheless, the definition of the ten categories is consistent with the methodology used to
distribute equipment populations geographically and to estimate activity levels, and so it is
considered to be valid for that purpose. Equipment types used for similar purposes were
grouped into categories and a methodology was developed for distributing state or national
population data to the local level for each equipment category. While these categories were
used for distributing population data, activity levels were developed for each equipment type.
Grouping equipment types into categories also provides a convenient means of reporting the
results in a format which is more readily understood.^^® A detailed list of equipment
types included in each equipment category is found in Appendix H.
Table 2-02. Nonroad Mobile Source Equipment Categories.
Equipment Category
Examples of Included Types of Equipment
Lawn and Garden
Airport Service
Recreational
Recreational Marine
Light Commercial
Industrial
Construction
Agricultural
Logging
Commercial Marine
lawnmowers, snow blowers, trimmers, tillers, chain saws < 4 hp
aircraft and baggage towing tractors, airport service vehicles
ATVs, off-road motorcycles, golf carts, snowmobiles
inboard and outboard recreational boats
air and gas compressors, welders, generator sets, pumps
aerial lifts, forklifts, self-propelled elevating platforms, sweepers
asphalt pavers, rollers, scrapers, rubber-tired dozers
agricultural tractors, combines, balers, harvesters
chain saws > 4 hp, delimbers, log skidders
harbor vessels, fishing vessels, ocean-going commercial vessels
IHH These categories are neither definitions of "farm equipment" or "construction equipment" (terms that will
be denned by EPA in a future rulemaking) nor necessarily appropriate for the classification of new nonroad engines
and new nonroad vehicles for which regulations may be promulgated under section 213(aX3) or 213(a)(4) of the
CAA.
12
November 1991
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Methods and Approach
For the categories in Table 2-02, EPA developed separate emission factors for
equipment types using diesel, gasoline 4-stroke, and 2-stroke and LPG engines where
appropriate. A detailed discussion of the development of emission factors is contained in
Appendix I.
2.3. Development of Emission Factors
A key element necessary to determine emission inventories for nonroad sources is the
emission factor. An emission factor is the average emission rate when a vehicle or unit of
equipment is operated in an average manner. Emission factors are commonly mass-based and
expressed in units of mass per unit of work (e.g., grams per horsepower hour), mass per unit
of fuel consumed, or, in the case of on-highway vehicles, mass per mile traveled.
For this study, Inventories A and B were calculated with a common set of emission
factors, except for diesel particulate emission factors, which are different for the two
inventories. A list of the emission factors selected by EPA is presented in "2.7. Comparison
of Data Used in Inventories A and B." Emission factors for Inventory C required special
aggregation to be compatible with SIP guidance.
EPA used data available from past studies and testing, as well as new information
supplied by the engine manufacturers, to develop emission factors for tailpipe exhaust,
refueling, evaporative, and crankcase emissions.£f£f£ Appendix I describes the various
methodologies used to determine and select the most appropriate emission factors for each
type of equipment. The emission factors developed for this study were reviewed by die
technical review group.
The test data on which the emission factors are based consist almost exclusively of
tests on new engines. While more testing needs to be completed before in-use emissions can
be fully characterized, EPA believes that inventories incorporating emission factors based
***** EPA contracted with Southwest Research Institute (SwRI) to perform a study to recommend categorization
of nonroad sources and the best available exhaust emission factors for nonroad sources. SwRI completed this task
in two parts. The first part focused on emission factors for VOC, CO, and NOX, while the second part focused on
particulate matter and air toxic emission factors. The final reports, "Non-Road Emission Factors Interim Report"
and "Non-Road Emission Factors of Air Toxics" can be found in the public docket (#A-9I-24). Appendix I provides
detail on emission factors and how they were used. EPA received emission factor information from a number of
industry sources. Appendix J indicates the sources of additional data.
November 1991 13
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Nonroad Engine and Vehicle Emission Study
solely on new engine data would grossly understate the contribution of nonroad engines to air
pollution. Therefore, to estimate the magnitude of the effect of in-use emissions, which
includes engine malfunctions, improper maintenance, and engine wear, EPA also developed a
second set of emission factors that takes into account these effects.
Two sources of data were used to estimate in-use adjustment factors. One source was
recent testing of in-use small utility engines performed by Southwest Research Institute
(SwRI) under contract by EPA. The limited testing that has been done thus far suggests that
in-use emissions could be 2 times higher, for some engines, than the emission factors based
on new engines. The second source of data was a joint Engine Manufacturers Association
(EiMA)/EPA program conducted in 1983 which developed in-use emission factors for heavy-
duty diesel and heavy-duty gasoline engines. The data obtained from this program suggests
that, while in-use impacts are minimal for pre-controlled diesel engine emissions (i.e., diesel
engine emissions do not increase with mileage/hours of operation), heavy-duty gasoline
engine emissions increase with in-use operation. A detailed discussion of the in-use
adjustments to emission factors is contained in Appendix I. Inventories A and B were
calculated using both the new engine emission factors and the in-use emission factors. The
results are presented so that the reader can clearly distinguish the estimated in-use portion of
each inventory.
Another issue which is necessary to consider in the assessment of the magnitude of
emission rates for nonroad equipment is whether the test cycle is representative of in-use
operation. There is an ongoing debate regarding the appropriateness of using a steady state or
a transient test cycle for testing the emissions of nonroad engines. This is an important issue,
since measured emissions of most pollutants, especially paniculate matter (PM), are sensitive
to the test cycle. For instance, a steady state cycle used on a piece of equipment that
experiences transient operation in-use may misrepresent the level of in-use emissions. EPA
adjusted the PM, CO, and VOC emission factors which were developed using steady state
procedures to account for in-use transient operation for those equipment types expected to
encounter such operation. The equipment types that were adjusted are indicated by
Footnote "a" in Table 2-07a. The adjustments were only made to diesel engines since the
only data available was on diesel engines. A more detailed discussion of these adjustments
for transient operation is contained in Appendix I.
14 November 1991
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Methods and Approach
2.4. Development of Activity Levels for Inventory A
Due to limitations in the existing guidance for developing emission inventories for
nonroad mobile sources, EPA contracted to develop improved methodologies for all nonroad
sources. The equipment populations, annual hours of use, average horsepower ratings, and
load factors used in Inventory A are primarily based on a market research data base
commercially available though Power Systems Research (PSR). This data base is continually
updated through surveys of equipment manufacturers and end users. For the study,
population data were disaggregated to individual nonattainment areas using commonly
available economic indicators and census data. The emissions analysis for
commercial marine vessels was handled separately from other categories of
equipment,ttfttt as discussed in Section 2.8.
The development of emission inventories for recreational boats relied on local
registrations of pleasure craft. Because boats are often used outside areas where they are
registered, adjustments to registration data were made based on a survey of boat owners in
eight nonattainment areas conducted by Irwin Broh and Associates, Inc. for the National
Marine Manufacturers Association (NMMA).6 Annual fuel consumption from the same
survey was also used in calculating recreational boat emissions.
While relying primarily on contractor input, EPA also used other data and infonnation
in calculating Inventory A. Documentation of adjustments to the contractor data are
contained in Appendix K. Documentation of adjustments to the data to reflect variations in
usage patterns by region of the country and season of the year is contained in Appendix L.
Summaries of the data used to develop Inventory A are presented in "2.7. Comparison of
Data Used in Inventories A and B," with more detailed information presented in Appendix M.
The methodology is documented in the Energy and Environmental Analysis final report entitled
"Methodology to Estimate Nonroad Equipment Populations by Nonattainment Areas," available for review in
Docket #A-91-24.
twtt This is due to the fact that the types of commercial marine vessels are not as diverse as other nonroad
categories, and to the fact that records of specific levels and types of vessel activities are more readily available.
November 1991 ~~~ ~ 15
-------
Nonroad Engine and Vehicle Emission Study
2.5. Development of Activity Levels for Inventory B
In developing emission inventories for Inventory B, EPA incorporated data submitted
by the following manufacturers and associations:
• Outdoor Power Equipment Institute - nonhandheld lawn and garden equipment
• Portable Power Equipment Manufacturers Association - handheld lawn and
garden equipment
• Industrial Truck Association - forklifts
• Equipment Manufacturers Institute - agricultural and construction equipment
• National Marine Manufacturers Association - recreational marine equipment
• International Snowmobile Industry Association - snowmobiles
• Motorcycle Industry Council - ATVs, off-road motorcycles
Some of the equipment populations used in Inventory B were based on confidential
sales data that are not commercially available. Where gaps existed, EPA used data from
Inventory A; however, for most high volume categories the data used in Inventory B were
submitted by manufacturers.
In some cases, it was necessary to adjust the data provided by manufacturers for use in
constructing Inventory B. The use of and adjustment to manufacturer data is documented in
Appendix N. EPA made seasonal adjustments to data in Inventory B similar to those made
for Inventory A, as documented in Appendix L. In cases where manufacturers only supplied
annual hours of use at the national level, these hours of use were used for all areas without
regional adjustments. Summaries of the data used to develop Inventory B are presented in
"2.7. Comparison of Data Used in Inventories A and B." More detailed information is
presented in Appendix O.
2.6. Comparison of Results from October Draft and Final Study
EPA made some adjustments to the data used to construct Inventories A and B for this
final report in response to public comments on the October draft study report. The most
significant adjustments to Inventory B data impacting inventory results included revisions to
the recreational marine inventory methodology, revisions to annual hours of use for
16 November 1991
-------
Methods and Approach
lawnmowers, revisions to the methodology for distributing handheld equipment (trimmers,
blowers, and chain saws) to the local level, revisions to population estimates for agricultural
tractors and combines, and emission factors for outboard motors and crankcase emission from
lawn and garden equipment. Some of these adjustment were also made to Inventory A, but
with less impact on overall inventory results. A summary of the comments received to the
October draft is in Appendix Q.
Charts 2-01 and 2-02 depict the results from Inventory A and Inventory B before and
after adjustments were made to the draft results. Each chart shows the median local nonroad
contributions to total VOC, NOX, and CO inventories.
Chart 2-01. Median Contributions -- Draft Inventory A and B
r\
o
M-
O
c
o
-M
3
C
0
o
(0
O
(0
-------
Nonroad Engine and Vehicle Emission Study
Chart 2-02. Median Contributions -- Final Inventory A and B
(0
o
a?
c
o
C
O
o
_
c
o
20
10 -
5 -
VOC/A VOC/B NOx/A NOx/ B CO/ A CO/ B
Pol lutant/ Inventory
il Based on Tests of New Engines
I _ I Estimated In- Use Effects
2.7. Comparison of Data Used in Inventories A and B
The national equipment population estimates used in constructing Inventories A and B
are compared in Table 2-03. As discussed above, Inventory A incorporated population
estimates developed by EPA contractors, while Inventory B incorporated, to the extent
possible, data from manufacturer associations. Local population estimates used in developing
Inventories A and B are included in EPA Technical Memorandum - Nonroad Inventory
Tables: Inventory A and B, November 15, 1991. The equipment populations are presented by
equipment and fuel type, including diesel, LPG/CNG, 4-stroke gasoline, and 2-stroke gasoline.
Comparisons of equipment horsepower and load factor estimates used in Inventory A
and Inventory B are presented in Tables 2-04 and 2-05, respectively. Reported ranges of
annual hours of use estimates, which vary by region, are compared in Table 2-06. Emission
factors for diesel engines and gasoline 2- and 4-stroke engines, which were used in both
Inventories A and B, are presented in Table 2-07. Seasonal adjustments, which were used in
both Inventories A and B, are presented in Table 2-08, expressed in terms of the percentage
of yearly activity occurring during summer and winter.
November 1991
18
-------
Methods and Approach
Table 2-03. Inventory A and B National Population Estimates
Cb»
1
1
1
1
1
1
1
1
1
1
I
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
National Populations
Equipment Type
Tilmtneii/Eageti/Brush
Cutttri
Lawn Mowerfl
Leaf Blowers/Vacuums
Rear Engine Riding
Front Mo«™
Chafe Saws < 4 hp
Shredder* <5bp
Tiller* < 5 rtp
Lawn and Garden
Tfacton
Wood Splitters
Snowbfowers
drippers/Stump Grinders
Commercial Turf
Ecxripment
Other Lawn and Garden
Equ^mene
Aircraft Support
Terminal Tractori
All Terrain VeWciw
(ATV.)
Minibikes
Off-Road Motorcycle!
Golf Cart.
Snowmobiles
Specialty Vehicles Cut.
Vessels w/mboard
Engine*
Vessels w/Outboard
Engine.
Vessels w/Stemdrive
Engkies
Sailboat Auxiliary
Sailboat Auxiliary
Outboard Engine.
Generator Sets < 50 hp
Pump. < 50 hp
Air CoropresioTs < 50 bp
Gas Cornpresson< 50 hp
Welders < 50 hp
Pressure Wasbers< 50 hp
Aerial Ufa
ForMift.
Sweepers/Scrubber.
Other General Industrial
Other Material Handling
Equipment
Asphalt Pavers
DteMl
IOT. A
0
0
0
8,713
0
0
0
0
211,631
79
0
17,087
0
180
9,529
tH598
0
0
0
0
0
3344
73,945
0
0
443,056
0
198,391
61,810
15,713
0
100,490
3,943
12,310
160,583
36,977
18,366
5,258
15,536
Mod
tnr. B
0
0
0
9,4*0
0
0
0
0
184,567
79
0
17,087
0
180
9,529
64,598
0
0
0
0
0
33M
73,945
0
0
443,056
0
198,391
61,810
15,713
0
100,490
3,943
12,310
47,068
36,977
18,366
5,258
12,000
LPG/CNO
Inr. A
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
130
0
0
0
0
0
0
0
0
0
0
0
0
91,236
0
436
0
0
3,407
82,117
9,062
0
0
0
LPO/CNG
Inr. B
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
130
0
0
0
0
0
0
0
0
0
0
0
91,236
0
43
0
0
3,407
191,327
9,062
0
0
0
4-tjde t«
Inr. A
21,921
32,169,997
228
1,575,407
257,880
0
87,107
3,794,457
5,903,369
502,181
3,537,376
16,791
568,732
285,889
2,767
6,386
1,180,001
48,990
63,348
93,850
0
91,026
436,018
41,228
2,713,420
110,764
3,738
2,921,263
560,451
176,124
0
350,545
290,959
24,981
100,365
1«,830
21,753
2,03
3,022
4-cyde.as
Inr. B
21,921
28,784,172
228
1,710,540
280,000
0
87,107
2,724,966
5,148,433
502,181
3,537,376
16,791
568,732
285,889
2,767
6^86
1,180,001
48,990
63,348
93,850
0
91,02«
436,018
41,228
2,713,420
110,764
3,738
2,921,263
560,451
176,124
0
350,545
290,959
24,981
120,557
16,830
21,753
2,036
2-cjdegas
IHT. A
18,150,361
3,594,099
2,025,558
0
0
16,124,970
20,215
17,543
0
0
1,244,624
0
0
110.565
0
0
132.980
0
137.777
28,820
776,559
175,070
0
8,204,304
0
0
141,152
22,023
0
0
0
0
0
0
0
0
1,971
0
2-cyde faa
Inr. B
13,561,414
3,215,828
2,870,936
0
0
7,895,502
20,215
12,598
0
0
1,244,624
0
0
1 10,563
0
0
132,980
0
137,777
28,820
1,200,000
175,070
0
8,204,304
0
0
141,152
22,023
0
0
0
0
0
0
0
0
1,971
0
0
Total
InT. A
18,172,282
35,764,096
2,025,786
1,584,120
257,880
16,124,970
1O7.322
3,812,000
6,115,000
502,260
4,782,000
33,878
568,732
396,634
12,296
71,114
1,312,981
48,990
201,125
122,670
776,559
269,440
509,962
8,245,531
2,713,420
553,820
144,890
3,141,677
713,498
191,837
436
451,035
294,902
40,698
343,065
62,869
42,090
7,294
18,558
Tola!
Inr. B
13,583,333
32,000,000
2,871,164
1,720,000
280,000
7,895,502
107,322
2,737,564
5,333,000
502,260
4,782,000
33.878
568,732
396,634
12,296
71,114
1,312,981
48,990
201,125
122,670
1,200,000
269,440
509,962
8,245,531
2,713,420
553,820
144,890
3,141,677
713,498
191,837
436
451,035
294,902
40,698
358,952
«2,869
42,090
7,294
12,000
November 1991
19
-------
Nonroad Engine and Vehicle Emission Study
Table 2-03 (Continued)
dm
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
a
9
9
9
9
National Populations
Equipment Type
Tampers/Rammers
Plate Compactor*
Concrete Paver*
Roller,
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trencher*
Bore/DriJI Rigi
Excavators
Concrete/Industrial Saws
Cement and Mortar
Mixers
Cranes
Oraders
Off-Highway Trucks
Ciushing/Proc.
Equipment
Rough Terrain Forklifts
Rubber Tired Loader)
Rubber Tired Dozers
TractorsA'Oaders/B ackho
es
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction
Equipment
2-Wheel Tractors
Agricultural Tractors
Combines
Sprayers
Balers
Tillers > 5 hp
Swathe™
Hydro Power Units
Other Agricultural
Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Fellers/Bunchen
Diesel
InT. A
0
2,322
5.511
36,300
26,700
43,615
0
20,384
50,510
7,761
61,336
135
4,016
98,357
70,045
16,529
7,207
53,853
209,454
7,757
299,265
285,923
150,054
38,921
194
11,867
0
2,519,295
284,854
9,692
4,260
78
50,032
2,366
18,042
0
0
30,911
15,581
IMtJMl
IDT. B
0
2,322
8,400
42,800
16.400
43,615
0
20,384
53,390
7,761
52,295
61,336
4,016
98,357
64,000
19,400
7,207
25,132
130,000
7,757
189,000
159,050
140,000
38,921
194
1 1,867
0
2,519,295
284,854
9,692
4,260
29
50,032
2^66
18,042
0
0
30,911
15,58!
