Proceedings Of The
Diesel Particulate Control/
Alternative Fuels Symposium
January 27-28, 1987
Bismarck Hotel
Chicago, Illinois
Sponsored By
U.S. EPA
Region 5, Chicago, Illinois
Motor Vehicle Emissions Laboratory
Ann Arbor, Michigan
Chicago Lung Association,
Chicago, Illinois
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th
Chicago, |L 60604-3590
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Table of Contents
Agenda
Opening Remarks Frank M. Covington
The EPA Perspective on the Need for
Alternative Fuels Charles L. Gray, Jr.
Factors Influencing the Emission of Vapor and Particulate
Phase Components from Diesel Engines Dennis Schuetzle
James A. Frazier
Bioassay-Directed Chemical Analysis in
Environmental Research Dennis Schuetzle
Dr. Joel!en Lewtas
Slide Presentation .... Dr. Rashid Shaikh
Settlement of Case Against GM Establishes
Clean Bus Fuel Research Program.-;".. .........Natural Resources Defense Council
Engine Modification to Meet Future Diesel Standards Thomas Baines
Diesel Particulate Control: Emerging Control Technologies
to Address A Serious Pollution Problem Bruce T. Bertelsen
Status of Exhaust After-treatment Projects Thomas Baines
Fuel Quality Control Issues Timothy Sprik
The Environmental Protection Agency View of
Methanol As A Transit Bus Fuel Jeff Alson
Emissions from Two Methanol Powered Buses Terry L. Ullman
Charles T. Hare
Thomas Baines
Operational Aspects of the Canadian
Methanol in Large Engines Program Thomas J. Timbario
Federal Government Policies On Use of
Alternative Transportation Fuels E. Eugene Ecklund
Slide Presentation E. Eugene Ecklund
UMTA Methanol Program Presentation Vincent DeMarco
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* I
U.S. Environmental Protection Agency
Region 5
Chicago, Illinois
Emission Control Technology Division
Motor Vehicle Emissions Laboratory
Ann Arbor, Michigan
Chicago Lung Association
Chicago, Illinois
Diesel Participate Control/
Alternative Fuels Symposium
January 27-28, 1987
JANUARY 27, 1987
8 a.m. Registration
9 a.m. Introduction Steve Rothblatt,
Chief, Air and Radiation Branch, Region 5, U.S.EPA
9-05 a.m. Welcome to U.S. EPA Region 5 Frank M. Covington
Deputy Regional Administrator, Region 5,
U.S. Environmental Protection Agency (U.S. EPA)
9:15 a.m. Keynote Address Charles Gray.
Director, Emission Control Technology Division,
Office of Mobile Sources, U.S.EPA
10:00 a.m Break
10:15 a.m. Environmental and Health Issues (panel discussion) moderator,
John Kirkwood,
Chicago Lung Association
Characteristics of Diesel Emissions Dennis Schuetzle,
Ford Motor Company
Risk Analysis... Dr. Joellen Lewtas,
Chief, Genetic Bioassay Branch, U.S. EPA
Overview of Health Effects Institute Research on
Diesel Particulates Dr. Rashid Shaikh,
Health Effects Institute (HEI)
12 noon Lunch
1:30 p.m. Inhalation Studies ....Dr. Robert K. Jones.
Lovelace Inhalation Toxicology Research Institute
Health Effects of Methanol ....Dr. Robert Kavet,
ERI Incoporated.
formerly of HEI
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I i
Agenda
Diesel Participate Control/
Alternative Fuels Symposium
Health Effects Studies at General Motors...Or. Jaroslav J. Vostal ,
General Motors Research Laboratory
Present/Future Standards David Ooniger.
Natural Resources Defense Council
'2:50 p.m. Break
3-00 p.m. Diesel Control Technology (panel discussion) moderator,
Sarah LaBelle.
Chicago Transit Authority
Engine Modifications to Meet Future Standards Thomas Baines.
Emission Control Technology Division, U.S.EPA
Trap Oxidizers Bruce Bertelsen,
Manufacturers of Emission Controls Association
Status of Trap Oxidizer Projects Thomas Baines
Impact of Cleaner Diesel Fuels on Cost Timothy Sprik,
Emission Control Technology Division, U.S.EPA
JANUARY 28, 1987
9 a.m. Survey of Alternative Fuels (panel discussion) .moderator.
Dr. Barry Nusshaum.
Chief, Operations and Compliance Policy Branch. U.S.EPA
Methanol• sources, markets, emissions, safety Boh Murray,
Director, Worlwide Methyl Fuels,
Celanese Chemical Company
Methane- sources, markets, emissions, safety..Dr. Jeffrey Seisler,
American Gas Association
Operational Aspects of the Canadian Methanol in Large
Engine Program Tom Timhario,
Sypher-Mueller International
10:30 a.m. Break
-2-
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1 ]
Agenda
Diesel Participate Control/
Alternative Fuels Symposium
10:45 a.m. The Use Of Methanol Fuels To Achieve
Heavy Duty Engine Standards moderator,
Thomas 3aines,
Emission Control Technology Division. U.S.EPA
Environmental Benefits of Methanol Fueled
Heavy Duty Engines Jeff Al son,
Emission Control Technology Division, U.S. EPA
Meeting EPA Emission Standards Charles Napier.
M.A.N.
Methanol Engine Development Don Petersen.
Detroit Diesel Allison - GM
12 noon Lunch
1:30 p.m. Government Policies: The Choices (panel discussion) moderator
Steve Rothhlatt.
Chief, Air and Radiation Branch, Region 5, U.S.EPA
Existing Alternative Fuel Fleets Vincent DeMarco,
Urban Mass Transportation Administration (UMTA)
Methanol/Ethanol/Natural Gas Eugene Ecklund.
Department of Energy
Opportunities for Future Demonstration Projects Paul Fish,
Region 5, UMTA
3 p.m. Closing Statement Steve Rothhlatt
-3-
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OPENING REMARKS
DIESEL PARTICULATE CONTROL/ALTERNATIVE FUELS SYMKJSIUM
JANUARY 27, 1987
CHICAGO, ILLINOIS
MR. FRANK M. COVINGTON
DEPUTY REGIONAL ADMINISTRATOR
REGION 5
GOOD MORNING LADIES WU GENTLtMEN. I WOULD LIKE Tu EXTEND TO YOU MY
PERSONAL WELCOME TO REGION V. I AM GLAD TO SEE SO MANY OF YOU HERE AT THE
DIESEL PARTiCULATE CONTROL/ALTERNATIVE FUELS SYMPOSIUM WHICH WE ARE SPONSOR-
ING /LONG WITH EPA'S MOTOR VEHICLE EMISSIONS LABORATORY AND THE CHICAGO
LUNG ASSOCIATION.
IF YOU HAVE HAD THE MISFORTUNE If BEING CAUGHT BEHIND A BUS, AS IF LEAVES A
STOP, OR BEING STOPPED IN RUSH HOUR TRAFFIC ON THE HIGHWAY, SURROUNDED BY 18
WHEELERS, YOU UNDERSTAND THE PUBLIC'S CONCERN OVER DIESEL PARTICULATES.
UNLIKE THE INVISIBLE HYDRXARBON, NITROGEN OXIDES, AND CARBON MONOXIDE
EMISSIONS FROM GASUL1NE-POWERED VEHICLES, DIESEL EMISSIONS ARE MOST NOTICE-
ABLE- THEIR BLACK SMOKE AND MALODOROUS SMELL BRING UNIVERSAL DISMAY.
YET, UNTIL 1978, THERE WAS LITTLE RESEARCH ON THE HEALTH EFFECTS OF, AND
CONSEQUENTLY, LITTUE REGULATION OF, DIESEL PARTICULATES. NONETHELESS,
EVIDENCE HAS ACCUMULATED WHICH HAS CONVINCED EPA THAT STEPS NEEDED TO BE
TAKEN TO PROTECT THE PUBLIC FROM THIS POLLUTANT.
IN RESPONSE TO THIS CONCERN, EPA HAS ISSUED NEW REGULATIONS FOR CONTROLLING
DIESEL EMISSIONS FROM HEAVY-DUTY ENGINES THAT WILL BEGIN TO BE PHASED IN, IN
1988. IT IS OUR UNDERSTANDING THAT THE ENGINE MANUFACTURERS WILL MOST
LIKELY BE ABLE TO MEET THE 1988 STANDARDS THROUGH ENGINE MODIFICATIONS.
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HOWEVER, THE MORE STRINGENT STANDARDS FOR 1991 BUS ENGINES IS ANOTHER SIORY.
MOST EXPERTS AGREE THAT THIS STANDARD CANNOT BE HET WITHOUT ADDITIONAL
EXHAUST CONTROLS, MOST LIKELY CATALYST-TRAP OXIUIZERS. THIS RAISES MANY
QUESTIONS:
•WILL THE ENGINE MANUFACTURERS AND EMISSION CONTROL l£SIGUERS t£
ABLE TO MEET THE 1991 STANDARDS ON TIME?
•WHAT WILL HAPPEN IF THEY CAN'T?
•WILL THEY BE ABLE TO 1ESIGN CATALYST TRAP OXIDIZERS THAT WILL WORK?
•WILL THE SULFUR CONTENT OF DIESEL FUEL HAVE TO BE REDUCED?
•WHAT KIND OF COST INCREASES CAN WE EXPECT FROM THIS NEW TECHNOLOGY?
