United States Office of Air and Radiation
Environmental Protection (ANR-443)
Agency Washington, DC 20460
June 1996
O EPA Regulatory Impact Analysis
Control of Air Pollution Emission Standards for
New Nonroad Spark-Ignition Marine Engines
Note: The there may be minor differences in formatting and page numbers
in this version of this document versus the original hardcopy.
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REGULATORY IMPACT ANALYSIS
Controf of Air Poffution;
Emission Stendartte for
New Nonroad Spark-Ignition
Marine Engines
June 1996
U S. Environmental Protection Agency
Office of Mobile Sources
Engine Programs and Compliance Division
2565 Plymouth Road
Ann Arbor, MI 48105
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ACKNOWLEDGMENTS
This Regulatory Support Document was authored by Mr. Bill Charmley, Ms. Deanne R.
North, Mr. Michael Samulski, and Ms. Sujan Srivastava.
Members of the National Marine Manufacturers Association and many individual
manufacturers have provided EPA with input on the technical and economic aspects of the engines
impacted by the this rulemaking. A number of manufacturers provided essential test data,
production engines for testing, or prototype engines for testing. EPA sincerely appreciates the
cooperation of industry in EPA's technical evaluation of these engines and equipment.
i
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Table of Contents
Introduction 1
Chapter 1: Technology Assessment 1-1
1.1. Adequacy of Test Procedures 1-2
1.1.1. Emission Test Procedures 1-2
1.1.1.1. Known Marine Duty Cycles 1-2
1.1.1.2. Steady-State and Transient Test Options 1-4
1.1.1.3 Emission Sampling and Test Set-Up Options 1-6
1.1.1.4 Summary of EPA Emission Test Procedures 1-9
1.1.2. Durability Test Procedures 1-9
1.1.2.1. Engine and Emission Control System Deterioration Factors
1-10
1.1.2.2. Durability Demonstration 1-11
1.1.2.3. Representation of Available Fuel 1-12
1.2 Emission Control Technology 1-12
1.2.1. Current Technology 1-13
1.2.1.1. Outboard and Personal Watercraft Spark-ignition Engines
1-13
1.2.1.2 Sterndrive and Inboard Spark-ignition Engines 1-14
1.2.2. Potential Emission Control Technology 1-14
1.2.2.1. 4-stroke Technology 1-15
1.2.2.2. Direct Injection 2-Stroke Technology 1-15
1.2.2.3. Catalyst Technology 1-16
1.2.3 Control Technology Pollutant Levels 1-17
1.2.3.1 Outboard and Personal Watercraft Engines 1-17
1.2.3.2. Sterndrive and Inboard Engines 1-20
1.2.4. Technology Costs 1-20
1.2.4.1. Industry Cost Data Submissions 1-21
1.2.4.2. Technology Cost Per Engine Family 1-22
1.2.5. Cost-Effectiveness of Available Technologies 1-26
1.2.6. Resultant Technology Market Mix 1-28
1.3. Performance Impacts 1-29
1.3.1. Fuel Consumption 1-29
1.3.2 Weight and Performance 1-30
1.3.3. Noise 1-32
1.3.4. Safety : 1-32
1.3.5. Maintenance 1-34
1.4 Impacts on Vessel Design 1-35
Chapter 1: References 1-37
Chapter 2: Aggregate Cost Analysis and Economic Impacts 2-1
2.1. Industry Description and Market Analysis 2-1
2.2. Aggregate Cost Estimate 2-7
2.3. Consumer Cost Summaiy 2-9
2.4. Incremental Economic Impacts 2-11
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2.4.1. Capital 2-11
2.4.2. Sales and Employment 2-11
2.4.3. Energy 2-13
Chapter 2: References 2-15
Chapter 3: Environmental Benefit 3-1
3.1. Estimated HC+NOx Emissions Reduction 3-2
3.1.1. Aggregate Estimated Annual HC+NOx Reduction 3-4
3.1.1.1. Sales Projections 3-4
3.1.1.2. Survival Probabilities 3-6
3.1.1.3. In-Service Population 3-7
3.1.1.4. Aggregate Source Emissions Inventory 3-8
3.1.3. Cost-Effectiveness 3-9
3.2 Air Quality Benefits 3-10
3.2.1. Tropospheric Ozone 3-10
3.2.1.1. Health and Welfare Effects of Ozone 3-12
3.2.2. Volatile Organic Compounds 3-13
3.2.2.1. Health and Welfare Effects of VOC Emissions 3-13
3.2.3. Benzene 3-13
3.2.3.1 Projected Benzene Emission Reductions 3-15
3.2.3.2 Health and Welfare Effects of Benzene Emissions- 3-16
3.2.4. 1,3-Butadiene 3-18
3.2.4.1 Projected 1,3-Butadiene Emission Reductions 3-18
3.2.4.2 Health and Welfare Effects of 1,3-Butadiene Exposure- 3-19
3.2.5 Formaldehyde 3-19
3.2.5.1. Projected Formaldehyde Emission Reductions 3-20
3.2.5.2. Health and Welfare Effects of Formaldehyde 3-20
3.2.6 Acetaldehyde 3-20
3.2.6.1. Projected Acetaldehyde Emission Reductions 3-20
3.2.6.2. Health and Welfare Effects of Acetaldehyde 3-21
3.2.7 Carbon Monoxide 3-21
3.2.7.1. Health and Welfare Effects of CO 3-21
Chapter 3 : References 3-24
Appendix A: Supplementary Tables A-l
iii
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Introduction
This document presents the Regulatory Impact Analysis (RIA) for the Final Rule for New
Gasoline Spark-Ignition Marine Engines, herein after referred to as the final rule. The final rule
is promulgated pursuant to EPA's authority under § 213(a)(3) of the Clean Air Act.
This RIA includes the Agency's written statement in accordance with section 202 of the
Unfunded Mandates Reform Act of 1995. The RIA does not analyze the effects of the final rule on
State, local, or tribal governments because the rule imposes no enforceable duties on such
governments. The RIA does offer an assessment of the anticipated costs and benefits of the rule,
including future compliance costs for the affected industry, the effect on public health and the
environment, and estimates of the effect on the national economy to the extent such effect is
relevant and material and accurate estimates are reasonably feasible.. A summary of the
significant comments and concerns presented by State, local, or tribal governments in response to
the proposal is provided in the Summary & Analysis of Comments Document, together with the
Agency's responses to such comments and concerns.
This RIA is organized into chapters and appendices. Chapter 1 presents the engineering
evaluation EPA has undertaken to determine the possible technical solutions for emission
reductions from these engines and the specific technology and the related cost of such solutions.
Chapter 2 considers the aggregate costs of the final rule and analyzes economic impacts.
Chapter 3 quantifies the emission reduction benefits of the final rule and assesses impacts on
environmental and health effects of these emissions. Also, Chapter 3 presents the schedule of
emission reductions and costs of the rule and relates them to one another in terms of cost-
effectiveness. An appendix is provided which contain supporting data.
1
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Chapter 1: Technology Assessment
This chapter presents an assessment of various emission control technology that
may be applied to gasoline spark-ignition (SI) marine engines. The main focus of this
regulation is a large reduction in hydrocarbons (HC) with a minimum increase in
oxides of nitrogen (NOx) from OB/PWC engines. Though no standards have been
finalized for carbon monoxide (CO), this section also discusses the impact the Agency
expects this final regulation will have on CO emissions from gasoline SI marine
engines. Emission control technology for each of these constituents will be discussed in
this chapter.
Both current and potential emission control technology are discussed in detail
along with the impact on pollutant level of each technology. Based on these emission
control technology options, the lowest feasible emission standards are calculated.
Engine modifications for emission reductions will also affect engine performance and
maintenance. These impacts are discussed in this chapter as well as possible impacts
on vessel design.
Standardized test procedures for exhaust emissions and durability are required
for setting an emission standard and for assessing the impacts of emission control
technology. Before the emission control technology options are discussed, an
understanding of the test procedures is required. Therefore, this chapter begins with a
discussion of the emission and durability test procedures.
1-1
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1-2
1.1. Adequacy of Test Procedures
In order for EPA to successfully regulate exhaust emissions from marine
engines, test procedures are required that can accurately measure emissions from new
and in-use marine engines. This section will discuss the ability of the finalized test
procedures to measure exhaust emissions for regulation and the test procedure options
that were considered by EPA when developing this regulation. In addition, durability
demonstration issues will be discussed.
1.1.1. Emission Test Procedures
The marine exhaust emission test procedures being finalized by EPA are based
on test procedures developed by the marine industry and interested governments.
Before adopting any test procedure, EPA had to investigate the test procedure
development and possible cases where the test procedures are not representative of in-
use operation. In addition, EPA had to determine when in-use representativeness
must be compromised for test repeatability. The process leading to the final test
procedures is discussed here.
1.1.1.1. Known Marine Duty Cycles-Two sets of test procedures were established,
prior to this rulemaking effort, for determining exhaust emission levels from spark-
ignition recreational marine engines. The duty cycles associated with each of these test
procedures are. composed of steady-state modes. For each mode, the speed and torque
relationship is based on an assumed propeller curve.
In 1993, emission regulations were enacted for marine engines operated on Lake
Constance in Europe(l). Lake Constance (also known as the Bodensee) is a major
source of drinking water for Austria,.Germany, and Switzerland. The purpose of these
regulations is to protect water quality.
Hydrocarbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx) are
regulated by the Bodensee Shipping Regulations or Bodensee-Schiffahrts-Ordnug (BSO).
These emission levels are determined using the BSO eight-mode steady-state test
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1-3
procedure. A ninth mode may also be required depending on the operating
characteristics of a given engine. This duty cycle has a power factor of 0.305.
The International Standards Organization (ISO) has developed test procedures
for determining emissions from several classes of nonroad engines. For the ISO
procedures, a five-mode duty cycle was developed for spark-ignition marine engines.
This duty cycle is known as the ISO E4 cycle.
The E4 duty cycle for spark-ignition marine engines was developed from
operational data collected from 33 boats with outboard marine engines and three boats
with sterndrive marine engines(2). Normalized speeds were calculated, and a time
distribution at normalized speed intervals (10 percent of rated) was developed. This
speed distribution was used to develop five operation modes with accompanying
weighting factors. In addition, an empirical relationship was determined between
speed and torque. This relationship was used to determine the torque for each mode..
This duty cycle has a power factor of 0.207.
The duty cycles discussed in this section are presented in Table 1-01.
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1-4
Table 1-01: Steady-State SI Marine Duty Cycles
Mode
1
2
3
4
5
6
7
8
BSO Duty Cycle
Speed %
idle
40
50
60
70
B0
90
100
Torque %
0
25.3
35.4
46.5
58.6
71.6
85.4
100
Power %
0
10.1
17.7
27.9
41.0
57.2
76.8
100
Weight %
30
10
10
10
20
5
5
10
ISO E4 Duty Cycle
Speed %
100
80
60
40
idle
Torque %
100
71.6
46.5
25.3
0
Power %
100
57.2
27.9
10.1
0
Weight %
6
14
15
25
40
EPA has incorporated the ISO E4 duty cycle in the test procedure for gasoline
spark-ignition marine engines. This duty cycle should not cause harmonization
problems with the BSO procedure since all five of the E4 modes are included in the
BSO duty-cycle. Therefore, a manufacturer testing an engine using the BSO duty cycle
could also calculate a value for the E4 cycle. EPA chose the five-mode duty cycle for
several reasons. One reason is that the generation of the E4 cycle is published, but EPA
is not aware of how the three additional modes were created by BSO. In addition, EPA
does not believe these extra modes will generate enough additional control to warrant
the increase in the length of the tests (3). Finally, most of the emission data used to
develop this rule was based on engines tested on the five-mode duty cycle.
1.1.1.2. Steady-State and Transient Test Options--A test procedure should be capable of
serving two purposes: First, a test procedure must be repeatable so that useful results
may be determined for comparing emission control technologies and for regulating
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emissions. Second, a test procedure must be representative of actual operation of the
engine so that the emission results may be used for air quality analysis. One concern
with a steady-state test procedure is that it overlooks transient operation that may be
found in actual marine engine use.
NMMA(4) and EPA(5) have both collected test data regarding the sensitivity of
transient operation on sterndrive marine engine exhaust emissions. HC, CO, and fuel
consumption tended to increase as the engines experienced more transient operation.
However, NOx tended to decrease under the same conditions for the carburetted
engines and remain constant for the electronic fuel injected engines. Both NMMA and
EPA simulated transience by running the ISO E4 modes together in order, then in
reverse order. The effects of increased transience were studied by increasing the cycle
frequency in a given amount of time. This cycle is presented in Figure 1-01.
100 -
¦a
a» 80
n
c
a)
o
a)
CL
"O
(0
o
a>
a>
a.
CO
60 -
40 -
20 -
[L
— Speed ¦ - Load
ol i i i ii i i i :j...
0 100 200 300 400 500 600 700 800 900 1000
Time [seconds]
Figure 1-01: Low-Transience S! Marine Duty Cycle
To EPA's best knowledge, transience sensitivity testing has not been performed
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on outboard marine engines1. EPA did not perform transient testing on these engines
due to technical difficulties in the transient testing of outboards, especially two-strokes.
EPAs testing experience has indicated raw gas sampling has difficulties associated with
trying to measure emissions from an engine in transient operation since it requires a
steady flow of fuel and air into the engine so that a carbon balance may be performed
to determine the mass flow of exhaust constituents out of the engine. However, at
present, EPA believes that raw sampling is the best method for measuring emissions
from OB/PWC marine engines. This is discussed in more detail later in this chapter.
EPA has decided to use a steady-state procedure in this action for several
reasons. First, the six test engines referenced in this section were not consistent on the
amount of transience necessary to significantly affect emissions from the inboard
marine engines. In addition, EPA has collected little information on the amount of
transience seen in actual marine engine operation. In actual operation, marine engines
are used for diverse applications. Personal watercraft would be expected to be highly
transient with their typical "stop and go" usage, while large cruisers would be
expected to run fairly steady. Information on the operation of marine engines would
be necessary to determine the need for and possibly develop a transient test procedure,
and EPA may collect this sort of information in the future. In any case, EPA believes
that a steady-state test is capable of characterizing emissions with sufficient accuracy to
guarantee real emission reductions from the class of engines covered in this final rule
considering the types of control technology the Agency believes will be utilized.
1.1.1.3 Emission Sampling and Test Set-Up Options—The most challenging aspect of
testing marine engines seems to be how to take the emission sample. This difficulty
rises as a result of water jacketing of the exhaust and actual mixing of cooling water
and exhaust within the drive package. Water jacketing of the exhaust is required to
1 The Agency has performed some limited transient testing of one existing technology PWC, however,
the review of the test data from that program was not completed in time to include in this R1A.
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1-7
meet Coast Guard surface temperature regulations while the mixing of water and
exhaust is used to lower discharge temperatures, tune the exhaust, and muffle noise
from the engine.
The two established methods of sampling exhaust are raw and dilute. For the
purpose of this document, raw sampling refers to inserting a probe into the exhaust
stream (upstream of the water and exhaust mixing) and pulling out a portion of the
exhaust during engine operation. Dilute sampling refers to pulling the entire exhaust
stream through a critical flow venturi (CFV). Because the volume flow through the
venturi must be constant, dilution air is used to offset the changes in exhaust flow from
mode to mode. A sample is then taken from this diluted, well mixed exhaust stream.
EPA has compared emission results from three inboard marine engines that
were tested using both raw and dilute emission sampling. (6) The results from these
three engines show poor and inconsistent correlation between raw and dilute sampling
for HC, NOx, and CO emissions. This was especially surprising on the one engine that
was tested with simultaneous sampling using the two techniques. This marine engine
did not even show consistent emissions trends from mode to mode for raw and dilute
sampling.