LPO/CNG
InT. A
0
0
0
0
0
0
0
0
0
0
o
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
LPG/CNG
Inr. B
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4-cycle gas
Inr. A
1,045
117,50
0
21,999
0
218,942
30,833
1,559
27,170
8,395
18
36,900
232,152
2,541
0
0
1,007
2,217
3,433
0
1,365
0
27,805
0
24,301
1,103
13,802
5,808
1,835
72,721
0
783,102
32,857
15,042
6,405
0
100,271
0
0
4-crd* |aa
IHT. B
1,045
117,507
0
0
218,942
30,833
1,559
27.170
8,395
36,900
132,152
2,541
0
1,007
2,217
0
0
0
0
0
0
24,301
1,103
13,802
5,808
1,835
72,721
0
562,407
32,857
15,042
6,405
0
100,271
0
0
2-CTde (•»•
InT. A
22,566
17,716
0
11,868
0
0
0
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
51,775
0
0
0
2-cjde gaa
Inr. B
22,566
27,726
0
0
0
11,868
0
0
0
106
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
25,351
0
0
0
Total
InT. A
23,611
147,555
5,511
58,299
26,700
274,425
30,833
21,943
77,680
16,262
61,354
37,035
236,168
100,898
70,045
16,529
8,214
56,070
212,887
7,757
300,630
285,923
177,859
38,921
24,495
12,970
13,802
2,525,103
286,689
82,413
4,260
783,180
82,889
17,408
24,447
51,775
100,271
30,911
15,581
Total
UIT. B
23,611
147,555
8,400
42,800
16,400
274,425
30,833
21,943
80,560
16,262
52,295
98,236
236,168
100,898
64,000
19,400
8,214
27,349
130,000
7,757
189,000
159,050
140,000
38,921
24,495
12,970
13,802
2,525,103
286,689
82,413
4,260
562,436
82,889
17.408
24,447
25,35!
100,271
30,911
15,581
Key:
1 = Lawn and Garden
2 = Airport Service
3 = Recreational Equipment
4 = Recreational Marine
5 = Light Commercial
6 = Industrial
7 = Construction
8 = Agricultural
9 = Logging
20
November 1991
-------
Methods and Approach
Table 2-04. Inventory A and B Average Rated Horsepower Estimates
Clara
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
7
7
7
Horsepower
Equipment Type
Trimmers/Edgers/Brush Cutters
Lift winnowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Front Mowers
Chain S*ws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Chippers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden
Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard
engines
Sailboat Auxiliary Outboard
Engines
Generator Sets < 50 hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
Forklifts
Sweepers/Scrubbers
Other General Industrial
Equipment
Other Material Handling
Equipment
Asphalt Pavers
z aiiipeis/Kaiiinici'S
Plate Compactors
Concrete Pavers
Rollers
Scrapers
Paving Equipment
Surfacing Equipment
Diesel
Inr. A
NA
NA
NA
17.0
NA
NA
NA
NA
16.0
58.0
NA
99.0
NA
18.0
137.0
96.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
22.0
23.0
37.0
NA
35.0
21.0
43.0
83.0
97.0
107.0
111.0
91.0
NA
8.0
130.0
99.0
311.0
99.0
NA
Diesel
Inv. B
NA
NA
NA
10.2
NA
NA
NA
NA
13.3
58.0
NA
99.0
NA
18.0
137.0
96.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
22.0
23.0
37.0
NA
35.0
21.0
35.0
83.0
97.0
107.0
111.0
77.0
NA
8.0
77.0
99.0
290.0
99.0
NA
LPO/CNG
IHT. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
7.0
NA
30.0
NA
NA
36.0
62.0
39.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LPG/CNG
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
82.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
7.0
NA
30.0
NA
NA
36.0
62.0
39.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-cycle gas
Inr. A
1.0
4.0
2.0
9.0
12.0
NA
4.0
4.0
12.0
5.0
6.0
62.0
13.0
3.0
48.0
82.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
11.0
7.0
9.0
NA
19.0
7.0
36.0
62.0
39.0
19.0
51.0
31.0
4.0
5.0
NA
17.0
NA
7.0
8.0
"•-cycle gas
Inv. B
1.3
3.8
2.0
10.2
13.3
NA
4.0
4.3
13.3
5.0
5.1
62.0
11.4
3.0
48.0
82.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.0
11.0
7.0
9.0
NA
19.0
7.0
36.0
62.0
39.0
19.0
51.0
NA
4.0
5.0
NA
NA
NA
7.0
8.0
2-<-ycle gas
Inv. A
1.0
4.0
2.0
NA
NA
2.0
4.0
4.0
NA
NA
6.0
NA
NA
3.0
NA
NA
NA
NA
NA
NA
26.0
NA
NA
NA
NA
NA
NA
11.0
NA
NA
NA
NA
NA
NA
NA
NA
19.0
NA
NA
4.0
50
NA
NA
NA
7.0
NA
2-crclt gas
Inv. B
1.3
3.8
2.0
NA
NA
3.2
4.0
4.3
NA
NA
3.8
NA
NA
3.0
NA
NA
NA
NA
NA
NA
26.0
NA
NA
NA
NA
NA
0.0
1 1.0
NA
NA
NA
NA
NA
NA
NA
NA
19.0
NA
NA
4.0
5.0
NA
NA
NA
7.0
NA
November 1991
21
-------
Nonroad Engine and Vehicle Emission Study
Table 2-04 (Continued)
Class
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
9
Horsepower
Equipment Type
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forkltfts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction Equipment
2- Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swat hers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Follers/Bunchers
Diesel
Inr. A
6.0
60.0
209.0
183.0
56.0
11.0
194.0
172.0
489.0
127.0
93.0
158.0
356.0
77.0
157.0
42.0
214.0
23.0
161.0
NA
98.0
NA
152.0
92.0
74.0
7.0
79.0
35.0
57.0
NA
NA
150.0
183.0
Diesel
Inv. B
6.0
27.0
209.0
143.0
56.0
11.0
194.0
147.0
658.0
127.0
84.0
175,0
356.0
71.0
134.0
44.0
214.0
23.0
161.0
NA
98.0
NA
152.0
92.0
98.0
7.0
82.0
35.0
57.0
NA
NA
131.0
183.0
LPG/CNG
Inv. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LPG/CNG
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-cycle gas
IDT. A
8.0
27.0
54.0
80.0
13.0
7.0
55.0
NA
NA
60.0
88.0
67.0
NA
63.0
NA
33.0
NA
9.0
150.0
7.0
87.0
11.0
131.0
24.0
NA
7.0
106.0
14.0
55.0
NA
8.0
NA
NA
4-cycle gas
Inv. B
8.0
27.0
54.0
NA
13.0
7.0
55.0
NA
NA
60.0
88.0
NA
NA
NA
NA
NA
NA
9.0
150.0
7.0
87.0
11.0
131.0
24.0
NA
5.6
106.0
14.0
55.0
NA
8.0
NA
NA
2-cycle gas
IDT. A
NA
NA
54.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
6.0
NA
NA
NA
2-cycle gas
Inv. B
NA
NA
54.0
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
6.4
NA
NA
NA
NA = Not applicable
Key:
1 = Lawn and Garden
2 = Airport Service
3 = Recreational Equipment
NA = Not applicable
4 = Recreational Marine
5 = Light Commercial
6 = Industrial
7 = Construction
8 = Agricultural
9 = Logging
22
November 1991
-------
Methods and Approach
Table 2-05. Inventory A and B Typical Operating Load Factor Estimates
Clan
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
7
7
7
Load Factor*
Equipment Typ«
Trimmers/Bdgers/Brush Cutters
Lavnunowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Front Mowers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Cnippers/Sfump Grinders
Commercial Turf Equipment
Other Lawn and Garden
Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard
Engines
Sailboat Auxiliary Outboard
Engines
Generator Sets < 50 hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lift*
Forklifts
Sweepers/Scrubbers
Other General Industrial
Equipment
Other Material Handling
Equipment
Asphalt Pavers
Tall luei s/Ranuiiei s
Plate Compactors
Concrete Pavers
Rollers
Scrape™
Paving equipment
Surfacing Equipment
Diesel
Iny. A
NA
NA
NA
38%
NA
NA
NA
NA
50%
50%
NA
37%
NA
50%
51%
82%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
74%
74%
48%
NA
45%
30%
46%
30%
68%
51%
59%
62%
NA
43%
68%
56%
72%
53%
NA
Diesel
DIT. B
NA
NA
NA
38%
NA
NA
NA
NA
38%
50%
NA
37%
NA
50%
51%
82%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
74%
74%
48%
NA
45%
30%
55%
30%
68%
51%
59%
56%
NA
43%
56%
59%
60%
53%
NA
LPG/CNG
IDT. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
78%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
69%
NA
60%
NA
NA
46%
30%
71%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LPG/CNG
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
78%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
69%
NA
60%
NA
NA
46%
30%
71%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-cyck gas
IDT. A
36%
36%
36%
38%
50%
NA
36%
40%
50%
50%
35%
39%
50%
50%
56%
78%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
68%
69%
56%
NA
51%
85%
46%
30%
71%
54%
53%
66%
55%
55%
NA
62%
NA
59%
49%
4-crck gas
Inv. B
36%
30%
36%
38%
38%
NA
36%
40%
38%
50%
35%
39%
5O%
50%
56%
78%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
68%
69%
56%
NA
51%
85%
46%
30%
71%
54%
53%
NA
55%
55%
NA
NA
NA
S9%
49%
2-cyck gas
Inv. A
50%
36%
50%
NA
NA
50%
36%
40%
NA
NA
35%
NA
NA
50%
NA
NA
NA
NA
NA
NA
81%
NA
NA
NA
NA
NA
NA
68%
NA
NA
NA
NA
NA
NA
NA
NA
54%
NA
NA
55%
55%
NA
NA
NA
59%
NA
2-cjrdc gas
Inv. B
50%
30%
50%
NA
NA
50%
36%
40%
NA
NA
35%
NA
NA
50%
NA
NA
NA
NA
NA
NA
81%
NA
NA
NA
NA
NA
NA
68%
NA
NA
NA
NA
NA
NA
NA
NA
54%
NA
NA
55%
55%
NA
NA
NA
59%
NA
November 1991
23
-------
Nonroad Engine and Vehicle Emission Study
Table 2-05 (Continued)
Class
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
g
8
8
9
9
9
9
Load Factors
Equipment Type
Signal Bonds
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction Equipment
2-Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Pellers/Bunchers
Diesel
IHT. A
82%
75%
75%
57%
73%
56%
43%
61%
57%
78%
60%
54%
59%
55%
58%
55%
65%
38%
62%
NA
70%
NA
70%
50%
58%
78%
55%
48%
5t%
NA
NA
74%
71%
Diesel
1m. B
82%
64%
75%
59%
73%
56%
43%
54%
25%
78%
35%
54%
59%
38%
57%
48%
65%
38%
62%
NA
70%
NA
70%
50%
58%
40%
62%
48%
51%
NA
NA
49%
71%
LPG/CNG
lav. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LPG/CNU
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-cycle gas
Inr. A
76%
66%
79%
53%
78%
59%
47%
NA
NA
85%
63%
54%
NA
48%
NA
58%
NA
41%
48%
62%
62%
48%
74%
50%
NA
71%
52%
56%
55%
NA
80%
NA
NA
4-cycle gas
Int. B
76%
0%
79%
NA
78%
59%
47%
NA
NA
85%
63%
NA
NA
NA
NA
NA
NA
41%
48%
62%
62%
48%
74%
50%
NA
40%
52%
56%
55%
NA
36%
NA
NA
2-cyclt gas
Inr. A
NA
NA
79%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
92%
NA
NA
NA
2-CYcl* gas
Inv. B
NA
NA
79%
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
50%
NA
NA
NA
NA = Not applicable
Key:
1 = Lawn and Garden
2 = Airport Service
3 = Recreational Equipment
NA = Not applicable
4 = Recreational Marine
5 = Light Commercial
6 = Industrial
7 = Construction
8 = Agricultural
9 = Logging
24
November 1991
-------
Methods and Approach
Table 2-06. Inventory A and B Annual Use Estimates
CUn
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
Hoan/Ycar
(* - G*0on*/¥«ar)
Equipment Type
Trimmers/Edgers/Brush
Cutters
Lawnmowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Rent Mowers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
SnowMowers
Chippers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden
equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibuses
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard
Engines < 250 hp*
Vessels w/Outboard Engines*
Vessels w/Stemdrive
Engines*
Sailboat Auxiliary Inboard
Engines*
Sailboat Auxiliary Outboard
Engines*
Generator Sets < 50 hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
Forklifts
Sweepers/Scrubbers
Other General Industrial
Equipment
Other Material Handling
Equipment
Asphalt Pavers
laiiipbi's/Raiiiiiici's
Plate Compactors
Concrete Pavers
Rollers
Diesel
Inv. A
NA
NA
NA
22-50
NA
NA
NA
NA
173-340
64-95
NA
367-525
NA
101-197
651-856
1081-1433
NA
NA
NA
NA
NA
370-496
343-959
NA
NA
17-50
NA
345-483
318-488
595-954
NA
418-759
93-183
265-407
1513-1751
1183-1318
571-1089
366-463
534-846
NA
286-610
534-854
454-775
Dksd
IDT. B
NA
NA
NA
28-45
NA
NA
NA
NA
37-340
64-95
NA
367-525
NA
101-197
651-856
1081-1433
NA
NA
NA
NA
NA
370-496
100-1183
NA
NA
12-102
NA
345-483
318-488
595-954
NA
418-759
93-183
2053-2587
850-850
1183-1318
571-1089
366-463
594-1016
NA
286-610
594-1016
647-1016
LPG/CNG
Inv. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
711-943
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
175-267
NA
8500-8500
NA
NA
249-383
1602-1854
501-557
NA
NA
NA
NA
NA
NA
NA
LPG/CNG
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
711-943
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
175-267
NA
8500-8500
NA
NA
2053-2587
850-850
501-557
NA
NA
NA
NA
NA
NA
NA
4-cycl« gas
Inv. A
8-21
27-73
7-20
22-50
25-46
NA
3-5
16-25
33-65
18-27
8-18
386-551
410-931
14-28
606-797
711-943
88-142
25-67
62-139
637-1231
NA
55-74
187-524
69-134
206-576
9-28
4-8
117-164
175-267
353-566
NA
135-245
74-145
249-383
1602-1854
501-557
463-884
336-425
255-404
1 10-186
98-209
NA
379-646
4-cyclc gas
Inv. B
19-19
33-49
25-25
28-45
28-45
NA
75-75
27-31
35-65
18-27
8-18
386-551
410-931
14-28
606-797
711-943
9-15
9-15
9-15
637-1231
NA
55-74
93-637
63-213
168-416
19-55
2-54
117-164
175-267
353-566
NA
135-245
74-145
2053-2587
850-850
501 -557
463-884
336-425
NA
110-186
98-209
NA
NA
2-cvcle gas
Inv. A
8-21
33-91
7-20
NA
NA
13-21
3-5
16-25
NA
NA
8-18
NA
NA
14-28
NA
NA
88-142
NA
62-139
637-1231
77-189
55-74
NA
110-214
NA
NA
7-14
117-164
NA
NA
NA
NA
NA
NA
NA
NA
463-884
NA
NA
110-186
98-209
NA
NA
2-cvcle gas
Inv. B
19-19
41-61
25-25
NA
NA
23-23
3-5
27-31
NA
NA
8-18
NA
NA
14-28
NA
NA
9-15
NA
9-15
637-1231
90-90
55-74
NA
63-213
NA
NA
2-54
117-164
NA
NA
NA
NA
NA
NA
NA
NA
463-884
NA
NA
110-186
98-209
NA
NA
November 1991
25
-------
Nonroad Engine and Vehicle Emission Study
Table 2-06 (Continued)
Class
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
$
8
8
8
8
8
8
8
8
9
9
9
9
Hours/Year
(* = Gallons/Year)
Equipment Type
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Du mpers/Tenders
Other Construction
Equipment
2- Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Fellers/Bunchers
Diesel
IDT. A
667-1024
348-722
NA
448-978
409-652
261-550
593-91 1
400-603
157-305
629-814
591-837
1149-1871
592-1165
410-775
624-890
647-1034
772-1203
655-1067
524-859
778-992
266-685
388-624
NA
309-542
NA
74-186
53-121
52-142
188-289
52-139
600-830
236-453
NA
NA
994-1413
880-1467
Diesel
Inr. B
667-1647
348-722
NA
448-978
267-593
261-550
1051-1358
400-603
157-305
629-814
811-1110
1149-3951
592-1165
662-1024
1191-1587
647-1034
653-797
871-1422
615-730
778-992
266-685
388-624
NA
309-542
NA
74-186
53-121
308-308
61-68
100-539
600-830
236-446
NA
NA
994-1454
880-1467
LPG/CNG
Inv. A
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LPG/CNG
Inv. B
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4-cyd« gas
Inr. A
NA
98-203
278-512
133-289
277-442
60-126
261-401
421-634
48-93
324-419
NA
NA
149-294
256-483
420-599
NA
592-922
NA
198-326
NA
60-154
237-382
177-346
358-627
82-250
61-155
47-107
NA
47-72
45-120
342-473
77-148
NA
156-252
NA
NA
4-cycle gas
IOT. B
NA
98-203
278-512
133-289
0-402
60-126
NA
421-634
48-93
324-419
NA
NA
149-294
NA
NA
NA
NA
NA
NA
NA
60-154
237-382
177-346
358-627
82-250
61-155
47-107
NA
27-31
0-100
342-473
77-148
NA
75-75
NA
NA
2-cycle gas
Inv. A
NA
98-203
NA
NA
NA
60-126
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
142-228
NA
NA
NA
2-crcle gas
IOT. B
NA
98-203
NA
NA
NA
60-126
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
405-405
NA
NA
NA
NA = Not applicable
* = Values reported are gallons/year - not hours/year
Key:
1 = Lawn and Garden
2 = Airport Service
3 = Recreational Equipment
NA = Not applicable
4 = Recreational Marine
5 = Light Commercial
6 = Industrial
7 = Construction
8 = Agricultural
9 = Logging
26
November 199
-------
Methods and Approach
able 2-07. Emission Factors for Inventories A and B
DIESEL EQUIPMENT (grams/hp-hr)
Clan
1
1
1
1
1
1
1
1
I
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
S
5
5
6
6
6
6
6
7
7
7
7
Equipment Types
Trimmera/Edgers/Brush Cutters
Lawnmowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Front Mowers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Cruppers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard Engines
Sailboat Auxiliary Outboard Engines
Generator Sets < 50 hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
Borklifts
Sweepers/Scrubbers
Other General Industrial Equipment
Other Material Handling Equipment
Asphalt Pavers
Tampef s/RaiiuiM>is
Plate Compactors
Concrete Pavers
a
a
*
*
*
*
*
**
**
**
**
**
a
a
a
a
a
HC
Exhaust
NA
NA
NA
1.20
NA
NA
NA
NA
1.20
1.20
NA
1.20
NA
1.20
1.57
1 57
NA
NA
NA
NA
NA
1.20
24.39
24.39
24.39
122.45
122.45
1.20
1.20
1.20
NA
1.20
1.20
1.57
1.57
1.57
1.57
1.57
0.60
0.00
0.80
1.10
Crank
NA
NA
NA
0.02
NA
NA
NA
NA
0.02
0.02
NA
0.02
NA
0.02
0.03
0.03
NA
NA
NA
NA
NA
0.02
NA
0.49
NA
NA
2.45
0.02
0.02
0.02
NA
0.02
0.02
0.03
0.03
0.03
0.03
0.03
0.01
0.00
0.02
0.02
Evap*
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Refueling
NA
NA
NA
0.005
NA
NA
NA
NA
0.005
0.003
NA
0.003
NA
0.005
0.003
0.003
NA
NA
NA
NA
NA
0.350
0.040
0.000
0.000
0.040
0.040
0.003
0.003
0.003
NA
0.003
0.003
0.003
0.003
0.003
0003
0.003
0.003
NA
0.007
0.003
CO
NA
NA
NA
5.00
NA
NA
NA
NA
5.00
5.00
NA
5.00
NA
5.00
6.06
6.06
NA
NA
NA
NA
NA
5.00
37.01
37.01
37.01
217.72
217.72
5.00
5.00
5.00
NA
5.00
5.00
6.06
6.06
6.06
6.06
6.06
3.20
0.00
3.10
4.57
NO,
NA
NA
NA
8.00
NA
NA
NA
NA
8.00
8.OO
NA
8.00
NA
8.00
14.00
14.00
NA
NA
NA
NA
NA
8.00
172.49
172.49
172.49
163.29
163.29
8.00
8.00
8.00
NA
8.00
8.00
14.00
14.00
14 (X)
14.00
14.00
10.30
0.00
9.30
10.02
PM
NA
NA
NA
1.00
NA
NA
NA
NA
1.00
1.00
NA
1.00
NA
1.00
1.60
1.60
NA
NA
NA
NA
NA
1.00
10.89
10.89
10.89
10.89
10.89
1.00
1.00
1.00
NA
1.00
1.00
1.60
1.60
1 60
1.60
1.60
0.90
0.00
0.90
0.90
Aldehydes
NA
NA
NA
0.06
NA
NA
NA
NA
0.06
006
NA
0.06
NA
0.06
0.06
006
NA
NA
NA
NA
NA
0.06
0.92
092
0.92
0.92
0.92
006
0.06
0.06
NA
0.06
0.06
0.21
0.21
0.21
0.21
021
0.20
0.00
0.20
0.20
SO,
NA
NA
NA
0.93
NA
NA
NA
NA
0.93
0.93
NA
0.93
NA
0.93
0.93
0.93
NA
NA
NA
NA
NA
0.93
12.20
12.20
12.20
12.20
12.20
0.93
0.93
0.93
NA
0.93
0.93
0.93
0.93
093
0.93
0.93
0.93
0.00
0.93
0.93
ovember 1991
27
-------
Nonroad Engine and Vehicle Emission Study
Table 2-07a. (Continued)
Clan
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
g
8
8
8
8
8
8
9
9
9
9
Equipment Types
Rollers
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction Equipment
2-Whcel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skiddcrs
Fellers/Bunchers
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
HC
Exhaust
0.80
0.70
1.01
0.00
1.20
1.54
1.41
0.70
1.41
1.01
1.26
1.54
0.84
1.41
1.68
0.84
0.84
1.40
1.26
2.10
2.46
0.84
1.41
NA
2.23
NA
1.26
2.23
2.23
1.20
0.90
2.23
1.82
NA
NA
0.84
0.84
Crank
0.02
0.01
0.02
0.00
0.02
0.03
0.03
0.01
0.03
0.02
0.03
0.03
0.02
0.03
0.03
0.02
0.02
0.03
0.03
0.04
0.05
0.02
0.03
NA
0.04
NA
0.03
0.04
0.04
0.02
0.02
0.04
0.04
NA
NA
0.02
0.02
Evap*
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Refueling
0.003
0.003
0.003
NA
0.007
0.003
0.003
0.003
0.003
0.005
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
0.003
NA
0.003
NA
0.003
0.003
0.003
0.007
0.003
0.003
0.003
NA
NA
0.003
0.003
CO
3.10
5.00
4.60
0.00
5.00
9.14
9.20
5.20
9.20
4.60
4.20
3.80
2.80
920
10.00
4.80
2.80
6.80
4.80
9.00
14.68
2.SO
9.20
NA
8.94
NA
4.20
3.78
3.78
5.00
2.10
3.78
4.37
NA
NA
5.20
5.20
NO,
9.30
8.70
11.01
0.00
8.00
10.02
11.01
10.75
11.01
11.01
10.30
9.60
9.60
11.01
8.00
10.30
9.60
10.10
10.30
9.60
11.91
9.60
11.01
NA
11.21
NA
11.50
7.78
7.78
8.00
11.50
7.78
11.12
NA
NA
11.30
11.30
PM
0.78
1.26
0.90
0.00
1.00
1.44
1.44
1.44
1.44
0.90
1.44
1.00
0.80
1.44
1.60
1.29
0.66
1.05
1.11
1.44
2.03
1.44
1.44
NA
2.05
NA
2.42
1.51
1.51
1.00
1.51
1.51
1.51
NA
NA
1.44
1.44
Aldehydes
0.20
0.28
0.20
0.00
0.20
0.20
0.20
0.20
0.20
0.20
0.20
0.12
0.22
0.20
0.20
0.20
0.16
0.10
0.17
0.20
0.28
0.20
0.20
NA
0.34
NA
0.30
0.30
0.30
0.06
0.30
0.30
0.30
NA
NA
0.20
0.20
SO,
1.0
0.9
0.9
0.0
O.S
0.9
0.9
0.9
0.9
0.9
0.9
0.8
O.f
0.9
O.S
O.f
O.S
O.f
O.f
0.9
0.9
O.f
O.t
N
O.f
N
0.!