THESE QUESTIONS WILL BE ADDRESSED BY THIS I'lORNING'S DIESEL CONTROL TECHNOLOGY
PANEL-
EPA HAS HAD A LONG STANDING INTEREST IN EMISSION REDUCTIONS THAT MIGHT BE
DERIVED BY CONVERTING ENGINES SO THAT THEY CAN USE ALTERNATIVE FUELS. MANY
FUELS HAVE BEEN CONSIDERED, SUCH AS f€THANOL, ETHANOL AND METHANE, TU NAME
A FEW. THE SECOND DAY OF OUR COHERENCE WILL BE DEVOTED MOSTLY TO THIS
TOPIC- THE ALTERNATIVE 'FUELS AND GOVERNMENT POLICIES PANELS WILL ADDRESS
WHICH FUELS COULD CONTRIBUTE MOST TO IMPROVED AIR QUALITY, WHAT THE COSTS
MAY BE, THE ROLE INDUSTRY SEES FOR ALTERNATIVE FUELS, AND WHAT GOVERNMENT
PROGRAMS EXIST TO ENCOURAGE THE EXPERIMENTAL USE OF THESE FUELS, PMD OTHER
MEANS OF CONTROL TECHNOLOGY.
REPRESENTATIVES FROM DIVERSE GROUPS ARE PRESENT FOR THIS SYMPOSIUM- SOME OF
YOU ARE AIR POLLUTION CONTROL AGENCY OFFICIALS, SOME OF YOU REPRESENT THE
INTERESTS OF INDUSTRY. OTHERS OF YOU SEEK TO REPRESENT THE INTERESTS UF
THE ENVIRONMENTAL GROUPS, WHILE STILL OTHERS ARE ACTIVELY ENGAGED IN RESEARCH
ON HEAVY DUTY ENGINES. WE ALSO HAVE HERE REPRESENTATIVES FROM VARIOUS
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GOVERNMENT mi) PLANNING AGENCIES WHO, IN ONE WAY UK ANOTHER, ARE CONCERNED
WITH THE QUESTION UF ENERGY USE.
LAST BUT NUT LEAST, SUME UF YOU WURK FOR THE TRANSIT COMPANIES. YUU WILL
BE FACED WITH SOME HARD DECISIONS IN THE COMING YEARS CONCERNING EMISSION
CONTROL DEVICES PND WHICH ENGINES TO PURCHASE. HOPEFULLY, THIS SYMPOSIUM
WILL PROVIDE YOU WITH INFORMATION THAT MAY MAKE THESE DECISIONS EASIER-
RESEARCHERS ARE NOW ACTIVELY ENGAGED IN THE STUDY OF THE CHARACTERIZATION AND
HEALTH EFFECTS OF DIESEL PARTICULATE- AS IN ANY NEW FIELD, SCIENCE HAS NOT
YhT ESTABLISHED A UNIVERSALLY HELD TRUTH CONCERN ING I HE TRUE LEVEL (h
DANGER OF THIS POLLUTNT- OUR PANELISTS TODAY WILL SHARE WITH YOU THEIR
LATEST FINDINGS, AND AS TO BE EXPECTED, SOME OF THESE MAY CONTRADICTORY.
BUT THAT'S O.K., BECAUSE THAT'S WHAT WE IN REGION V BELIEVE OUR ROLE SHOULD
BE-TU FACILITATE A SHARED DISCUSSION AND DEBATE IN THE ENVIRONMENT
COMMUNITY. WE EXPECT THE HEALTH EFFECTS PANEL TO ENGENDER A LIVELY QUESTION
AND ANSWER PERIOD.
AS YOU CAW SEE, WE HAVE A FULL AGENDA OVER THE NEXT TWO DAYS. I WANT TO
THANK EACH AND EVERY ONE OF YOU FOR ATTENDING WHAT I CONSIDER TO BE AN
IMPORTANT REGIONAL SYMPOSIUM. IT IS MY PERSONAL HOPE THAT THIS SYMPOSIUM
WILL SERVE AS A FURTHER CALL TO ACTION TO REDUCE DIESEL PARTICULATE POLLUTION.
NOW I WOULD LIKE TO INTRODUCE OUR KEYNOTE SPEAKER, CHARLES GRAY. CHARLES
IS THE DIRECTOR OF THE EMISSION CONTROL TECHNOLOGY DIVISION OF THE EPA'S
OFFICE OF MOBILE SOURCES. THE EMISSION CONTROL TECHNOLOGY DIVISION IS
RESPONSIBLE FOR: 1) THE DEVELOPMENT AND ESTABLISHMENT OF ALL FEDERAL
MUTUR VEHICLE EMISSION STANDARDS (FROM MOTORCYCLES TO AIRCRAFT) AND TEST
PRXEDURES; 2) EVALUATION AND ASSESSMENT OF NEW EMISSION CONTROL AMD ENERGY
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CONSERVATION TECHNOLOGY DEVELOPMENTS; 3) CHARACTERIZATION OF POTENTIALLY
HAZARDOUS AND CURRENTLY UNREGULATED EMISSIONS FROM NEW TECHNOLOGIES AND
ALTERNATIVE FUELS; 4) SURVEILLANCE PROGRAMS TO ESTABLISH IN-IISE VEHICLE
EMISSIONS AND FUEL ECONOMY PERFORMANCE; AND 5) NATIONAL LEADERSHIP IN THE
IMPLEMENTATION OF MOTOR VEHICLE EMISSIONS INSPECTION AND MAINTENANCE PROGRAMS.
MR. GRAY WAS BORN AND RAISED IN ARKANSAS. HE HAS A BACHELOR OF SCIENCE
DEGREE 1U CHEMICAL tNGINEERlNG FROM THE UNlVERSIfY OF MISSISSIPPI AND A
MASTER OF SCIENCE DEGREE FROM THE UNIVERSITY OF MICHIGAN. HE WORKED WITH
ESSO EXPLORATION AND PRODUCTION RESEARCH COMPANY ON PROBLEMS ASSOCIATE
WITH PETROLEUM EXPLORATION AND PRODUCTION, AND WITH GULF GENERAL ATOMIC IN
THh AREAS OF NUCLEAR ENERGY UTILIZATION AND FUEL REPROCESSING. FOR THE PAST
SIXTEEN YEARS HE HAS WORKED FOR THE U.S. ENVIRONMENTAL PROTECTION AGENCY
PLAYING A MAJOR ROLE IN THE DEVELOPMENT OF REGULATIONS FOR AIR POLLUTION
CONTROL FROM MOBILE SOURCES.
MR. GRAY HAS HAD A LONGSTANDING INTEREST IN ALTERNATIVE FUELS, AND IN THE
BENEFITS THAT SUCH FUELS COULD PROVIDE WITH RESPECT TO A CLEANER ENVIRONMENT,
INCREASED ECONOMIC GROWTH, AND ENHANCED NATIONAL SECURITY. IN THE flID-19/U'S
HE WAS THE EPA PROGRAM MANAGER FOR ALTERNATIVE TRANSPORTATION FUELS, AND HE
CUKRENILY HEADS THt EPA DIVISION WHICH OVERSEES MOST OF THE AGENCY'S ALTERNATIVE
FUELS RESEARCH AND ANALYSIS- HE IS CO-AUTHOR OF "MOVING AMERICA TO METHANOL:
A PLAN TO REPLACE OIL IMPORTS, REDUCE ACID RAIN, AND REVITALIZE OUR DOMESTIC
ECONOMY/ A BOCK PUBLISHED BY THE UNIVERSITY OF MICHIGAN PRESS.
/
WITHOUT FURTHER ADO I GIVE YOU CHARLES GRAY
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FEB 1 7 1987
AiJ,* f^diation Branch
U.S. EPA Region V
The EPA Perspective on the Need for Alternative Vehicle Fuels
Highlights of the Keynote Address for the
EPA Region 5 Diesel Particulate Control/Alternative Fuels Symposium
January 27, 1987
Charles L. Gray, Jr.
Director of the Emission Control Technology Division
Office of Mobile Sources
Environmental Protection Agency
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f 1986 Elsevier Science Publishers 8 V (Biomedicat Division)
Carcinogenic and Mutagenic Effects of Diesel Engine Exhaust
N Ishimshi, A. Koizumi. fl.O. McCle/lan and W Stober «ds 41
FACTORS INFLUENCING THE EMISSION OF VAPOR AND PARTICULATE PHASE
COMPONENTS FROM DIESEL ENGINES
DENNIS SCHUETZLE
Ford Motor Co Research Staff, Scientific Research Lab.-S306l,
, Box 2053, Dearborn, MI 48121, USA
JAMES A. FRAZIER
National Research Council, National Academy of Sciences,
Washington, D. C. 20418, USA.
INTRODUCTION (1-10)
Vehicle emissions are comprised of thousands of chemical
components. However, only a small percentage of these many
compounds have potential toxicological significance. The
probability for identification of the most biologically active
compounds presents an enormous, if not an impossible task. An
equally difficult task is to make a quantitative assessment of the
human health risks associated with exposure to these chemicals.
Considerable progress has been made during the past several
years in the identification of several chemicals with significant
mutagenic activity in diesel exhaust. Approximately 40% of the
total mutagenicity (TA98 strain) of diesel particulate extracts
can be accounted for by several nitrated polynuclear aromatic
hydrocarbons (nitro-PAH). Much of this progress has come about by
the use of an analytical tool called "bioassay directed chemical
analysis" which is a combination of short-term bioassays and
chemical analysis (1). Some of the mutagenic nitro-PAH have also
been found to be carcinogenic in animal tests as reported by
others in this volume.
In 1983 the U.S. National Academy of Sciences (NAS) initiated a
study on the "Feasibility of Assessment of Health Risks from
Vapor-Phase Organic Chemicals in Gasoline and Diesel Exhaust"
(2) . In that study several organic chemicals, identified in the
1 vapor phase, were selected as based upon the availability of
toxicological and epidemiological information. This information
was used in making quantitative and qualitative assessments of the
human health risk associated with exposure to each chemical. The
purpose of this paper is to summarize the results of the NAS study
and extend it to include recent emissions data on chemicals in the
gas-phase and particulate-phase as given in Table 1.