EPA does not believe that raw sampling, in of itself, is an unacceptable method
for collecting an emission sample. Raw sampling is slightly less accurate than dilute
sampling because of the added error associated with measuring the mass flow into the
engine; however, this does not account for the large discrepancies seen in the test
engines. The difficult aspect of raw sampling is inserting the probe so that a partial
sample is taken that is representative of the total flow from the engine. If the sample
probe is too close to the exhaust ports, the exhaust may not have had enough time to
mix well; this would result in overly high or low concentrations depending on the flow
characteristics of the exhaust. In addition, if the probe is located too close to the
exhaust port, there may not be enough time for completion of thermal reactions
between the constituents in the exhaust.
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Another disadvantage of raw sampling would be if the need arose to perform
transient testing, in the future, on marine engines. Although a transient test has not
been developed for marine engines, EPA has not ruled out the possibility of converting
to a transient test procedure in the future. Raw sampling has not been proven to be
acceptable for transient testing due to the lag time between fuel flow and emission
measurements. A test facility using raw sampling would run the risk of having its
emissions measurement system becoming obsolete in the future.
Despite the disadvantages of raw sampling, EPA's final test procedures use this
emission sampling technique for outboards and allow it as an option for other marine
engines. This is because raw sampling does have advantages to dilute sampling,
especially in the testing of marine engines. For emission testing of marine engines
using dilute sampling, the cooling water must be routed so that it does not mix with the
exhaust. For raw sampling, the exhaust sample may be taken upstream of where the
water and exhaust mix. The advantage of raw sampling is that the addition of a probe
should have a smaller effect on the exhaust tuning than routing the cooling water away
from the exhaust would have. Especially for two-stroke engines, the engine operation
(power, fuel consumption, and emissions) is sensitive to the exhaust tuning. Because of
the effects of water and exhaust mixing on engine tuning, EPA believes that raw
sampling is the appropriate sampling technique for outboard marine engines. Note
that care should be taken to achieve an appropriate back pressure on the test engine
and to collect a partial sample that is representative of the entire exhaust flow.
Tied into the exhaust sampling method is the actual set-up of the engine in a test
cell. Two major set-up options are crankshaft and propshaft testing. Crankshaft testing
refers to removing the drive unit and applying the load directly to the crankshaft.
Propshaft testing refers to applying the load to the output shaft of the drive unit. The
significance of the drive unit on testing is a result of power losses in the gears and,
more significantly, "tortuous" exhaust passages within the drive unit.
Crankshaft testing allows the reported emission results to be purely engine
based. In addition, dilute sampling is much simpler with crankshaft testing. Engine
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1-9
cooling water can be routed so not to mix with the exhaust and the total exhaust can be
collected easily. However, EPA recognizes that removing the lower unit from an
engine may significantly affect the engine's performance and emission characteristics.
Propshaft testing is probably more representative of actual engine operation
because of the effects of the drive unit on engine performance. However, EPA has
collected little data on the effects of the drive unit on emissions. EPA expects that the
effects of exhaust tuning on emissions would be more significant for two-stroke engines
than for four-stroke engines. EPA recommends propshaft testing for outboards and
two-stroke personal watercraft engines. Note that with propshaft testing of outboards,
a single test would be used for the same engine offered with both a jetdrive and a
propeller option.
1.1.1.4 Summary of EPA Emission Test Procedures— The ISO E4 duty cycle will be used
for measuring HC, and NOx from spark-ignition marine engines. A steady-state cycle
was chosen over a transient cycle in large part due to a lack of data on the
appropriateness of a transient cycle. Sfifi § 1.1.1.2 for further discussion of the transient
vs steady-state cycle. The ISO E4 was chosen over the BSO cycle (See §1.1.1.1).
Outboard marine engines have been reported to be significantly sensitive to
exhaust tuning. In addition, a given marine outboard engine will be typically sold with
a single drive unit. For these reasons, EPA will allow propshaft testing with a raw
emission sample. EPA would only require a single certification test for a given engine
family that offers both jetdrive and propeller options. The marine engine test
procedures will also allow the options of crankshaft testing and dilute sampling..
1.1.2. Durability Test Procedures
When an engine is certified to meet a given set of emission standards, the engine
is expected to comply with these standards throughout its useful life. Experience with
on-highway engines has shown EPA that deterioration, over time, of the engine and
emission control equipment can have a significant effect on emissions. Therefore,
deterioration factors (DFs) must be developed to account for changes in emission
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characteristics over the useful life of the engine. EPA does not have sufficient data for
determining the effects of deterioration on marine engines or on the emission control
technology expected to be used to meet the requirements of this rulel. Therefore, a
demonstration of emission control durability is necessary during the certification
process.
EPA(7) and manufacturers(8) have collected some data on new versus in-use
emissions for existing technology outboard marine engines. For today's crankcase
scavenged two-stroke outboards, there does not appear to be a significant deterioration
of HC+NOx emission over the useful life of the engine. Based on this information, EPA
has concluded that a DF of 1.0 for HC+NOx for existing technology charge scavenged
two-stroke OB/PWC engines is appropriate. EPA will issue certification guidance
indicating EPA's intent to accept manufacturer requests to apply a DF of 1.0 for
existing technology charge scavenged two-stroke OB/PWC engines based on this
information. However, if new information becomes available suggesting this DF is not
appropriate, EPA will consider revising the certification guidance.
1.1.2.1. Engine and Emission Control System Deterioration Factors~EPA is finalizing a
certification durability demonstration program similar to that used for spark-ignition
on-highway heavy-duty engines. This program includes a requirement that for each
engine family, the manufacturer shall determine emission deterioration factors for each
pollutant based on testing of engines, subsystems, or components and/or sound
technical judgment. The deterioration factors would be submitted to EPA and applied
to the new engine emission results to determine compliance with the emission
standards. The deterioration factors would be required to simulate deterioration for
350 hours of use for all spark-ignition gasoline OB/PWC marine engines. These factors
would also be expected to simulate deterioration over a period of 10 years for spark-
ignition gasoline OB engines and 5 years for SI gasoline personal watercraft.
Should a manufacturer choose to use exhaust aftertreatment to meet the emission
standards for any engine family, deterioration factors would have to be determined
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and applied in the same manner as is currently done for an on-highway durability
demonstration. However, no durability demonstration or deterioration factors are
required when an engine that was certified without aftertreatment is later retrofitted
with an aftertreatment device or package. These retrofits are not designed to interfere
with the original design and, therefore, should not result in worse emissions than the
original design. Since the engine has already been demonstrated to be in compliance
without the aftertreatment device, demonstration of the durability of a retrofitted
aftertreatment device is not necessary.
1.1.2.2. Durability Demonstration-Once the manufacturer determines the form and
the extent of engine and/or component selection and testing methodologies,
deterioration factors may be established for a given engine family. These DFs would be
applied to the new engine emission levels and the resulting emission levels would be
required to comply with the emission standards (or the family emission limits). EPA
has established a manufacturer run in-use testing program contained in this final rule.
Engine manufacturers will test engine families selected by EPA in their own fleets.
EPA would use this in-use data to confirm the methodology for establishing
deterioration factors. For example, if in-use testing indicates that an engine family's
emission control system is deteriorating at a faster rate than predicted by the
manufacturer's DF, EPA would challenge the use of the manufacturer's methodology
for determining DFs for other engine families. The manufacturer would have to revise
it's methodology for determining DFs or provide data and information to support the
use of the DF generation methodology for other engine families.
EPA believes that this approach will best ensure that marine emission control
systems will be designed and built to be durable. This program requires
manufacturers to assess deterioration of emission control before such engines enter into
commerce, and to continue monitoring in-use performance once engines have entered
the market place through the in-use testing program. Systems with inadequate
durability can be identified and corrected before they are used on the waterways. Also,
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this approach provides a means of determining the adequacy of the deterioration factor
methodology through actual in-use data.
1.1.2.3. Representation of Available Fuel-Although the certification fuel is
representative of fuel sold for on-highway applications, marine engines may come
across fuel with different blends. The fuel found in most marinas is not required to
meet the same quality and environmental standards as fuel supplied for use in on-
highway applications. Finally, there is no guarantee that all two-stroke oils will
perform equally in marine engines.
Manufacturers have informed EPA of some of the problems associated with non-
certification fuels and oils. Fuel with too high of a volatility may cause vapor lock. Old
fuel may result in plugged injectors. On-highway reformulated fuels may have
detrimental effects on rubber or metal not designed for use with alcohol. Low grade oil
in an engine designed for TCW3 oil may result in unsatisfactory lubrication of the
piston and gears. All of these conditions affect the durability of the marine engine.
EPA recommends that manufacturers specify the fuel and oil in the engine
owner's user manual that are required for the proper operation of the engine.
Whatever fuel is used by the boat owner will be considered typical of in-use operation
unless the manufacture has a strong argument to the contrary for that particular engine.
EPA expects the manufacturers to design their engines to operate on fuels typically
used in marine engine applications.
1.2 Emission Control Technology
This section describes in detail the current technology and the potential emission
control technologies as well as pollutant levels for each technology for spark-ignition
marine engines.
1.2.1. Current Technology
1.2.1.1. Outboard and Personal Watercraft Spark-ignition Engines—The current technology
for outboard and personal watercraft engines is predominantly crankcase fuel/air/oil
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scavenged two-stroke. This technology was used on the first outboard marine engines
produced and continues to be used today. After combustion of the air/fuel/oil
mixture, the resulting exhaust gases are "pushed" or "scavenged" from the cylinder by
the crankcase air/fuel/oil charge. Thus a portion of the air/fuel/oil charge exits the
cylinder along with the exhaust gases resulting in extremely high hydrocarbon
emission levels. Up to 25-30 percent of the fuel consumed by such engines can exit the
cylinder unburned.
Another technology used in the market today, although only making up about
0.1 percent of the current market is 4-stroke technology. Historically, only one
manufacturer has sold 4-stroke gasoline outboards in the U.S. In recent years an
additional manufacturer has begun to market 4-stroke outboards in the lower power
range, ie., no greater than 37kW. However, in the relatively short two-year time frame
between the proposal for this regulation and the final rule, the number of
manufacturers offering 4-stroke OBs has increased to at least four manufacturers, and
the power range available to consumers has increased up to 67 kiloWatts.
EPA has collected test data from outboard marine engines in-house(9) and
through contract{7). This data is presented in the following table:
Table 1-02: Emission Test Data from Outboard Marine Engines
Rated Power
Cycle
New/
HC
NOx
CO
kW
In-Use
g/kW-hr
g/kW-hr
g/kW-hr
6.0
4-stroke
new
22.5
2.17
478
7.4
2-stroke
new
253
0.72
423
7.4
4-stroke
in-use
14.8
3.72
298
11
4-stroke
new
19.5
4.69
349
56
2-stroke
new
139
1.43
200
56
2-stroke
in-use
145
1.07
311
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1.2.1.2 Sterndrive and [riboard Spark-ignition Engines—The current technology used on
nearly all spark-ignition marine sterndrive and inboard engines is 4-stroke. Most of
these engines are derived from marinizing truck or automobile engine blocks.
Marinizing often includes the addition of intake manifolds, fuel systems, and water
jacketed exhaust manifolds to automotive or truck engine blocks.
Currently, the majority of sterndrive and inboard spark-ignition engine utilize
carbureted fuel systems. However, there is a trend toward the increased application of
electronic fuel injection (EFI) for these engines. EFI has the potential to reduce
emissions from SD/I engines, but without specific calibration of the EFI systems for
reduced emissions, the EFI systems are not expected to result in a significant emissions
benefit.
EPA has collected test data from SD/1 marine engines in-house(5). This data is
presented in the following table:
Table 1-03: Emission Test Data from Inboard Marine Engines
Rated Power
Fuel System
HC
NOx
CO
kW
g/kW-hr
g/kW-hr
g/kW-hr
158
carburetted
7.14
5.84
224
167
carburetted
7.93
6.39
172
185
port fuel injection (PFI)
5.27
9.91
151
190
PFI (low HC calibration)
3.30
18.2
71.9
196
carburetted
4.42
10.2
100
1.2.2. Potential Emission Control Technology
1.2.2.1. 4-stroke Technology-One relatively clean (that is, low hydrocarbon
emissions) technology that is feasible for outboard and personal watercraft engines is 4-
stroke technology. This technology eliminates the exhaust gas scavenging by the
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1-15
crankcase air/fuel/oil mixture, thus significantly reducing hydrocarbon emissions.
Four-stroke technology has been used for years for automotive applications as well as
nonroad engine applications such as sterndrive and inboard marine engines and lawn
and garden spark-ignition engines. At the time of the proposal, EPA believed 4-stroke
OB engine technology would be limited by power-to-weight considerations to about
75kW. At the time of the proposal the highest rated 4-stroke OB available in the U.S.
was rated at 37kW. In the short time frame since the proposal, a 4-stroke OB engine
manufactured by Honda Marine has been introduced with a rating of 67kW and a
displacement of 1.61iters. Product literature from Honda states that many of the engine
components for the new 67kW engine come directly from Honda's on-highway 1.61iter
Civic engine. It appears the trend toward higher power 4-stroke OB's will continue,
and the upper limit assumed by EPA at the time of the proposal will likely be
surpassed. It also appears likely that as 4-stroke OB's increase in power, the spill-over
from on-highway 4-stroke engine design and components will continue.
1.2.2.2. Direct Injection 2-Stroke Technology-Direct injection 2-Stroke technology is
another potentially feasible technology for application on outboard and personal
watercraft engines to significantly reduce hydrocarbon emissions. This cleaner type of
2-stroke technology directly injects the fuel into the combustion chamber, thus avoiding
the air/fuel/oil scavenging losses inherent with current technology 2-stroke engines.
For direct injection designs, exhaust gases are pushed out, or scavenged from the
combustion chamber with the air/oil mixture from the crankcase, not the air/fuel/oil
crankcase mixture that is used to scavenge current technology 2-strokes. This not only
results in significant hydrocarbon emissions reduction, but also improves fuel
economy. There are a number of different variations of direct injection technologies.
Two main grouping are those that use air assisted (pneumatic) systems to inject fuel
and those that are not air assisted that rely on mechanical means to develop the
necessary injection pressures. An example of an air assisted system, developed by
Orbital Corp. of Australia is discussed in more detail in the following.
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Orbital's Small Engine Fuel Injection System (SEFIS): This technology consists of
applying a Small Engine Fuel Injection System (SEFIS) consisting of a Fuel and Oil
Metering Pump (FOMP) and a Direct Cylinder Injector (DCI). The FOMP controls the
amount of fuel and oil delivered to the engine. The oil is measured as a function of
engine speed and fuel flow. Because the FOMP injects oil into the air intake, fuel and
oil are not mixed in the fuel tank. The fuel injection is accomplished by an air assisted
(pneumatic) fuel injector used to achieve a stratified charge. The air and fuel are
injected into the cylinder. Electronic control of the injection timing is used to prevent
scavenging losses at high loads and excessive fuel dispersion at light loads (to control
hydrocarbons and stability).
At the time of the proposal, no DFI two-stroke engines had been introduced in
the U.S. or were being manufactured. However, beginning with the 1996 model year,
Mercury Marine introduced a 200hp DFI 2-stroke.
1.2.2.3. Catalyst Technology-A third technology that EPA believes to be potentially
feasible for reducing hydrocarbon emissions from outboards and personal watercraft is
catalyst technology. Catalysts have been used for reducing emissions from automobiles
since the mid 1970's. Catalysts can also be used for marine applications, but there are a
number of technological hurdles that must be overcome.
A main complication with the use of catalysts with marine engines is that water
is mixed with the exhaust for engine surface temperature reduction to comply with U.S.
Coast Guard regulations and for noise reduction purposes. Catalysts would have to be
designed to be located upstream of the point where water is introduced into the
exhaust system. Also, especially for outboard and personal watercraft engines, severe
packaging constraints make the application of catalysts very challenging. One last
point is that since these engines can often operate at wide open throttle for extended
periods of time, high catalyst temperatures limit the conversion efficiency levels to
which the catalysts can be designed. Catalysts along with the closed loop electronic
fuel injection systems used for automobile applications often achieve greater than 90
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1-17
percent hydrocarbon conversion efficiency. However, automobiles do not operate for
extended periods of time at wide open throttle where catalysts temperatures can cause
severe catalyst deactivation or safety hazards. Therefore, for marine applications,
catalyst conversion efficiency may need to be limited to lower conversion efficiency
levels (70-80 percent) due to these temperature concerns.