O.i
o.<
0.'
0.'
O.1
0.'
N
1^
0."
0.'
Bvap* = g/day
*g/hr
** g/gallon
a = Exhaust HC. CO, and PM adjusted for transient speed and/or transient load operation
NA = Not applicable
28
November 1
-------
Methods and Approach
Table 2-07. (Continued)
b. GASOLINE 4-STROKE EQUIPMENT (grams/hp-hr) Not Adjusted for In-Use Effects
Class
I
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
Equipment Types
Trimmen/Edgers/Bnuh Cutters
Lawnmowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Front n4owers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Chippers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stcmdrive Engines
Sailboat Auxiliary Inboard Engines
Sailboat Auxiliary Outboard Engines
Generator Set* < JO hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
Forklifts
Sweepers/Scrubbers
Other General Industrial Equipment
Other Material Handling Equipment
Asphalt Pavers
Taikhptid/Kftiibikhcrs
Plate Compactors
Concrete Pavers
Rollers
*
*
*
*
*
**
**
**
**
**
HC
Exhaust
24.18
37.70
19.40
9.30
9.30
NA
37.70
37.70
9.40
37.70
37.70
37.70
9.40
37.70
6.68
6.68
100.00
100.00
100.00
100.00
NA
100.00
72.46
87.71
72.46
72.46
87.71
9.50
9.50
9.50
NA
9.50
9.50
6.68
6.68
6.68
6.68
6.68
6.49
6.49
6.49
NA
9.25
Crank
7.98
12.44
6.40
3.07
3.07
NA
12.44
12.44
3.10
12.44
12.44
12.44
3.10
12.44
2.20
2.20
33.00
33.00
33.00
33.00
NA
33.00
NA
28.94
NA
NA
28.94
3.14
3.14
3.14
NA
3.14
3.14
2.20
2.20
2.20
220
2.20
2.14
2.14
2.14
NA
3.05
Erap*
0.54
1.16
0.61
3.30
18.60
NA
1.75
1.38
7.13
1.16
2.50
94.86
15.50
1.16
73.44
17,13
600
1.50
6.00
18.00
NA
18.00
260.10
NA
63.00
18.00
NA
3.06
2.25
3.38
NA
9.75
2.25
55.08
54.00
59.67
29.07
78.03
47.43
2.81
2.81
NA
9.00
Refueling
21.98
8.60
6.61
3.21
1.30
NA
7.68
9.39
1.84
8.60
5.82
0.42
1.38
8.60
0.48
0.52
31.15
21.68
30.92
5.44
NA
7.04
5.13
875
5.26
8.75
8.75
3.43
6.33
3.20
NA
1.72
6.33
0.49
0.49
0.48
0.93
0.48
0.45
5.34
5.34
NA
1.61
CO
393.34
430.00
380.30
353.00
353.00
NA
430.00
430.00
354.00
430.00
430.00
430.00
354.00
430.00
19900
199.00
97500
975.00
975.00
975.00
NA
975.00
1214.03
1421.95
1214.03
1214.03
1421.95
353.00
353.00
353.00
NA
353.00
353.00
199.00
199.00
199.00
199.00
199.00
198.00
198.00
198.00
NA
202.00
NO,
2.02
2.02
2.03
2.03
2.03
NA
2.02
2.02
2.11
2.02
2.02
2.02
2.11
2.02
5.16
5.16
9.00
9.00
9.00
9.00
NA
9.00
45.79
66.58
45.79
45.79
66.58
2.03
2.03
2.03
NA
2.03
2.03
5.16
5.16
5.16
5.16
5.16
4.79
4.79
4.79
NA
5.28
PM
0.41
0.74
0.29
0.05
0.05
NA
0.74
0.74
0.10
0.74
0.74
0.05
0.10
0.05
0.06
006
1.15
1.15
1.15
1.15
NA
1.15
0.74
0.74
0,74
0,74
0.74
0.06
0.06
O.O6
NA
0.06
006
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
NA
0.06
Aldehydes
0.53
0.53
053
0.24
0.24
NA
0.53
0.53
0.24
0.53
0.53
0.53
0.24
053
0.22
0.22
I 18
1.18
1.18
1.18
NA
1.18
3.07
3.07
307
3.07
3.07
0.22
0.22
0.22
NA
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
NA
0.26
SOX
0.37
0.37
0.37
0.37
0.37
NA
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
027
0.27
055
0.55
0.55
0.55
NA
0.55
2.90
290
2.90
2.90
2.90
0.27
0.27
0.27
NA
0.27
0.27
0.27
0.27
0.27
027
0.27
0.25
0.25
0.25
NA
0.28
November 1991
29
-------
Nonroad Engine and Vehicle Emission Study
Table 2-07b. (Continued)
Class
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
S
g
8
8
8
8
8
8
8
8
9
9
9
9
Equipment Types
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhocs
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction Equipment
2- Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Fclters/Bunchers
HC
Exhaust
NA
649
6.49
6.49
6.49
6.49
6.49
6.49
6.49
6.49
NA
NA
6.49
6.49
5.56
NA
6.49
NA
6.49
NA
6.49
6.49
5.49
5.49
7.18
7.18
7.18
NA
37.70
7.18
7.18
7.18
NA
9.30
NA
NA
Crank
NA
2.14
2.14
2.14
2.14
2.14
2.14
2.14
2.14
2.14
NA
NA
2.14
2.14
1.83
NA
2.14
NA
2.14
NA
2.14
2.14
1.81
1.81
2.37
2.37
2.37
NA
12.44
2.37
2.37
2.37
NA
3.07
NA
NA
EYBD*
NA
3.00
3.00
3.06
7.69
82.62
122.40
4.13
3.75
84.15
NA
NA
91.80
134.64
102.51
NA
96.39
NA
25.01
NA
9.00
229.50
7.13
133.11
8.01
200.43
4.50
NA
3.63
162.18
15.00
84.15
NA
3.00
NA
NA
Refueling
NA
5.02
4.84
4.94
0.94
0.42
OA2
2.74
4.09
0.42
NA
NA
0/42
0.42
0.42
NA
0.42
NA
0.44
NA
1.74
0.41
2.69
0.42
1.84
0.41
1.39
NA
4.38
0.42
1.40
0.42
NA
5.02
NA
NA
CO
NA
198.00
198.00
198.00
198.00
198.00
198.00
198.00
198.00
198.00
NA
NA
198.00
198.00
163.00
NA
198.00
NA
198.00
NA
198.00
198.00
143.00
143.00
218.00
218.00
218.00
NA
430.00
218.00
218.00
218.00
NA
353.00
NA
NA
NOX
NA
4.79
4.79
4.79
4.79
4.79
4.79
4.79
4.79
4.79
NA
NA
4.79
4.79
5.42
NA
4.79
NA
4.79
NA
4.79
4.79
6.62
6.62
5.24
5.24
5.24
NA
2.02
5.24
5.24
5.24
NA
2.02
NA
NA
PM
NA
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
0.06
NA
NA
0.06
0.06
0.06
NA
0.06
NA
0.06
NA
0.06
0.06
0.06
0.06
0.06
0.06
0.06
NA
0.74
0.06
0.06
0.06
NA
0.05
NA
NA
Aldehydo
NA
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
NA
NA
0.22
0.22
0.22
NA
0.22
NA
0.22
NA
0.22
0.22
0.30
0.30
0.22
0.22
0.22
NA
0.22
0.22
0.22
0.22
NA
0.24
NA
NA
SOX
N/
0.2'
0.2J
0.2'
0.2i
0.2.'
0.25
0.2.1
0.25
0.25
NA
NA
0.2i
0.2?
0.24
N*
0.25
NA
0.25
NA
0.25
0.25
0.23
0.23
0.28
0.2f
0.2f
NA
0.37
0.2F
0.2F
0.2*
NA
0.3"
NA
NA
Evap* = g/day
*g/hr
** g/gatlon
NA m Not applicable
30
November 19'
-------
Methods and Approach
Table 2-07. (Continued)
c. GASOLINE 4-STROKE EQUIPMENT - (grams/hp-hr) Adjusted for In-Use Effects
Class
1
1
1
1
1
1
1
1
!