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42
SELECTION OF CANDIDATE COMPOUNDS
Table l lists the candidate compounds chosen for this study.
The choice of these compounds was based upon 1) . how represent-
ative these candidate compounds are for other components emitted
in vehicle exhaust, 2). the availability of emission rate data as
a function of operating conditions and aromaticity of the fuel,
3). the availability of emission rate data for light-duty diesel,
heavy-duty diesel, and gasoline engines from various manu-
facturers, 4). the reliability of the emissions data as determined
by the analytical protocol (e.g. minimization of artifact
formation), 5) . the availability of data to determine compound
distribution between the particle and gas phases after atmospheric
dispersion, 6). the potential to undergo atmospheric reactions to
form reaction products of toxicological significance, 7). the
reliability of models to determine exposure levels, 8). the
availability of relevant toxicological data, and 9) . the
availability of biomarker (e.g. measurement of chemical adducts in
blood) to determine actual levels of exposure.
Table 1 lists the sixteen compounds chosen as candidates for
risk assessment studies as based upon these nine criteria. Some
of the compounds listed in this table were chosen because they
represent a particular class of compounds. For example, a number
of quinone derivatives of PAH have been identified in vehicle and
ambient air particulates (3,4). The relative proportion of each
quinone is dependent on the degree of oxidation, reactivity, and
abundance of each PAH species. Since 9,10-anthracenequinone is
one of the most abundant PAH-quinones, we chose it as a
representative compound. There are possibly hundreds of
nitrated-PAH derivatives in vehicle exhaust; 1-nitropyrene being
one of the most abundant species (5). The dinitropyrenes (1,3;
1,6; 1,8) are formed from further nitration of the 1-nitropyrene
and are present at approximately 1% of the 1-nitropyrene
concentration. Therefore we have used 1-nitropyrene to be
representative of the dinitropyrenes and other nitro-PAH. Similar
arguments can be made for the other species.
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43
TABLE 1
CHEMICALS CHOSEN AS CANDIDATES FOR RISK ASSESSMENT STUDIES
Gas-Phase
CO
N°x
formaldehyde
propylene
benzene
toluene
Gas and Particle Phases
anthracene
pyrene
fluoranthene
2-nitrofluorene
Particle Phase
benzo( a) pyrene
benz o ( e ) pyrene
9, 10-anthracenequinone
9-fluorenone
1-nitropyrene
2 -nitropyrene
FACTORS THAT INFLUENCE EMISSIONS
The emission rates of the candidate compounds from exhaust are
dependent upon a large number of factors including engine type,
operating conditions and fuels. The purpose of this section is to
critically review several studies on this subject including a
recent Coordinating Research Council study (6) undertaken at
Southwest Research Institute. This study examined the influence
of several factors on the emission of four of the candidate
compounds, pyrene, benzo(a)pyrene, benzo(e)pyrene and
1-nitropyrene as well as total sample mutagenicity for diesel
exhaust. Particulate samples were collected from four different
vehicles using a variety of fuels and operating conditions. The
following analyses were made on the data generated from that
study.
The results of eight tests on the effect of engine type and
make on PAH are given in Table 2. The emission rates of the four
compounds mentioned above varied by a factor of three. The
mutagenicity of the total exhaust particulate extract material
varied from 0.8 to 1.3 x 10+6 rev./mile for TA98 strain without
activation (-S9) and 0.5 to 0.7 x 10+6 rev/mile for TA98 strain
with activation (+S9). These results are comparable to those
reported previously for several of light-duty diesel vehicles (1.0
x 10+6 rev./mile (-S9) and 0.4 x 10+6 (+S9)) (7).
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44
TABLE 2
EFFECT OF ENGINE TYPE AND MAKE ON EMISSIONS*
Emissions Rate
Vehicle Tvoe
Oldsmobile
Pyrene (ug/mi )
BaP (ug/mi)
BeP( ug/mi)
1— NP (jjg/mi)
Mutagenicity
(rev./mi/lO*6)
TA98(-S9)
TA98(+S9)
1
2
3
1
0
39 -t—
.3 +-
.3 +-
.0 +-
.0 +-
.5 +-
16
0.9
1.2
1.0
0.4
0.2
Mercedes
62 +-
1.9-1—
5.1 +-
7.8-1—
1.3-1-
0.7 -t—
15
0.1
0.2
2.2
0.3
0.2
Volkswaaen
29
1.6
3.0
1.8
0.8
0.6
-1 —
H —
-1 —
-(•—
-1 —
T™
15
0.2
0.4
0.9
0.3
0.2
Peuaot
24
0.6
1.3
3.8
0.8
0.5
H —
-1 —
H —
+ -
+ -
-I'-
ll
0.1
0.4
1.4
0.2
0.1
"Duplicate tests for each vehicle run on four different fuels
at 22% aromatic composition.
Table 3 shows that the emission of PAH and total mutagenic
species are increased by a factor of 3-4 when the fuel aromaticity
(e.g. benzene, toluene content) is increased from 22% to 55%.
These results are consistent with those of Gross (8), Candelli
(9), and Hare (10) for studies of fuel aromatic content on BaP in
gasoline engine emissions.
The 22% and 55% aromatic fuels contained 2-24 and 2-60 mg/1 of
pyrene, respectively. The amount of pyrene in the particulate
emissions was not related to the fuel pyrene content, which shows
the primary source is formation in combustion and not the amount
present in unburned fuel in the exhaust.
Fuel aromaticity has no effect on the emission of 1-nitropyrene
(1-NP) . These data indicate that some NOX species such as HN03
and not pyrene is the limiting factor in the chemical formation of
1-NP. Further work will be needed to determine if the emission of
other nitro-PAH species follows the trend of the 1-nitropyrene.
TABLE 3
EFFECT OF FUEL AROMATICITY ON EMISSIONS AND MUTAGENICITY*
Emission Rate
Pyrene (;ag/mi )
Benzo (a) pyrene (ug/mi)
Benzo(e) pyrene Qug/mi)
1-Nitropyrene (;ug/mi)
Mutagenicity (rev/mi/10+6)
TA98 (-S9)
TA98 (+S9)
Fuel
22%**
39 V- 18
1.3 +- 0.5
3.0 +- 1.1
4.1 +- 1.9
0.99 +- 0.35
0.61 +- 0.18
Aromatic itv
55%**
125 +- 39
7.1 +- 3.6
10.3 +- 4.1
3.7 +- 1.6
2.9 +- 0.80
2.1 +- 0.49
Duplicate tests for four vehicles run on standard timing.
**Four different fuels were used for each group of tests.
-------
45
Table 4 presents data which demonstrate the effect of engine
operating conditions on emissions. Changes in engine timing have
little effect on the PAH emissions but both the 1-nitropyrene and
mutagenicity increase by several times. These increases correlate
directly with the increase in NOX emissions.
In our laboratory we have found that engine load has the most
significant effect on the emission of PAH and PAH derivatives. An
increase of engine load results in reduction of PAH and mononitro-
PAH relative to the partially oxidized PAH derivatives (11).
TABLE 4
EFFECT OF ENGINE OPERATING CONDITIONS ON EMISSIONS*
Emission Rate Engine Conditions
Ret. Timing Std. Timing Adv. Timing
Pyrene ()ig/mi) 31 +- 20 39 +- 18 35 +- 22
Benzo(a)pyrene (>jg/mi) 1.7 +- l.l 1.3 +- 0.5 1.5 +- 0.6
Benzo(e)pyrene (ug/mi) 3.6+- 2.1 3.0 +- l.l 4.2+- 0.5
1-Nitropyrene (ug/mi) 2.3 +- 0.5 4.1 +- 1.9 15.5 +- 7.7
NOX (g/mi) 0.9 +- 0.02 1.0 +- 0.01 1.3 +- 0.10
Mutagenicity (rev/mi/10+6)
TA98 (-S9) 2.2 +- 1.6 3.4 +- 1.5 6.4 +- 2.7
TA98 (+S9) 1.0 +- 0.5 1.8 +- 0.7 2.5 +- 1.1
"Duplicate tests for two different vehicles
Emissions data were compiled to determine if the ratios of PAH
concentrations could be used to distinguish diesel emissions from
other sources of vehicle emissions. The only emissions data
compiled was from 1979 and later model vehicles, where samples
were collected after dilution. Table 5 summarizes data on the
concentration ratios for four of the candidate
compounds. Fluoranthene and pyrene are produced in nearly the
same quantities, irrespective of engine type and make, engine
timing, and fuel. These results indicate that chemical formation
and degradation of these two species are similar. Approximately
twice as much BeP is emitted as BaP for LDD, HDD and LDG-catalyzed
vehicles, irrespective of engine timing and fuel. However, BeP
and BaP are emitted in nearly equal quantities for non-catalyzed
engines (1.3) which is comparable to BeP/BaP ratios for roadway
soil and tunnel particulates.
The ratio of pyrene/BaP is approximately ten times greater for
diesel engines than it is for gasoline engines. This ratio may be
used to fingerprint the fractional contribution of gasoline to
-------
46
diesel particulate matter in ambient air. The ratio of
pyrene/1-nitropyrene is dependent upon the engine type varying
from 10 for light-duty diesels to 56 for gasoline engines with
catalysts and 102 for gasoline engines without catalysts.
PAH ratios are compiled also for particulates collected from
vehicle tunnels and roadway soil. The average ratio of pyrene/BaP
(1.5) was similar to that of vehicle particulates collected from
gasoline engines (without catalyst) . The contribution of diesel
emissions to the roadway or tunnel samples using these limited
results appears to be minimal .
We have found that the compounds 9 ,10 anthracenequinone and
9-fluorenone are two of the most abundant PAH derivatives in
vehicle exhaust and ambient air particulates. The concentrations
of these compounds are dependent upon engine operating
conditions. We recommend that routine monitoring of these two
compounds be undertaken to establish their concentration and
source in ambient air samples.