EPA also considered a number of other emission control techniques to reduce
emissions from outboard and personal watercraft engines. These include recalibration
of current technology 2-stroke engines and electronic fuel injection on current
technology 2-strokes. These methods are expected to achieve much less emission
reduction (see the section "Control Technology Pollutant Levels" below) compared to
the other technologies.
1.2.3 Control Technology Pollutant Levels
1.2.3.1 Outboard and Personal Watercraft Engines—Several technologies were
considered for reduction of HC emissions from current two-stroke outboard and
personal watercraft engines: conversion to four-stroke, direct-injection two-stroke,
recalibration of current two-strokes, and the use of catalytic convertors. In determining
the benefits from these technologies, EPA has compared emissions rates (on a brake
specific work basis) from current two-stroke outboard and personal watercraft engines
without these emission control technologies to estimates and test data from engines
with these emission control technologies. Most of this data was received from the
marine engine manufacturers. EPA has also made independent estimates as well and
both are summarized in Table 1-04.
Table 1-04
EPA and Marine Engine Manufacturer Range of Estimates of Potential Hydrocarbon
Emission Reduction, per Engine, for Current Two-Stroke Outboards and Personal
Watercraft
Technology
HC Percent Reduction Estimate
Ranges, per Engine Mass Specific
Emission Rate (%)
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1-18
Conversion to Four-Stroke
75-95
Two-stroke direct injection
75-90
Recalibration of current two-strokes
8-20
Catalytic converters on current two-strokes
55-75
Electronic Fuel Injection on current two-strokes
15-25
Electronic Fuel Injection w/ Catalytic converter on current
two-strokes
65-75
EPA's estimate for per engine mass emission rate reductions of carbon monoxide
(CO) for personal watercraft and outboards ranges between 8 and 45 percent for most
technologies, depending on the engine size. The direct injection two-stroke technology
is the one exception. Due to the lean-burn nature of direct injection, EPA expects this
technology to result in a per engine reduction in the brake specific emission rate of CO
to be between 40 and 80 percent, depending on the particular engine size.
One inherent result of current air-fuel crankcase scavenged two-stroke engines is
the low emission rate for oxides of nitrogen (NOx). The primary source of NOx in
spark-ignited engines is the oxidation of atmospheric nitrogen. The chemical reactions
\ for production of NOx have large activation energies, therefore NOx formation is
strongly dependent on temperature. In addition, since NOx is formed by the oxidation
of N2, NOx formation is also dependent on the availability of oxygen, (excess oxygen
results from lean air-fuel ratios (A/F)). The condition at which the air-fuel ratio is
chemically balanced for full combustion is called stoichiometry. At a rich A/F, when
there is not enough oxygen present to fully burn the fuel, NOx formation will be low
relative to the same engine running under lean A/F, when there is more oxygen than
necessary to fully burn the fuel. The current state of the marine outboard and personal
watercraft industry has developed around the two-stroke, crankcase-scavenged, spark-
ignition power source. These engines are run at A/Fs on the rich side of stoichiometry,
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1-19
resulting in relatively low combustion temperature, incomplete combustion, and,
therefore, low NOx production.
However, the richness of the charge does not explain why current two-stroke
engines have lower mass emission rates of NOx than comparably powered four-strokes
running at the same A/F. The explanation lies in the exhaust remaining in the
combustion chamber of two-stroke engines from the previous power stroke. This
exhaust, which was not completely scavenged by the air-fuel intake mixture, acts as
internal exhaust gas recirculation (EGR). EGR is a well documented technique used to
lower NOx production in four-stroke spark-ignition engines. EGR acts as a diluent to
the fresh charge in the cylinder, reducing peak burned gas temperatures, and thereby
reducing NOx formation.
Currently unregulated two-stroke crankcase-scavenged outboard and PWC
engines have NOx emission rates which range from 0.5 g/kW-hr up to 4.0 g/kW-hr.
EPA estimates that the two primary technologies which will be used to meet the
emission reductions required by this regulation, conversion to. four-stroke engines and
two-stroke direct injection, will both result in an increase in the level of NOx produced
by outboard and PWC engines. In order to meet the stringent HC emission reductions
contained in the final rule, EPA estimates that manufacturers will need to recalibrate
their engines to run at leaner air-fuel ratios, resulting in higher combustion
temperatures, more complete combustion, and some increase in NOx formation. In
addition, four-stroke and direct-injection two-stroke technology have little "internal
EGR" which could reduce NOx emission rates. On a per engine basis, depending on
the engine size and technology used to meet the finalized HC+NOx standard, the
mass-specific emission rate of NOx will increase to values in the range between 4 and
12 g/kW-hr. However, EPA estimates the overall average NOx for outboard and
personal watercraft engines will be 6 g/kW-hr at the completion of the phase-in
period. Some of this increase in NOx emissions may be counter-balanced by use of
forced EGR technology.
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1.2.3.2. Sterndrive and Inboard Engines—EPA has examined a range of technologies
for the control of exhaust emissions from sterndrive and inboard spark-ignited engines.
These technologies include the following; recalibration of current carbureted and
electronic fuel injection (EFI) engines for maximum emission reduction benefit,
conversion of current carbureted marine engines to electronic port fuel injection, and
the application of oxidizing (or three-way) catalytic convertors to current four-stroke
spark-ignited marine engines. Table 1-05 shows the range of hydrocarbon reductions
estimated by EPA and industry on a per engine basis for the three technologies
investigated by EPA.
Table 1-05:
Range of Estimates of Potential Hydrocarbon Emission Reduction per Engine, for
Current Sterndrive and Inboard Engines
Technology
HC Percent Reduction Estimate
Ranges, per Engine Mass Specific
Emission Rate (%)
Recalibration of Current Engines
8-20
.Electronic Fuel injection
8-20
Application of Catalytic Convertors
65-75
However, EPA has determined that SD/I engines are already significantly cleaner
then the OB/PWC model year 2006 HC+NOx standard (See factual memo from
William Charmley to EPA Air Docket A-92-28, "Emission Levels of Sterndrive and
Inboard Engines", Item # IV-B-01).
1.2.4. Technology Costs
This section describes technology costs. The results of the technology cost
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1-21
analysis is used with the pollutant levels associated with the various technologies as
presented in the previous section to arrive at the presentation of marginal cost-
effectiveness which will be presented in section 1.2.5. Cost-Effectiveness of Available
Technologies.
1.2.4.1. Industry Cost Data Submissions-For purposes of setting the emission
standard, EPA used cost estimates as submitted by industry. EPA reviewed the data
for reasonableness. EPA feels that the industry data is reasonable and is likely to be a
good estimate of the total extent of costs due to regulation. Costs may be different for a
number of reasons, including changes in product offerings, consumer popularity of
engines with emission control, how supply and demand actually determine price, if
maintenance costs are different than estimated, if the submitted data contained cost
over- or under-estimates based on uncertainty, or similar occurrences. Overall, the
extensive amount of data which was submitted appears a fair estimate.
Industry submitted confidential data to National Economic Research Associates,
Inc., (NERA) for analysis and allowed EPA full access to the same data. Information
was submitted for over 90% of the sales in the market, including sales of outboards,
personal watercraft, and sterndrive/inboard engines. Information was only submitted
with respect to engine families marketed in the U.S..
The following types of data were submitted.
• identification of engine family and sales-weighted hp
• 1990 U.S. sales volume per outboard and sterndrive/inboard engine family
• 1993 U.S. sales volume per personal watercraft engine family
• uncontrolled emission rates (g/kw-hr) for HC, NOx, CO, and fuel consumption
at the rated power output
• potential engine control technologies
• controlled emission rates (g/kw-hr) by technology for HC, NOx, CO, and fuel
consumption at the rated power output
• technology or generic costs associated with the development and licensing of a
new technology
• changes in capital costs-incremental changes in emissions testing, tooling,
equipment, and research and development associated with each HC control
technology
• changes in factory parts costs-estimates of specific and miscellaneous costs,
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1-22
additions and subtractions associated with production costs, include variable
hardware costs
• changes in other variable engine costs-royalty payments on a per piece basis,
additional emissions testing, added product support, arid added warranty.
Combined with "changes in factory parts costs," these represent all variable cost
additions.
The following are assumptions used in calculating costs.
• All costs are reported in 1993 dollars.
• Fixed costs to the manufacturers of emission control technology (capital costs)
are assumed to be recoverable over 10 years. These capital costs are amortized
at 7 percent.
• The lifetime of outboard engines ranges from 28 to 54 years according to power
output. The lifetime of sterndrive and inboard engines.is 40 years. Personal
watercraft engines are assumed to last 20 years.
• Outboards are used annually, on the average for 34.8 hours.
Sterndrive/inboards are used 47.6 average hours annually. For Personal
watercraft the average annual usage is 77.0 hours.
• The discount rate for purposes of calculating present value is 3%.
• Dealer costs are 24% of manufacturer costs.
• Maintenance costs are relative to engine size and are based on confidential data
provided by Mercury Marine.
• Fuel price is assumed to be $1.49 per gallon. This is based on $1.25 per gallon
for gasoline and $.24 per gallon for oil.
• Fuel usage is 1.02 gallons per horsepower per year, based on Coast Guard data
on fuel consumption.
1.2.4.2. Technology Cost Per Engine Family—Due to the concern over confidentiality,
specific cost estimates for different technologies cannot be presented. For several
technologies, it is the case that it would be cost-effective for only one manufacturer to
introduce a technology and not cost-effective for any other manufacturers. Further, for
some technologies there is only one manufacturer developing the technology.
Therefore, to present either costs or cost-effectiveness would seem likely to impinge on
the confidentiality of the information submitted.
The technology cost estimates will only address technology costs to the engine
manufacturer. Clearly, the consumer will face additional cost components. Dealer
markup and maintenance costs are expected to increase, yet consumers should realize
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1-23
decreases in fuel and oil expense due to the control technologies in general. These costs
which are not experienced by the engine manufacturer are included in the aggregated
cost estimate of the rulemaking, the consumer cost estimate, and the program cost-
effectiveness. Only the engine manufacturer cost was used to evaluate marginal cost-
effectiveness. This implies that the costs not experienced by the engine manufacturer
(e.g., dealer markup, maintenance cost, fuel savings) do not affect the relative product
mix choices of engine manufacturers. It is probably fair to make this assumption as
manufacturers have indicated varying opinions regarding the relative importance
ratings of fuel savings and maintenance increases on consumer purchase decisions.
However, although EPA did not use these non-manufacturer cost components to
determine the lowest feasible emission standard, one would expect that if fuel savings
and maintenance cost increases are important to consumers, then the manufacturers
will factor these costs into their product offering decisions.
If EPA were to have included these non-manufacturer costs in the marginal cost-
effectiveness estimates, the result would be as follows. First, the inclusion of deader
markup would not affect the relative ranking of marginal cost-effectiveness or the
judgement on the lowest feasible average emission standard. Second, four-stroke
technology should achieve slightly more fuel savings than 2-stroke direct injection
technology. Third, maintenance cost increases generally tend to offset the fuel savings
experiented. The result of the effects of fuel savings and maintenance cost increases
may be to change the relative ranking of marginal cost-effectiveness slightly, may
generally shift the entire marginal cost-effectiveness curve up slightly, yet should not
affect the judgement on the lowest feasible emission standard as the shape of the
marginal cost-effectiveness curve should not change significantly.
Therefore, due to concerns over confidentiality of data and the costs
manufacturers will use to make product offering decisions, EPA will present an
example of how manufacturer technology costs are calculated for a fictitious engine
family. The result of this type of calculation is used in an analysis of cost-effectiveness
per engine family which is presented in section 1.2.5., Cost-Effectiveness of Available
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1-24
Technologies. This calculation is an estimate of the increase in manufacturer cost
expected to be incurred for all the engines sold in the engine family in a given year of
sales.
As exemplified in Table 1-06, capital costs are annualized as if the manufacturer
had to take out a loan to cover the increase at a 7% rate of interest. It is assumed that
the amortized capital costs are recovered over the approximate ten year average
production period for an engine family. Essentially, this method assumes that the true
cost of incurring capital expenses is related to the earnings which the capital costs could
have produced if used differently than as an investment in emission reduction
technology. The variable costs were aggregated for the engine family according to the
total amount of sales.
Table 1-06:
Sample Cost Calculation
(Fictitious Engine Family)
calculation
result
1
output (kW)
100
2
U.S. sales in model year
1,000
3
capital costs for engine
family
$2,500,000
4
variable cost per engine unit
$100
5
amortized capital cost to be
recovered over engine sales
in this model year
(3) * .14 = this year's payment on
a loan used to cover the
increased capital cost where the
annual interest rate is 7% and the
production period of the engine
family is 10 years
$350,000
6
total annual increase in
variable engine costs
(4) x (2)
5100,000
7
manufacturer's total
annualized cost for this
engine family
<5) + (6)
$450,000
8
total cost to the manufacturer
per engine
(7)/(2)
$450
Although EPA cannot present the actual technology costs specific to the different
control technologies in this document, it is acceptable to present the overall costs
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1-25
without identifying which technologies or engine families those costs apply to. In this
way EPA can present the magnitude of the engine family specific costs without
revealing any confidential information. Presented in Figure 1-02 is the marginal
annualized engine manufacturer cost per engine family. Marginal costs are appropriate
when comparing several technologies which could be applied to an engine family,
each resulting in varying degrees of emission control relative to baseline emission
levels. For example, technology A for an engine family may cost X dollars to apply yet
only result in a 25% decrease in emissions relative to the baseline level. Technology B
could be applied to the engine family costing X+Y dollars and resulting in a 80%
decrease in emissions, relative to the baseline level. Therefore, the marginal cost for
technology A for this engine family is X dollars. The marginal cost for technology B for
this engine family is (X+Y)-X dollars, or simply Y dollars. According to this
methodology, the actual manufacturer marginal costs per engine family are ranked and
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1-2S
presented in Figure 1-03. Marginal costs do not imply that the technologies are
Figure 1-02
ACTUAL MARGINAL MANUFACTURER COSTS
additive. In other words, it may not be the case that technology B can be added to an
engine which already has technology A. Technology B may be entirely different type
of engine, such as a 4-stroke engine whereas technology A may be 2-stroke control
technology. The main reason for calculating marginal costs is to determine how much
more cost would have to be incurred to produce a more stringent control technology.
1.2.5. Cost-Effectiveness of Available Technologies
The chosen standards structure is that of averaging and trading of emission
levels with respect to exceedances and shortfalls to an average emission standard. With
this chosen standards structure, EPA's goal is to set the average standard at the greatest
emission reduction relative to baseline levels achievable through the application of
technology that EPA determines will be available, taking the cost of such technology
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1-27
and other factors into account. See 42 USC 7547(a)(3). EPA has chosen to use cost-
effectiveness as a tool in establishing the appropriate emission standard for gasoline SI
marine engines.
In order to determine the degree of emission reduction which can be achieved
most cost-effectively from this source, it is most appropriate to consider the marginal
cost-effectiveness of achieving emission reductions on an engine family basis for the
entire sales fleet. This was done by rationing the annualized marginal cost per engine
family on a technology basis to the relative emission reduction effectiveness of the
technology over the useful lives of the engines sold in one model year. The annualized
margined cost methodology was presented in the previous section. The relative
emission reduction effectiveness calculation methodology was presented in section
1.2.3., Impacts on Pollutant Levels. The result of the rationing is the marginal cost-
effectiveness per engine family with respect to each technology, as presented in Figure
1-03. The actual data submitted by manufacturers is used to develop the curve
presented in Figure 1-03.
Based on the shape of this curve and other considerations, EPA has decided to
establish an HC+NOx emission standard for OB/PWC engines that achieves
approximately a 75% reduction in HC from baseline levels. Seg the Preamble and the
Summary and Analysis of Comments documents for further discussion.