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
Equipment Tjpcs
Trlmmers/Bdgers/Brush Cutters
Lawnmowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
JRront Mowers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 3 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Chippers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicle! Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard Engines
Sailboat Auxiliary Outboard Engines
Generator Seta < SO hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
ForUifts
Sweepers/Scrubbers
Other General Industrial Equipment
Other Material Handling Equipment
Asphalt Pavers
TaiiipGi s/Raiimici s
Plate Compactors
Concrete Pavers
Rollers
b
b
b
b
b
b
b
b
b
b
c
b
b
c
c
*, b
*, b
*, c
*, b
*, b
**, c
**, c
**, c
**, c
**, c
b
b
b
c
b
b
c
c
c
c
c
c
b
b
b
HC
Exhaust
50.78
79.17
40.74
19.53
19.53
NA
79.17
79.17
19.74
79.17
79.17
56.55
19.74
79.17
10.02
10.02
210.00
210.00
150.00
210.00
NA
210.00
108.69
131.57
108.69
108.69
131.57
19.95
19.95
19.95
NA
19.95
19.95
10.02
10.02
10.02
10.02
10.02
9.74
13.63
13.63
NA
19.43
Crank
7.98
12.44
6.40
3.07
3.07
NA
12.44
12.44
3.10
12.44
12.44
12.44
3.10
12.44
2.20
2.20
33.00
33.00
33.00
33.00
NA
33.00
NA
28.94
NA
NA
28.94
3.14
3.14
3.14
NA
3.14
3.14
2.20
2.20
2.20
2.20
2.20
2.14
2.14
2.14
NA
3.05
Erap*
0.54
1.16
0.61
3.30
18.60
NA
1.75
1.38
7.13
1.16
2.50
94.86
15.50
1.16
7344
17.13
6.00
1.50
6.00
18.00
NA
18.00
260.10
NA
63.00
18.00
NA
3.06
2.25
3.38
NA
9.75
2.25
55.08
54.00
59.67
29.07
78.03
• 47.43
2.81
2.81
NA
9.00
Refueling
21.98
8.60
6.61
3.21
1.30
NA
7.68
9.39
1.84
8.60
5.82
0.42
1.38
8.60
0.48
0.52
31.15
21.68
30.92
5.44
NA
7.04
5.13
8.75
5.26
8.75
8.75
3.43
6.33
3.20
NA
1.72
6.33
0.49
0.49
0.48
0.93
0.48
0.45
5.34
5.34
NA
1.61
CO
747.35
817.00
722.57
670.70
670.70
NA
817.00
817.00
672.60
817.00
817.00
559.00
672.60
817.00
258.70
258.70
1852-50
1852.50
1267.50
1852.50
NA
1852.50
1578.24
1848.54
1578.24
1578.24
1848.54
670.70
670.70
670.70
NA
670.70
670.70
258.70
258.70
258.70
258.70
258.70
257.40
376.20
376.20
NA
383.80
NO,
0.81
0.81
0.81
0.81
0.81
NA
0.81
0.81
0.84
0.81
0.81
2,02
0.84
0.81
5.16
5.16
3.60
3.60
9.00
3.60
NA
3.60
45.79
66.58
45.79
45.79
66.58
0.81
0.81
0.81
NA
0.81
0.81
5.16
5.16
5.16
5 16
S.lrt
4.79
1.92
1.92
NA
2.11
PM
1.48
2.66
1.04
0.18
0.18
NA
2.66
2.66
0.36
2.66
2.66
0.05
0.36
0.!8
0.06
006
4.14
4 14
1 15
4.14
NA
4.14
0.74
0.74
0.74
0.74
0.74
0.22
0.22
0.22
NA
0.22
0.22
0.06
0.06
0.06
0.06
006
0.06
0.22
0.22
NA
0.22
Aldehydes
0.53
0.53
0.53
0.24
0.24
NA
0.53
0.53
0.24
0.53
0.53
0.53
0.24
0.53
0.22
0.22
!.18
I.IH
1.18
1.18
NA
1.18
3.07
3.07
3.07
3.07
3.07
0.22
0.22
0.22
NA
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
NA
0.26
so,
0.37
0.37
0.37
0.37
0.37
NA
0.37
0.37
0.37
0.37
0.37
0.37
0.37
0.37
027
027
0.55
0.55
0.55
055
NA
0.55
2.90
2.90
2.90
2.90
2.90
0.27
0.27
0.27
NA
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.25
0.25
0.25
NA
0.28
November 1991
31
-------
Nonroad Engine and Vehicle Emission Study
Table 2-07c. (Continued)
Class
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
g
8
8
8
8
8
8
8
8
9
9
9
9
Equipment Types
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpers/Tenders
Other Construction Equipment
2- Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 lip
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidder*
Fellera/Bunchcrs
b
b
b
c
c
c
b
b
c
c
c
c
c
c
b
c
b
c
b
c
c
b
c
b
c
b
HC
Exhaust
NA
13.63
13.63
13.63
9.74
9.74
9.74
13.63
13.63
9.74
NA
NA
9.74
9.74
8.34
NA
9.74
NA
9.74
NA
13.63
9.74
11.53
8.24
15.08
10.77
10.77
NA
79.17
10.77
15.08
10.77
NA
19.53
NA
NA
Crank
NA
2.14
2.14
2.14
2.14
2.14
2.14
2.14
2.14
2.14
NA
NA
2.14
2.14
1.83
NA
2.14
NA
2.14
NA
2.14
2.14
1.81
1.81
2.37
2.37
2.37
NA
12.44
2.37
2.37
2.37
NA
3.07
NA
NA
Erap*
NA
3.00
3.00
3.06
7.69
82.62
122.40
4.13
3.75
84.15
NA
NA
91.80
134.64
102.51
NA
96.39
NA
25.01
NA
9.00
229.50
7.13
133.11
8.01
200.43
4.50
NA
3.63
162.18
15.00
84.15
NA
3.00
NA
NA
Refueling
NA
5.02
4.84
4.94
0.94
0.42
0.42
2.74
4.09
0.42
NA
NA
0.42
0.42
0.42
NA
0.42
NA
0.44
NA
1.74
0.41
2.69
0.42
1.84
0.41
1.39
NA
4.38
0.42
1.40
0.42
NA
5.02
NA
NA
CO
NA
376.20
376.20
376.20
257.40
257.40
257.40
376.20
376.20
257.40
NA
NA
257.40
257.40
211.90
NA
257.40
NA
257.40
NA
376.20
257.40
271.70
185.90
414.20
283.40
283.40
NA
817.00
283.40
414.20
283.40
NA
670.70
NA
NA
NO,
NA
1.92
1.92
1.92
4.79
4.79
4.79
1.92
1.92
4.79
NA
NA
4.79
4.79
5.42
NA
4.79
NA
4.79
NA
1.92
4.79
2.65
6.62
2.10
5.24
5.24
NA
0.81
5.24
2.10
5.24
NA
0.81
NA
NA
PM
NA
0.22
0.22
0.22
0.06
0.06
0.06
0.22
0.22
0.06
NA
NA
0.06
0.06
0.06
NA
0.06
NA
0.06
NA
0.22
0.06
0.22
0.06
0.22
0.06
0.06
NA
2.66
0.06
0.22
0.06
NA
0.18
NA
NA
Aldehydes
NA
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
0.22
NA
NA
0.22
0.22
0.22
NA
0.22
NA
0.22
NA
0.22
0.22
0.30
0.30
0.22
0.22
0.22
NA
0.22
0.22
0.22
0.22
NA
0.24
NA
NA
so,
NA
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
NA
NA
0.25
0.25
0.24
NA
0.25
NA
0.25
NA
0.25
0.25
0.23
0.23
0.28
0.28
0.28
NA
0.37
0.28
0.28
0.28
NA
0.37
NA
NA
Evap* = g/day
*g/hr
** g/gallon
h = adjusted for in-use effect* using small utility engine data
c = adjusted for in-use effects using heavy duty engine data
NA = Not applicable
32
November 1991
-------
Methods and Approach
Table 2-07. (Continued)
d. GASOLINE 2-STROKE EQUIPMENT (grams/hp-hr) Not Adjusted for In-Use Effects
Clan
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
Equipment Types
Trimmers/Edgers/Brush Cutters
Lawnmowers
Leaf Blowers/Vacuums
Rear Engine Riding Mowers
Hx>nt Mowers
Chain Saws < 4 hp
Shredoers ^ 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Chippera/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Carts
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard Engines
Sailboat Auxiliary Outboard Engines
Generator Sets < 50 hp
Pumps < 50 hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
Forklifts
Sweepers/Scrubbers
Other General Industrial Equipment
Other Material Handling Equipment
Asphalt Pavers
Tampers/Rammers
Plate Compactors
Concrete Pavers
Rollers
**
*
*
*
*
*
***
***
***
***
***
*+
**
**
**
**
Exhaust
224.56
208.00
215.29
NA
NA
298.00
208.00
208.00
NA
NA
208.00
NA
208.00
208.00
NA
3.00
600.00
NA
600.00
600.00
109.00
600.00
728.06
728.06
728.06
NA
728.06
208.00
4.28
NA
4.28
NA
NA
3.00
3.00
3.00
208.00
NA
NA
208.00
208.00
NA
NA
I
Crank
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.99
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.41
NA
1.41
NA
NA
0.99
0.99
0.99
NA
NA
NA
NA
NA
NA
NA
1C
Erap*
0.54
1.16
0.61
NA
NA
0.32
1.75
1.38
NA
NA
2.50
NA
15.50
!.16
NA
17.13
6.00
NA
6.00
18.00
24.24
18.00
260.10
NA
63.00
NA
NA
3.06
2.25
NA
NA
NA
NA
55.08
54.00
59.67
29.07
NA
NA
2.81
2.81
NA
NA
Refueling
21.98
8.60
6.61
NA
NA
35.93
7.68
9.39
NA
NA
5.82
NA
1.38
8.60
NA
0.52
31.15
21.68
30.92
5.44
0.67
7.04
5.13
8.75
5.26
NA
8.75
3.43
6.33
NA
NA
NA
NA
0.49
0.49
0.48
0.93
NA
NA
5.34
5.34
NA
NA
CO
728.22
486.00
716.81
NA
NA
699.00
486.00
486.00
NA
NA
486.00
NA
486.00
486.00
NA
63.70
800.00
NA
800.00
800.00
169.00
800.00
1357.34
1357.34
1357.34
NA
1357.34
486.00
113.00
NA
113.00
NA
NA
63.70
63.70
63.70
486.00
NA
NA
486.00
486.00
NA
NA
NO,
0.91
0.29
0.96
NA
NA
0.96
0.29
0.29
NA
NA
0.29
NA
0.29
0.29
NA
17.90
1.50
NA
1.50
1.50
1.70
1.50
8.77
8.77
8.77
NA
8.77
0.29
7.04
NA
7.04
NA
NA
17.90
17.90
17.90
0.29
NA
NA
0.29
0.29
NA
NA
PM
3.89
7.70
3.60
NA
NA
3.60
7.70
7.70
NA
NA
7.70
NA
7,70
7.70
NA
0.05
8.20
NA
820
8.20
4.80
8.20
48.10
48.10
48.10
NA
48.10
7.70
0.05
NA
0.05
NA
NA
0.05
0.05
005
770
NA
NA
7.70
7.70
NA
NA
Aldehydes
2.04
2.04
2.04
NA
NA
1.60
2.04
2.04
NA
NA
2.04
NA
2.04
2.04
NA
0.22
2.75
NA
2,75
2.75
0.40
2.75
3.07
3.07
3.07
NA
3.07
2.04
0.22
NA
0.22
NA
NA
0.22
0.22
0.22
2.04
NA
NA
2.04
2.04
NA
NA
SO,
0.54
0.54
0.54
NA
NA
0.54
0.54
0.54
NA
NA
0.54
NA
0.54
0.54
NA
0.00
0.95
NA
0.95
0.95
0.15
0.95
2.90
2.90
2.90
NA
2.90
0.27
0.00
NA
0.00
NA
NA
0.00
0.00
0.00
0.27
NA
NA
0.25
0.25
NA
NA
November 1991
33
-------
Nonroad Engine and Vehicle Emission Study
Table 2-07d. (Continued)
Clan
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
9
Equipment Types
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Tractors/Loaders/Backhocs
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
DumpeiVTenders
Other Construction Equipment
2- Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Fellers/Bunchers
HC
Exhaust
NA
208.00
NA
NA
NA
208.00
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
152.00
NA
NA
NA
Crank
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
ET«P»
NA
3.00
NA
NA
NA
82.62
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.66
NA
NA
NA
Rtftellng
NA
5.02
NA
NA
NA
0.42
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
18.22
NA
NA
NA
CO
NA
486.00
NA
NA
NA
486.00
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
513.00
NA
NA
NA
NO,
NA
0.29
NA
NA
NA
0.29
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.96
NA
NA
NA
PM
NA
7.70
NA
NA
NA
7.70
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
3.60
NA
NA
NA
Aldehydes
NA
2.04
NA
NA
NA
2.04
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.60
NA
NA
NA
so,
NA
0.25
NA
NA
NA
0.25
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.37
NA
NA
NA
Evap* = g/day
*g/hr
** Emission factors for 4-stroke propane-fueled equipment
*»« g/gallon
NA = Not applicable
34
November 1991
-------
Methods and Approach
Table 2-07. (Continued)
e. GASOLINE 2-STROKE EQUIPMENT - (grams/hp-hr) Adjusted for In-Use Effects
Cb»
1
1
1
1
1
1
1
1
1
1
1
1
1
I
2
2
3
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
5
6
6
6
6
6
7
7
7
7
7
Equipment Types
Trimmers/Bdgers/Bnish Cutters
Lawtimowers
Leaf Blowers/Vacuums
Rev Engine Riding Mowers
ftont Mowers
Chain Saws < 4 hp
Shredders < 5 hp
Tillers < 5 hp
Lawn and Garden Tractors
Wood Splitters
Snowblowers
Chippers/Stump Grinders
Commercial Turf Equipment
Other Lawn and Garden Equipment
Aircraft Support Equipment
Terminal Tractors
All Terrain Vehicles (ATVs)
Minibikes
Off-Road Motorcycles
Golf Cart,
Snowmobiles
Specialty Vehicles Carts
Vessels w/Inboard Engines
Vessels w/Outboard Engines
Vessels w/Stemdrive Engines
Sailboat Auxiliary Inboard Engines
Sailboat Auxiliary Outboard Engines
Generator Sets < 50 hp
Pumps < SO hp
Air Compressors < 50 hp
Gas Compressors < 50 hp
Welders < 50 hp
Pressure Washers < 50 hp
Aerial Lifts
ForklifU
Sweepers/Scrubbers
Other General Industrial Equipment
Other Material Handling Equipment
Asphalt Pavers
Tampers/Rammers
Plate Compactors
Concrete Pavers
Rollers
d
d
d
d
d
d
d
d
d
**, c
*, d
*. d
*. d
d
*, d
***, e
***, c
*»*, c
***, e
d
»*, b
**, c
**, c
**, c
**, c
c
d
d
HC
Exhaust
471.58
436.80
452.1 1
NA
NA
625.80
436.80
436.80
NA
NA
436.80
NA
436.80
436.80
NA
4.50
1260.00
NA
1260.00
1260.00
228.90
1260.00
873.67
873.67
873.67
NA
873.67
436.80
8.99
NA
6.42
NA
NA
4.50
4.50
4.50
312.00
NA
NA
436.80
436.80
NA
NA
Crank
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.99
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.41
NA
1.41
NA
NA
1.49
1.49
1.49
NA
NA
NA.
NA
NA
NA
NA
Evap*
0.54
1.16
0.61
NA
NA
0.32
1.75
1.38
NA
NA
2.50
NA
15.50
1.16
NA
17.13
6.00
NA
6.00
18.00
24.24
18.00
260.10
NA
63.00
NA
NA
3.06
2.25
NA
NA
NA
NA
55.08
54.00
59.67
29.07
NA
NA
2.81
2.81
NA
NA
Refueling
21.98
8.60
6.61
NA
NA
35.93
7.68
9.39
NA
NA
5.82
NA
1.38
8.60
NA
0.52
31.15
NA
30.92
5.44
0.67
7.04
5.13
8.75
5.26
NA
8.75
3.43
6.33
NA
NA
NA
NA
0.49
0.49
0.48
0.93
NA
NA
5.34
5.34
NA
NA
CO
1383.62
923.40
1361.94
NA
NA
1328.10
923.40
923.40
NA
NA
923.40
NA
923.40
923.40
NA
82.81
1520.00
NA
1520.00
1520.00
321.10
1520.00
1628.8!
1628.81
1628.81
NA
1628.81
923.40
214.70
NA
146.90
NA
NA
82.81
82.81
82.81
631.80
NA
NA
923.40
923.40
NA
NA
NOi
0.91
0.29
0.96
NA
NA
0.96
0.29
0.29
NA
NA
0.29
NA
0.29
0.29
NA
17.90
1.50
NA
1.50
1.50
1.70
1.50
8.77
8.77
8.77
NA
8.77
029
2.82
NA
7.04
NA
NA
17.90
17.90
17.90
0.29
NA
NA
0.29
0.29
NA
NA
PM
3.89
7.70
3.60
NA
NA
3.60
7.70
7.70
NA
NA
7.70
NA
7.70
7.70
NA
0.05
8.20
NA
8.20
8.20
4.80
8.20
48.10
48.10
48.10
NA
48.10
7.70
0.18
NA
0.05
NA
NA
0.05
0.05
0.05
770
NA
NA
7.70
7.70
NA
NA
Aldehydes
2.04
2.04
2.04
NA
NA
1.60
2.04
2.04
NA
NA
2.04
NA
2.04
2.04
NA
0.22
2.75
NA
2.75
2.75
0.40
2.75
3.07
3.07
3.07
NA
3.07
2.04
0.22
NA
0.22
NA
NA
0.22
0.22
0.22
2.04
NA
NA
2.04
2.04
NA
NA
so,
0.54
0.54
0.54
NA
NA
0.54
0.54
0.54
NA
NA
0.54
NA
0.54
0.54
NA
0.00
095
NA
0.95
0.95
0.15
0.95
2.90
2.90
2.90
NA
2.90
0.27
0.00
NA
0.00
NA
NA
0.00
0.00
0.00
0.27
NA
NA
0.25
0.25
NA
NA
November 1991
35
-------
Nonroad Engine and Vehicle Emission Study
Table 2-07e. (Continued)
Clan
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
9
Equipment Types
Scrapers
Paving Equipment
Surfacing Equipment
Signal Boards
Trenchers
Bore/Drill Rigs
Excavators
Concrete/Industrial Saws
Cement and Mortar Mixers
Cranes
Graders
Off-Highway Trucks
Crushing/Proc. Equipment
Rough Terrain Forklifts
Rubber Tired Loaders
Rubber Tired Dozers
Trectors/Loaders/Backhoes
Crawler Tractors
Skid Steer Loaders
Off-Highway Tractors
Dumpcrs/Tendcrs
Other Construction Equipment
2-Wheel Tractors
Agricultural Tractors
Agricultural Mowers
Combines
Sprayers
Balers
Tillers > 5 hp
Swathers
Hydro Power Units
Other Agricultural Equipment
Chain Saws > 4 hp
Shredders > 5 hp
Skidders
Pel fcfs/Dti ncncrs
d
d
d
HC
Exhaust
NA
436.80
NA
NA
NA
436.80
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
319.20
NA
NA
NA
Crank
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Evap* = g/day
*g/hr
** Emission factors for 4-stroke propane-fueled equipment
*** g/gallon
b s adjusted for in-use effects using smalt utility engine data
Erap*
NA
3.00
NA
NA
NA
82.62
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.66
NA
NA
NA
Refueling
NA
5.02
NA
NA
NA
0.42
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
18.22
NA
NA
NA
CO
NA
923.40
NA
NA
NA
923.40
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
974.70
NA
NA
NA
NOX
NA
0.29
NA
NA
NA
0.29
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.96
NA
NA
NA
PM
NA
7.70
NA
NA
NA
7.70
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
12.96
NA
NA
NA
Aldehydes
NA
2.04
NA
NA
NA
2.04
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
1.60
NA
NA
NA
SO,
NA
0.25
NA
NA
NA
0.25
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.37
NA
NA
NA
c = adjusted for in-use effects using heavy duty engine data
d = adjusted for in-use effects using small utility engine data except
no NOX or PM adjustment
e = adjusted for in-use effects by a factor of 1.2 for HC and CO
NA = Not Applicable
Key:
1 = Lawn and Garden
2 = Airport Service
3 = Recreational Equipment
4 = Recreational Marine
5 = Light Commercial
6 = Industrial
7 = Construction
8 = Agricultural
9 = Logging
36
November 1991
-------
Methods and Approach
Table 2-08a. Summer and Winter Percentages of Yearly Activity.
Equipment Class
Agricultural
Construction
Industrial
Lawn and Garden (excl. chain
saws)
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (including chain saws)
Light Commercial
Cold/Northern
Summer
(%)
50
43
30
50
0
25
25
25
25
Winter
(%)
6
10
20
6
100
25
25
25
25
Medium/Central
Summer
(%)
40
38
25
40
0
25
25
25
25
Winter
(%)
6
15
25
6
100
25
25
25
25
Warm/Southern
Summer
(%)
34
33
25
34
0
25
25
25
25
Winter
(%)
6
20
25
6
100
25
25
25
25
Table 2-08b. Summer and Winter Percentages of Yearly Activity
for Recreational Marine Equipment
Region
Northeast
Southeast
Mid-Atlantic Coast
Great Lakes
Southwest
Rocky Mountains
Northwest
West Coast
% During Summer
68
48
57
70
48
69
57
48
% During Winter
1
7
2
0
7
0
5
7
November 1991
37
-------
Nonroad Engine and Vehicle Emission Study
Table 2-08c. Summer and Winter Percentages of Yearly Activity
for Recreational Equipment.******
Region
East
Midwest
South
West
New England
Mid-Atlantic Coast
East Central
West Central
Southeast
Southwest
Rocky Mountains
Pacific
National Average
% During Summer
42%
46%
36%
44%
44%
41%
48%
44%
35%
37%
44%
43%
42%
% During Winter
12%
8%
15%
11%
14%
12%
9%
8%
17%
12%
8%
13%
12%
*m**Exduding snowmobiles.
38
November 1991
-------
Methods and Approach
2.8. Emissions from Commercial Marine Vessels
A detailed analysis of commercial marine vessel activity and emissions was developed
for the following nonattainment areas:§§§§§§
1. Baltimore, MD MSA
2. Baton Rouge, LA MSA
3. Houston-Galveston-Brazoria, TX CMS A
4. New York-Northern New Jersey-Long Island, NY-NJ-CT CMSA/NECMA
5. Philadelphia-Wilmington-Trenton, PA-NJ-DE-MD CMS A
6. Seattle-Tacoma, WA CMSA
For other nonattainment areas, estimates of emissions from commercial vessels were
based on information obtained from different sources, including SIP emission inventories and
the 1985 National Emission Report.7
When the latter was used, marine vessel activity was assumed to be uniform during
the year. Emissions from commercial marine vessels are shown in Table 2-09.
988899 This analysis is documented in the Booz»Allen & Hamilton final report entitled "Commercial Marine
Vessel Contributions to Emission Inventories," which may also be found in the public docket.
November 1991 " ~~39
-------
Nonroad Engine and Vehicle Emission Study
Table 2-09. Emissions from Commercial Marine Vessels
m T- v> in in in
V) r- U) *- *- in W tf> tO CTT-*- t- CT •»-
in T- in CO *- ••- in in in <
,- c*> co *- to
csW o'duicor^ ^ odd ddaior^
I o>
s
pj to c\i d OD
.
co csj o> (0 in
»- m «5h-
r- ^- wciw
T-" in V V r*-~
CM
10 eg of of r-T T-
OOr».
zgg)
! OQI
of
Jjtf
•c i •
o.««
^i^]
40
November 1991
-------
Methods and Approach
2.9. Emissions from Other Sources
EPA compared its estimates of emissions from nonroacl engines and vehicles to
emissions from highway and other area and point sources. At the national level, 1989
emissions were obtained from the National Air Pollutant Emission Estimates: 1940-1989.8
For all but five nonattainment areas ,£f££f£ emissions from highway and other sources
were available from the following sources:
VOC: Phase II Volatility Control Support Runs, April 5, 1990 - VOC emissions were
reported in tons per summer day for 1990.