TABLE 5
RATIOS OF PAH IN PARTICULATES OBTAINED FROM A NUMBER OF VEHICLE
SOURCES
Sample Source
Light Duty Diesels (LDP)
Table 3, this report
Reference 7
Reference 12
Reference 13
Reference 14
Reference 14
Reference 15
Average
Heavy Duty Diesels
FLU/PYR PYR/BAP BEP/BAP PYR/l-NP
Reference 16
Reference 16
Average
Light Duty Gasftline (LOG)
Reference 14
Reference 17 •
Reference 18
Reference 19
Average
0.8
1.3
1.3
1.3
1.0
1.1
0.7
0.8
0.8
0.9
1.4
-
1.1
30
44
42
24
30
20
£1
30
12
34.
23
2.5
1.6
11.7*
1.3
1.8
2.1
-
4.3
3.0
-
2.2
l.l
2.5
1.6
2.0_
1.8
l.l
1.5
_^_
1.3
10
12
10
22
22.
22
no
95
102
-------
47
TABLE 5 (continued)
Sample Source FLU/PYR PYR/BAP BEP/BAP PYR/l-NP
Light Duty Gasoline (LOG)-catalyst
Reference 16 2.9* 2.0 3.0
Reference 17 1.2 1.6 1.8 62
Reference 19 3.3 50
Reference 20 1.0 2.0 2.0 -
Average 1.1 2.2 2.3 56
Tunnel and Roadway Samples
Roadway soil (Toronto) (21)
Roadway soil (England) (21)
Baltimore Harbor Tunnel (21)
Caldecott Vehicle Tunnel (21)
Average
1.1
1.0
0.8
1±1
1.1
1.4
1.9
1.7
0.8
1.5
1.0
1.0
1.0
0^2
1.0
-
-
-
-
•"
values not used in average
COLLECTION OF A REPRESENTATIVE SAMPLE
Since the discovery of nitrated-PAH in vehicle emissions,
research has been undertaken to determine if these compounds are
formed in exhaust or as a result of the combustion process.
A number of studies (22,23) have been undertaken in our
laboratory and others that demonstrate conversion of particulate
phase components can occur during sampling. Several investigators
have shown that some loss of PAH occurs during sampling resulting
in the formation of PAH derivatives. However, this phenomena can
be controlled by adequate air dilution ("10/1) and short sampling
times (1 Federal Test Procedure (FTP) cycle). Bradow (24) found
that the concentration of 1-nitropyrene was not affected when
particulates from a light-duty diesel engine were sampled through
a denuder which reduced NO2 and HNO3 by 80%. These findings have
been confirmed by the work of Lies and Klingenberg as described in
this volume.
The ratio of pyrene/BaP and BeP/BaP increases by at least 3^
times when 7 ppm N02 is added during dilution tube sampling of
light-duty diesel exhaust (13) (Table 6) . An important
consideration is the amount of HN03 present in the N02 as an
impurity. These data confirm that BaP is much more reactive than
either pyrene or BeP and that these ratios can be used as an
indicator of whether or not chemical reactions have
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48
occurred. Several other studies have shown that BaP is more
reactive that BeP or pyrene (25).
TABLE 6
RATIOS OF PAH IN VEHICLE PARTICULATES AS A FUNCTION OF SAMPLING
TIMES AND CHEMICAL CONVERSION
Sample Source (ref.)
FLU/PYR PYR/BAP BEP/BAP PYR/l-NP
Vehicle Particulates (aged or reacted)
HDD (26) (SRM1650)
LDD (13)
LDD + 7 ppm N02 (13)
LDD + 24 ppm N02 (13)
Used motor oil (27)
1.2
1.3
1.6
1.5
0.7
39
20
760
710
19
4.8
2.2
>99
>67
4.8
14
-
-
-
—
Hayano (28) and Kittleson (29) have undertaken studies to
directly sample exhaust from a combustion chamber. Hayano found
that the concentration of PAH in the combustion chamber was 200
times as high as those in the exhaust gas. This study suggests
that the PAH were produced during combustion in the combustion
chamber and decomposed during the exhaust process. Kittleson
found that 1-nitropyrene is formed primarily during the expansion
stroke and/or in the exhaust manifold.
PARTICLE/GAS PHASE DISTRIBUTION
The distribution of the emissions between the gas-and particle
phase is determined by the vapor pressure, temperature and
concentration of the individual species. The partitioning of
constituents between the particulate- and gas- phases have been
measured by several investigators (2,30-33). Based upon this data
an empirical relationship was derived for the boiling point and
the particle- to gas-phase partition coefficient (P/G) for several
compounds of different molecular weight. It was found that a
linear relationship exists between boiling point for the various
PAH compounds and the aliphatic hydrocarbons as shown in Figure
1. This relationship was used in our study to calculate gas-phase
emission rates for three of the candidate compounds from the
particulate- phase emission rates (Table 7).
-------
49"
TABLE 7
PARTICLE TO GAS PHASE DISTRIBUTION (P/G) VALUES FOR THE CANDIDATE
COMPOUNDS
Compound
anthracene
pyrene
fluoranthene
MW
211
202
202
Distribution
Factor (P/G)
0.05
0.75
0.75
Van Vaeck et al., (34) and others have shown that the
distribution of particle to gas-phase components increases as the
temperature decreases but the magnitude of this effect is
difficult to assess in greater detail without additional data.
1.8 r-
1.6 -
a
w
i
cc
o
5
O
o
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Boiling Point 300
MW (PAH compounds) 160
MW (hydrocarbons)
320
170
340
180
360
190
380
200
400
210
420
220
440
230
460
240
258 270 282 296 308 320 332 344 356 368 380 392
Figure 1 ( • ref. 7; 0 ref. 13; • ref. 30)
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50
EMISSION LEVELS FOR CANDIDATE COMPOUNDS
A number of studies have been undertaken during the past five
years to determine emission levels for a wide variety of vehicles.
Emission levels for the sixteen candidate compounds, mutagenicity,
and total particulates from (1980-1985) light-duty diesel,
heavy-duty diesel, gasoline engines (with catalyst) and gasoline
engines (without catalyst, 1973-1981) are summarized in Table 8.
The emission levels from all pertinent literature sources are
given as an average of all values. These tabulated values can
serve as a basis for semi-quantitative studies of exposure.
TABLE 8
A SUMMARY OF EMISSION LEVELS FROM CURRENT (1980-1985) DIESEL AND
GASOLINE ENGINES (FTP CYCLE ONLY)
Parameter
Gas-phase fq/mil
CO
NOV
HDD
10(36,23)
8(35)
28(35)
LDP
3(37)
1(37)
Gasoline Car
No Cat.
15(39)
4(38)
Catalyst
5(35)
2(35)
Gas-phase
formaldehyde
propylene
benzene
toluene
20(39)
24(39)
11(40)
56(39)
230(40)
162(39)
215(40)
4(39)
18(40)
13(39)
32(40)
Gas-ohase fug/mi)
/
2-nitrofluorene
anthracene
pyrene
fluoranthene
-
8960(37)
1580(37)
1580(41)
1240(37)
90(7)
2100(37)
380(37)
1130(41)
300(37)
910(7)
-
3200(37)
580(37)
200(41)
450(37)
300(18)
60(37)
9(37)
7(37)
-------
5!
TABLE 8 (cent.!
Parameter
Particle-phase
anthracene
pyrene
fluoranthene
2 -nitrof luorene
1-nitropyrene
benzo( a) pyrene
benz o ( e ) pyrene
Other Emissions
Total Part.
(mg/mi)
Total Ext.
(mg/mi)
Mutagenicity**
(rev./mi/icr6)
TA98 (-S9)
TA98 (+S9)
HDD
(ua/mi)
439(37)
1182(37)
933(37)
-
45(37)
54(37)
142(41)
64(37)
1660(7)
1490(35)
301(7)
335(35)
0.37(7)
0.33(7)
LDD
105(37)
284(37)
848(7)
284(41)
39*
224(37)
683(7)
933 (41)
97(7)
11(37)
4*
13J37)
3(41)
34(41)
15J37)
394(7)
607(35)
198(7)
124(35)
0.95(7)
0.99*
0.36(7)
0.59*
Gasoline
No Cat. Cat.
160(37)
431(37)
150(18)
19(35)
47(39)
340(37)
225(19)
224(41)
-
0.3(37) <0
0.2(35) 0
20(37) 0
5(39)
2(42) 0
15(35)
23(37) 0
3(39)
99(7)
103(35)
16(7)
21(35)
0.10(7)
0.15(35)
0.22(7)
0.26(35)
Car
( 3 -wav )
3(37)
7(37)
10(35)
26(39)
5(37)
-
.1(37)
.2(35)
.4(37)
.1(42)
3(35)
.4(37)
18(7)
32(35)
10(7)
14(35)
0.05(7)
0.04(35)
0.07(7)
0.08(35)
Table 3, this report (22% fuel aromaticity)
**Mutagenicity values given in Table 8 of Ref. 7 should be given
as rev/Jon x 10"' instead of rev/Jon.
ATMOSPHERIC REACTIONS
Several of the compounds listed in Table 1 may undergo
atmospheric conversion to potentially hazardous products that may
have significant toxicological importance. Nitrogen oxides (e.g.
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52
NO3, N205) , 03 and free radical species (e.g. OH, NO3) can react
with gas-phase hydrocarbons (e.g. propylene) and aromatic
hydrocarbons (e.g. toluene, anthracene, pyrene, fluoranthene and
BaP) to produce nitrated, peroxynitrated and oxygenated
derivatives. These six candidate compounds were chosen because
they are representative of the types of compounds in vehicle
exhaust which could undergo • atmospheric transformations. The
chemistry and identification of these reaction products have been
summarized recently by Finlayson-Pitts and Pitts (43) and Atkinson
(44).