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1-28
Per Engine Family Marginal Cost-Effectiveness Curve
Outboards and Personal Watercraft
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1-29
Table 1-07:
Outboard Technology Market Mix
Technology
Before
Regulation
After Phase-In
2-stroke, closed crankcase,
carbureted or crankcase electronic
fuel injection
99.0%
14.9%
4-stroke, closed crankcase,
carbureted or
crankcase electronic fuel injection
1.0%
34.5%
2-stroke, closed crankcase,
•carbureted or crankcase electronic
fuel injection, ignition changes
0.0%
1.3%
2-stroke, closed crankcase,
carbureted or crankcase electronic
fuel injection, catalyst
0.0%
3.2%
2-stroke, closed crankcase, direct
injection
air assisted
0.0%
18.4%
2-stroke, closed crankcase, direct
injection,
not air assisted
0.0%
27.8%
Table 1-08
Personal Watercraft Technology Market Mix
Technology
Before
Regulation
After Phase-In
2-stroke, closed crankcase,
carbureted or crankcase electronic
fuel injection
100.0%
5.4%
4-stroke, closed crankcase,
carbureted or electronic fuel injection
0.0%
94.6%
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1-30
1.2.6. Resultant Technology Market Mix
Upon setting the average emission standard at a 75% level of reduction, the
technology market mixes presented in Tables 1-07, and 1-08, result These market
mixes are derived directly from the marginal cost-effectiveness curve presented in the
preceding section.
1.3. Performance Impacts
1.3.1. Fuel Consumption
For outboard and personal watercrafc engines, the use of technologies that
significantly reduce hydrocarbon levels should also result in significant fuel savings.
Current technology two-stroke crankcase air/fuel/oil scavenged engines, which are
very widely used for outboard and personal watercraft applications, do not use fuel
efficiently. An unburned air/ fuel/oil mixture is used to push out, or "scavenge" the
exhaust gas From the cylinder. As a result, a substantial portion of the unburned fuel
and oil is pushed out of the cylinder with the exhaust gases. This combustion
technology can result in wasting more than 25-35 percent of the fuel consumed. These
losses will be greatly alleviated by using direct injection technology or 4-stroke
technology to meet the hydrocarbon emission standards. The regulation's are likely to
encourage the widespread use of 4-stroke technology, direct injection technology, or
other "clean" technologies to alleviate the problem. These technologies use a more
complete combustion process and do not use air/fuel scavenging of exhaust. As a
result, more fuel will be burned in the engine instead of being exhausted unburned,
and work done per unit of fuel will be increased.
For example, based on manufacturer data from 1991, EPA estimates that
changing outboard engines from two-stroke to four-stroke technology will result in an
average decrease in fuel consumption of approximately 31.5 percent. EPA expects
similar results from engines that use direct injection technology. However,
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aftertreatment technologies, such as catalysts, used to reduce hydrocarbon emissions
are not expected to significantly impact fuel consumption. So, to the extent that
catalysts are used to meet the emission standards, no fuel savings would be realized
using this technology as an add-on to current technology two-stroke engines.
1.3.2 Weight and Performance-Historically, the primary performance difference
between traditional two-stroke crankcase- scavenged engines and four-stroke engines
is the decrease in power to weight ratio. At the time of the proposal, EPA estimated
the weight penalty for the power unit for both OB and PWC engines would result in an
increase weight between 23 and 35 percent. EPA is now revising that estimate. During
the comment period EPA received information from a 4-stroke OB manufacturer
suggesting the Agency had over predicted any penalty in weight associated with the
conversion to 4-stroke technology(10). In addition, since the time of the proposal,
several new 4-stroke OB engines have been introduced into the market place, adding to
the available data set for the comparison between current technology crankcase
scavenged 2-stroke engines and 4-stroke engines. Finally, in the estimates EPA made in
the Regulatory Support Document for the NPRM, the Agency used data comparing
existing 4-stroke engines to many of the lightest available 2-stroke engines of equivalent
power rating. Based on the comments received and the new data available, the Agency
believes it is inappropriate to use a single number to represent potential weight
increases from the conversion to 4-stroke technology. Existing product literature for
both existing technology 2-strokes and 4-stroke OBs indicate consumers have a wide
range of weight options to choose from. Table 1-09 summarizes weight data from
existing product literature comparing 4-stroke OBs to current technology 2-strokes.
Table 1-09:
Weight Comparison between Existing 2-stroke and 4-stroke Outboard Engines
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1-32
Engine Rated Power
(kiloWatts)
Weight Comparison of Existing
4-stroke OB to Current
Technology 2-strokes
1.5
6 to 23 %
3.7
24 to 26 %
6
6 to 29 %
7.4
2 to 34%
11.2
-2 to 31%
18.6
-2 to 31%
22.4
0toi7%
37
-7 to 24%
67
5 to 33 %
Table 1-09 indicates that in the 1.5kW engine class, currently available 4-stroke OBs
range from 6 to 23% higher weight than available current technology 2-stroke engines.
In the 11.2kW engine class, available 4-stroke OBs range from -2% to 31% higher than
available 2-stroke OBs. The data makes it clear that a wide range of products with
many different weights are currently available to consumers, and in many categories
the consumer can find 4-stroke OBs lighter than or with very small weight increases in
comparison to existing technology 2-stroke engines.
Power to weight impacts resulting from the use of two-stroke direct injection
technology should be minimal. EPA estimates the additional weight increase from the
added components necessary for two-stroke direct injection technology may result in
power unit weight increases between 5 and 10 percent for a given rated power.
EPA considers the use of catalytic convertors (with limited conversion efficiency)
on two-stroke crankcase-scavenged engines as a technologically feasible and cost
effective control method for outboards and PWC. The increase in packaging size will
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add some minimal additional weight to the engine. EPA does not believe there will be
any significant performance changes to engines with the application of catalytic
convertors other than the decrease in power to weight ratio.
1.3.3. Noise--Although EPA performed no testing of noise on engines with
emission reduction technologies, the Agency expects no negative impact on noise due
to emission control technologies. Noise levels are expected to remain the same as on
current technology engines, or to decrease. Several recent trade journal articles of new
technology outboards, both DFI 2-stroke and 4-stroke engines, indicated decreased
noise output from the engines compared to existing technology crankcase charge
scavenged 2-strokes (11), (12), (13).
1.3.4. Safety—The federal agency that regulates safety issues for marine vessels is
the U.S. Coast Guard. The regulations promulgated by the Coast Guard fall into three
general categories: ensuring the safety of passengers (regulations for personal flotation
devices, and so forth), reducing the risk of fire hazards (regulations for electrical
systems, fuels systems, and ventilation systems), and, for larger vessels, ensuring vessel
integrity (strength and adequacy of design, construction, choice of materials for
machinery, boilers, pressure vessels, and safety valves and piping)2
It is EPA's view that the finalized marine SI regulations do not violate or conflict
with Coast Guard safety mandates. The final regulations in this rulemaking could be
affected by two sets of Coast Guard regulations: (1) compartment ventilation
requirements and (2) fuel tank ventilation requirements.
Coast Guard regulations require that boats with compartments not open to the
air and containing a permanently installed gasoline engine with a cranking motor be
equipped with power-assisted ventilation. This ventilation system is necessary because
gasoline fumes may accumulate in these compartments through evaporation, posing a
2 See Memorandum to the Docket regarding marine safety issues on recreational boats.
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fire hazard when the engine is started. The Coast Guard also mandates that
compartments that contain: (1) an enclosed engine, (2) openings between it and a
compartment that requires ventilation, (3) permanently installed fuel tanks, (4) a fuel
tank with a vent that opens into the compartment, or (5) a nonmetallic fuel tank be
equipped with natural ventilation to the exterior of the boat: The requirements
contained in this final rule do not require any systems that would violate any of the
Coast Guard requirements. If, in the future, EPA determines that evaporative
emissions regulations are necessary, EPA will work with the Coast Guard to ensure
that safety is not compromised.
Second, Coast Guard regulations mandate fuel tank vents on all fuel tanks. Since
fuel gauges are not well-calibrated on boats, in part because fuel tanks come in so many
sizes and shapes, and since boat operators want to be sure they have a full tank when
they leave the dock, refueling often continues until some fuel spills out of the tank. The
vent is to ensure that the spillage does not fall in the boat, creating a fire hazard.
However, fuel vents also permit the release of evaporative emissions. Coast Guard
representatives expressed concern about closed fuel systems that could be mandated to
reduce these evaporative emissions. Closed fuel systems are not currently permitted
under Coast Guard regulations and could cause a potential safety hazard. The
provisions contained in this final rule do not require any systems that would violate
any of these requirements, since EPA has decided not to regulate evaporative emissions
at this time. However, EPA intends to continue working with the Coast Guard and
boat manufacturer groups to encourage closure of this vent at most times and especially
when fueling is completed.
The discussions between EPA and the Coast Guard which have occurred during
the rulemaking process has raised new safety issue that had not been previously
considered by the Coast Guard. In discussions with EPA, representatives of the Coast
Guard expressed concern about the use of fuel injection systems on marine engines.3 In
2 See Memorandum to the Docket, cited previously.
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1-35
these systems, the fuel must be under pressure in the fuel line. This is a potential safety
hazard that could be dangerous, especially when the craft is far from shore. However,
fuel injection has become common in both the OB and the SD/I markets in recent years,
therefore, the Agency believes engine manufacturers have already taken into
considerations any potential safety implications associated with the use of fuel
injection. The Agency believes the Coast Guard will continue to work with marine
engine and vessel manufacturers in developing and enforcing safety standards for the
marine industry, and that these standards will be modified as needed to address fuel
injection systems.
1.3.5. Maintenance-Section 1.2 details the emission control technologies EPA
believes will be used to reduce HC emissions from marine engines. For outboard and
personal watercraft engines, EPA believes manufacturers will primarily use one of
three control technologies; conversion to four-stroke, direct injection two-stroke, or the
application of catalytic convertors to current engines. Any additional maintenance
costs discussed qualitatively below have been included in EPA's cost analysis for this
rule, including training for service dealership technicians. In general, EPA believes
most end-users do not service their own marine engines, engines are generally serviced
by marine engine service and repair shops. End users may do routine items such as
spark plug and air filter cleaning/replacing. EPA does not anticipate any of the
technologies used to meet the emission requirements of this rule will require a change
in the routine maintenance practices of the end-user. The one exception would be the
need for routine oil and oil filter changes for four-stroke engines.
The conversion of crankcase-scavenged two-stroke to four-stroke engines will
require additional maintenance skills and tools for the repair shop technicians. The
added parts that make a four-stroke engine work, a valve train, cam shaft, oil pump,
etc., will require additional knowledge for technicians. EPA does not anticipate that
four-stroke marine engines will require repairs on a more frequent basis than current
crankcase-scavenged two-stroke engines. In addition, many marine engine repair
-------
1-36
shops also sell and repair other types of recreational or lawn and garden engines, such
as all-terrain vehicles, lawn mowers, motorcycles, etc. Many of these equipment types
are powered by four-stroke engines, so technicians may not need additional training on
the operation and maintenance practices for four-stroke engines.
The application of direct injection two-strokes will be a new technology for the
marine maintenance and repair industry. The type of additional training, diagnostic
equipment, and repair tools necessary to work on DI two-strokes will depend on the
particular type of DI used by a given engine manufacturer, but whatever the type of DI
used, it will be a new technology for the marine servicing dealer. EPA anticipates that
marine engine manufacturers will spend a considerable amount of funds in the
retraining of their serving dealers to handle the need for technicians who are
knowledgeable in the servicing of DI two-stroke engines. EPA does not anticipate that
DI two-stroke engines will require more frequent servicing than current production
charge crankcase scavenged two-stroke engines.
The application of catalytic converters to charge crankcase scavenged two-stroke
engines should not require any additional maintenance requirements for the end user
or servicing dealerships. EPA's experience with on-highway applications using
catalytic convertors has shown that a well designed catalyst does not require servicing
or maintenance.
1.4 Impacts on Vessel Design
EPA anticipates minimal impacts on marine vessel design due to this rule.
Currently marketed four-stroke outboard engines have essentially identical packaging
to currently marketed crankcase charge scavenged two-stroke outboard engines. The
only significant impact on vessel design resulting from the use of four-stroke outboard
engines is the potential lower power to weight ratio. As discussed in Section 1.3.2,
Weight and Performance, EPA believes there may be increases in the weight of 4-stroke
OBs compared to current technology 2-stroke OBs at a given power rating. However,
-------
in many instances 4-stroke OBs have small if any weight penalties compared to some of
the currently available 2-stroke OBs. Any increases in weight will need to be taken
into account when designing a vessel/engine package, but this necessity exists today.
This will be particularly true for personnel watercraft vessels which utilize four-stroke
engines due to the very small size of the personnel watercraft hull.
EPA anticipates little or no impact to vessel design resulting from the use of
direct-injection two-stroke engines in either outboard engines or as power units for
personnel watercraft. EPA also anticipates the application of catalytic convertors to
crankcase charge scavenged two-stroke engines will have minimal impacts on vessel
design. EPA believes catalytic convertors would be built into the engine package, and
would not be designed as part of the vessel structure.
1-37
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1-38
Chapter 1: References
1. International Bodensee Shipping Commission (IKSB), Article 13.11 of the
Bodensee Shipping Regulations (BSO): Exhaust Gas Regulations for Marine
Engines, June 4,1991.
2. Morgan, E., Lincoln, R., Duty Cycle for Recreational Marine Engines, SAE
Paper Number 901596.
3. Samulski, M., Sensitivity of Test Cycle and Fuel Type on a Crusader 350 Inboard
Marine Engine; Test Results - 1992, NTIS Order Number PB 94-128105, May 26,
1993.
4. Michigan Automotive Research Corporation, A Comparison of Exhaust
Emissions on a Marine Engine Run on Steady State and Simulated Transient
Cycles, October 8, 1992, Prepared for National Marine Manufacturers
Association.
5. Memo from Michael Samulski to the Marine Docket #A-92-28, Effects of
Transience on Emissions from Inboard Marine Engines, May 30, 1996.
6. Memo from Michael Samulski to the Marine Docket #A-92-28, Effects of Raw and
Dilute Exhaust Gas Sampling on Emissions Measured from Inboard Marine
Engines, May 30,1996.
7. Carroll, J., White, J., "Marine Engine Emission Testing: Spark-Ignited Engines,
Final Report Volume II," for Environmental Protection Agency, Contract No. 68-C2-
0144 & 68-C4-0042, September 1995.
8. Memorandum from Michael Samulski to Chester France, "Deterioration Factors for
Existing Technology, Gasoline, Outboard Marine Engines," March 4, 1996.
9. Memorandum from Michael Samulski to Docket #A-92-28, "Exhaust Emission
Testing of a Two-Stroke Marine Engine; Results and Procedures," May 30, 1996.
10. EPA Air Docket A-92-28, Item Number IV-D.
11. "Trailer Boats" magazine, June, 1996, pages 38-41.
-------
Popular Mechanics" magazine, Feb., 1996, page 71.
Boating" magazine, Jan., 1995, page 62.
-------
Chapter 2: Aggregate Cost Analysis and Economic Impacts
This chapter describes the industry, presents aggregate costs, consumer costs,
and describes potential economic impacts.
2.1. Industry Description and Market Analysis
The spark-ignition marine industry is comprised of a small number of engine
manufacturers. The engine manufacturers noted in Table 2-01 make up over 90% of the
market. Table 2-01 also lists the major types of propulsion systems: outboards,
personal watercraft, and sterndrives & inboards.
Table 2-01
Engine Manufacturers
OUTBOARD
PERSONAL WATERCRAFT
STERNDRIVES & INBOARDS
OUTBOARD MARINE CORP.
MERCURY MARINE
YAMAHA
SUZUKI
TOHATSU
HONDA
NISSAN
YAMAHA
KAWASAKI
ART CO.