CO: Support computer runs for Cold CO Rulemaking documentation, Jan. 18,
1991 - CO emissions were reported in tpy for 1987. To estimate tons per
winter day, highway vehicle CO emissions were divided by 365 and corrected
for decreased driving during the winter. Emissions from other area and point
sources were simply divided by 365.
NOX: 1985 National Emission Report - NOX emissions were reported in tons per
year for 1985. To estimate tons per summer day, highway vehicle NOX
emissions were divided by 365 and corrected for increased summer driving.
Emissions from other area and part sources were simply divided by 365.
PM: 1985 National Emission Report - PM emissions were reported in tons per year
for 1985.
SOX: 1985 National Emission Report - SOX emissions were reported in tons per year
for 1985.
five areas (Boston NECMA, Springfield NECMA, Hartford NECMA, South Coast Air Basin, and San
Joaquin Valley Air Basin), the geographical definition of the nonattainment areas differed slightly from that used
in the analyses discussed above. In these cases, EPA relied on estimates of emissions from highway and other
sources that were developed in the most recent State Implementation Plans.
November 1991 41
-------
Nonioad Engine and Vehicle Emission Study
For both VOC and CO, the original estimates of nonroad mobile source emissions
from the Phase II and Cold CO emission inventories could not be readily distinguished from
other area sources. To avoid counting nonroad sources among other area and point sources,
EPA computed the ratio of nonroad to the sum of nonroad and other area and point sources
for both VOC and CO emissions in each nonattainment area using data from the 1985
National Emission Report. These ratios were applied to the VOC and CO emissions from all
nonhighway sources reported in the Phase II and Cold CO emission inventories. It was thus
possible to estimate emissions from all other area and point sources without including
nonroad engines and vehicles.
Emissions from highway vehicles and other area and point sources are shown in
Tables 2-10 and 2-11, respectively. The data sources are also indicated by area in these
tables.
These total inventories do not include emissions of VOCs from vegetation (biogenic
VOCs). Although recent studies have shown that, in some cities, emissions of VOCs from
plants may be more important in ozone formation than previously thought, EPA has only
recently completed a computer model for estimating biogenic emissions in urban areas and
has determined that reliable biogenic inventories do not exist for most areas. While the
biogenic inventories to be included in future State Implementation Plans will affect the
fine-tuning of nonattainment areas' pollution control strategies, the magnitude of VOC
inventories from biogenic sources will not alter the need to reduce anthropogenic VOCs
substantially to bring many urban areas into attainment of the ozone standard.
42 November 1991
-------
Methods and Approach
Table 2-10. Emissions from Highway Vehicles
I??1!
mm m m — m m m m « m m — «- m m m m — «o
CM CM CM CM — — CM CM CMCyCJCM'-'-W Ol
"- iJiii
) 0. — O "
— CM m -*r in
£ g lim S
' '
PJ - -
35
co CM --t
§QQOQOQQOQQQQOOOQOQOO
zzzzzzzzzzzzzzzzzzzz
OQ
zz
« g
CM
.
as 88 at'a
s
ss
QQQQQQQDOOQOQQOQQQQDQOQQ3t
zzzzzzzzzzzzzzzzzzzzzzzz$ a
S l
I \
^
%2ti&o>£cS5'
November 1991
43
-------
Nooroad Engine and Vehicle Emission Study
Table 2-11. Emissions from Other Area and Point Sources
coco co co *- »- co co co co co co •?- »- co T- co co •»- in
OJ C\J (\J CM T- i- CM CM CM CM CM CM »- »- CM CM CM CM .- in
18
10 r^ mdc
fj »T-
cvl -r- incvj
T
in
CM
-
rJ ~«ZQZ
s
S'n
o
oi m co act
cn CJCJ»- c\ieo *-
(D
ojc
w
T-IO'SCOCD*- r>i O C3>
o>o>orN.r«-*- oor^tot
en^-cn tno» cjojeo
Ot Q
^c»
QOQOQOOOOO
QQOOQQ
i CO CO
I CO CO
si
fl
of *-" *
cstcot
»- r^- r-- CM T-
fi-o
" o> **•" CM* Is-"
*
CM" CM" CM o" in' co"
O>CD<0CM COtD
QQQQQQQQQQI
zzzzzzzzzz:
Q
! i
November 1991
-------
Chapter 3. Results
As described in Chapter 2, EPA developed two new sets of inventories for nonroad
engines and vehicles. Inventory A was developed from data supplied by EPA contractors,
and Inventory B incorporated information supplied by manufacturers.
Both inventories were developed by multiplying the activity levels by the appropriate
emission factors. Where possible, the resulting data were compared to emission inventories
for highway mobile sources and other area and point sources.
The results of Inventories A and B are summarized in this chapter. Detailed
presentations of both inventories can be found in Appendixes M (Inventory A) and O
(Inventory B). This chapter also contains a summary of the results from EPA's analysis of
SIP and CARB inventories.
3.1. VOC, NOY, CO, and Particulate Nonroad Inventories
Table 3-01 presents nonroad emissions of VOC, NOX, CO, and particulates as
percentages of the total emission inventory for each of the 24 nonattainment areas studied.
For each entry, a range is provided. The lower end of each range was calculated using new
engine emission factors, while the upper end utilized in-use emission factors.
Due to the seasonal nature of ozone and CO nonattainment in many areas, EPA made
adjustments to the emission inventories developed for VOC, NOX, and CO. The results are
reported as percentage tons per summer day for VOC and NOX and percentage tons per
winter day for CO. Table 3-01 also provides a comparison of results from Inventory A and
Inventory B.
To help visualize the nonroad contribution to total local emission inventories, stacked
bar charts are used to display the distribution of the results from Table 3-01 in eight charts
following the table. Calculations using both new engine and in-use emission factors are
presented in each chart to illustrate the range of potential nonroad emission contributions. Of
the 24 nonattainment areas included in the inventories, 19 were studied for NOX and VOC, 16
were studied for CO, and 13 were studied for particulates.
November 1991 45
-------
Notiroad Engine and Vehicle Emission Study
Table 3-01. Total Nonroad Emissions by Nonattainment Area and Pollutant (%)
Nonattainment
Area
Atlanta
Baltimore
Baton Rouge
Boston
Chicago
Cleveland
Denver
El Paso
Hartford
Houston
Miami
Milwaukee
Minneapolis
New York
Philadelphia
Provo-Orem
San Diego
Seattle
South Coast, CA
San Joaquin
Valley
Springfield, MA
Spokane
St. Louis
Washington, DC
Inventory A
VOC
tpsd
10-14*
10-14
7-10
7-11
6-9
7-9
8-12
10-14
7-10
12-16
10-14
9-13
9-12
14-20
13-19
4-5
9-12
11-14
10-14
*The range presented is
emission factors.
NOX
tpsd
13
19
13
19
16
15
22
25
15
18
16
20
17
39
29
19
15
12
17
based on
CO
tpwd
11-14
9-15
5-8
6-9
5-8
9-13
4-7
9-14
3-4
9-14
9-12
8-13
6-10
2-4
5-8
5-8
calculation
PM
tpy
2
2
1
0.4
1
3
0.4
2
5
2
0.6
2
2
Inventory B
VOC
tpsd
7-10
9-12
4-6
12-16
5-8
7-10
6-9
11-16
6-8
7-10
9-13
8-11
6-8
8-11
6-9
3-4
9-13
10-14
11-16
of emissions
NOX
tpsd
13
18
8
25
12
12
15
31
10
16
13
14
14
31
20
17
15
10
13
from new
CO
tpwd
(%)
11-14
8-13
4-7
5-8
4-7
4-11
3-6
8-13
2-4
7-11
9-11
6-9
5-8
2-4
4-7
6-9
and in-use
PM
tpy
1
1
0.5
0.2
0.7
2
0.3
1
3
0.7
0.4
1
1
46
November 1991
-------
Results
20.00%
13.00%
I
3
£
•s
§
10.00%
3.00%
0.00%
Nonroad VOC tpsd
Inventory A
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
20.00%
0.00%
Nonroad VOC tpsd
Inventory B
OU^Ch'fcJ^Y^«^^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
47
-------
Nonroad Engine and Vehicle Emission Study
40.00%
30.00%
-------
Results
20.00*
15.00%
I
H
"S
3
t>
10.00%
5.00%
0.00%
Nonroad CO tpwd
Inventory A
_
Nonattainment Area
I I New Engine Emissions •• Estimated In-Use Increment
BO..O*
20.00%
B-
jj 15.00%
1
1
o 10.00%
5.00%
0.00%
Nonroad CO tpwd
Inventory B
•Mi
fffffll*
—U—U ll II II. II II
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
49
-------
Nonioad Engine and Vehicle Emission Study
6.00%
£^5.00%
w
a
4.00%
£
3.00%
•y 2.00%
Q
«
g
1.00%
0.00%
Nonroad PM tpy
Inventory A
n
nH
r 1
Provo-Onm S«i
E1PMO
Denver _^ Cleveland
South Co«t SnDtofo ^^ S^atlaOt
Nonattainment Area
New Engine Emissions H Estimated In-Use Increment
*j 2.00%
c
1.00%
0.00%
ElPuo
Nonroad PM tpy
:al Inventory
7* H* P
••••
D.over
Co-
Nonattainment Area
— 1 1 — 1 1 1
1 j
—
1 1
[—
1
L i
1
j
New Engine Emissions
Estimated In-Use Increment
50
November 1991
-------
Results
3.2. VOC, NOX, CO, and Particulate Nonroad Inventories bv Categories
The following charts summarize the contribution of each category of nonroad
equipment to total emission inventories. Each chart presents the VOC, NOX, CO, and
particulate contribution detemiined by each of the two inventory methods for one equipment
category.
November 1991 51
-------
Nomroad Engine and Vehicle Emission Study
1.40%
"*
1.00%
0.80%
o
H
*o
a
1
0.60%
0/40%
0.20%
0.00%
nu
Agricultural VOC tpsd
tl 1 r
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
Agricultural VOC tpsd
Inventory B
l.W»
£1**
o
1
S
o
0.60%
0
4) O-W*
ts
rtnrw,
1
n
',
] i
i i
[__ j i— t
ti i
U L
n
1
DlBte^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
52
November 1991
-------
Results
12.00%
Agricultural NOx tpsd
Inventory A
£/ 10.00%
8.00%
6-00%
*•> 4.00%
g
g
rP 2-00%
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
12.00%
Agricultural NOx tpsd
Inventory B
'10.00%
> 8.00%
£
13
Q 6.00%
O
•M 4.00%
Q
§
2-00%
0.00%
rnn
r
^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
53
-------
Nonroad Engine and Vehicle Emission Study
1.40%
£.**
2
§ 1-00%
jg
-g 0.80%
3
H
0.40%
0.00%
Agricultural CO tpwd
Inventory A
EIPMO South Cout Denvw Hartford S«n Diego WMMngtonDC Spokane Saint
Boilon NewYoft Scattte-Tacooa Cleveland Trovo-Owm Bdtimore NQnnrapotis
Nonattainment Area
! I New Engine Emissions Hi Estimated In-Use Increment
1.40%
"1"
I
0.60%
O
fl
D
6
0.40%
0.00%
Agricultural CO tpwd
Inventory B
Nonattainment Area
New Engine Emissions •§ Estimated In-Use Increment
54
November 1991
-------
Results
1,40% <—
Agricultural PM tpy
1.00%
^•^
-H 0.80%
•*->
|Tj O-60*
O
4-1
g 0.40%
I
OH 0.20%
0.00%
1
El PMO Denver New York Chicago MhnMpoH* , _ San Joaquin Spokane
South CoMt Sn Diego Provo-Orem Qevehnd Suttle-TiconHi Saint LOUM
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
Agricultural PM tpy
Inventory B
53 1.00%
I
—j 0.80%
["^ 0.60%
O
•w
§ 0/40%
O
OH 0^0%
0.00%
Elftuo Denver New Yoilc __ Chkxgo ^^ , JMtaie«poU< S«iJo«juhi, SpoUne
South Cowt Sn Diego Provo-Oem Oevetand Se«ttte-T«com« ' Saint Louii *^
Nonattainment Area
I New Engine Emissions
Estimated In-Use Increment
November 1991
55
-------
Nonroad Engine and Vehicle Emission Study
1.40%
£,*»
I
(3 t.oo%
I
—J 0.8O%
•<_>
(2
•s
g 0.40%
O
Airport Service VOC tpsd
Inventory A
©
£
P^ 0.20%
0.00%
***"£ Jbjfi"
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
1.40%
1.00%
0.80%
O
H
O.(50%
0X0%
Airport Service VOC tpsd
Inventory B
t
O.CK)%
nnn
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
56
November 1991
-------
Results
4.00%
3.00%
Airport Service NOx tspd
Inventory A
H
•8
*_>
d
i>
I
OM
2-00%
1.00%
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
4.00% —
Airport Service NOx tpsd
Inventory B
JH 3.00%
-------
Nonroad Engine and Vehicle Emission Study
1.40%
gj.,00*
2
§ 1.00%
I
r—j 0.80%
•w
(2
0.60%
o
a
I
1.00%
0.8O%
(2
o.«o%
§ 0.40%
I
P* 0.20%
0.00%
Airport Service CO tpwd
Inventory B
n
H«tfori
Nonattainment Area
New Engine Emissions •! Estimated In-Use Increment
58
November 1991
-------
Results
1.40%
.1.20%
1.00%
o.so%
0.60%
0.40%
Airport Service PM tpy
Inventory A
I
3
O
H
g
O
0.20%
0.00%
____ ! __ i i _ L .
Provo-Orem. QPvo . _
Sin Jomqutn Sou* Co«c
New Engine Emissions
1 ! ! I i I I
MhmeapoHi Denver N«
X ^ San Diego SrirtLouk
Nonattainment Area
missions HH F.^timatP
; _ , _ L
New Yotk
Spokjne
J ___ „ _ : ____
Chicago Cfcvebnd
SeXtle-TicooM
Estimated In-Use Increment
1.40%
Airport Service PM tpy
Inventory B
1.00%
0.00%
r"1 o.6o% H
0^0%
o
(X
0.00%
Provo-Orem . HP»o ^_ MhnMpoHi
5»n loMjuhi "—•• "—•
______ T — „ ^ Denver . _ . . New York
Sou* Cowl SOT Dtogo Sdnt tool* Spobne
develind
Seattle-Ticonw
Nonattainment Area
[ZH New Engine Emissions
Estimated In-Use Increment
November 1991
59
-------
Nonroad Engine and Vehicle Emission Study
1.40%
1.00%
0.80%
0.60%
0.00%
Commercial Marine VOC tpsd
Inventory A
•H H
1 M M
fc-n^0*^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
§ 1.00%
0.80%
—
(2
"8
0.40%
O
0.00%
Commercial Marine VOC tpsd
Inventory B
«p^^^ •
Nonattainment Area
SihKLoiris
Imoie
New Engine Emissions
Estimated In-Use Increment
60
November 1991
-------
Results
20.00%
15.00%
I
13
10.00%
Commercial Marine NOx tpsd
Inventory A
C
y
&
AH
5.00%
0.00%
ElPuo SpringfieU WaiMnflcnDC SanJoaqufci Saint Lori* Bortqn „ NewYort Houftan 9,*lriin«e Sw Diego
Atlanta Clevelnd MDwwibe Hiutford ItUuni Baton Roafe CMcago TOledelphU ^SouthCowt
Nonattainment Area
New Engine Emissions
timated In-Use Increment
20.00%
Commercial Marine NOx tpsd
Inventory B
15.00%
(U
I
10.00%
a
1)
Q
fe
OH
5.00%
0.00%
-J I—
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
61
-------
Nonroad Engine and Vehicle Emission Study
i
a
£M
M-H
O
8
g
nrfOL
Commercial Marine CO tpwd
Inventory A
! 1
"
Nonattainment Area
New Engine Emission^ !• Estimated In-Use Increment
Commercial Marine CO tpwd
Inventory B
a
'o
C
1>
O
^ '.00%
AfVMC.
1 1
i
""
Nonattainment Area
New Engine Emissions !• Estimated In-Use Increment
62
November 1991
-------
Results
2.00%
I
c
o-
1.00%
0.50%
0.00%
Clevelmi ElPuo Spokane SfftJocquin Skint Louii South Cowt Se»ttle-T«eom»
Denver Provo-Orem MimeapoUi CHc«go NewYort Sm Diego
Nonattainment Area
[Hi New Engine Emissions •• Estimated In-Use Increment
2.00%
Commercial Marine PM tpy
Inventory B
1.50%
1
1.00%
H
c
1)
0.00%
Oevelmd EJ PMO __ Spotame ,__ ..
Denver Provo-Orcm ^ MhmeapoHi
Nonattainment Area
Saint Louif South Co«t Sewfle-Ticonw
CMcafO New York Sm Diego
New Engine Emissions
Estimated In-Use Increment
November 1991
63
-------
Nonroad Engine and Vebicie Emission Study
2.00%
Construction VOC tpsd
Inventory A
a
I
H
•8
4->
a
u
I
'•»»
OJO%
0.00%
n
u
N
Nonattainment Area
I New Engine Emissions Hi Estimated In-Use Increment
2.00%
I
(2
a
Q 0.30%
0.00%
Construction VOC tpsd
Inventory B
nHH
-•F
n
^r
h
M N
H
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
64
November 1991
-------
Results
25.00%
Construction NOx tpsd
Inventory A
20.00%
g
o
•M
d
u
15.00%
10.00%
5.00%
0.00%
-I
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
Btton
Construction NOx tpsd
Inventory B
O ^flfYMBi
+-»
d
q
o
H
a
u
Jj 5.00%
nnn*
| 1
1
1
^
_,_
~
—
~
-
1 ,
j
_, ! '
i
i
r [
i
^^.D^^p^^fcT*-11 Bo-on
Nonattainment Area
New Engine Emissions H Estimated In-Use Increment
Hwlfocd
November 1991
65
-------
Nonroad Engine and Vehicle Emission Study
2.00%
uo%
I
H
<+H
o
•4~>
a
1.00%
0.50%
Construction CO tpwd
Inventory A
n
Provo-Owm Oevebnl SrfrtLouii ftutfoid New YorC~T,BIPMp ' T^W«*ingfonpC. South C
SpoUne VflnoMpofij Denver BoMon BilHmon SeMlte-T*coma SinJoiquin
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
2.00%
I
1.00%
2
£)
s
OH
0.00%
Construction CO tpwd
Inventory B
Provo-Orem
5]
nnn
ipota,
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
i Diego
66
November 1991
-------
Results
Construction PM tpy
Inventory A
3.00%
L*2JO%
5
•4_>
s
J3
3
H
VM
O
•w 1.00%
C
u
nrwx.