1-Nitropyrene is one of the more predominant nitrated-PAH
compounds in vehicle exhaust. There is no significant formation
of this compound in the atmosphere. In addition, this compound is
relatively stable (45) and therefore could serve as a good tracer
for primary combustion sources, especially vehicle sources.
2-Nitropyrene (2-NP) has been identified in ambient air
particles but not in vehicle emissions (46). . This compound is
formed in the atmosphere from the gas-phase reaction of the OH
radical in the presence of NOX with pyrene (47) . In conclusion,
2-NP could be used as a good tracer for determining the degree to
which gas-phase species have been chemically converted into
particle-phase components. The concentration ratio of pyrene/2-NP
in the particles could be used for this purpose.
Table 9 lists some ratios of PAH concentrations obtained from a
number of ambient air particulate sources. These ratios can be
used to estimate the relative contribution of vehicular emissions
to PAH in ambient air particulates and the stability of the PAH in
these samples.
The fluoranthene/pyrene ratio is nearly constant for ambient
air ("1.2 average for all sites) and combustion emission ("1.1
average) particulates, irrespective of their source. Since pyrene
is more reactive than fluoranthene (25) it would appear that PAH
are stable once they are absorbed on particulates.
The BeP/BaP ratio shows little variation ("1.9 average) for
ambient air particulates, irrespective of the sample source.
However, this ratio varies for particulates emitted from
combustion sources. As discussed previously, BaP is more reactive
than BeP but the BeP/BaP shows little variation in ambient air
samples. Thus it can be concluded that once the PAH are absorbed
on particulates they do not undergo any significant degradation in
-------
53
the atmosphere. Two of the samples, NBS-SRM1648 and NBS-SRM1649,
were collected over periods of several hundred hours. However,
the PAH ratios are not significantly different from samples
collected for 24 hours or less. The samples collected in Norway
were transported from other parts of Europe and therefore had 2 or
3 days to undergo conversion. However, the pyrene/BaP ratios in
these samples did not differ much from those for other rural
samples.
The data for pyrene/BaP ratios presented in Tables 5 and 9 can
be used to determine the relative contribution of diesel emissions
to PAH in ambient air particulates. The average pyrene/BaP ratios
for LDD and HDD vehicles averaged 30 and 23, respectively,
compared to 1.8-2.2 for gasoline powered vehicles, while the
ratio for all urban samples averaged 1.7. It can be concluded
from these data that the diesel engine has had little impact on
the concentration of PAH particulate species in U.S. urban
environments. The ratio of pyrene/BaP for European urban samples
is 2.6 which would be consistent with the higher proportion
(compared to the U.S.) of diesel vehicles. The higher values of
pyrene/BaP for rural locations (4.1) may be due to contributions
from other sources such as wood smoke. Based upon the analysis of
PAH ratios in atmospheric samples, it appears that most of the PAH
found in U.S. urban particulates originate predominantly from
light- duty gasoline (LOG) vehicular sources as based upon the
ratios of fluoranthene/pyrene, pyrene/BaP, and BeP/BaP for U.S.
(1.0, 1.7 and 2.0, respectively) compared to these ratios in LDG
particulates (1.1, 2.0, 1,8, respectively), assuming a 1/1 mix of
catalyst and non-catalyst vehicles. However, these observations
need further validation since our data base for other primary
emission sources (Table 9) is limited, and data on PAH ratios were
not available. For instance, reliable PAH emission values from
residential oil burning sources were not available.
TABLE 9
RATIOS OF PAH CONCENTRATIONS OBTAINED FROM A NUMBER OF AMBIENT AIR
PARTICULATE SOURCES
Sample Source fref.l Flu/Pvr Pvr/BaP BeP/BaP Pyr/l-NP
Air Particulates (urban)
Europ_e
Germany (48) (5 sites) 1.6 3.9 2.0
Goteborg, Sweden (49) 1.1 2.1 2.1
-------
54
TABLE 9 (cont.)
Sample Source (ref.) Flu/Pyr Pyr/BaP BeP/BaP Pvr/l-NP
Denmark (50) 0.9 2.2 1.0 140
Sweden, urban (49) 1.0 2.3 2.1
Average 1.2 2.6 1.8
United States
Wash. D. C. (NBS-SRM1649)(51) 1.1 2.4 1.3 75
St. Louis (NBS-SRM1648)(51) 1.2 2.4 1.7
Los Angeles (12) 1.0 1.0 2.4
Los Angeles (52)(3-41) 1.4 1.9 2.6
Los Angeles (53) 0.7 1.0 2.0
Detroit (54) 0.8 1.7 -
Average 1.0 1.7 2.0
Air Particulates (rural1
Baltic Sea (48) 1.9 6.3 2.8
England/Scotland (55)(2 sites) 1.3 3.3 1.2
Norway (55)(2 sites) 1.2 2.6 1.3
Midwest, Northeast(52) (3.-20) 1.5 4.3 1.9
Average 1.5 4.1 1.8
Other Sources
Power plant-coal (56)
Coke oven (57)
Wood Smoke (58)
Wood Smoke(58) (reacted)
Wood Smoke (59)
Carbon Black (60)
Coal oven
(Heinrich, this volume)
Aluminum smelter (61)
Average
1.6
1.0
1.1
1.1
1.4
0.6
1.4
1. 6
1.2
3.0
1.0
-
-
6.9
2.2
2.8
0.8
—
-
0.7
-
-
6.9
0.8
0.7
3.0
—
-
-
-
-
-
-
-
—
ESTIMATION OF EXPOSURE LEVELS
There are many existing models for describing exposure levels
(2, 62-65). The annual mean concentration of gas and particulate
phase components in a selected location can be estimated by tracer
or surrogate models (2, 62). The model uses CO as the tracer for
gas-phase components and assumes that, under similar dispersion
conditions, the proportionality between the ambient concentration
of CO and the emission rates of carbon monoxide and the subject
nonreactive airborne species is similar for all chemical species.
The emission levels presented in Table 8 can be used in a
comparative way to determine the relative impact of diesel and
gasoline engine emissions if information on the proportion of
-------
55
vehicular types in a particular area is known.
TOXICOLOGICAL DATA
Several of the candidate compounds were chosen on the basis of
current knowledge or interest in the area of potential
toxicological effects. These compounds include CO, NOX,
formaldehyde, propylene, benzene, 2-nitrofluorene, benzo(a)pyrene
and 1-nitropyrene (and the dinitropyrenes). Several studies have
been undertaken by the MAS and others and their findings are
summarized as follows:
Carbon Monoxide - CO exposure can cause acute and chronic
effects on susceptible populations (66,67). CO binds to
haemoglobin in the blood with an affinity 200-250 times greater
than oxygen thus affecting the capacity to oxygenated body
tissues. Because of this greater affinity for haemoglobin
binding, CO releases slowly and consequently incremental doses of
CO from different exposure sources are additive. Individuals with
intermittent claudication, cardiovascular problems (angina),
emphysema, asthma, sickle cell anemia, and other diseases that may
cause reduced oxygen tension in the blood, have an increased risk
due to CO exposure.
NOX - NO2 is the major NOX species on which most toxicological
studies have been undertaken (68). Studies of short-term
exposures of firemen have shown increased airway resistance,
decreased pulmonary diffusion capacity, increased alveolar
arterial partial oxygen pressure difference and conditions such as
diffuse pneumonitis. In most epidemiological studies there are
other pollutants present and their combined effects are impossible
to separate from those of N02. There is a time dependent
continuum of effects ranging from mild reversible and irreversible
effects in pulmonary function to more severe short-term
substantial chronic tissue damage, functional impairment and
aggravation of other disease processes. Reported results of
epidemiologic studies in children are increased incidence of
respiratory disease (upper and lower), greater incidences of
bronchitis, and adverse effect on specific airway conductance.
Persons who might be operating at or near the limit of their
pulmonary functional capacity or sensitive persons, asthmatics,
might experience chest tightness or wheezing.
The U. S. Environmental Protection Agency (EPA) standard for
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56
atmospheric concentrations is 0.053 ppm annually. A short-term
exposure standard is currently being considered by EPA.
Formaldehyde - There have been numerous studies of the irritant
properties of formaldehyde showing that the eyes, respiratory
tract, and skin are the organ system predominantly affected (69).
Formaldehyde has been shown to be mutagenic in several
nonmammalian test systems, such as microorganisms and insects, but
negative in the Ames test and there have been conflicting findings
in mammalian test systems. Similarly, the results of long-term
experimental studies in animals on the carcinogenic effects of
exposure to formaldehyde have been brought into question.
Although some experimental studies have shown nasopharyngeal
carcinoma in animals, other studies have not shown these effects.
There are people known to be sensitive to formaldehyde exposure
who do react adversely but there are no systematic studies of
them. At present, the irritant effects appear to be the most
sensitive responses to formaldehyde exposure.
Benzene - Benzene has been designated as a "hazardous air
pollutant" by EPA and a "toxic air contaminant" by the California
Air Resources Board. Based on human epidemiologic evidence,
benzene exposure is associated with an increased incidence of
certain forms of leukemia, as well as a variety of other cancers
(70). The lowest average concentration of benzene vapor reported
to have been associated with human leukemia and aplastic anemia is
1 ppm and 5 ppm, respectively. There is an increasing amount of
evidence that indicates latent diseases such as cancer, birth
defects, and genetic disease may be initiated by alterations in
cellular DNA resulting from benzene exposure. A number of studies
have shown that benzene is not mutagenic in bacterial systems.
Benzene has not been shown to be teratogenic at doses that are
feto-lethal.