BOMBARDIER
SUZUKI
MERCURY MARINE
INDMAR
VOLVO PENTA/OMC
CRUSADER
VARIOUS MARINIZERS
The engine industry exhibits characteristics of an oligopolistic market structure:
a few engine manufacturers dominate market share with a high degree of product
differentiation.
EPA contracted for two market studies to gather information on the marine
2-1
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2-2
engine and vessel markets. The first study was performed by ICF Incorporated and the
second study was performed by Specialists in Business Information. The following
excerpts contain the points EPA thinks are most relevant to the regulation of emissions
from spark-ignition marine engines.
"Demographics of Boat Ownership: There are numerous ways to report boating
activity ownership patterns, including ownership registration, and total and mean
passenger hours of use. These measures are further described according to such
characteristics as geographic distribution, as well as various socio-economic characteristics
including age, household size, income, gender, and race. National estimates of boat
ownership vary depending upon the data source. For example, although the [National
Marine Manufacturers Association] NMMA estimates that there are approximately 16
million recreational boats owned in the U.S., estimates of number of boats registered is
closer to 11 million (in part because of the differences among states in registration
requirements as well as compliance by boat owners with registration requirements). Five
states (Michigan, California, Minnesota, Florida, and Texas) account for 33.1 percent of
U.S. boat registration. When states are ranked according to boaters as a percentage of all
U.S. boaters, the five top states are California, Michigan, Texas, New York, and Illinois.
Boaters tend to fall into the 20-30 and 31-40 age groups, but analysis of data related to
intensity of use indicates that boating use is relatively constant among population groups
when adjusted for the number of individuals in each age category. Also, at upper income
levels, the percentage of total boaters tends to be larger than the U.S. population for that
income range. For all age groups, the percentage of male boaters exceeds the
corresponding U.S. census percentage, as does the percentage of white boaters. With
respect to the characteristics of the boats, the average age of the fleet is increasing. In
particular, between 1976 and 1989 the average age for speedboats, cabin sailboats, and
cabin cruisers increased from 8.6 years to 10.5 years, 8.5 years to 11.9 years, and 9.7 years
to 11 years, respectively.
Overall Size of the Marine Industry: Trends for marine industry retail
expenditures reflect those for the economy as a whole, showing prosperity during the mid-
1980s, peaking in 1988, and decreasing since 1988. As a percentage of the GDP, marine
industry retail expenditures exhibit the same pattern over the period. Although there is no
conclusive explanation for these trends, it appears likely that the economy as a whole and
the January 1991 luxury tax exacerbated trends for the marine industry. Both the tax and
the uncertainty associated with speculation that it would be repealed may have caused
consumers to delay purchases. Not surprisingly, the top ten states include those states
with extensive coastal area, large populations, and relatively high per capita income.
These data correspond to boat registration by state data presented elsewhere in this report.
The total number of people employed in boat building and repairing increased
steadily from 1982 to 1987 (except for 1985). The number of people employed in engine
manufacturing and in ship building have generally decreased since 1981.
The marine industry is concentrated in relatively few states: four states account
for 56 percent of marinas, eight states account for nearly half of all boat dealers, and 10
states account for almost two-thirds of all boat manufacturers.
The value added by manufacturing in the marine industry was more than $12
billion in 1987, a 30 percent increase form the approximately $8 billion in 1982. Value
added in boat building nearly doubled, while value added in ship building and engine
-------
manufacturing increased less rapidly and uniformly.
Structure of the Pleasure Boating Industry: The pleasure craft industry is
extremely complicated, with numerous distribution channels, large numbers of highly
specialized manufacturers, and a smaller number of well-diversified manufacturers. For
example, even though a small number of engine manufacturers dominate the industry in
terms of overall market share, there are relatively large numbers of manufacturers willing
to compete in the industry, and overall levels of competition are high. As discussed in
Chapter 6, this study identified more than 40 engine manufacturers producing more than
1,200 distinct engines. The vessel industry has a large number of distinct product
categories that cater to very specific boating needs. Although a few major manufacturers
have a significant overall market share, the specialization has supported a large number of
individual manufacturers of all sizes. The major manufacturers themselves are internally
organized to produce boats under numerous distinct, often competing brand names.
Similarly, distribution channels are complicated. As relatively high dollar value
consumer items, much like automobiles, manufacturers of individual engines and vessels
(and especially smaller vessel manufacturers) frequently deal directly with their
customers, rather than through chains of intermediaries. Even so, some lines of boats and
engines are marketed to dealers through distributorships; distributorships and dealers can
be either independent or owned by manufacturers.
Boat construction is geographically dispersed. Although only four states account
for half of all establishments, 29 other states have some level of boat building and
repairing. Similarly, 24 states have active shipyards.
One measure of the complexity of the industry is the number of distinct product
classes and classification schemes. Sources that are primarily directed towards
establishing the value of specific boats (e.g., the new and used boat guides published by
BUC Research, Inc.) use very narrow categories to allow analysis within very discrete
subsets of vessel types. Sources that focus on major industry market segments (e.g..
Boating Industry magazine) rely on relatively broad categories of engine type and material
of construction. The American Red Cross, which is primarily interested in safety concerns,
categorizes boats in terms of factors that affect operation of the craft. The Bureau of the
Census uses categories that appear to relate to differences in overall design factors that
may affect methods of production. Because of the wide differences in the classification
schemes used, it is virtually impossible to correlate the data from these different sources.
Industry Trends in 1992: The marine industry has experienced several changes
over the last decade. First, there has been an increasing level of vertical integration
between the engine and vessel manufacturing sectors, as reflected primarily in the efforts
of Mercury Marine (Brunswick Corporation) and OMC to purchase boat manufacturers as
captive companies to guarantee outlets for their products, build brand loyalty, and capture
potential economies of scale in design, production and distribution. Although this trend
may have been abated somewhat by the recession, during which both Brunswick and
OMC have suffered from reduced flexibility, the prospects that integration offers for high
volume, standardized designs should continue to be enticing in the long run.
Second, foreign manufacturers have, played an increasing role in the engine sector
of the industry. Such innovations as Yamaha's counter-rotating engines (to smooth the
ride of twin engine boats) and Kawasaki's personal watercraft have opened market niches
and increased consumer acceptance of foreign engine manufacturers that did not exist in
the early 1980s. Foreign manufacturers that have developed reputations for quality in
other engine markets (e.g., Honda) may be able to use those reputations to compete in the
marine industry as well, further crowding the market. This effect may be mitigated by the
increasing development of foreign markets for pleasure craft. U.S.-made boats are highly
-------
regarded in world markets, and the overall size of foreign markets appears likely to
increase as levels of awareness of boating-as-recreation increase and as disposable income
increases. To the extent that competition in foreign markets requires more sophistication,
however, the increasing levels of imports and exports may further encourage the trend
towards consolidation and integration.
Third, the significance of product innovations appears to have slowed recently.
The enhancements to the reliability and durability of both engines and vessels made from
the early 1970s through the mid-1980s may have encouraged boat buyers to purchase the
newer, better boats rather than older vessels. Many of the recent innovations, such as
improved navigation and communication, may not require the purchase of new vessels.
Consequently, consumers may be more willing than before to purchase used boats rather
than new boats, leading to a relatively softer market for new boats and continued intense
competition.
In addition to shifts in the structure of the industry, there have been shifts in the
nature of the consuming population. First, as a consequence of improved boats and
vessels, consumers may be more likely to consider used boats as viable alternatives to new
boats. The increased durability of fiberglass boats relative to wooden boats means that
buyers need be less concerned about upkeep costs and remaining lifetimes. Thus, builders
of new boats must compete not only with other builders, but also with the increasingly
large resale market. Second, the domestic industry faces increased competition from other
spending alternatives. U.S. consumers may weigh boating against a wider array of
alternatives. Consequentiy, the domestic marine industry must compete not only within
itself, but also with other luxury and vacation industries.
Third, the overall demographics of the population are shifting. In the near-term,
the aging of the "baby boomer" generation should extend recent trends towards larger,
more luxurious new boats. ... [T]he segment which has increased most rapidly in size since
1983 has been boats with engines larger than 100 horsepower. Average boating levels, in
terms of boating hours per capita, remain relatively constant from the ages of about 20 to
50. Thus, as the population continues to age, there will be continuing shifts in the
proportion of older boaters, with commensurate shifts in purchasing patterns. Over the
longer term, as the population ages beyond 50 (when levels of boating participation tend
to decrease), actual boating levels and boating demand may decrease. The extent of the
decrease will depend on the extent of boating by the generation of baby-boomers' children.
The effects of the luxury tax are not easily analyzed. The apparent influence of the
surcharge in terms of reductions in the number of vessels sold appears may have been
exacerbated by three factors: increases in the average vessel size and price (which may
have led to disproportionate concentration on the larger boats subject to the tax), other
consumer confidence issues such as the Persian Gulf War, and widely publicized efforts to
repeal the tax. The long-term effects of the luxury tax are difficult to foresee."(1)
"Market Profile Highlights: The U.S. pleasure boat industry is recovering from the
severe 1990-1991 recession due to stronger personal income gains, lower interest rates and
the repeal of the luxury tax. However, industry growth has entered a more mature period
due to changing demographic patterns and rising saturation levels. As a result, U.S.
manufacturers and marketers must resort to innovative new products and boat designs to
stimulate demand. Producers should also strengthen foreign distribution channels to take
advantage of emerging world boat markets.
U.S. factory shipments of pleasure boats are estimated to have increased at a 9.8%
annual average compound rate over the past three years. This compares to a 17% annual
decline during the previous three year period. The recovery was primarily driven by a
rebound in personal income, lower interest rates, and declining gasoline costs.
So far, the recovery has been led by low cost product lines such as personal
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2-5
watercraft and canoes. Unit sales of personal watercraft increased by some 41% between
1992 and 1994. This compares to a 20% rise in total retail boat sales.over this period. The
growing popularity of low cost watercraft reflects the sluggish nature of personal income
gains and consumer cautiousness during the current recovery.
Boat demand, however, could shift up-market in 1994 as the August 1993 repeal of
the luxury tax boosts sales of luxury boats and yachts. Stronger personal income gains in
1994 could also lead to the breakout of pent-up demand for higher end product lines.
The recovery has also resulted in improved plant profit margins. Gross plant
profit margins are estimated to reach 21.8% during 1994. This compares to 17.5% in 1991.
The increase in operating efficiency reflects moderating material costs, rising labor
productivity, and an expanding industry capital spending effort. The industry's desire to
maximize plant efficiency is imperative in the face of rising foreign competition. Imports
could capture 14% of the total U.S. market sales during 1994, versus 7% in 1990.
Domestic manufacturers and marketers must also increase spending on new
products in order to remain competitive in a rapidly maturing market structure. Future
industry growth is forecast to remain below long term trends over the next decade due to
the aging of the baby boom population and the decline in the potential number of first-
time boat purchasers.
Boat producers will be marketing increasingly to an aging boating population,
who generally cut back on boating spending as they enter the 45 to 54 year old age group.
The leading edge of the huge baby boom population, which helped boost boat demand
dramatically during the 1980's, is now entering this age cohort. The boating industry must
target new boat designs and amenities to this important boating population. At the same
time, the number of potential first time buyers is drying up as the population of 25 to 44
year olds declines.
New designs and innovations must also be used as a marketing tool to entice the
relatively large base of existing owners to trade in existing watercraft. This reflects the
doubling of existing boat-owning families over the past twenty-five years.
In order to offset maturing domestic demand, manufacturers must seek out
growth opportunities in foreign markets. Producers should seek out growing marketing
opportunities in relatively untapped markets, such as Eastern Europe, Mexico and the
emerging Asian economies. U.S. manufacturers should exploit their competitive
advantage of developed distribution channels and other economies of scale that come from
supplying the world's largest domestic market. As a result, export shipments are seen
leading the recovery for the remainder of the 1990's.
Market Sector Analysis, Summary of Major Findings:
1. U.S. factory shipments of outboard motorboats could reach $1 billion during 1994,
a 12.3% annual average gain over the past two years. This reverses most of the
decline in shipments that occurred between 1987 and 1992. Runabouts and bass
boats dominate this sector of the pleasure boat industry, however, cabin cruisers
have made inroads since the late 1970's.
2. Inboard motor sales also experienced a rebound in shipments over the past two
years. This is important to this industry, since inboard boats is the largest sector of
the U.S. pleasure boat industry on a dollar basis. Cabin cruisers account for over
60% of inboard motorboat sales, however, runabouts have outpaced sector
shipment trends since the late 1960s.
3. Inboard-outdrive boats have been the most adversely affected by the past
recessionary period and the relatively sluggish recovery. Dollar factory shipments
could reach $975 million during 1994, however, this remains 34% below 1987
levels.
4. Sailboat shipments also remain weak. Dollar factory sales are estimated to reach
-------
$125 million during 1994 or 2.9% of total U.S. pleasure boat shipments.
This compares to 4.2% of total shipments during 1987, and 11.8% in 1982.
5. On the other hand, a relatively strong growing nonpowered line on a unit basis is
canoes and kayaks. The popularity of these watercraft reflects their inexpensive
price and portability, and that they are seen as environmentally friendly. There is
also growing interest in battery powered boats since internal combustion engines
are prohibited from a growing number of lakes.
6. However, the strongest growing market sector is personal watercraft. ...
Kawasaki, Yamaha, and Bombardier are the largest manufacturers. However, in
1993, a number of traditional boat manufacturers such as Sea Ray and Boston
Whaler began producing personal watercraft.
7. Over the past five years, prices have been strongest for inboard motorboats and
rubber boats.
Economic Structure of Domestic Boat Builders and Repair Services, Highlights:
1. The U.S. pleasure boat industry continues to be dominated by relatively small boat
builders despite a consolidation in the number of players since the mid-1980s.
However, industry sales are increasingly concentrated among the top U.S. boat
producers who manufacture pleasure boats in larger and integrated operations
that benefit from economies of scale. During 1992, the top four companies
captured 39% of total U.S. factory sales. This compares to only 14% in 1982.
2. The industry also experienced an improvement in plant profit margins as U.S.
pleasure boat demand began to recover from the past recession. Gross plant profit
margins are estimated to reach 21.8% during 1994. This compares to 17.5% in
1991. The increase in operating plant efficiency reflects moderating material costs
and a surge labor productivity.
3. The major competitors, Brunswick and OMC, are also increasing their capital
expenditures to boost plant efficiency.
4. Key producing states include Florida, California, Tennessee, Louisiana, Michigan,
Washington, Texas, and Indiana."(2)
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2-7
TOTAL COST —O— FIXED ~-£s— VARIABLE
Figure 2-01
Aggregate Cost Estimates
2.2. Aggregate Cost Estimate
EPA's aggregate cost estimate to meet the standards contained in this final rule
is presented in Figure 2-01 and Table 2-02. The annualized costs of this rulemaking
exceed $370 million in 2006. Variable hardware costs required to reduce emissions
from the controlled engine families contribute the largest portion of total costs.
It should be noted that the magnitude of these costs can be put in perspective by
comparing them to the total retail expenditures on outboards and personal watercraft
for 1993 as given in Table 2-03. In 2006, total annualized costs due to this regulation are
roughly 8% of projected retail expenditures in that year. Additionally, it should be
recognized that the increased costs for these engines are typically financed by
consumers.