! ,
^M
1
n
;
i i
^
, l
i
L Li
n ;
i
U i
j !
1 1 i
1 : \
SorthCo^
Provo-Orem H Paao Denver Spokane San Diego _.
SsnJoaquin MhmeapoHi Cleveland Saint Louis CMcafo New Y.
Nonattainment Area
I I New Engine Emissions •• Estimated In-Use Increment
SeUtte-
orf
Tccofiw
3.00%
Construction PM tpy
Inventory B
*2JO%
a
I
3
o
H
2.00%
•y 1.00%
c
(U
H
0.00% '
San
JbMUtn El PMO Denver , „ Sou* Coast CMca(o „ ^ Saint LouU
Provo-Orem VUmeapoto Sin Diego Cleveland Spokane Sewte-Tacoma
Nonattainment Area
[ZU New Engine Emissions •• Estimated In-Use Increment
New York
November 1991
67
-------
Nonroad Engine and Vehicle Emission Study
1.40%
00%
1.00%
I
0.80%
0,40%
0.20%
0.00%
Industrial VOC tpsd
Inventory A
H
!
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
1.40%
0.00%
Industrial VOC tpsd
Inventory B
Nonattainment Area
I New Engine Emissions HI Estimated In-Use Increment
68
November 1991
-------
Results
Industrial NOx tpsd
Inventory A
2
3.00%
13
O 2-00%
c
Q 1.00%
0.00%
M
u
H
—i
^ i— -j
Nonattainment Area
New Engine Emissions IH Estimated In-Use Increment
4.00%
S"
"j-j 3.00%
I
13
Q 2.00%
O
o
I
1.00%
0.00%
Industrial NOx tpsd
Inventory B
n
— ,
— i
—
,
-
i
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
November 1991
69
-------
Nonroad Engine and Vehicle Emission Study
3.00%
d
2.00%
1.50%
o
*•» 1,00%
d
-------
Results
140%
Industrial PM toy
Inventory A
0.00%
CHcago New York
• develmd
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
Industrial PM tpy
Inventory B
a
§ 1.00%
I
-3 0.80%
3
o
. 0.60%
it
OH 0^0%
0.00% L
San Joaquhi El Paw „ ^ NflnrMpoHi .^ SpoUoe CMc«o ^ „ SeaMe-Tacomi. New York
^ Provo-Orem SmDt«|o Denver ' Saint Loub ^ South COM Cleveland
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
71
-------
Nonroad Engine and Vehicle Emission Study
12.00%
0.00%
Lawn & Garden VOC tpsd
Nonattainment Area
New Engine Emissions WM Estimated In-Use Increment
12.00%
Lawn & Garden VOC tpsd
Inventory
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
72
November 1991
-------
Results
1.40%
Lawn & Garden NOx tpsd
Inventory A
1.00%
0.80%
0.60%
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
5^,1.20%
5
a
u 1.00%
I
.—1 0.8O%
(2
0.60%
O
S3
020%
Lawn & Garden NOx tpsd
Inventory B
Nonattainment Area
CHI New Engine Emissions •! Estimated In-Use Increment
November 1991
73
-------
Nonroad Engine and Vehicle Emission Study
6.00%
0.00%
Lawn & Garden CO tpwd
Inventory A
Nonattainment Area
I New Engine Emissions IB Estimated In-Use Increment
6.00%
0.00%
Lawn & Garden CO tpwd
Inventpr^B
Blfno
B
-------
Results
1.40%
Lawn & Garden PM tpy
Jnventor^ A
1.00%
I
0.80%
o
H
VM
O
4-1
a
6
0.60%
0.40%
0.20%
0.00%
~S«JoMirin MimeMoHt
BlFtao Provo-Oiem
Cleveland „ Spokane New York „ Seante-Tacoma
Denver Chicago San Diego Sooth Cowt
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
&
•4—»
§ 1.00%
I
.-H 0.80%
•M
, 0.60%
O
OH 020%
0.00%
Lawn & Garden PM tpy
Inventory B
Hfl
S«i Jownrin _ Provo-Orem MhrntooHi „ _. Denver New YoA Clevebnd SpoUne
1 El P»»o ^o«h Co«» ' San Dtego CMcifo S«lnt Loub Seotife-Tacom* r
Nonattainment Area
LZ] New Engine Emissions I
Estimated In-Use Increment
November 1991
75
-------
Nonroad Engine and Vehicle Emission Study
3.00%
0.00% t—ir—
Light Commercial VOC tpsd
Inventory A
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
3,00%
0.00%
Light Commercial VOC tpsd
Inventory B
Nonattainment Area
I New Engine Emissions
Estimated In-Use Increment
76
November 1991
-------
Results
1.40%
£,1.20%
s
§ 1.00%
I
-.3 0.80%
•*->
O
5~* 0.60%
<4-l
O
*J
§ 0.40%
I
CM o^O%
0.00%
Light Commercial NOx tpsd
Inventory A
.1
Nonattainment Area
[ZH New Engine Emissions •§ Estimated In-Use Increment
1.40%
3
1.00%
I
0.80%
0.60%
0,40%
O
H
t^-i
o
d
D
O
I
t*< OJO%
0.00%
Light Commercial NOx tpsd
i I
*"1^
Nonattainment Area
I New Engine Emissions
Estimated In-Use Increment
November 1991
77
-------
Nonroad Engine and Vehicle Emission Study
8.00%
0,00%
«.eo%
Light Commercial CO tpwd
Inventory A
New York
Nonattainment Area
New Engine Emissions •§ Estimated In-Use Increment
Light Commercial CO tpwd
JnventOTyJB
&
0.00%
Mllllllll"
vO • ^ - H 1 1 >'
_ J_l_.JLJ_LJJ_[_J __ LL_J __ 1 ^L_L
_
T'^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
78
November 1991
-------
Results
Light Commercial PM tpy
Inventory A
Total Inventory
3 P r — r-
— -
0.40*
OH 0.20%
0.00%
iJoaqufci EIPa»o San Diego South Coaat „ Spokane Cleveland
^^^Provo-Orem Mkwapoto ^ Saint Louto Denver "^ Chicago ISeattl
[New York
to-Tacouw
Nonattainment Area
New Engine Emissions Hi Estimated In-Use Increment
1.40% i
Light Commercial PM tpy
Inventory B
I
0.80%
•-
o
0.60%
0.40%
O
0.20%
0.00%
Smloaquin ElPno „, Mli«iMi»ufli South Cost
Provo-Orem S«n Diego SahKLouii Denver
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
November 1991
79
-------
Nonroad Engine and Vehicle Emission Study
1.40%
000%
ing VOC tpsd
A
Nonattainraent Area
New Engine Emissions •§ Estimated In-Use Increment
1.40%
5J
~
3
V
£
0.90%
0X0%
ogging VOC tpsd
Tnventory B
Nonattainment Area
I New Engine Emissions HI Estimated In-Use Increment
80
November 1991
-------
Results
1.4O%
-ogging NOx tpsd
inventory A
entory
r -
P
P
o
H
<4-l
O
s
g 0.40%
8
QH 0.20%
0.00%
_
Nonattainment Area
New Engine Emissions H Estimated In-Use Increment
1.40%
r»
§ 1.00%
I
*73 o.8o%
4_>
o
H
MH
O
ogging NOx tpsd
inventory B
9
'ercen
P
0.20%
0.00%
Nonattainment Area
New Engine Emissions •• Estimated In-Use Increment
November 1991
81
-------
Nonroad Engine and Vehicle Emission Study
1/40%
000%
ogging CO tpwd
Inventory A
Nonattainment Area
I New Engine Emissions Hi Estimated In-Use Increment
1.40%
Logging CO tpwd
Inventory B
.1.20%
s
I
1.00%
0.80%
O
H
8
I
0.60%
0.40%
020%
0.00%
Nonattainment Area
New Engine Emissions •§ Estimated In-Use Increment
82
November 1991
-------
Results
1.40%
Logging PMA tpy
inventory A
i-oo%
0.80%
.2
0.60%
0.40%
I
MH 0.20%
0.00%
El Paao MinneapoUi Chicago San Dtego _ , . South Coart New York Seattle-Tacoma
Provo-Orem Denver Cleveland SaM Louto San Joequin Spokane
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
Logging PM tpy
Tnvemory B
0.00%
El Pluo Denver „ „ San Diego „ South Coast Cleveland _ . , New York Seattle-Tacoira
Provo-Orem MbmeapoHt SanJoaquin Chicago Saint Louli Spokane
Nonattainment Area
LH] New Engine Emissions •• Estimated In-Use Increment
November 1991
83
-------
Nonroad Engine and Vehicle Emission Study
3.00%
> 2.00%
£
|
H
•y 1.00%
H
1>
a.
Recreational VOC tpsd
Inventory A
nnnnH
& LaS** Yofcwmwf IWMlk1SMBttii
A*.*,
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
Recreational VOC tpsd
Inventory B
Percent of Total Inventory
3 O — — W *° ***
I
_ — ••••••"""
^^F^mf-irnnnnHnnnnnni i
B
;AS^CMc^^"H«toS>rin«SlU^^
Nonattainment Area
I New Engine Emissions
Estimated In-Use Increment
84
November 1991
-------
Results
1.40%
Recreational NOx tpsd
Inventory A
j 1.00*
I
—3 0.80%
3
*"* 0.60%
I
P*
0.00%
Y^
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
r
1.20%
1.00%
Recreational NOx tpsd
1
(2
0.80%
0.6O%
0.40%
o
050%
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
85
-------
Nonroad E"p"* "*< Vebicte Emission Study
4.00*
3.00%
2-00%
y
1.00%
0.00%
Recreational CO tpwd
Inventory A
iJondn Southern* ._ SeaMe-Tinm SMDtofo , BtdHann SdntLoafa Denver Barton
^BlFtao Spokme wSBngtonDC *CkvehnT ;MaMpoit NewYotk Provo-Onm Hwlfort
Nonattainment Area
I I New Engine Emissions
Estimated In-Use Increment
4.00%
3.00%
•3
2.00%
c
Q
£
1.00%
0.00%
Recreational CO tpwd
Inventory B
t Loirii^^Ttew Yoik ""Pwvo-Orem'
Nonattainment Area
I I New Engine Emissions
Estimated In-Use Increment
86
November 1991
-------
Results
1.40%
Recreational PM tpy
Inventory A
S3 '•«)*
I
-^ o.so%
1
H
. o.eo%
55 °-*°*
I
Mi 070%
0.00% i—
San Joaqufci South Coart MhneapoHf . Spokane Saint Lenrii Denver New York
^^ ElPiuo S«n Diego ' Oevelmt ' SeaNte-Tacoraa Provo-Orem Chk«go
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
Recreational PM tpy
Inventory B
o
^-»
C!
|
'ctf
O
*
a
Q) O.40%
Uaii n'ynoL
\
I
-• - - -
\
\
\
i
0.00%
S«n Joaquin South CoaM MkneapoHs . Spokane SaM Loui*. __ Denver New York
BIPMo SanOtefO Cleveland ^^ Seattfe-Tacoma Provo-Ofem Chicago
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
November 1991
87
-------
Nonroad Engine and Vehicle Emission Study
8.00%
0.00%
Recreational Boat VOC tpsd
Inventory A
R»^1"*aH«tftT™'Sn, Lo^"*
NewY<
lore
Nonattainment Area
I I New Engine Emissions •• Estimated In-Use Increment
8.00%
7.00%
6.00%
5.00%
s
I
13
"O 4.cio%
H
«tj
O 3.00%
O
I
OH
2.00%
0.00%
Recreational Boat VOC tpsd
Inventory B
^DteloMn«,w.ata^ix&^
Nonattainment Area
I I New Engine Emissions HH Estimated In-Use Increment
88
November 1991
-------
Results
2.00%
Recreational Boat NOx tpsd
Inventory A
'-30*
I
H
1.00%
0.50%
0.00%
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
2.00%
I-
4-»
a
I
13
1.00%
a
Recreational Boat NOx tpsd
Inventory B
0.00%
_IH New Engine Emissions
^vel^^'P%^^^«»o^^ffewY<5r^fl6l?Uo«.BMt0n
Nonattainment Area
•I Estimated In-Use Increment
November 1991
89
-------
Nonroad Engine and Vehicle Emission Study
1.40%
Recreational Boat CO tpwd
Inventory A
§ 1.00%
0.80%
0.60%
g
I
0.20%
0.00%
u
^^ ,_^
Oevetaxl
^_¥
SrinrLouh Borton W»*hig«on
Nonattainment Area
Hptfonl S«n
DC
BaM
Sou* Co-)
Sw Diego
.
-Ticomii
I I New Engine Emissions
Estimated In-Use Increment
1.40%
S3 I.OO%
I
•-H 0.80%
3
. 0,60%
§ 0.40%
O
0.00%
Recreational Boats CO tpwd
Inventory B
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
90
November 1991
-------
Results
1.40%
.1.20%
0
53 1.00%
I
-^ 0.80% j-
3
o
H
Recreational Boat PM tpy
Inventory A
0.60%
0.40%
0.20%
0.00%
ElPuo Provo-Orem CWcmgo S«i Diego, ,. _ Spokane S«in« Loui« Seaole-Taconw
SinJoaquhi Denver Clevel«nd So«h Coert ' New Yott Mbneap
Nonattainment Area
New Engine Emissions
Estimated In-Use Increment
1.40%
Recreational Boat PM tpy
T- -____n • J
1.00%
I
0.80%
•
o
0.60%
0.40%
0.00% L-
BJPiuo Provo-Orem South Coart Chicago SairHLouti
San Joaquta Denver San Diego Cleveland
Nonattainment Area
ions HI Estimate
.
Spofane
.Jea^e,
New Engine Emissions
Estimated In-Use Increment
November 1991
91
-------
Nonroad Engine and Vehicle Emission Study
3.3. National PM, SOv, and Air Toxics Inventories
Table 3-02 summarizes national emission inventories for paniculate matter,
formaldehyde, benzene, 1,3-butadiene, gasoline vapors, and oxides of sulfur for all nonroad
sources. Inventories from highway vehicles and other area and point sources are presented
where available and the contribution of nonroad sources to total inventory is calculated. Due
to the extremely limited availability of data for toxic inventories for highway and other area
and point sources, the data in the table are from the most recent year for which data was
available. Therefore, the data can only be used for approximate comparisons of the
contributions from the various sources of air toxic emissions. The nonroad inventories for air
toxics in Table 3-02 are the in-use adjusted Inventory A numbers. The formaldehyde and
benzene inventories for highway and other area and point sources were taken from an EPA
technical report by P. Carey.10 The PM and SOX inventories were derived from EPA's 1989
emission trends report.11 The highway vehicle value for 1,3-butadiene was based on
assuming that this toxic accounted for 0.35% of the total exhaust hydrocarbons emitted from
highway vehicles.12 The aldehyde emission factors used in this study for nonroad sources
are in terms of total aldehydes. To compare formaldehyde inventories from nonroad to other
sources, EPA assumed that 60% of the total nonroad aldehyde emissions were
r u u j *******
formaldehyde.
******* The 60% estimate was typical for engines which had separate formaldehyde, as well as total aldehyde,
emission measurements reported in Nonroad Emission Factors of Air Toxics by Melvin N. Ingalls, Southwest
Research Institute, SwRI 08-3426-005.
92 November 1991
-------
Table 3-02. Air Toxics Emission Inventories
Results
Toxic
paniculate*
formaldehyde
benzene
1 .3-butadiene
gasoline vapors
SOX
Nonroad Sources
tpy
457,396
41,663
109,783
47,816
237,048**
230,495
% of
Total
5.55
13.05
25.37
0.99
Highway Sources
tpy
1,397,738
74,961
275,579
9,869
2,819,727
652,572
% of
Total
16.96
23.48
63.68
2.81
Other Area And
Point Sources
tpy
6,384,620
202,670
47,400
22,311,998
% of
Total
77.49
63.47
10.95
96.19
Total tpy
8,239,754
319,294
432,762
23,195,065
* Does not include fugitive dust from unpaved roads and airstrips which accounts for about 77% of total
suspended particles.
** Does not include running losses or hot soak evaporative emissions.
November 1991
93
-------
Nonroad Engine and Vehicle Emission Study
3.4. SIP and CARB Inventory Analysis
As discussed in Chapter 2, inventories were prepared using data from SIPs and CARB
analyses. The following tables summarize the results from the SIP- and CARB-based
inventories. It should be noted that the emission factors used to develop SIP- and CARB-
based inventories do not include in-use or transient operation adjustments. A discussion of
the emission factors used to develop these inventories can be found in Appendix I. A
discussion of the methodology used to create these inventories and a more detailed report of
the results can be found in Appendix G.
Table 3-03. SIP-Based Inventory Summary
CMSA/NECMA
Atlanta, GA
Beaumont-Port Arthur, TX
Boston, MA
Chicago, D
Connecticut
Dallas, TX
Denver, CO
Duluth, MN
El Paso, TX
Fort Collins, CO
Hartford, CT
Houston, TX
Louisville, KY
Minneapolis, MN
New Jersey
Seattle, WA
Springfield, MA
State of Mass.
voc
tpy tpsd
3 4
1
6
5
10
4
3
7
4
12
6
12
8
NOX
tpy tpsd
7 8
18
9
7.6
21
14
18
25
6
44
13
9
8
CO
tpy tpwd
6
4
3
6
4
4
16
16
9
6
94
November 1991
-------
Results
Table 3-04. CARB-Based Inventory Summary
Air Basin
Mountain Counties
Sacramento Valley
San Diego
San Francisco Bay Area
San Joaquin
South Central Coast
South Coast
VOC tpsd
(%)
5
4
3
2
2
2
3
NOX tpsd
(%)
31
19
29
21
13
13
17
CO tpwd
(%)
6
10
10
11
13
12
11
November 1991
95
-------
Chapter 4. Discussion and Analysis of Results
Chapter 3 presented a summary of the inventories calculated from the data collected
for this study. This chapter contains EPA's analysis of these inventories and its interpretation
of the results. Specifically, the first section contains an analysis of nonroad contributions to
total emissions by pollutant and equipment categories. A discussion of the methodologies
used to calculate the inventories and their potential impact on die results is presented in the
second section. Last, the contribution of nonroad emissions is compared to other categories
that are currently regulated.
4.1. Discussion of Inventory Results
Following are discussions of the results for emissions of VOC, NOX, CO, and other
pollutants, and the relative contribution of equipment categories. The overall nonroad
emission contributions are summarized by pollutant.
4.1.1. Volatile Organic Compounds (VOC) Inventories
Both Inventory A and Inventory B estimate that substantial summertime VOC
emissions derive from nonroad sources. Inventory A estimates that 18 of the 19 ozone
nonattainment areas examined have nonroad contributions over 6-9% (lower limit represents
new engine and upper limit represents in-use emission factors) of total summertime VOC
inventories, with a median contribution of 9.1-12.6%. The estimates in Inventory B are about
15-20% lower than those in Inventory A. However, Inventory B still estimates that 14 of the
19 areas have nonroad contributions over 6-9%, with a median contribution of 7.4-10.3%.