2 -Nitrof luorene - This compound has been found to be
carcinogenic for subcutaneous exposure to rats (47% tumor
incidence). it was found to induce a high incidence of papillomas
and carcinomas of the forestomach and it is carcinogenic in rats
when administered either in food or painted on the skin in a 2%
acetone solution. More tumors were induced by skin application
than by ingestion in the food (71).
Benzofaloyrene - The 1983 IARC (72) report concluded that BaP
is carcinogenic and teratogenic in mice; the induction of aryl
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57
hydrocarbon hydroxylasa activity in fetuses is an important factor
in determining these two effects. Also, reactive electrophiles
are formed in the metabolism of BaP that are capable of binding
covalently to DNA, however, the importance of this finding is not
known at this time.
In short-term bioassays, BaP is active in bacterial DNA repair,
bacteriophage induction and bacterial mutation; it forms mutations
in Drosophila elanogaster. It was found to be active in DNA
repair, sister chromatid exchange, chromosomal aberrations, point
mutations and transformations in mammalian cell cultures. BaP was
active in chromosomal abberation, sister chromatid exchange, DNA,
sperm abnormalities and in the somatic specific locus (spot) test.
A 1983 NRC study showed several metabolic sites on the
molecule where epoxides could be formed. The primary precursor
implicated was the 7,8-diol which in the second round forms the
highly electophilic 7,8-diol-9,10-epoxide.
BaP may not be the best indicator of the biologic effects of
other PAH, however, the literature on this compound is
considerably more voluminous than that on other PAH.
1-Nitropvrene - This compound has been found to be a weak
carcinogen in rats (73). The dinitropyrenes are active
carcinogens as described by Tokiwa et al., Sato et al, King et al
and Odagiri et al in this volume.
RISK ASSESSMENT
At this time there is sufficient information on the sixteen
candidate compounds to begin applying semi-quantitative and
comparative risk assessment models. However, we recommend that
biomarker techniques need to be developed for several of the
compounds to determine actual exposure.
Mutagens and cancer initiators act directly or are metabolized
to electrophilic reagents. At the molecular level these react in
a random fashion, with probabilities determined by reaction
kinetics laws, with nucleophilic centers (mainly S, N and O atoms)
in tissues. The degree of chemical change (e.g. alkylation) could
be demonstrated to be proportional to exposure doses (or absorbed
amount per kg body weight) in proteins (74) or DNA (75).
Although DNA is the biological target in genotoxic action,
haemoglobin (Hb) is a better media for monitoring or dosimetry of
electrophiles. Since Hb has a life-span of approximately 4 months
-------
58
in healthy individuals, it can be used to determine the integrated
exposure dose during that period of time. In addition, it is
relatively easy to obtain. Amino-acid adducts are more easily
determined and identified than DMA-base adducts.
The Advisory Subgroup on Toxicology (AST) of the European
Medical Research Councils (EMRC) has evaluated the "Hb adduct
method" and concluded that it gives relevant information on the
formation of DNA adducts.
Haemoglobin adducts have been used to monitor exposure to
alkenes such as propylene, N02 and approximately 50 carcinogens.
Work is underway to study the effects of vehicle emissions on
adduct formation (76).
Mass spectrometric methods are being developed which allow the
determination of down to 1 ppb of a component in blood (76, 77) .
This adduct level could be expected by occupational exposure to
about 0.01 ppm ethylene oxide. However, determination of exposure
to compounds such as PAH and PAH-derivatives will require
detection limits below the 50 ppt range, a level which is not
currently attainable.
Breath analysis is a technique, that potentially can indicate
the extent to which an individual has been exposed to gaseous
pollutants. As an example, a recent study has been undertaken to
help estimate exposure to ambient air levels of benzene (79). in
some cases it was found that the level of expired benzene was
greater than that of the ambient air concentration. It will be
difficult to quantitatively determine exposure to gaseous
pollutants using this technique since the dynamics of inhalation,
absorption, metabolism and exhalation are not well understood.
CONCLUSIONS
A number of conclusions can be made as a result of the data
presented in this paper as follows:
-Dilution tube sampling of vehicle emissions yields reliable
data which can be used to estimate ambient air exposure levels
to gas and particulate phase pollutants.
-Sixteen candidate compounds have been chosen for detailed study
and gas-and particle-phase emission levels for these candidate
compounds have been compiled for diesel and gasoline powered
engines.
-The concentration of these candidate compounds can vary by
-------
59
several times, depending upon vehicle operating conditions.
-PAH appear to be formed primarily as a result of the combustion
process and not due to the content of unburned fuel in the
exhaust.
-An increase in fuel aromaticity results in increased emission
of PAH and total mutagenicity.
-The concentration ratio of pyrene to BaP in particulates can be
used to estimate the contribution of diesel emissions to PAH in
ambient air particulates. It was demonstrated that diesels
contribute less than 10% of the total PAH found in U.S. urban
particulate matter.
-The chemical components emitted in the particle phase from
vehicles undergo very little chemical conversion in the
atmosphere.
-The gas-phase components of intermediate volatility (Cg-C16)
may undergo significant chemical conversion to form particulate
species of potential toxicological significance.
-The most difficult problem associated with the toxicology
studies is extrapolation of high-level exposure data to the low
concentrations encountered in ambient air environments.
-The measurement of haemoglobin adducts can be used to measure
long-term integrated exposure to some gas-phase species such as
propylene. However, these techniques are not sensitive enough
at this time to measure exposure to trace components found in
particulates (e.g., PAH and PAH-derivatives).
ACKNOWLEDGMENTS
We would like to acknowledge the assistance of S. Baker, B.
Goldstein, H. Cornish, B. Jaffe, E. Paulson, J. Perrin, J. Van
Ryzin, R. Schuetzle, L. Smith, and G. Witz in this study and the
helpful comments of J. Butler, H. Niki, W. Pierson and I. Salmeen,
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-------
Reprinted from Analytical Chemistry 1986, 58, 1060A.
Copyright © 1986 by the American Chemical Society and reprinted by permission of the copyright owner.
-------
Bioassay-Directed
Chemical Analysis
in Environmental
Reseach
.
he im-
lution on
uding mutagenic
enic effects, is a primary
'.. Cancer is a generic term for
'arious neoplastic diseases that can
occur many years after exposure to a
carcinogenic substance. The best
means of eliminating cancer is to de-
fine precisely the nature of the carci-
nogenic chemical, mixture of chemi-
cals, or enhancing factors in the envi-
ronment that produce the cancer (1).
Bioassay studies in the early 1960s
showed that environmental mixtures
such as cigarette smoke and ambient
air particulates can cause cancer in
animals. Extensive studies were un-
dertaken to determine the chemical
components that could be responsible
for such an effect. It was found that
most environmental samples were
chemically complex and comprised of
thousands of chemical compounds
(2. .3). Identification of the most bio-
logically active compounds presented
an enormous if not an impossible task.
During the mid-1970s several micro-
bial tests were developed that were
simple, cheap, rapid, and above all ge-
netically very well defined (4). The
bacterial reverse mutation test battery
in Salmonella as developed by Ames
et al. (5) provided a vast body of infor-
mation on the presence of genotoxic
activity not only in defined industrial
chemicals, pesticides, and cosmetics
but also in complex mixtures such as
air, water, and other complex sources
of pollutants. Although this test, and
others like it, were used to determine
the relative mutagenic potency for a
wide variety of environmental sam-
ples, such studies did not yield infor-
0003-2700/86/A358-1060$01.50/0
© 1986 American Chemical Society
-------
Report
Dennis Schuetzle
Research Staff
Ford Motor Company
Dearborn, Mich 48121
Joellen Lewtas
U S Environmental Protection Agency
Research Triangle Park, N C 27711
mation on which specific compounds
were primarily responsible for this ac-
tivity.
The Ames tester strains were select-
ed so that types of mutations (e.g.,
frame shift vs. base pair substitutions)
can be distinguished. This informa-
tion, together with differential re-
sponses (e.g., with and without micro-
somal activation), can be used to pro-
vide information about the general
classes of chemicals causing the re-
sponse. More recently, new tester
strains that are sensitive to certain
classes of chemical mutagens have
been developed. For instance, strain
TA98NR (Rosenkranz nitroreductase
strain) is deficient in nitroreductase
enzymes and therefore gives a reduced
response to certain nitrated PAH
compounds. The magnitude of results
varies depending on the type of assay
used, as shown for diesel particles
in Table I. In addition, the contribu-
tion of an individual compound to
total fraction mutagenicity is depen-
dent on the type of bacteria used in
the assay. These differences make it
possible to apply these strains in a
diagnostic way. Because strain TA98
has been used most frequently for as-
says of environmental samples, we will
limit our discussion to its use in this
REPORT.
It became apparent in the late 1970s
that these bioassays could be used in
combination with chemical fraction-
ation to greatly simplify the process of
identifying significant mutagens in
complex environmental samples, such
as diesel particles, petroleum and pe-
troleum substitutes, chemicals in
drinking water (6), and commercial
products (7). The use of short-term
bioassays in conjunction with'analyti-
cal measurements constitutes a power-
ful tool for identifying environmental
contaminants. We have coined the
Tabtel. Dkect-Actfcigiyiirtag«Ticftyo
-------
| No
„ ...
Modify
procedure
No
Sampling
t
Extraction
t
Preparative fractionation
f
Mass/
mutagenicity
recovery?
W Yes
Mutagenicity
high?
• No
t
1 tract
t
Yes
Level 1 fractionation
procedure
Mass/
mutagenicity
recowry?
No
Mutagenicity
high?
Yes
Level 2 fractionation
Mutagenicity
high?
No
No
No
Yes
Chemical analysis
f
Mutagenicity
high?
Synthesize selected
isomers
Mutagenicity
high?