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2-8
Table 2-02:
Total Annualized Cost Estimate
YEAR
TOTAL COST
1998
$15,538,137
1999
$26,534,042
2000
$46,295,786
2001
$99,337,986
2002
$131,321,287
2003
$207,223,873
2004
$273,948,157
2005
$314,081,468
2006
$374,948,862
2007
$383.992,911
2008
$374,817,899
2009
$362,501,272
2010
$357,969,394
2011
$346,631,280
2012
$338,373,411
2013
$329,723,011
2014
$318,603,389
2015
$321,300,323
2016
$326,101,258
2017
$320,254,666
2018
$328.021,332
2019
$337,705,195
2020
$340,138,753
2021
$342,944,594
2022
$345,476,282
2023
$347,518,811
2024
$349,308,355
YEAR
TOTAL COST
2025
$349,632,996
2026
$351,535,188
2027
$352,462,647
2028
$353,289,501
2029
$354,050,391
2030
$354,760,328
2031
$355,429,111
2032
$356,058,899
2033
$356,650,609
2034
$357,205,434
2035
$357,727,389
2036
$358,223,037
2037
$358,701,310
2038
$359,172,918
2039
$359,646,293
2040
$360,125,510
2041
$360,615,855
2042
$361,120,817
2043
$361.640,497
2044
$362,176,335
2045
$362,726,803
2046
$363,291,313
2047
$363,868,795
2043
$364,456,892
2049
$365,053,150
2050
$365,655,636
2051
$366,261,992
Table 2-03:
1993 Retail Expenditures
Engine Type
1993 Retail Expenditures
OUTBOARDS
$1,364,000,000
PERSONAL WATERCRAFT
$618,000,000
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2-9
2.3. Consumer Cost Summary
EPA cannot present specific consumer costs with respect to different control
technologies due to concerns over confidentiality of manufacturer data. However, it
seems clear that no confidential information could be gleaned by presenting the overall
sales-weighted average per-engine cost increase for outboards and personal watercraft.
The following average per-engine cost estimates reflect costs averaged across all
engine families for outboards and personal watercraft. It should be noted that actual
prices and costs in the market will differ from the information presented here for a
number of potential reasons. First, not all costs of control will average across all engine
families if the market for emission reduction credits does not work well. Second, prices
of engines are set by the market forces of supply and demand. Even if the market for
emission reduction credits worked well, prices could be different than expected if
people were willing to pay more or less than the changes in the cost to supply engines.
For example, if people value most highly the engines with the lowest emissions and
those people are willing to pay a lot more than the engines cost to produce, one would
expect the engine price to reflect consumer willingness to pay. On the other hand, if
people demand more of the clean engines than predicted, the price may fall due to
economies of scale or increased competition in the market from entry of competing
engine families. Third, consumer willingness to pay is most likely linked to engine
output. Therefore, a $100 increase in price for a 10 kW engine will likely have a
different effect on sales than a $100 increase in price for a 100 kW engine. These effects
will be played out in the market and the market price may be different than expected.
With these qualifications in mind, the estimated per engine cost estimate is
presented in Table 2-04. Figures 2-02 and 2-03 graphically present the relative cost
components and cost estimates over time.
Table 2-04:
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2-10
ee
<
($200)
a ($400)
($600)
Figure 2-02
Average Consumer Cost Components Per Engine
Estimated Per Engine Consumer Cost Increase
Variable
Dealer
Fuel
Maintenance
Admin.
Year
Fixed Cost
Cost
Cost
Savings
Cost
Cost
Total Cost
1998
$10
$20
$5
($67)
$50
$14
$32
1999
$20
$39
$9
($135)
$115
$7
$55
2000
$29
$108
$25
($176)
$151
$7
$143
2001
$46
$189
$44
($227)
$203
$7
$261
2002
$52
$250
$58
($267)
$219
$7
$319
2003
$68
$301
$69
($327)
$284
$7
$402
2004
$84
$386
$89
($394)
$349
$7
$520
2005
$95
$438
$101
($429)
$380
$7
$591
2006
$103
$511
$118
($478)
$434
$7
$695
-------
2-11
L
4
I
n
cr
e
m
e
n
Figure 2-03
Estimated Average Price Increase &
1 Economic Impacts
2.4.1. Capital
Impacts on capital as a result of this rule are the result of increased investment
by manufacturers in order to make their engines comply with the average emission
standards. These costs become part of the cost of manufacturing and are recaptured in
price increases. As a result, private capital investment is unlikely to be displaced. All
expenditures related to this rule can be expected to be borne from consumer savings or
consumer credit markets, not from private capital markets. As shown in the aggregate
cost section, the capital costs are the lesser costs of this rulemaking. In the year 2006,
the peak year for costs, the capital costs are approximately $55 million.
2.4.2. Sales and Employment
Impacts on sales and employment are difficult to assess for this rulemaking.
EPA considered impacts on engine manufacturers, boat manufacturers, boat
dealerships, and manufacturers of other recreational marine products such as
m $800
2003
2008
2013 2018
MODEL YEAR
2023
2028
-------
2-12
accessories.
EPA does expect sales to be affected by the price increases which will result from
this rulemaking. See the benefits chapter for the specific sales estimates EPA has
projected.
Engine manufacturers have indicated to EPA that any sales decrease due to this
regulation may be made up by exports. If this is the case, employment may not be
affected by a sales decrease. Several manufacturers have indicated that employment
may increase for engine and boat manufacturers due to the broadening of product lines
expected as a result of this regulation. Manufacturers of engines will carry controlled
engines for sale to the U.S. market and uncontrolled engines for sale to the world
market. However, it is difficult to assess exactly what might be the increased
employment. Employment increases will depend on individual manufacturers specific
types of production lines.
EPA expects that if any decreases in employment do occur, it is most likely that
they will occur in boat dealerships and in companies who make accessory products.
These effects would be due to decreased sales of outboard engines and to reduced
consumer budgets for consumers who purchase new outboard or personal watercraft
engines.
Boat dealerships have been in poor financial shape in the past 5 years. The
number of boat dealers has fallen as demand for pleasure craft has decreased and the
competitive market has greatly intensified. Boat dealers, boat builders, and industry
service sectors, such as marinas, have all experienced decreased demand, "...50 percent
of the boat dealers in the U.S. are behind in interest payments, and at least 30 percent of
all retailers have failed since 1989".(3) Although sales of pleasure boats are
dramatically increased in the past three years4 making up for recent downturns, any
potential sales decrease in the future may adversely affect the boat dealership sector
which is very sensitive to changes in the economy. Further, sales decreases may affect
4 Based on sales statistics supplied by the National Marine Manufacturers Association
-------
2-13
boat dealers' employment more than engine or boat manufacturers since boat dealers
do not participate in the expanding world markets. However; EPA is only in a position
to recognize this potential effect and does not have any certainty over the potential
extent of the effect.
Reduced outboard and personal watercraft sales and increased prices of
remaining sales might mean that consumers have less money to purchase other marine
accessory products. If this is the case, then employment may be affected for those
manufacturers who produce accessory marine products, assuming that consumers total
budgets for all marine products do not change. Quantification of these kinds of
potential effects was not performed and would be uncertain at best.
In summary, EPA is uncertain as to the exact employment effects due to this
rulemaking.
2.4.3. Energy
Reduced energy consumption will be one result of this regulation.. Resultant
increases in fuel economy of these engines mean demand for energy will decrease
marginally in the U.S. The resultant impact on the U.S. balance of trade is
approximately $270 million per year. The estimate of gasoline savings is presented in
Figure 2-04.
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2-14
350
CO
O
z
s
w
111
o
w
6
Figure 2-04
Expected Gasoline Savings
-------
Chapter 2: References
ICF Incorporated, "Marine Industry Characterization Report," March 25,
1993, pages ES-1..ES-5.
Specialists in Business Information, Incorporated, "The SBI Market Profile
on Pleasure Boats, Profile No. R-716," May 1994.
ICF Incorporated, "Marine Industry Characterization Report," March 25,
1993, page 4-6.
2-15
-------
Chapter 3: Environmental Benefit
This chapter presents the methodology used by EPA to quantify the emission
benefits that will be realized because of both the HC+NOx emission standard
contained in this final rule for SI gasoline OB/PWC marine engines, and the lack of
SD/I engine emission standards in the final rule. Since the emission levels of gasoline
SI marine engines are dependent both on technology and the power rating of the
specific engine, for purposes of calculating aggregate emissions, the technologies
relevant to an application are grouped together. In all, 16 technology types distributed
over 9 kilowatt-based niche categories have been considered for the analysis.
Emission inventory changes, in terms of HC emission reductions and NOx
increments, are presented in the form of aggregate source benefits. "Aggregate
Source" benefits are the estimated, future nationwide application-specific emission
reductions from affected engines. Estimated "aggregate source" benefits illustrate the
future effect of the standards contained in this final rule on the emission inventory of
the source. Air quality benefits are discussed qualitatively for both ozone and specific
hydrocarbon air toxins. Though the regulation does not contain emission standards for
3-1
-------
3-2
CO, the Agency does expect some reduction in CO emissions from this source category
(gasoline SI marine engines); therefore, a qualitative discussiion of CO health effects has
been included.
Many of the detailed results discussed below are presented in separate tables
included in Appendix A - Supplementary Tables.
3.1. Estimated HC+NOx Emissions Reduction
To estimate the average annual emissions per current nonroad SI gasoline
marine engine, EPA used data provided by NMMA (National Marine Manufacturers
Association) and confidential data provided by individual manufacturers on sales,
kiloWatt (kW) ratings, and average load factor. Data from the Price Waterhouse
study(l) was used in arriving at average annual hours of application-specific engine
usage. Table A-01 of the Appendix presents average kW-ratings for each of nine niche
categories as they apply to technology types.
Average annual emissions calculated for each valid niche category are based on
in-service population of engines, an activity factor, and a technology -based sales-
weighted emission factor. The technology types include current and manufacturer-
proposed future cleaner technologies that are expected to replace current ones in order
to meet the HC+NOx standard contained in this final rule. Each of the technology
types, by definition, is mutually exclusive in the sense that each one is associated with
one and only one of the three types of engines within the source category - outboard
(OB) , personal watercraft (PWC) and sterndrive/inboard (SD/I). For each of these
engine types, the emission inventory is calculated separately using the following
equation:
INVn = N, HP, * LOAD* HOURS* EF,.
'J 'J 'J J J 'J
-------
where
N.J
kWy
LOAD,
HOURS.
EF,
INV,
nationwide in-use population of engines that belong to niche
category i and application type j.
average rated power in kilowatts, for category i and application j.
rated ratio (%) between average operational power output and
rated power for application j
average annual hours of engine usage for application j
brake specific emission rate (grams/kilowatt-hr) for category i and
application j
annual nationwide emissions inventory in tons per year (tpy) for
engines that belong to niche category i and application type j
In-service population and activity information used to construct the inventory
relied predominantly on data provided by NMMA and the individual manufacturers.
Table 3-01 presents data used in calculating the activity rate per niche for the three
application types. The Average Load Factor (LOADj) is assumed to be 0.207 for every
engine irrespective of Kw rating and technology class.
-------
3-4
Table 3-01:
Average Annual Hours of Use by
Niche Category and Technology Class
Technology Class*
Outboard Personal Watercraft
Inboard/Sterndrive
(OB) (PWC) (IB/SD)
Niche
Category
Power Interval
T1,T4-T9,T15
T2.T13.T14
T3,T10-T12,T16
1
0-2.91
34.8
2
2.98-7.38
34.8
3
7.46-22.29
34.8
4
22:37-37.21
34.8
77.3
5
37.28-55.85
34.8
77.3
6
55.92-74.49
34.8
7
74.56-111.77
34.8
47.6
8
111.84-149.05
34.8
47.6
9
149.12+
34.8
47.6
* The Technology Classes are referenced by the letter T.
3.1.1. Aggregate Estimated Annual HC+NOx Reduction
The calculation of aggregate HC+NOx reductions is described in this section.
The calculation takes into account U.S sales by model year, engine survival rates and
average annual rates of usage. Estimates of technology-based sales-weighted average
emission rate for each niche is calculated, which were then used to derive projected
nationwide aggregate annual HC and NOx emissions through 2051, the year of
complete fleet turnover. Here the "fleet" refers to fleet of all engines independent of
application. It should be noted that the outboards have the longest useful life and
therefore contributes to the long fleet turnover time.
3.1.1.1. Sales Projections-To estimate future emission levels, some projection of the
future population of uncontrolled and controlled engines is needed. Because engines
are introduced into the field through sales, estimates are needed not only of sales prior
to the implementation of the standard, but also of sales after the standard goes into
-------
3-5
effect. The finalized emission standards begin to take effect starting 1998 for OBs and
in model year 1999 for PWC, and would involve a phase-in period ending in year 2006.
Beginning in 1998, an appropriate fraction of engines sold are assumed to comply with
the standards.
Projection of future outboard engine sales was done in two steps. In the first
step a regression curve was fitted to historical sales data, available for the period 1961
through 1993. The functional form assumed is:
Sy = CIaRbPc[exp kBy.,]d
where Sy = Per capita Outboard sales in year y
C,a,b,c and d are constants determined from the regression.
The sales projection for 1994 through 2051 assumes that all economic variables
remain constant except for a steady 1.25% growth per year in human population and a
steady increase in price of outboards over the nine-year phase-in period ending in year
2006. As for SD/I, the same equation is used to project sales, except that engine price
remains constant over the phase-in years and beyond, this results in higher sales of
SD/I in the controlled cased as compared to the uncontrolled case, as evident in Tables
A-02 and A-03. For PWCs and Jet Boats, sales projections Sy for the phase-in years and
beyond -up to year 2011, were made using the equation :
R
I
P
Per capita income adjusted for CPI
Real interest rate
Outboard price adjusted for CPI
Total boat population in the previous year
(1+.04*(y-1997))* Sy.,* (Py/P93)-20 where
y
calendar year
sales in previous year
current year compared to base year (1993)
-------
3-6
For years 2012-2051, sales projections were calculated as above, but assuming no
change in both sales growth and price increase from the year 2011.
However, it should be recognized that, while national growth is measured at the
level of the economy as a whole, growth in specific areas of the country is likely to vary
from area to area in response to the specific demographic and commercial trends in
those areas. These effects should be taken into account in estimating growth at
the local level.
EPA distinguished between sales of controlled and uncontrolled engines in each
future year starting in 1997, when an appropriate proportion of engines manufactured
and sold are assumed to comply with the standards. The standards are effective
beginning in 1998, but EPA anticipates introduction of controlled engines in 1997, in
response to the early banking program offered through this rule. Although the
averaging and trading provisions allow for engines to emit at rates above the standard,
they must be balanced by cleaner (i.e., below the standard) engines. Tables A-02 and
A-03 present estimated sales of uncontrolled and controlled engines by engine
category for model years 1993-2051.
3.1.1.2. Survival Probabilities--In calculating the emission reductions that are
expected to occur during the life of an engine, whose emissions are controlled in
response to the standard, EPA relied on estimates of average useful life provided by
manufacturers. For outboard engines the average useful life (p) is determined to be a
function of the kilowatt rating and is of the form:
\i = 41.27*(l/.075kW)"oz°4 , where kW is the kilowatt rating of the
engine.
Also the life distribution of marine engines in the field is assumed to be a 2-parameter
Weibull distribution function of the form:
F = 1-exp -(t/0)b
where
F
cumulative fraction of engines failed
age of the engine or time to failure
scale parameter or characteristic life
t
0
-------
b = shape parameter or slope
3-7
The characteristic life 0 is related to the mean life p and slope b through the equation
p = br(6 +1/0)
Based on information obtained from reliable source, EPA assumed the shape parameter
for the Weibull-based life distribution of marine engines to be 4.0. Hence 0 for each
outboard niche category is computed as displayed in Table A-04. As for personal
watercraft and inboard/sterndrive engines the average useful life was assumed to be
10 and 20 years respectively and are independent of kilowatt ratings.
3.1.1.3. In-Service Population-By coupling the estimated sales projections given in
Table A-02 with the engine survival function described above, EPA calculated the
estimated in-service populations for calendar years 1990 to 2051 for engines in each
niche category of an application. In doing so, EPA distinguished between controlled
and uncontrolled engines, so that the effect of the standards could be ascertained.
Table A-05 shows the resulting population projections for 1990-2051 for un-controlled
and controlled engines used in all three application types. These projections are
represented graphically in Figure 3-01.