The largest contributors to nonroad VOC emissions are the lawn and garden and
recreational marine categories. In Inventory A, the median contribution of lawn and garden
equipment to total summertime VOC inventories is 2.7-4.7%, with the lowest reported
contribution being 1.1-1.9%. Inventory B is slightly lower, on average, with estimates of the
median lawn and garden contribution at 2.4-4.2%, and 18 areas above 1.1-1.9%.
96 November 1991
-------
Discussion and Analysis of Results
Contributions of recreational marine equipment to nonroad VOC emissions are similar
to lawn and garden contributions. Inventory A estimates the median contribution of
recreation marine equipment to be 3.4-4.0%, with 15 of the 19 areas above 2%. Inventory B
estimates are about a third lower, overall, but still estimates a median contribution of 2.2-
2.5%, with 10 of the 19 areas above 2%.
The light commercial and construction categories each contribute at least 0.5% of total
summertime inventories in 17 of the 19 nonattainment areas. Table 4-01 shows the number
of nonattainment areas in which the equipment category listed contributes at least 1% of the
VOC inventory.
Table 4-01. Equipment Categories Contributing at least 1% of
Total Summertime VOC Inventory
Equipment Category
Lawn and Garden
Recreational Equipment
Recreational Marine
Light Commercial
Construction
Agricultural
Commercial Marine
Number of Areas
Inventory A
19
2-3
17
2-11
11-14
1
1
Inventory B
18-19
0-2
17
2-12
5-6
1
1
It should be noted that exhaust emissions account for less than three-quarters of the
total VOC emissions from the lawn and garden category. The remaining VOC emissions
from this category are due to crankcase, evaporative, and refueling spillage emissions.
Spillage during refueling of the equipment is estimated to contribute 7.5% of the total lawn
and garden VOC inventories and 8.9% of the lawnmower VOC inventories.
November 1991
97
-------
Nonroad Engine and Vehicle Emission Study
4.1.2. Nitrogen Oxide (NOX) Inventories
Total summertime NOX emissions from nonroad sources are estimated to be larger, as
a percentage of total emissions, than nonroad VOC emissions. Nonroad NOX emissions in all
of the ozone nonattainrnent areas in Inventory A are estimated to be greater than 12% of the
total summertime NOX inventory, with a median contribution of 17.3%. Although lower,
Inventory B still estimates that nonroad emissions contribute over 11% of total summertime
NOX emissions in 16 of the 19 nonattainrnent areas studied, with a median contribution of
14.5%.
Construction equipment is the largest contributor to nonroad NOX emissions in 17 of
the 19 nonattainrnent areas studied. Inventory A estimates that construction equipment
contributes at least 6.4% of total summertime NOX emissions in each area, with a median
contribution of 9.7%. Inventory B is more than 15% lower, but still estimates that 15 of the
19 areas have construction equipment contributions of over 5%, with a median contribution of
8.4%.
NOX contributions from airport service equipment, industrial equipment, and
agricultural equipment are each estimated to be at least 1% in most of the nonattainment areas
studied. However, only in one case (agricultural equipment in the San Joaquin Valley) does
the contribution from any of these categories exceed 3.6% in any nonattainment area. The
commercial marine vessel contributions are more variable, with larger contributions in a
limited number of areas. The inventories estimate contributions of over 4% in three
nonattainment areas for the commercial marine category. Table 4-02 shows the number of
nonattainment areas in which the category listed contributes at least 1% of the NOX inventory.
98 November 1991
-------
Discussion and Analysis of Results
Table 4-02. Equipment Categories Contributing at least 1% of
Total Summertime NOX Inventory
Equipment Category
Airport Service Equipment
Recreational Marine
Industrial
Construction
Agricultural
Commercial Marine
Number of Areas
Inventory A
12
2
13
19
12
10
Inventory B
12
1
13
19
13
9
4.1.3. Carbon Monoxide (CO) Inventories
Inventory A estimates that nonroad emissions contribute at least 9-12% of total
wintertime CO emissions in 7 of the 16 CO nonattainment areas studied, with a median
contribution of 5.9-9.4%. Although slightly lower, with a median contribution of 5.2-8.5%,
Inventory B estimates that nonroad emissions contribute at least 6.9-10.5% of total wintertime
CO emissions in 6 areas.
Unlike nonroad emission contributions to VOC and NOX, the nonroad emission
contribution to CO is not dominated by any one or two equipment categories. The lawn and
garden, light commercial, industrial, recreational, and commercial marine equipment
categories each contribute a minimum of 1.4-2.2% of total wintertime CO emissions in at
least 2 nonattainment areas. The single largest nonroad contributor to winter CO emissions is
light commercial equipment. Both Inventory A and Inventory B estimate that this category
contributes at least 2.0-3.6% of total emissions in 8 of the 16 nonattainment areas studied.
Table 4-03 shows the number of nonattainment areas in which the category listed contributes
at least 1% of the CO inventory.
November 1991
99
-------
Nonroad Engine and Vehicle Emission Study
Table 4-03. Equipment Categories Contributing at least 1% of
Total Wintertime CO Inventory
Equipment Category
Lawn and Garden
Recreational Equipment
Commercial Marine
Light Commercial
Industrial
Construction
Number of Areas
Inventory A
5-9
3-7
2
15
12-13
3-4
Inventory B
3-6
2-5
2
15
10-11
0-1
4.1.4. Particulate (PM) Inventories
Inventory A estimates that nonroad emissions contribute over 3% of total PM
inventories in 2 of the 13 PM nonattainment areas studied, with a median contribution of
1.8%. Inventory B is substantially lower, with a median contribution of about 1.0%, and only
estimates that 1 area has nonroad contributions of over 3%.
Table 4-04 shows the number of nonattainment areas in which the category listed
contributes at least 1% of the PM inventory.
Table 4-04. Equipment Categories Contributing at least 1% of
Total PM Inventory
Equipment Category
Construction
Commercial Marine
Number of Areas
Inventory A
2
1
Inventory B
0
1
100
November 1991
-------
Discussion and Analysis of Results
4.1.5. National Air Toxics Inventories
Section 3.3 presented estimates of toxic emissions from nonroad sources (Table 3-02).
The limited availability of toxic emission data for nonroad sources made it difficult to
quantify precisely the inventory from these sources. Uncertainties also exist as to the health
effects (example: number of cancer incidences per year) of toxic emissions. A summary table
of cancer risk estimates for air toxics is provided in Table 4-05. In this section, PM is treated
as a toxic emission because of its long-term health effects (carcinogenicity) and its status as a
criteria pollutant.
A rough approximation of the cancer risk from nonroad toxic emissions relative to
highway toxic emissions can be determined from the ratio of nonroad inventory to highway
inventory which is derived from Table 3-02. Table 4-06 shows the ratio using this method
for 1986. These risk estimates are intended to be used to rank the nonroad toxic pollutants
and should not be viewed as actual numbers of cancer cases per year. In addition, the model
used to derive the values in Table 4-05 was developed for national highway vehicles which
are more likely to be used in populated urban areas than nonroad engines and vehicles on a
national level. Therefore, the accuracy of the nonroad estimates is dependent on the
differences in urban/rural usage of on-highway vehicles and nonroad equipment.
November 1991 101
-------
Nonroad Engine and Vehicle Emission Study
Table 4.05. Summary of Risk Estimates from Motor Vehicle Air Toxics.*tmttt
Motor Vehicle Pollutant
1,3-butadiene
Diesel Paniculate
Benzene
Formaldehyde
Gasoline Vapors
Asbestos
Acetaldehyde
Gasoline Participate
Ethylene Dibromide
Cadmium
Dioxins
Vehicle Interior Emissions
U.S. Cancer Incidences/Year**
1986
236-269
178-860
100-155
46-86
17-68
5-33
2
1-176
1
< 1
ND
ND
1995
139-172
106-662
60-107
24-43
24-95
ND***
1
1-156
< 1
< 1
ND
ND
2005
144-171
104-518
67-114
27-48
30-119
ND
1
1-146
< 1
< 1
ND
ND
**
The risk estimates are 95% upper confidence limits.
The risk estimates for asbestos, cadmium and ethylene dibromide are for urban exposure only. Risks
for the other pollutants include both urban and rural exposure.
ND = Not Determined.
ttmttThe risk estimates are upper bound estimates; therefore, they are not intended to represent actual numbers
of cancer cases but rather can be used to rank the mobile source pollutants and to guide further study. Table taken
from "Air Toxics Emissions and Health Risks from Motor Vehicles," presented by J.M. Adler and P.M. Carey at
the AWMA Annual Meeting, 1989.
102
November 1991
-------
Discussion and Analysis of Results
Table 4-06. Risk Estimates for Nonroad Toxic Emissions.
Nonroad/Highway Inventory Ratio
1,3-Butadiene
Particulates
Benzene
Formaldehyde
4.85
0.33
0.40
0.56
As Table 4-06 shows, 1,3-tmtadiene cancer risk estimates are extremely high for
nonroad sources compared to on-highway sources. This is due primarily to two factors. The
first factor relates to emission levels of 1,3-butadiene and the use of catalysts. Most on-
highway vehicles use catalysts and have 1,3-butadiene emissions that are about 0.35% of total
exhaust emissions. In comparison, few nonroad engines are so equipped, and as a result,
have 1,3-butadiene emissions that comprise about 1.3% of total exhaust hydrocarbons.
Further discussion of this difference is found in Appendix I. The second factor relates to
crankcase use. While the majority of on-highway vehicles use a closed crankcase system,
most nonroad engines do not and, as a result, have higher 1,3-butadiene emissions.
Many toxics such as benzene, 1,3-butadiene, aldehydes, and gasoline vapors are
included in the broad category of pollutants referred to as volatile organic compounds
(VOCs). Measures to control VOC emissions should reduce emissions of these air toxics.
However, the magnitude of reduction will depend on whether the control technology reduces
the individual toxics in the same proportion that total VOCs are reduced.
As evidenced by the 1990 Clean Air Act Amendments, Congress recognized the need
to study and regulate emissions of air toxics from motor vehicles and fuels. The
Amendments require that EPA complete a study of emissions that pose the greatest risk to
human health or about which significant uncertainties remain by May 15, 1992. Also, EPA
must promulgate vehicle or fuel standards containing reasonable requirements to control toxic
emissions, applying at the minimum to benzene and formaldehyde, by May 15, 1995.
November 1991
103
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Nooroad Engine and Vehicle Emission Study
4.2. Analysis of Inventory Methodologies
As outlined in Chapter 2, many of the inputs used to generate Inventory A and
Inventory B are based upon different sources of information. This section discusses the effect
that these differences could have on the inventory estimates. The results of this study could
also be affected by methodologies which overestimate or underestimate emission inventories,
as well as factors such as photochemical modeling, nonseasonal temporal adjustments,
photochemical reactivity and transport. The potential impact of these factors on emission
inventories is also discussed in this section.
4.2.1. Data Differences
The results and analysis presented in Chapters 3 and 4 reveal that Inventory A
generally estimates higher nonroad emissions than Inventory B. This difference in emissions
is primarily due to different local amounts of boat usage and annual fuel consumption
estimates for the recreational marine category, activity level estimates for lawnmowers and
population estimates for the construction category. The following highlights the differences
in each category.
Lawn and Garden Equipment—Both the Outdoor Power Equipment Institute (OPEI)
and the Portable Power Equipment Manufacturers Association (PPEMA) submitted local and
national population estimates, annual hours of use, average horsepower, and load factors for
lawn and garden equipment. This data was used to estimate the emissions inventory for
Inventory B. Although there are several differences between the national populations, annual
hours of use, average horsepowers, and load factors for lawn and garden equipment in
Inventories A and B, these tend to offset one another in most cases, resulting in similar
estimates of emissions from most lawn and garden equipment. The primary exception is
lawnmowers. Inventory A estimates for lawnmower populations, annual hours of use,
horsepower, and load factor are higher than those for Inventory B by 10%, 20%, 5%, and
20%, respectively, leading to activity level estimates for Inventory A that are, in general,
about 70% higher than for Inventory B. Overall, Inventory A estimates lawn and garden
emissions that are about 10-15% higher than Inventory B.
104 ~~November 1991
-------
Discussion and Analysis of Results
Recreational Equipment—The Motorcycle Industry Council (MIC) submitted survey
results for actual miles driven and seasonal activity for off-road motorcycles and all-terrain
vehicles. The seasonal activity levels were used by EPA to make seasonal adjustments for
both inventories. The International Snowmobile Industry Association (ISIA) submitted
national population and annual hours of use estimates for snowmobiles. The only substantial
difference between Inventories A and B, is the latter's lower annual usage estimates. While
this caused Inventory B's emission estimates from recreational equipment to be significantly
lower than Inventory A's, the impact on total nonroad emissions is small due to the relatively
low contribution of the category.
Recreational Marine—Both inventories used local boat registration data as the basis
for making population estimates. However, the methods of allocating the number of boats
actually used in the nonattainment areas differ significantly. Inventory A relies on survey
results submitted by the National Marine Manufacturers Association (NMMA) from eight
nonattainment areas to establish the ratio of boats used to boats registered in the
nonattainment area. For Inventory B, NMMA supplied a method of estimating the ratio of
boats used to boats registered based on the amount of water surface area in the nonattainment
are per registered boat. The methodology used for Inventory B yields estimates of boat usage
in the nonattainment areas that are about 10% lower than those in Inventory A. Another
factor accounting for the difference between the two inventories is the estimate of annual
gallons of fuel consumed. The average fuel use calculated for Inventory A from annual hour
of use, average horsepower, and load factor estimates is very similar to the fuel use survey
results reported by NMMA. However, NMMA believes that the reported fuel use in the
survey is overstated. Thus, for Inventory B, EPA adjusted the average amount of fuel
reported in the survey by the ratio of a national average fuel use calculation for outboard
motors, 91 gallons/year, to the average reported in the NMMA survey for outboard motors,
142 gallons/year, before applying the results to the unsurveyed areas. Overall, emission
estimates in Inventory B are about a third lower than those in Inventory A.
Industrial—The Industrial Truck Association (ITA) submitted population, annual hours
of use, load factor, and engine type estimates for forklifts. The load factor estimates were
adopted by EPA for both inventories. Overall, ITA's estimates yield emission inventory
estimates substantially lower than the forklift estimates in Inventory A, primarily due to much
November 1991 105
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Nonroad Engine and Vehicle Emission Study
lower annual hours of use estimates. Due to the relatively small amount of emissions from
forklifts compared to some other equipment types, the impact on the overall NOX inventory
was less than 3% (the impact on the VOC and CO inventories is much lower yet). No
information was submitted by industry for the other equipment types in mis category.
Construction—Equipment Manufacturers Institute (EMI) submitted national
horsepower, national load factor, regional hours of use, and regional population estimates for
most of the equipment types in this category. Overall, the horsepower, load factor, and
annual hours of use estimates are similar to the estimates used in Inventory A. However,
EMTs population estimates are lower than those in Inventory A.
Agricultural, Airport Service, Light Commercial, Logging, and Commercial
Marine—No substantial amount of information was submitted by industry for these equipment
categories.
4.2.2. Factors Causing Overestimation or Underestimation
EPA had sufficient information in several areas to know that methodologies used to
quantify emission inventories could tend to overstate or understate the actual inventories.
Where sufficient data was available to quantify the bias, corrections were incorporated into
the data used for the inventories developed for this study. However, in some cases, which are
discussed in this section, sufficient data was not available to make adjustments.
The estimates used for NOX emissions from highway vehicles and other area and point
sources are taken from the 1985 National Emission Report. While more recent NOX data is
available on the national level, no general source of local NOX emissions is available after
1985. The level of emissions from highway vehicles in 1990 is actually somewhat lower due
to the replacement of older vehicles with new vehicles having more effective emission
controls.******* In mis study, use of the 1985 data has the effect of overestimating NOX
emissions from other sources and, hence, underestimating the proportion of NOX emissions
from nonroad engines.
*******Based on National Air Pollutant Emission Estimates: 1940-1989, highway NOX emissions dropped 16%
between 1985 and 1989.
106 November 1991
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Discussion and Analysis of Results
No estimates of emissions from personal watercraft (e.g., Jet Skis) are included in this
study due to lack of data. PSR does not compile information on personal watercraft and the
survey conducted by Irwin Broh and Associates for NMMA contained numerous cases where
the respondent obviously misunderstood the category. This omission has the effect of slightly
understating the inventory estimates.
The emission factors developed by EPA for this study include new and more extensive
test data than previously incorporated into emission factor estimates. For the first time, the
emission factors also consider evaporative and refueling emissions. In addition, in-use
deterioration estimates were incorporated into a second set of emission estimates for each
inventory. Nevertheless, the potential for inaccuracies still exist due to lack of data in some
areas.
Factors that may cause the emission factors and, hence, the inventories to be
understated are:
• Spillage factor. Application of the spillage factor for on-highway vehicles to
large nonroad engines could result in underestimation of emission factors, since
on-highway users are likely to be more conscious of spilling fuel on themselves
and/or damaging the car's finish. Further, spillage from all equipment is likely
to be underestimated due to the fact that all refuelings were assumed to be
complete fill-ups.
• Evaporative emissions. The absence of data on hot soak or running loss
emissions for nonroad vehicles and vapor displacement for gas can refueling
may have resulted in underestimation of total evaporative emissions.
• Wintertime CO emissions. All emission factor testing has occurred at typical
summertime temperatures (roughly 75°F). CO emissions, however, increase at
colder temperatures due to additional fuel enrichment and longer warmup
times. This effect was not accounted for in the determination of CO rpwd for
nonroad engines due to lack of data. The proportion of cold start operation on
nonroad engines is unknown, but is likely to be much lower than for
November 1991 107
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Nonroad Engine and Vehicle Emission Study
automobiles due to the tendency for most nonroad engines to be used for
extended periods of time. It should be noted that the on-highway mobile
source inventories used to determine the relative contribution of nonroad
emissions did include the effect of wintertime temperatures on emissions.
• Crankcase CO and NOX emissions. Exclusion of crankcase CO and NOX
emissions could result in slight underestimation of nonroad emissions, even
though their contribution is relatively small.
4.2.3. Additional Considerations
Several factors that could potentially offset the contribution of nonroad engines to air
quality nonattainment were not incorporated into this study. Some were not included because
it was determined that to do so would not improve the validity of the results, while for others,
insufficient information was available to develop methodologies within the timeframe
mandated by Congress. This section discusses these factors, the reasons why they were
excluded, and the potential impact (if any) on the results.