Yes
Compound
quantitation
Percent contribution to
fraction mutagenicity
Percent contribution to
total sample mutagenicity
Figure 1. Protocol for bioassay-directed
chemical analysis
Marker
compound
Polarity
Fraction
Eluting
Button
time
1-Nitronaphthalene
Nonpolar
T
2
Hexane
1,6-Pyrenequinone
Moderately
polar
3-6
Polar
78 9
DCM ACN
M6^^r»
Figure 2. Designation of nonpolar, moderately polar, and polar fractions using nor-
mal-phase HPLC in the level 1 fractionation scheme
air particulate matter collected in
Washington, D.C.).
Extraction
Sequential extraction with increas-
ingly polar solvents, binary solvents,
and supercritical fluid extraction are
used to separate organic material from
particulates and other types of solid
environmental samples. A two-step
extraction process using methylene
chloride followed by methanol is effec-
tive for efficient recovery of mutagen-
icity and mass for several types of
combustion emission samples. Liquid-
liquid extraction using dichlorometh-
ane and diethyl ether is suitable for
extraction of mutagenic material from
heavily polluted waters. Adsorption of
pollutants on resins followed by sol-
vent elution is effective for concen-
trating organics that are present in
low concentrations (17).
Preparative fractionation
A number of prefractionation and
preseparation techniques have been
developed to help simplify the analy-
sis of environmental samples. They
are usually applied on a preparative or
semipreparative scale to yield gram to
milligram quantities, respectively, of
samples. The two most widely used
techniques are chromatography on an
open normal-phase silica column to
separate groups of compounds on the
basis of polarity and separation of
compounds into acidic, basic, and neu-
tral fractions.
Early attempts to chemically char-
acterize the trace components in sam-
ple fractions proved to be extremely
difficult, and it was estimated that
hundreds of compounds were present.
However, bioassay analysis helped re-
searchers decide which fractions
should be studied in more detail
(Figure 1).
One of the concerns of the early
work in the late 1970s was the poten-
tial loss and formation of mutagenic
substances during analysis. The proce-
dural recovery of mass and mutageni-
city is determined by combining the
individual fractions to produce a re-
constituted sample. The mass and
mutagenicity of this sample are then
compared with that of the unfraction-
ated sample. Another test is to deter-
mine if the biological activity of the
unfractionated sample equals the sum
of the activities of the individual frac-
tions. If they are unequal, the muta-
genicity may be due to synergistic or
toxic effects or to the fact that cell
killing was not taken into account. If
the separation removes highly toxic
components from the mutagenic com-
ponents, the additivity of the fraction
mutagenicities may be greater than
100%. Any bioassay that has enough
sensitivity to obtain good quantitative
results (6,13) on small (microgram)
quantities of material can be used in
the bioassay-directed chemical analy-
sis technique.
Level 1 fractionation
Normal-phase high-performance
liquid chromatography (HPLC) is a
highly reproducible technique that
separates environmental samples into
chemical fractions of increasing polar-
ity using hexane, dichloromethane
(DCM). acetonitrile (ACN), and meth-
anol (MeOH) as eluents (8) The refer-
ence materials 1-nitronaphthalene
and 1.6-pyrenequinone may be used as
chemical markers to designate the
separation of samples into nonpolar
(1-2), moderately polar (3-6), and po-
lar (7-9) fractions (Figure 2). Results
from a number of laboratories using
slightly different fractionation proce-
dures can be compared using this defi-
nition of polarity (78). It was found
that the nonpolar fractions accounted
for less than 2-3% of the total extract
mutagenicity and that the distribution
of moderately polar and polar materi-
als was dependent on the sample
source (Figure 3).
Table II gives the distribution of
mass and mutagenicity for nonpolar,
moderately polar, and polar fractions
of NBS SRM 1650. Although 54% of
the recovered mutagenicity is associat-
ed with polar compounds (fractions
7-9), the additivity of mass (94%) and
mutagenicity (79%) is good. Diesel
-------
Tbtal mutagenicity (%)
0 50 100
Light-duty diesel
Heavy-duty diesel
Heavy-duty diesel
(200-h accumulation)
Ambient air
Wood smoke
Wood smoke (reacted with Q», NOJ
Figure 3. Distribution of mutagenicity (direct-acting TA98) between the moderately
polar (green) and polar (blue) mutagenic fractions for six air paniculate samples
particulate extract samples usually
yield mass and mutagenicity additivi-
ties of greater than 90% and 70%, re-
spectively, and mass and mutagenicity
recoveries of better than 90%.
Chemical analysis
Studies were undertaken in the late
1970s, to determine the composition of
samples collected from the level 1
fractionation. High-resolution capil-
lary column gas ehromatography (GO
with selective detectors and coupled
with mass spectrometry (GC/MS)
proved to be powerful tools tor the
characterization of tractions.
By 1980 several laboratories, apply-
ing the techniques described so far, si-
multaneously made-some important
discoveries. Guenn et al. (10) and Wil-
son et al. (//) discovered the presence
of highly mutagenic polynuclear aro-
matic amines (PAH-NH^) in synfuels:
Schuetzle et al. (8) found a significant
mutagen, 1-nitropyrene. in diesel par-
ticles; and Lofroth et al. (19) and Ro-
senkranz et al. 120) identified 1..S-.
1.6-. and 1,8-dinitropyrenes as the ma-
jor mutagenic substances in commer-
cial carbon blacks The amines and
dinitropyrei1' - accounted for more
than half ol i:ie sample mutagenicity
in the case o! she synfuels and carbon
blacks, respei uvely. However, less
than 25-30r< <>i the mutagenicity of
diesel particle- could be accounted tor
by the 1-nitropyrene.
In the case ot SRM 1650. GC and
GC/MS analy^ showed that hun-
dreds of compounds were still present
in each fraction Figure 4 depicts a
portion of a chromatogram generated
Table II. Mass and Mutagenicity Distribution (TA98, Direct Acting)
for NBS SRM 1650*
Fraction
Nonpolar
1
2
Moderately polar
3
4
. 5
e
Polar
7 •"'''
8 " "•'...;•.
DMrKMtfcMol
num(%)
0.6
0.7
1.3 *_ ',",."<:
, .~2.fr; '::;i-v;f.;
'*" "- 2^4>' * " ''S:^^-
.'. •; "" "' ". • t^''-* ,«^K;|;i^
"••=- •:"-•'", ','••' '"'- VA'?^^.^"
' 'A* ;'j4. ;V^;'-r"'t^r ; J-\^^^^'
.^l^'^ltrr'^Jli^fS^^.;
rnuUffMileMy (%)
0
0
0
t9
to
: " "..',> ; -->,-.
, y . ' ^*- ,";, *'• P~ ";• /
r;''^ ':-,/-":'.-, -,
-."- :-;'i »;^"5..V- -
•Date from Reference 18 >-V.«iui£iSiiiS
|t^*; 3» -'° H^^w;'ls4^^lils^**a*^
•'?
-------
Figure 4. Capillary gas chromatogram of fraction 5 of a light-duty dlesel sample with
nitrogen-selective detection
Petri dishes at top illustrate results of Ames assays of subtractions of the diesel sample fraction
from the capillary column GC analysis
of fraction No. 5 of a light-duty diesel
sample using a nitrogen-selective de-
tector. Scores of nitrogen compounds
were found to be present in this frac-
tion. GC/MS analysis verified that
most of the nitrogen-containing com-
pounds were nitrated polynuclear aro-
matic hydrocarbons (nitro PAHs).
Ames assays of subfractions of frac-
tion No. 5 showed that most of the
mutagenicity was associated with
compounds that eluted in the last one-
third of the chromatogram.
Further analysis was made using di-
rect-probe high-resolution mass spec-
tiometry, high-resolution GC/high-
resolution MS, and mass spectrome-
try/mass spectrometry (MS/MS). An
important finding in these studies was
that the moderately polar chemical
fractions primarily consisted of substi-
tuted PAH compounds with ring sizes
of 2-6 and the substituents consisted
of hydroxy, aldehyde, anhydride, ni-
tro, ketone, dinitro, and quinone func-
tional groups (8). A potentially impor-
tant group of mutagens, the nitrohy-
droxypyrenes, was identified in these
studies (21).
Although a multitude of compounds
were identified or tentatively identi-
fied, it was obvious that such fractions
were still too complex to allow identi-
fication of chemical mutagens and
that further separation of each frac-
tion into subfractions would be neces-
sary.
Level 2 fracUonation
Further developments in HPLC,
high-performance thin-layer chroma-
tography (HPTLC) (22), and muta-
genicity testing (23) have contributed
to a much finer tuning of this com-
bined chemical and biological ap-
proach to the characterization of mu-
tagens in environmental samples.
HPLC can generate scores of frac-
tions, each of which is tested for muta-
genicity. We refer to this resulting re-
lationship of fraction mutagenicity to
Figure 5. Ames assay chromatogram (TA98, without activatlonl and HPLC-UV analysis of a light-duty diesel particulate extract
(level 1 fractionation)
-------
fraction elution time as a bioassay
chromatogram or an Ames assay chro-
matogram in cases in which the Ames
test is used (24). A bioassay chromato-
gram for a diesel participate sample is
illustrated in Figure 5. The lower por-
tion of the figure shows the corre-
sponding HPLC chromatogram using
a UV detector. The most mutagenic
fractions have elution times that ap-
proximately coincide with 1-nitropy-
rene, 3-nitrofluoranthene, 8-nitro-
fluoranthene, 1,3-dinitropyrene, 1,6-
dinitropyrene, 1,8-dinitropyrene, and
2,7-dinitro-9-fluorenone reference
compounds.