-------
3-8
-¦. BASELINE <~ CONTROL I
Figure 3-01
In-Use Engine Population by Calendar Year
3.1.1.4. Aggregate Source Emissions Inventory—EPA projected future annual
nationwide HC and NOx emissions from all gasoline SI marine engines under the
baseline (no controls applied) and controlled scenarios. This was accomplished using
the equation:
W t (SALESfS^ANN^)
j-y-M
In this equation.
y - evaluation year (same as calendar year)
j - model year of engine (new model year is assumed to begin
on October 1 of a calendar year)
INV HC y - aggregate HC emi ss io ns i n ven tor)' for calendar
yeary
SALES j - engine sales in year j
Sy_j - fraction of engines sold in year j that survive through yr. y
ANNavg>HC j - average annual per-engine HC emissions of engines sold in
year j
For each calendar year be ween 1990-2051, the aggregate HC and NOx emissions
-------
3-9
inventories were calculated, using the above formulae for all three engine types in use
during that year. The difference between the controlled and uncontrolled scenarios
reflects both the price effect as well as the new engine standards phased in over the
nine-year period.
Tables A-06(HC) and A-07(NOx) presents total annual nationwide HC and NOx
emissions from all SI gasoline marine engines under the baseline and controlled
scenarios. These are shown graphically in Figure 3-02.
In Figure 3-02, the annual HC reduction of the regulation is indicated by the
difference between the upper ("HC-BASELINE") and lower ("HC-CONTROL") curves.
The area between the curves represents the net HC reduction of the regulation during
the time required for the marine SI fleet to completely turn over. The stream of HC
benefits projected for year 2051 yields a reduction of 590,254 tons in HC emissions
which translates to 74.8 % reduction. The stream of NOx emissions predicted by EPA
in year 2051 results in an increase of NOx of 25,440 tons. The combined change in
HC+NOx is a reduction in 2051 of 564,814 tons HC+NOx emissions.
e
z
fe
o
s
i
<
i
1000
800
<2 600
400
ipcP1
%
\
200
X
'Ooo,
00e0000000000<>
1990
2000
2010 2020 2030
INVENTORY YEAR
2040
2050
. HC-BASELINE o- HC-CONTROL -A- NOx-BASELiNE NOx-CONTROL
Figure 3-02
Marine Spark-Ignition Projected Inventories
-------
3-10
3.1.3. Cost-Effectiveness
EPA has calculated the program cost-effectiveness for this rule as the ratio of the
net present value of the projected stream of costs given in Table 2-01 divided by the net
present value of the projected stream of emission reductions from projected baseline
levels. The ratio is $1026 per ton of HC+NOx reduction, including the increase
expected in NOx, at 3% discount rate. According to EPA guidance, the discount rate
used for purposes of calculating net present value was 3%. Alternatively, the Office of
Management and Budget recommends a default discount rate of 7% for the purposes of
calculating net present value. Using 7%, the cost-effectiveness for the program would
be $1617 per ton of HC+NOx emission reduction. EPA has decided to use the ratio
$1026 per ton of HC+NOx reduced as the official program cost-effectiveness for this
final rule as it applies to gasoline marine engines. These estimates are greater than
estimated for the NPRM primarily because the NPRM estimates only considered HC
reductions and because sales estimates have been revised for 1993, 1994, and 1995.
Sales in these years were higher than previously estimated.
3.2 Air Quality Benefits
Air quality benefits associated with reduction in VOC emissions are discussed in
this section. Health and welfare effects of the pollutants as they impact ozone
formation are also described. Thought the final regulation does not contain CO
emission standards, EPA does expect minor reductions in annual CO emissions from
OB/PWC engines to occur as a result of this rulemaking. For this reason, a brief
discussion of some of the health and welfare effects associated with CO are discussed.
3.2.1. Tropospheric Ozone
EPA's primary reason for controlling VOC emissions from gasoline OB/PWC
engines is the role of VOCs in ozone formation. Ozone is a product of the atmospheric
chemical reactions involving VOCs and nitrogen oxides. Ozone is one of the major air
pollutants for which National Ambient Air Quality Standards (NAAQS) have been.
A critical aspect of this problem is the formation of ozone both in and downwind
of large urban areas. Under certain weather conditions, the combination of VOC and
-------
3-11
N0X can result in urban and rural areas exceeding the national ambient ozone standard
by a factor of three. The ozone NAAQS represents the maximum level considered
protective of public health by the EPA.
The Agency has found that the contribution from gasoline marine engines to the
VOC emission inventory for several ozone nonattainment areas is large. In an emission
inventories study performed in 1991, the Agency reported large emission inventory
contributions from recreational marine engines in several nonattainment areas around
the country(2). The Nonroad Engine and Vehicle Emission Study (NEVES, reference 2)
report used 1990 as the baseline year. The Agency reported high VOC contributions in
several nonattainment areas in the northeastern portion of the U.S., several
nonattainment areas in California, and several areas in the eastern portion of the U.S.
Table 3-03 indicates the estimated range in percentage of total anthropogenic tons of
VOC per summer day for several of the NEVES study areas.
Table 3-03:
Recreational Marine Emission Inventory Contribution from Selected U.S.
Nonattainment Areas
Nonattainment Area
Contribution from recreational marine engines to
anthropogenic VOC inventory (% of tons/summer day)
Hartford, MA
4.56-5.24
Springfield, MA
3.41-3.97
New York, NY
3.11-3.59
Philadelphia, PA
3.75-4.37
San Diego, CA
4.02-4.57
South Coast Basin, CA
3.49-3.97
Miami, FL
5.89-6.78
Milwaukee, WI
4.87-5.59
Atlanta, GA
4.18-4.83
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3-12
The Northeast States for Coordinated Air Use Management (NESCAUM) is an
association of state air pollution control agencies representing Connecticut, Maine,
Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont.
NESCAUM reported in their written comments in response to the NPRM for this
rulemaking that marine engines (both spark-ignited and compression-ignition)
represent between 3 and 10% of the VOC emission inventories for their member states
(3).
The Regional Air Quality Planning Committee of the Houston-Galveston Area
Council (H-GAC) submitted written comments in response to the NPRM for this
rulemaking. H-GAC commented that they are classified as a severe nonattainment area
for ozone, and that marine vessels (both spark-ignited and compression-ignition)
account for 6.4% of all VOC emissions in the Houston-Galveston area. They
commented the reductions in this rulemaking could potentially be greater than 50 tons
of VOC per day for their nonattainment area (4).
The Agency believes the 75%HC reduction (590,254 tons HC/year) from the
OB/PWC category required by this regulation will make an important contribution in
the reduction of ozone precursors in many ozone nonattainment areas throughout the
U.S., and will help maintain ozone attainment in those areas which have demonstrated
attainment in recent years. The Agency believes the relatively small increase in NOx
emissions (25,440 tons NOx/year, roughly 23 times smaller than the HC reductions)
resulting from this regulation will have minimal impacts on ozone and be far
outweighed by the positive effects of the much larger HC reduction.
3.2.1.1. Health and Welfare Effects of Ozone—Ozone is a powerful oxidant causing
lung damage and reduced respiratory function after relatively short periods of
exposure (approximately one hour). The oxidizing effect of ozone can irritate the nose,
mouth, and throat causing coughing, choking, and eye irritation. In addition, ozone
can also impair lung function and subsequently reduce the respiratory system's
resistance to disease, including bronchial infections such as pneumonia.
Elevated ozone levels can also cause aggravation of pre-existing respiratory
conditions such as asthma. Ozone can cause a reduction in performance during
exercise even in healthy persons. In addition, ozone can also cause alterations in
-------
3-13
pulmonary and extrapulmonary (nervous system, blood, liver, endocrine) function.
The current NAAQS for ozone of 0.12 ppm is based on the level requisite to
protect public health allowing an adequate margin of safety. However, ozone has also
been shown to damage forests and crops, watershed areas, and marine life (5). The
NAAQS for ozone is frequently violated across large areas in the U.S., and after 25
years of efforts aimed at reducing ozone-forming pollutants, the ozone standard has
proven to be exceptionally difficult to achieve. High levels of ozone have been
recorded even in relatively remote areas, since ozone and its precursors can travel
hundreds of miles and persist for several days in the lower atmosphere. Recreation
gasoline marine engines are used both in rural and urban areas, therefore the reduction
in VOCs from this category may have a positive impact both on urban and rural ozone
formation.
Ozone damage to plants, including both natural forest ecosystems and crops,
occurs at ozone levels between 0.06 and 0.12 ppm (5). Repeated exposure to ozone
levels as low as 0.04 ppm can cause reductions in the yields of some crops above 10%
(5). While some strains of corn and wheat are relatively resistant to ozone, many crops
experience a loss in yield of 30% at ozone concentrations below the NAAQS (5). The
value of crops lost to ozone damage, while difficult to estimate precisely, is on the
order of $2 billion per year in the U.S. (5). The effect of ozone on complex ecosystems
such as forests is even more difficult to quantify. However, growth in many species of
pine appears to be particularly sensitive to ozone. Specifically, in the San Bernardino
Mountains of Southern California, the high ozone concentrations are believed to be the
predominant cause of the decline of the endangered ponderosa pine (5).
Finally, by trapping energy radiated from the earth, tropospheric ozone may
contribute to heating of the earth's surface, thereby contributing to global warming (6).
3.2.2. Volatile Organic Compounds (VOC)
EPA expects that reducing VOC emissions from spark ignition gasoline
OB/PWC marine engines will help to mitigate the health and welfare impacts of
ambient VOC's.
3.2.2.1. Health and Welfare Effects of VOC Emissions—VOC is the general term used to
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3-14
denote volatile organic compounds, a broad class of pollutants encompassing hundreds
of specific toxic compounds, including benzene, 1,3 butadiene, formaldehyde,
acetaldehyde, and gasoline vapors. VOC is a criteria pollutant for which the EPA has
established a NAAQS. Measures to control VOC emissions should reduce emissions of
air toxins. However, the magnitude of reduction will depend on whether the control
technology reduces the individual toxins in the same proportion that total VOC are
reduced. Spark ignition marine engines do have important VOC impacts, and it is
suspected they may have significant air toxins impacts as well.
3.2.3. Benzene
Benzene is a clear, colorless, aromatic hydrocarbon which has a characteristic
odor. It is both volatile and flammable. Benzene is present in both gasoline fuel and it
is formed during the incomplete combustion of gasoline. The benzene level of typical
unleaded gasoline sold today is approximately 1.5 percent. The fraction of benzene in
the exhaust varies depending on cycle type, control technology and fuel composition.
For on-highway motor vehicles, benzene is typically 3 to 5 percent of the exhaust
tailpipe total organic gases emitted. It has been found for on-highway motor vehicles
that benzene generally represents 1 percent of evaporative emissions, depending on
the control technology and fuel composition.
Mobile sources account for approximately 85 percent of the total benzene
emissions, of which approximately 30 percent can be attributed to nonroad mobile
sources. These estimates were obtained from EPA's NEVES report (7). In the NEVES
report, benzene was estimated to be about 3.0 percent of VOC emissions and 1.7
percent of evaporative VOC emissions for nonroad equipment. The split between
exhaust and evaporative benzene emissions was assumed to be 80 percent exhaust to
20 percent evaporative. Thus, the overall benzene fraction of nonroad VOC emissions
was estimated to be 2.74 percent.
However, the NEVES study did not distinguish between crankcase fuel/air
scavenged (CS) two-stroke and four-stroke engines. An examination of the air toxic
data used in support of the NEVES study{8), along with two additional reports from
SouthWest Research Institute^)(10) indicates a significant difference in air toxins as a
percentage of total VOC emissions between crankcase scavenged two-stroke and four-
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3-15
stroke spark Ignition gasoline engines. The data set consisted of nine unregulated,
spark-ignition engines. The data set includes two new CS two-stroke engines, two used
CS two-stroke engines, two new four-stroke engines, and three used four-stroke
engines, all engines were used in equipment for the lawn and garden industry. A
summary of air toxins as a percentage of total hydrocarbons from this data set is given
in Table 3-02.
Table 3-02:
Air Toxins as a Percentage of Total Hydrocarbons-
Mean Values for Small Nonroad Spark-Ignited Engines
Engine Cycle Type
benzene
1,3 butadiene
formaldehyde
acetaldehyde
CS Two-Strokes (four engines)
1.2%
0.16%
0.36%
0.08%
Four-Strokes (five engines)
4.0%
0.55%
0.62%
0.11%
The primary difference in air toxins as a percentage of total hydrocarbons between CS
two-strokes and four-stroke engines are the high scavenging losses inherent in the CS
two-stroke engine. Typically 80 to 95 percent of the exhaust hydrocarbons emitted
from a CS two-stroke engine are from the unburnt fuel which escapes during the
scavenging of the exhaust products with fresh charge. Though unburnt fuel does
contain benzene, incomplete combustion of non-benzene aromatics can contribute
significantly to an engines benzene emission rate. Therefore, when presented in terms
of a percentage of total hydrocarbons emitted, a four-stroke engine has a higher
percentage than a CS two-stroke because the CS two-stroke's mass emission rate of
benzene is being diluted by unburnt fuel which contains a small amount of benzene.
Fuel analysis done by SouthWest Research for the engine tests results shown in Table 3-
02. above indicated a fuel benzene content of approximately 1.0 percent by volume.
3.2.3.1 Projected Benzene Emission Reductions—The data set summarized in Table 3-
02. is the only publicly available air toxins data on nonroad spark-ignition engines.
EPA is not aware of any data which is available on air toxic emissions from spark-
ignition marine engines. EPA has estimated this marine rule will result in a 74 percent
(590,254 tons/year) reduction in VOC's from spark-ignition marine engines. It would
be inappropriate to assume that this rule would result in a 74 percent reduction in
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3-16
benzene emissions. As stated earlier, there is a very small data set available on air toxic
emissions from nonroad engines, and no data exists on marine engines or direct-
injection (DI) two-strokes. EPA expects manufacturers to meet the emission standards
through a mix of technologies, primarily the conversion of CS two-strokes to either
four-strokes or DI two-strokes engines. EPA is unaware of any air toxins data on DI
two-strokes. If the assumption is made that as a percentage of total hydrocarbons, DI
two-strokes will be similar to four-stroke engines with respect to air toxins, and that
marine CS two-strokes and future marine four-strokes will emit air toxins as percentage
of total hydrocarbons similar to the nonroad engines tested by SouthWest Research
Institute, the following estimate can be made. Using a benzene emission factor for CS
two-strokes of 1.2 percent of total VOC's, and a value of 4.0 percent for both four-stroke
and DI two-stroke engines, this rule making will result in approximately a 20 percent
(2,300 tons/year) annual decrease in benzene emissions from spark-ignition marine
engines. This assumes evaporative VOC emissions, and therefore evaporative benzene
emissions, remain unchanged. It should be stressed that this estimate is based on a
very limited data set of nonroad spark-ignition small engines, not on actual marine
engine data, and that no data is available on direct-injection two-stroke engines. In
order to produce an accurate estimate of benzene, and other air toxins, reduction from
marine engines, additional testing would need to be performed both on baseline and
controlled engines.
3.2.3.2 Health and Welfare Effects of Benzene Emissions—Health effects caused by
benzene emission differ based on concentration and duration of exposure. EPA's Total
Exposure Assessment Methodology (TEAM) Study identified the major sources of
exposure to benzene for much of the U.S. population. These sources turn out to be quite
different from what had previously been considered the important sources. The study
results indicate that the main sources of human exposure are associated with personal
activities, not with the so-called "major point sources". The results imply that personal
activities or sources in the home far outweigh the contribution of outdoor air to human
exposure to benzene. Since most of the traditional sources exert their effect through
outdoor air, some of the nonroad small SI engine sources could explain the increased
personal exposures observed. The TEAM Study is described in detail in a four-volume
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EPA publication (11).