Non-Seasonal Temporal Adjustments—As previously discussed, EPA adjusted
nonroad equipment activity levels for seasonal variation in usage. The inventories in this
study are expressed in average daily emissions during summer (tpsd) and winter (tpwd),
which are the seasons associated most strongly with ozone and CO nonattainment,
respectively. As discussed in Appendix L, ozone and CO exceedences occur during both
weekdays and weekends. Consequently, variations in source activity during the week and
during the day were not considered.
Photochemical ModeIing~As has been noted elsewhere in this report, the formation
of ozone is an extremely complex process. It is difficult to understand the exact role played
by emissions from the thousands of sources inside and upwind of a particular nonattainment
area without a detailed photochemical model that takes into account not only manmade
emissions but also local wind and weather patterns and biogenic emissions. Only recently
have reliable photochemical models come into widespread use. The Regional Oxidant Model
(ROM) for large, multi-state areas and the Urban Airshed Model (UAM) for individual urban
108 November 1991
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Discussion and Analysis of Results
areas represent the state of the art in air quality modeling for attainment planning. Congress
has mandated that the worst nonattainment areas use photochemical modeling as a tool in
developing individual customized plans for attaining the ozone standard.
EPA has not included photochemical modeling in this study for two reasons. First,
developing and calibrating these models for even one nonattainment area would not have been
possible within the deadline and budget for completion of this study. Second, the detailed,
localized information available from photochemical models of individual cities would have
added little additional relevant information to the overall question of the importance of
nonroad emissions to attainment problems nationwide. Photochemical models are useful in
deciding such questions as "On the margin, which kind of additional control would be more
effective in reducing ozone in a particular area, NOX or VOC?" Thus photochemical modeling
is important in severe nonattainment areas, where very large emission reductions are needed
and each additional emission reduction strategy is likely to be costly. Detailed photochemical
modeling of all nonattainment cities is not required to reach the conclusion that the ozone
problem in urban areas across the United States is serious and attainment of the ozone
standard will require large reductions of both VOC and NOX emissions nationwide; that
conclusion has already been reached in the establishment of the CAA itself. The
photochemical modeling of alternative emission control strategies contained in the recent
ROMNET report13 offers additional support: ROMNET found that reductions in both VOC
and NOX emissions beyond the minimum requirements of the CAA and across the
northeastern U.S. would be required to bring the major East Coast cities into attainment of the
ozone standard. Thus, EPA is satisfied that if nonroad sources are found to be a significant
contributor of either NOX or VOCs, then they are a significant contributor to nonattainment of
the ozone standard.
Photochemical Reactivity—An issue related to photochemical modeling is whether
nonroad VOC emissions are, on average, more or less photochemically reactive than
emissions from other sources. As is evident from the discussion of toxic emissions from
nonroad engines, very little data exists on the amount of individual species of VOCs emitted
by nonroad engines. For the purposes of this study, EPA has assumed that the photochemical
reactivity of nonroad VOC emissions is the same, on average, as VOC emissions from other
sources. This is a reasonable assumption given that most nonroad engines are related to on-
November 1991 109
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Nonroad Engine and Vehicle Emission Study
highway engines and that on-highway engines are the single most important source of VOC
emissions in nonattainment areas.
Transport—During the past few years, it has become more apparent that ozone is a
regional and not a local air quality problem. Recent studies l4 15 16 have shown that
ozone and ozone precursors can travel long distances and affect air quality in areas at least
two hundred miles from the source of ozone-forming emissions under some circumstances.
Obviously, ozone does not respect the political boundaries enclosed by city, county, state, or
nonattainment area lines.
Ozone transport complicates the assessment of nonroad emission contribution to urban
nonattainment. To keep this study to a manageable size, EPA decided to include only
equipment usage within the nonattainment areas in the inventory estimates. However, EPA is
aware that emissions from equipment outside the nonattainment area boundaries also will
affect the ozone level within nonattainment areas. Because emissions from equipment used
outside nonattainment area boundaries may affect air quality, but are not accounted for in the
inventories included here, the contribution of this equipment to urban nonattainment will be
underestimated in this study. Underestimation of the air quality impact of nonroad equipment
will be greatest for those types of equipment that have a substantial portion of their usage
outside urban areas, such as agricultural equipment and recreational equipment (including
marine pleasure craft).
It is difficult to quantify the underestimation of the nonroad impact on urban
nonattainment that is due to transport for several reasons. First, EPA does not have current
detailed information on nonroad populations and usage rates outside the areas considered in
this study. County-by-county inventories for nonroad equipment are contained in national
emission data bases, such as the inventories used in the National Acid Precipitation
Assessment Program (NAPAP), but these inventories are at a rather broad level of
categorization (such as "nonroad-diesel"), and use some obsolete emission factors. Second, it
is difficult to estimate exactly what proportion of the emissions outside nonattainment areas
affect nonattainment area air quality. It would seem reasonable to assume that emissions
from sources 50 miles from a nonattainment area would have a greater impact than an
identical source 150 miles from the nonattainment area, but currently no accepted "distance
discount factor" is available that could be applied to inventories outside nonattainment areas.
HO November 1991
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Discussion and Analysis of Results
Third, the impact of transported emissions in any given area may vary considerably with
meteorological conditions, particularly wind speed and direction. A study of transport in
California found that, in some air basins, transport may have an "overwhelming" impact on
ozone levels under one set of meteorological conditions, but an "inconsequential" impact
under another set of meteorological conditions. Finally, local topography would be expected
to influence the pattern and importance of transport in different areas. Transport
characteristics in a nonattainment area surrounded by mountains and valleys would be
different from those in nonattainment areas surrounded by flat land.
To adequately assess the impact of transport on individual areas, detailed regional
oxidant models (ROMs) must be constructed. These models include thousands of parameters,
such as spatially distributed emission inventories for manmade and biogenic emissions over a
wide area, detailed meteorological data, and topographical characteristics. Construction of
these models was beyond the scope of this study. However, EPA's Office of Air Quality
Planning and Standards, in association with EPA regions and state authorities, has recently
completed a five-year study of transport and ozone formation in the Northeast, the Regional
Oxidant Model for Northeast Transport (ROMNET). ROMNET concluded that emissions
outside the heavily urbanized northeast coastal "Corridor" contributed to nonattainment in the
Corridor. The ROMNET report states: "The results suggest that without stringent upwind
controls, ozone levels in parts of the Corridor may not be reduced to below the concentration
specified in the NAAQS even with stringent controls along the entire length of the Corridor."
(p. ES-11).
The ROMNET inventories and modeling results may be used to make an
"order-of-magnitude" assessment of the potential impact of transported nonroad emissions on
nonattainment. By looking at the effect of reducing upwind emission inventories on ozone
levels in particular nonattainment areas and at the proportion of nonroad emissions in the
upwind inventories, a rough estimate of the impact of transported nonroad emissions on these
cities under one set of meteorological conditions may be obtained. According to control
measure simulations in the ROMNET study, a reduction of 65% of the non-Corridor VOC
inventory and 60% of the non-Corridor NOX inventory resulted in an average peak ozone
reduction of 8.6 ppb in the Corridor as a whole and 11.5 ppb average peak ozone reduction in
the nonattainment areas of Washington/Baltimore and Philadelphia. This implies that 1% of
November 1991 ~~ ~
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Nonroad Engine and Vehicle Emission Study
the non-Corridor VOC and NOX inventories account for 0.14 ppb of the peak ozone
concentration in the Corridor cities on average and about 0.18 ppb of the peak ozone
concentration in the Washington/Baltimore and Philadelphia areas. The ROMNET Study
assumed that nonroad engines accounted for 2.3% of the non-Corridor VOC inventory and
4.4% of the non-Corridor NOX inventory in 1985. Very roughly, this implies that transported
pollutants from nonroad sources account for 0.5 ppb of the peak ozone concentrations in the
Corridor cities as a whole and 0.6 ppb of the peak ozone concentration in the Baltimore/
Washington and Philadelphia areas under the meteorological conditions modeled. If nonroad
sources are not controlled, transported pollutants from non-Corridor nonroad sources would
account for roughly 0.3-0.45% of the ozone level along the East Coast during nonattainment
episodes after implementation of the other measures in the 1990 CAAA. These estimates are
not included in the estimates of the impact of nonroad emissions on urban nonattainment in
the rest of this report, because they were available for only a few cities under specific
circumstances and because the ROMNET nonroad emission estimates are likely to be greatly
understated.
EPA and state and local air quality authorities are continuing their study of the impact
of transported emissions on urban nonattainment. Efforts are currently underway to further
characterize ozone formation and transport in the Northeast, and comprehensive ROMs
covering the Midwest and Southeast are also planned. A comprehensive study of ozone
transport in the Lake Michigan area has been launched by EPA's Region V and the states
surrounding Lake Michigan.
A more complete description of existing transport studies is contained in Appendix P.
4.3. Analysis of Nonroad Emission Impact
A great deal of effort and money has been expended on reducing emissions from a
wide variety of sources, from the automobile to area sources such as dry cleaning and
bakeries. The CAAA of 1990 mandate additional controls in many areas and more stringent
controls on most of the equipment currently regulated. The purpose of this section is to help
put the nonroad emission contribution into context by comparing nonroad emissions to
currently regulated sources.
112 November 1991
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Discussion and Analysis of Results
The nonroad emission inventories developed for this study estimate that the median
nonroad contribution to total VOC and NOX emissions for the nonattainment areas studied is
over 7% for VOC and over 14% for NOX. Based on emission inventories for all sources
given in National Air Pollutant Emission Estimates: 1940-1989, the only source categories
with larger VOC contributions at the national level are on-highway mobile sources and
solvent evaporation. Also at the national level, the only source categories with greater NOX
contributions are on-highway mobile sources and electrical generation. Among the source
categories with lower estimated contributions are industrial combustion, industrial processes,
petroleum refining, and petroleum product storage and transfer. All of these other source
categories are currently subject to emission control regulations. The estimated contributions
of these categories are presented in Table 4-07.
Table 4-07. Contribution to Total Inventory
Pollutant
VOC
NO,
Source Category
On-highway Mobile
Solvent Evaporation
Nonroad
Petroleum Refining
Petroleum Product
Storage and Transfer
On-highway Mobile
Electrical Generation
Nonroad
Industrial Combustion
Industrial Processes
% contribution§§§§§§§
25
24
7-13
3
7
29
32
14-17
14
3
Another comparison of nonroad emissions to other sources can be made by examining
the 1990 CAAA requirements for Reasonably Available Control Technology (RACT) on
stationary sources. RACT controls will now be required on all stationary sources with either
VOC or NOX emission above 50 tpy in serious nonattaimnent areas, 25 tpy in severe areas,
»«IIH Nonroad based on median contribution determined by this study; ranges reflect the largest and smallest
local contributions calculated by Inventories A and B with new engine and in-use emission factors. All other
contribution estimates are based on data from National Air Pollution Emission Estimates: 1940-1989, and are given
at the national level for 1989.
November 1991
113
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Nonroad Engine and Vehicle Emission Study
and 10 tpy in extreme areas. This means, for example, that an area designated as an extreme
ozone nonattainment area is required to install RACT control on every stationary source over
10 tpy. By comparison, Table 4-08 provides the number of new vehicles or pieces of
equipment that it would take to generate 10 tpy, based on their typical yearly operation. For
the nonroad sources, the chart indicates the range between data used to develop A and B
national inventories.
Table 4-08. Comparison of Ozone Precursor Emissions from Various Vehicles
and Equipment
Vehicles or Equipment
Off -highway trucks
Crawler tractors
On-highway heavy-duty
diesel truck*
Agricultural tractors
Boats with outboard motors
Passenger Cars*
Chain saws
Lawnmowers
String trimmers
No. for 10 tpy
1.6-2.1
10
20
24
74-142
700
730-1,630
1,680-2,380
2,810-4,630
* Based on first-year emissions of a current
technology vehicle.
Because CO nonattainment is usually more localized than ozone nonattainment,
comparisons of national CO emissions may be misleading. A comparison of nonroad and
highway CO emissions may, however, be made at the local level. Inventories developed for
this study indicate that the median nonroad contribution to local wintertime CO emissions
ranged from 5.2% to 9.4%, while the median contribution from highway vehicles was 81%.
114
November 1991
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Chapter 5. Conclusions
A significant quantity of new information was generated by CARB, EPA, EPA
contractors, and the industry in response to California's proposed nonroad regulations and this
study. EPA used this new information and existing data to develop Inventories A and B. As
a result, these inventories provide a more comprehensive picture of nonroad emission
contributions to VOC, NOX, CO and PM, than previously available. Among the findings of
this study are the following:
1. Median nonroad contributions to the total emission inventory for the 24 areas are
estimated to be:
Inventory A
Inventory B
VOC (%)
9.1-12.6
7.3-10.3
NOX (%)
17.3
14.5
CO (%)
5.9-9.4
5.2-8.5
PM (%)
1.8
1.0
Congress mandated that EPA study emissions from nonroad sources to determine
whether such emissions cause or significantly contribute to air quality problems, and
in particular whether they are contributors to ozone or CO concentrations in more than
one CO or ozone nonattainment area. Of the nonattainment areas studied, the second
highest contribution to total inventories from nonroad engines and vehicles for VOC,
NOX, and CO is as follows:
Inventory A
Inventory B
VOC (%)
13.1-18.7
11.4-16.0
NOX (%)
29.3
31.1
CO (%)
9.0-14.2
8.5-13.3
The results discussed throughout this report do not include the transport of ozone into
the nonattainment areas. The effect of ozone transport would be to increase the
emission contribution of typically nonurban equipment, such as agricultural,
November 1991
115
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Nonroad Engine and Vehicle Emission Study
recreational marine, and logging equipment. While this effect may be relatively small,
it is not insignificant.
4. Only on-highway vehicles, electric generation, and solvent evaporation have NOX
and/or VOC emissions that exceed those of nonroad equipment.
Recommendations for Inventory Improvements
The study identified a number of areas where inventory estimates could be affected by
the absence of data or the use of limited information. Nonroad inventory estimates could be
enhanced by collection of additional data, particularly in the area of emission factors. For
example, existing nonroad emission data allows an adequate assessment of tailpipe emissions
from relatively new engines. More information, however, is needed to quantify other types of
emissions, such as evaporative, crankcase, and toxic emissions, and the effect of in-use
deterioration. Specifically, data should be obtained for the following areas:
1. In-use emissions. Additional testing needs to be conducted on in-use engines
to further quantify the effects of deterioration on the different types of nonroad
engines.
2. Hot soak and running loss evaporative emissions. Currently, no hot soak and
running loss evaporative emission data exist for nonroad engines. Such
emissions are substantial for on-highway vehicles and can vary significantly
according to the type of equipment on which an engine is installed. Therefore,
tests should be conducted to determine whether these emissions from nonroad
equipment need to be controlled.
3. Toxic emissions. EPA used the limited data that was available on toxic
emission from nonroad engines to make the assumptions regarding such
emissions. Such assumptions, particularly those for 1,3-butadiene, should be
verified through further testing.
116 November 1991
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Conclusions
4. Crankcase emissions. Further studies should be conducted to improve the
measurement of crankcase emission levels from nonroad engines and to
determine which engines use open and closed crankcases.
5. Cold start emissions. Currently, no data are available on the contribution of
cold starts to nonroad emissions. Work should be undertaken to assess the
proportion of cold start fuel enrichment operation on different types of nonroad
equipment, and then to measure the impact of such operation on total
emissions.
6. Emission data representativeness. Currently, nonroad emission data are
uniformly applied to all similar nonroad engines. More accurate emission
factors could be developed if emission testing were performed on engines
representative of the population.
7. Cycle representativeness. Steady state test cycles do not adequately represent
VOC, CO, and paniculate emissions generated during in-use transient
operation. To the extent that nonroad equipment encounters transient operation
in-use, steady state cycles could significantly understate emissions, especially
paniculate matter. The adjustments made in this study to account for transient
operation were based on very limited test data which applied only to diesel
engines. More work should be done to assess the typical operating cycles of
nonroad equipment. Such characterizations would facilitate the assessment of
the amount and importance of transient operation on nonroad engines, as well
as improve load factor estimates.
November 1991 117
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References
1. U.S. Congress. House. Report of the Committee on Energy and Commerce U.S. House
of Representatives. 101 Cong., 2d Sess., 1990. H.Rept. 490, Pt 1, p.145.
2. U.S. Environmental Protection Agency. National Air Quality and Emissions Trends
Report, 1989. EPA-450/4-91-003. Research Triangle Park, NOOffice of Air Quality
Planning and Standards, February, 1991.
3. U.S. EPA, Trends Report.
4. U.S. EPA, Trends Report.
5. Ingalls, Melvin N. Nonroad Emission Factors of Air Toxics. Report 08-3426-005. San
Antonio, TX:Southwest Research Institute, June 1991.
6. Irwin Broh & Associates, Inc. NMMA Boat Usage Survey. Prepared for the National
Marine Manufacturers Association, Des Plaines, IL. August 1991.
7. U.S. Environmental Protection Agency. 1985 National Emissions Report. Research
Triangle Park, NQOffice of Air Quality Planning and Standards, September, 1988.
8. U.S. Environmental Protection Agency, National Air Pollutant Emission Estimates: 1940-
1989. EPA-450/4-91-004. Research Triangle Part, NGOffice of Ak Quality Planning
and Standards, March 1991.
9. U.S. Environmental Protection Agency. 1985 National Emissions Report. Research
Triangle Park, NC:Office of Air Quality Planning and Standards, September, 1988.
10. Carey, P.M. Air Toxics Emissions From Motor Vehicles. EPA-AA-TSS-PA-86-5. Ann
Arbor, MI:U.S. Environmental Protection Agency, September, 1987.
11. U.S. Environmental Protection Agency. National Air Pollutant Emission Estimates 1940 -
1989. EPA-450/4-91-004. Research Triangle Park, NC:Office of Air Quality Planning
and Standards, March 1991.
12. Adler, J.M., and P.M. Carey. Air Toxics Emissions and Health Risks from Mobile
Sources. AWMA 89-34A.6, presented at the Air & Waste Management Association 82nd
Annual Meeting, Anaheim CA, June 1989. Ann Arbor, MI:U.S. Environmental Protection
Agency, June 1989.
13. U.S. Environmental Protection Agency. Regional Oxidant Modeling for Northeast
Transport (ROMNET). EPA-450/4-9l-002a. Research Triangle Park, NCOffice of Air
Quality Planning and Standards, June 1991.
14. U.S. EPA, ROMNET.
15. Sillman, S., J. Logan, and S. Wofsy. "Sensitivity of Ozone to Nitrogen Oxides and
Hydrocarbons in Regional Ozone Episodes." Harvard University, Cambridge, MA.
Revised Manuscript, July 7, 1989.
118 November 1991
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; References
16. California Air Resources Board. Assessment and Mitigation of the Impacts of
Transported Pollutants on Ozone Concentrations within California. El Monte, CA: State
of California, June 1990.
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