The International Agency for Research on Cancer (IARC), classified benzene as a
Group I carcinogen . A Group I carcinogen is defined as an agent that is carcinogenic
to humans. IARC (1987) based this conclusion on the fact that numerous case reports
and follow-up studies have suggested a relationship between exposure to benzene and
the occurrence of various types of leukemia. The leukemogenic (i.e., the ability to
induce leukemia) effects of benzene exposure were studied in 748 white males
employed from 1940-1949 in the manufacturing of rubber products in a retrospective
cohort mortality study (Infante et al. 1977a,b). Statistics were obtained through 1975. A
statistically significant increase in the incidence of leukemia was found by comparison
to the general U.S. population. The worker exposures to benzene were between 100
ppm and 10 ppm during the years 1941-1945. There was no evidence of solvent
exposure other than benzene. In addition, numerous investigators have found
significant increases in chromosomal aberrations of bone marrow cells and peripheral
lymphocytes from workers with exposure to benzene (IARC 1982).
Exposure to benzene has also been linked with genetic changes in humans and
animals. EPA has concluded that benzene is a Group A, known human carcinogen
based on sufficient human epidemiologic evidence (Rinsky et al. 1981; Ott et al. 1978;
Wong et al. 1983) demonstrating an increased incidence of nonlymphocytic leukemia
from occupational inhalation exposure. The supporting animal evidence (Goldstein
1980; NTP 1986; Maltoni et al., 1983) showed an increased incidence of neoplasia in rats
and mice exposed by inhalation and gavage. EPA calculated a cancer unit risk factor for
benzene of 8.3x10'6 (pg/m3)'1 based on the results of the above human epidemiological
studies in benzene-exposed workers in which an increase of death due to
nonlymphocytic leukemia was observed.
The California Department of Health Services (DHS, 1984), which provides
technical support to CARB, has also determined that there is sufficient evidence to
consider benzene a human carcinogen. CARB performed a risk assessment of benzene
that was very similar to EPA's risk assessment. The CARB risk estimate is actually a
range, with the number calculated by EPA serving as the lower bound of cancer risk
and a more conservative (ie., higher) number, based on animal data, serving as the
upper bound of cancer risk. The CARB potency estimate for benzene ranges from
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8.3xl0'6 to 5.2xl0'5 (pg/m3)"1.
A number of adverse noncancer health effects have also been associated with
exposure to benzene. People with long-term exposure to benzene at levels that
generally exceed 50 ppm (162,500 pg/m3) may experience harmful effects on the
blood-forming tissues, especially the bone marrow. These effects can disrupt normal
blood production and cause a decrease in important blood components, such as red
blood cells and blood platelets, leading to anemia and a reduced ability to clot.
Exposure to benzene at comparable or even lower levels can be harmful to the immune
system, increasing the chance for infection and perhaps lowering the body's defense
against tumors by altering the number and function of the body's white blood cells. In
studies using pregnant animals, inhalation exposure to benzene in the range of 10-300
ppm (32,500-975,000 pg/m3) indicates adverse effects on the developing fetus,
including low birth weight, delayed bone formation, and bone marrow damage.
3.2.4. 1,3- Butadiene
1,3-Butadiene is a colorless, flammable gas at room temperature with a pungent,
aromatic odor, and a chemical formula C4H3. 1,3-Butadiene is insoluble in water and
because of its reactivity, is estimated to have a short atmospheric lifetime. The actual
lifetime depends upon the conditions a t the time of release, such as the time of day,
intensity of sunlight, temperature etc. 1,3 Butadiene is formed in vehicle exhaust by
the incomplete combustion of the fuel and is assumed not to be present in vehicle
evaporative and refueling emissions.
1,3- Butadiene emissions appears to increase roughly in proportion to exhaust
hydrocarbon emissions for a given engine design. However, when comparing
crankcase air/fuel scavenged (CS) two-stroke engines with either four-stroke or direct
injection (DI) two-stroke gasoline engines, a decrease in VOC would not be directly
proportional to the decrease in 1,3 butadiene. As discussed in section 3.2.3 , generally
80 to 95 percent of a CS two-stroke engines exhaust VOC emissions is unburnt fuel lost
during the scavenging process. This unburnt fuel does not contain 1,3 butadiene,
therefore a reduction in scavenging losses will not reduce 1,3 butadiene. Table 3-02
indicates that for nonroad CS two-stroke engines, approximately 0.16 percent of
exhaust VOC is 1,3 butadiene, while approximately 0.55 percent of nonroad four-stroke
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VOC is 1,3 butadiene.
3.2.4.1 Projected 1,3-Butadiene Emission Reductions-Current EPA estimates indicate
that mobile sources account for approximately 94 percent of the total 1,3-butadiene
emissions, out of which 41 percent can be attributed to nonroad mobile sources. The
remaining 1,3-butadiene emissions come from stationary sources mainly related to
industries producing 1,3-butadiene and those industries that use 1,3-butadiene to
produce other compounds. Using the emission factors from Table 3-02, and assuming
that controlled marine four-strokes and DI two-strokes will emit the same percentage of
1,3 butadiene with respect to total VOC, this rule will result approximately a 20
percent (280 tons/year) reduction in 1,3 butadiene emissions.
3.2.4.2 Health and Welfare Effects of 1,3-Butadiene Exposure-The annual average
ambient level of 1,3-butadiene ranges from 0.12 to 0.56 pg/m3. Long-term inhalation
exposure to 1,3-butadiene has been shown to cause tumors in several organs in
experimental animals. Epidemiologic studies of occupationally exposed workers were
inconclusive with respect to the carcinogenicity of 1,3-butadiene in humans. Based on
the inadequate human evidence and sufficient animal evidence, EPA has concluded
that 1,3-butadiene is a Group B2, probable human carcinogen. IARC has classified 1,3-
butadiene as a Group 2A, probable human carcinogen. EPA calculated a cancer unit
risk factor of 2.8X10 "4 (pg/m3)"1 for 1,3-butadiene based on the results of a study in mice
in which an increase in the incidence of tumors in the lung and blood vessels of the
heart, as well as lymphomas were observed.
Exposure to 1,3-butadiene is also associated with adverse noncancer health
effects. Exposure to high levels (on the order of hundreds of thousands ppm) of this
chemical for short periods of time can cause irritation of the eyes, nose, and throat, and
exposure to very high levels can cause effects on the brain leading to respiratory
paralysis and death Studies of rubber industry workers who are chronically exposed to
1,3-butadiene suggest other possible harmful effects including heart disease, blood
disease, and lung disease. Studies in animals indicate that 1,3-butadiene at exposure
levels of greater than 1,000 ppm (2.2xl06 pg/m3) may adversely affect the blood-
forming organs. Reproductive and developmental toxicity has also been demonstrated
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in experimental animals exposed to 1,3-butadiene at levels greater than 1,000 ppm.
3.2.5 Formaldehyde
Formaldehyde is formed as a result of incomplete combustion of gasoline in
internal combustion engines. Formaldehyde is not a component of gasoline, and
therefore it is not a component of evaporative emissions. For typical on-highway
motor vehicles, 1-4 percent of tailpipe exhaust VOC is formaldehyde. The EPA NEVES
study estimated that approximately 13 percent of atmospheric formaldehyde comes
from nonroad mobile sources. Formaldehyde exhibits a very complex atmospheric
behavior. Approximately 70 percent of the formaldehyde in the atmosphere is
"secondary" formaldehyde formed from reaction of other VOC gases.
3.2.5.1. Projected Formaldehyde Emission Reductions-Using the same arguments from
section 3.2.3, the reduction of formaldehyde from this rule will not be as great as the
total VOC reduction. EPA has estimated a VOC reduction of 642,211 tons/year, 74
percent from the uncontrolled scenario. Using the emission factors from Table 3-02 for
formaldehyde, 0.36 percent of VOC for crankcase fuel/air scavenged two-strokes
(uncontrolled case), and 0.62 percent of VOC for both four-stroke and direct injection
two-stroke marine engines (controlled case). EPA estimates approximately a 55 percent
reduction (1760 tons/year) in formaldehyde emissions. It should be stressed that this
estimate is based on nine engines used in the lawn and garden industry. Air toxins
data from controlled and uncontrolled marine engines would need to be gathered to
substantiate this reduction claim.
3.Z.5.2. Health and Welfare Effects of Formaldehyde-Based on laboratory Studies
involving rats, EPA has classified formaldehyde as a group B1 toxic, probable human
carcinogen. EPA has calculated a unit risk factor of 1.3x10"* (pg/m3)"1 for formaldehyde.
Formaldehyde is a known human irritant for the eyes, nose and upper
respiratory system.
3.2.6 Acetaldehyde
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Acetaldehyde is formed in internal combustion engines from the incomplete
combustion of gasoline. Acetaldehyde is not found in evaporative emissions. For on-
highway mobile sources, acetaldehyde is typically between 0.4 and 1.0 percent of
exhaust tailpipe VOC. The nonroad engines and vehicle, including marine engines,
contribution to the national inventory of acetaldehyde contains both primary and
secondary emissions. It is estimated that approximately 39% of the national
acetaldehyde inventory comes from motor vehicles. No attempts have been made to
estimate the contribution of nonroad sources, including marine engines, to the national
acetaldehyde inventory.
3.2.6.1. Projected Acetaldehyde Emission Reductions—Based on the data collected by
SouthWest Research Institute shown in Table 3-02, acetaldehyde emissions from
nonroad crankcase fuel/air scavenged small two-stroke engines is approximately 0.08
percent of total exhaust hydrocarbon emissions and a nonroad four-stroke small
engines acetaldehyde emission rate is approximately 0.11 percent of total exhaust
hydrocarbon emissions. As described in Section 3.2.3, the percentage emission
reduction from marine engines for VOC will be greater than the reduction in
acetaldehyde, primarily due to the nature of the VOC emissions coming from crankcase
fuel/air scavenged two-stroke engines. Using the emission factors for acetaldehyde
from Table 3-02, a very rough estimate of acetaldehyde reduction of 65 percent (450
tons/year) can be calculated for this rule. Air toxins data from controlled and
uncontrolled marine engines would need to be gathered to substantiate this reduction
claim.
3.2.6.2. Health and Welfare Effects of Acetaldehyde—EPA has classified acetaldehyde as
a group B2 toxic, probable human carcinogen. EPA has calculated a cancer unit risk
factor of 2.2xl0'6 (pg/m3)"1. Noncancer effects include irritation of the eyes, skin, and
respitory tract. Respitory paralysis and death have occurred at extremely high
concentrations.
3.2.7 Carbon Monoxide (CO)
The Clean Air Act directs the Administrator of the EPA to establish National
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Ambient Air Quality Standards (NAAQS) for several widespread air pollutants, based
on scientific criteria and allowing for an adequate margin of safety to protect public
health. The current primary and secondary NAAQS for CO are 9ppm for a 1-hour
average and 35 ppm for an 8-hour average. The information given below is a
description of the adverse health effects of CO, however, very little research has been
done concerning the health effects of CO emissions from marine spark-ignition engines.
EPA is not imposing any CO emission standards on gasoline SI marine engines in this
rule, however, the Agency does expect the technology changes which will be used to
meet the OB/PWC HC+NOx standard will result in some modest CO reductions from
this subcategory of gasoline SI marine engines.
3.2.7.1. Health and Welfare Effects of CO~Carbon monoxide is a colorless, odorless,
tasteless and nonirritating gas and gives no signs of its presence. It is readily absorbed
from the lungs into the bloodstream, there forming a slowly reversible complex with
hemoglobin (Hb) known as carboxyhemoglobin (COHb).
Blood COHb levels do not often exceed 0.5 to 0.7 percent in normal individuals
unless exogenous CO is breathed. Some individuals with high endogenous CO
production can have COHb levels of 1.0 to 1.5 percent (e.g. anemic). The presence of
COHb in the blood reduces the amount of oxygen available to vital tissues, affecting
primarily the cardiovascular and nervous systems. Although the formation of COHb is
reversible, the elimination half-time is quite long because of the right binding between
CO and Hb. This can lead to accumulation of COHb, and extended exposures to even
relatively low concentrations of CO may produce substantially increased blood levels
of COHb.
Health effects associated with exposure to CO include cardiovascular system,
central nervous system (CNS), and developmental toxicity effects, as well as effects of
combined exposure to CO and other pollutants, drugs, and environmental factors.
Concerns about the potential health effects of exposure to CO have been addressed in
extensive studies with various animal species as subjects. Under varied experimental
protocols, considerable information has been obtained on the toxicity of CO, its direct
effects on the blood and other tissues, and the manifestations of these effects in the form
of changes in organ function. Many of these studies, however have been conducted at
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extremely high levels of CO (i.e., levels not found in ambient air). Although severe
effects from exposure to these high levels of CO are not directly germane to the
problems from exposure to current ambient levels of CO, they can provide valuable
information about potential effects of accidental exposure to CO, particularly those
exposures occurring indoors.
Carbon monoxide poisoning can cause permanent brain damage , including
changes in personality and memory. Once inhaled, carbon monoxide decreases the
ability of the blood to carry oxygen to the brain and other vital organs. Even low levels
of carbon monoxide can set off chest pains and heart attacks in people with coronary
artery disease.
Although very little research measuring the human health effects of CO
emanating from marine spark-ignition gasoline engines have been conducted, ample
research results are available concerning general health effects of exposure to CO. The
effects of exposure to low concentrations-such as the levels found in ambient air - are
far more subtle and considerably less threatening than those occurring in direct
poisoning from high CO levels. Maximal exercise performance in healthy individuals
has been shown to be affected at COHb levels of 2.3 percent and greater. Central
nervous system effects, observed at peak COHb levels of 5 percent and greater, include
reduction in visual perception, manual dexterity, learning, driving performance, and
attention level. Of most concern, however, are adverse effects observed in individuals
with chronic heart disease at COHb levels of 3 to 6 percent. At these levels, such
individuals are likely to have reduced capacity for physical activity because they
experience chest pain (angina) sooner. Exercise-related cardiac arrhythmias have also
been observed in some people with chronic heart disease at COHb levels of 6 percent or
higher and may result in an increased risk of sudden death from a heart attack .
The NAAQS set by EPA are intended to keep COHb levels below 2.1 percent in
order to protect the most sensitive members of the general population (i.e., individuals
with chronic heart disease). However, elderly people, pregnant women (due to
possible fetal effects), small children, and people with anemia or with diagnosed or
undiagnosed pulmonary or cardiovascular disease are also likely to be at increased risk
to CO effects.
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Chapter 3 : References
1. Price Waterhouse Study, National Recreational Boating Survey, Final Report,
prepared for U. S. Fish and Wildlife Service and the United States Coast Guard,
Contract# 14-16-0009-90-006, June 30, 1992.
2. EPA, Nonroad Engine And Vehicle Emission Study, EPA Report 21A-2001,
Washington, D.C., November 1991, Appendix M.
3. EPA Air Docket A-92-28, Item Number IV-D-69.
4. EPA Air Docket A-92-28, Item Number IV-D-37.
5. U.S. Environmental Protection Agency, Review of the National Ambient Air Quality
Standards for Ozone - Assessment of Scientific and Technical Information: OAQPS Staff
Paper, EPA-450/2-92-001, June 1989.
6. National Research Council, Rethinking the Ozone Problem in Urban and Regional Air
Pollution, National Academy Press, Washington, DC, 1991.
7. EPA, Nonroad Engine and Vehicle Emission Study, EPA Report 21A-2001,
Washington, D.C., November 1991.
8. Carroll, J., SouthWest Research Institute, Emission tests of in-use small utility
engines, SwRI Report No. 3426-006, completed for the U.S. Environmental
Protection Agency, Contract No. 68-CO-0014, Work Assignment No. 0-6, Task 3,
September 1991.
9. Hare, C. and White, J., SouthWest Research Institute, Toward the Environmentally-
Friendly Small Engine: Fuel, Lubricant, and Emission Measurement Issues,
Society of Automotive Engineers Paper No. 911222, October 1991.
10. Hare, C. and Carroll, J., SouthWest Research Institute, Speciation of organic
emissions to study fuel dependence of small engine exhaust photochemical
reactivity, SwRI Report No. 9702, July 1993.
11. EPA, The Total Exposure Assessment Methodology (TEAM) Study: Summary and
Analysis: Volume I, Office of Research and Development, Washington, D.C., EPA
Report No. EPA/600/6-87/002a, June 1987.
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Appendix A: Supplementary Tables
A-1
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