GC/MS is a powerful technique for
quantitative analysis of these trace
constituents. Deuterated standards
are added to the extracts before sam-
ple analysis, and quantitative results
are readily obtained by comparing the
signals from the eluting native and
deuterated compounds. On the basis
of such analysis it was found that
30-40% of the total recovered extract
mutagenicity of SRM 1650 was attrib-
utable to the seven moderately polar
nitro PAHs. The remainder of the
mutagenicity (10-15%) was attribut-
able to the presence of an unidentified
compound or compounds eluting be-
tween 23 and 26 min; 30-35% was re-
covered in the polar fractions, and
5-10% was distributed about equally
among the remaining fractions.
Although separation of the sample
into acid, base, and neutral fractions is
usually done in the early stages of
sample preparation, this procedure
can be used to further simplify the po-
lar fractions. As an example, some
preliminary data on the distribution
of mutagenicity for the acid, base, and
neutral fractions 7, 8, and 9 of SRM
1650 are given in Table III. This anal-
ysis shows that the most mutagenic
compounds in the diesel sample are
neutral in character. The additive mu-
tagenicity for the acid, base, and neu-
tral fractions is close to that of the un-
fractionated fraction 7. However, the
additive mutagenicity for fractions 8
and 9 exceeded 100%. It is postulated
that these high recoveries are indica-
tive of chemical changes that may
have occurred during acid-base ex-
traction or separation of toxic com-
pounds from these fractions. High-res-
olution mass spectrometric analysis of
fractions 8 and 9 shows that organic
esters and acids of PAHs and aliphatic
compounds are major components.
Acid or base hydrolysis of PAH esters
could account for increased muta-
genicity.
The specific fractionation scheme
that most effectively separates the
mutagens from the nonmutagens
while minimizing the destruction or
creation of mutagens varies with the
types of complex mixture being ana-
lyzed. Diesel emissions from different
sources will vary in the amount of spe-
cific components but the general com-
position is sufficiently consistent to
develop one approach to the bioassay-
directed chemical analysis, although
several may be equally effective.
The scheme used to identify muta-
gens in synfuels has concentrated on
preparative separative techniques be-
cause large quantities of materials
were needed for extensive biological
and chemical characterization studies.
A relatively high level of mutagenic
activity was found in an 800-850 °F
distillation fraction of a synfuel sam-
ple (10). Nitrogen-containing com-
pounds were separated on an alumina
column using CHCls/ethanol. Level 1
fractionation was accomplished on a
silicic acid column. GC/MS was used
to identify PAH-amines as the major
mutagenic species in the synfuels.
Ambient air particulates contain
more chemical components than most
other types of environmental samples.
For this reason, the identification of
mutagenic species in ambient air par-
ticulates has been more difficult than
in diesel emissions. However, bioas-
say-directed chemical analysis proce-
dures are being used to single out
some potential candidate compounds.
LC and HPLC fractionation used in
combination with acid-base-neutral
separation appears to be an effective
protocol for this purpose, as illustrat-
ed in Figure 6 (25). Good recovery of
mass (98%) and mutagenicity (86%)
for an extract of the NBS SRM 1649
air particulate sample was obtained by
elution of five fractions on silica gel
using hexane, hexane-benzene, meth-
ylene chloride, methanol, and acidic
methanol (26).
SRM 1649 was used to develop the
Hexatw HexatMf
benzane
Methylene
chloride
9(23)
Methaool
-Aefcfc
Figure 6. Bloassay-directed chemical analysis scheme for the analysis of NBS SRM
1649 (air particulate matter)
The numbers under each fraction represent the percentage distribution of mass and mutagenicity (in pa-
rentheses)
-------
methodology for the ambient air sam-
ples. Once this methodology was de-
veloped, it was applied to fine
air particles (<1.7 yum in diameter)
collected in Philadelphia. The three
fractions of greatest interest were the
acid, methylene chloride, and metha-
nol fractions, which produced 38%,
23%, and 29%, respectively, of the re-
covered mutagenicity (Figure 6). Be-
cause the methylene chloride fraction
was more amenable to subfractiona-
tion by existing HPLC methods, this
fraction was chosen for further frac-
tionation. Normal-phase HPLC was
used to fractionate the methylene
chloride fraction (26).
The first HPLC subfractionation
resulted in one fraction, methylene
chloride-C, which contained nearly
50% of the mutagenicity in 25% of the
mass. Analysis of this fraction by both
electron impact and negative chemical
ionization high-resolution (HR) GC/
MS techniques indicated that the
complexity of the sample was not re-
duced sufficiently to identify individ-
ual components. Subfraction C was
further fractionated by normal-phase
HPLC into 12 fractions for bioassay.
As we proceeded to higher levels of
subfractionation, less and less mass
was available for bioassay. In this
study, the first-level fractions ob-
tained from the preparative tech-
niques were bioassayed in triplicate at
seven doses with and without activa-
tion so that we could quantitate the
distribution and recovery of muta-
gens. At the first and second levels of
fractionation, fewer doses and plates
were used for the bioassay until nearly
the entire fraction was used for a sin-
gle plate. Therefore, the ability to
quantitate the recovery of both mass
and mutagenicity decreases as we sub-
fractionate. The bioassay chromato-
gram showed peaks of relatively high-
er mutagenicity in fractions 4 and 11
with 29 and 37 rev/^g, respectively.
Mass spectral analysis of peak 4 dem-
onstrated that the goal of sequential
fractionation had been achieved such
that individual components could be
resolved and quantified using
HRGC/MS. The major mutagenic
compounds identified in the methy-
lene chloride-C-4 fraction were hy-
droxy-nitro-substituted fluoranthenes
(OH-N02-PAH) (26); work is continu-
ing to synthesize and identify the spe-
cific isomers. This class of compounds
(i.e., the hydroxynitropyrenes) also
has been identified in diesel particu-
\ates (21,27).
Development of new analytical
techniques
Despite the considerable progress
that has been made in determining
moderately polar organics in environ-
mental samples, there remain classes
Figure 7. Distribution of mutagenicity for a combined Ames assay-HPTLC analysis
of an ambient air paniculate extract
Reprinted with permission from Reference 36. Copyright 1982, American Association for the Advance-
ment of Science
of compounds that have not yet been
identified because of limitations in the
analytical methods and detection sys-
tems.
There has been much less success
with the determination of labile com-
pounds (e.g., organic peroxides) and
polar organic species. To date, only a
limited number of compounds have
been identified or tentatively identi-
fied as potentially important muta-
genic species in the polar fractions of
particulate extracts. This lack of in-
formation is the result of problems as-
sociated with determining polar PAH
derivatives, including sample loss
from physical adsorption, chemical in-
teractions among components, and
sample decomposition. Several labora-
tories are now developing and apply-
ing new methodologies for the deter-
mination of polar chemical mutagens.
Direct-insertion probe distillation
coupled with HRMS of whole ex-
tracts can be used as a survey tech-
nique to determine the types of com-
pounds present or in some cases to
identify groups of isomeric com-
pounds (e.g., nitropyrenes and nitro-
fluoranthenes) (8, 28). This tech-
nique is also useful for thermally la-
bile organics.
MS/MS coupled with direct-inser-
tion probe introduction of sample
yields a higher level of specificity than
can be obtained with the HRMS tech-
nique (29). Although this method does
not readily yield specific isomer infor-
mation, it is a valuable screening tool
with a high degree of compound speci-
ficity. Secondary ion mass spectrome-
try (SIMS) using ion and neutral atom
beams also may be useful for determi-
nation of polar and nonvolatile organ-
ic substances in environmental sam-
ples (78).
The above techniques are good for
screening analyses. However, chro-
matographic separation is needed for
positive identification of specific iso-
mers in highly complex fractions. The
poor recoveries GC and GC/MS
achieve in the identification of polar
compounds illustrate the limitations
of GC techniques. One of the most
promising analytical techniques for
the determination of polar PAH deriv-
atives appears to be supercritical fluid
chromatography (30) and HPLC cou-
pled with mass spectrometry (31).
New micromutagenesis methodolo-
gies that permit the quantitation of
mutagenic activity on microgram
quantities of material can now be used
together with analytical-scale re-
versed-phase HPLC. The micro-for-
ward mutation assay, which measures
both mutagenicity and survival (toxic -
ity), provides potentially more quanti-
tation of a single-fraction mutageni-
city (32, 33), whereas the micro-re-
verse suspension assay (34) uses the
standard Ames and Rosenkranz
strains. We have successfully coupled
these assays to analytical reversed-
phase HPLC separation and analysis
of polar mammalian metabolites of ni-
tropyrene. This approach shows
great promise in helping to identify
the polar mutagens in complex envi-
ronmental samples.
Recently, techniques have been de-
veloped to couple liquid chromatogra-
phy directly with bioassay analysis
(35, 36). Duplicate (HPTLC) plates
are used to fractionate organic matter.
-------
One plate is used for chemical class
tests and the second plate is used for
an in situ Ames bioassay. This system
has revealed some surprising and in-
teresting differences among particu-
late matter samples from different cit-
ies. Figure 7 shows the distribution of
mutagenicity for a combined Ames as-
say-HPTLC analysis of an ambient
air particulate extract. Although the
compounds responsible for the con-
centrated areas of mutagenicity are
not known, it is envisioned that future
advances in chemical analysis will
help this effort. One such aid would be
, direct chemical analysis of the
HPTLC plates using ESCA or SIMS
to generate spatial chemical maps of
the surface, which could be correlated
with the pattern of mutagenicity.
In the future, a substantial effort
will be needed to determine the com-
pounds responsible for the mutagenic-
ity of air and water pollutants. Bioas-
say-directed chemical analysis will
continue to be a valuable tool for this
purpose.
Acknowledgment
We gratefully acknowledge the
helpful comments of I. Alfheim, E.
Chess, H. Hertz, R. Gray, T. Jensen,
G. Lofroth, W. Pierson, H. Rosen-
kranz, I. Salmeen, and W. May.
The research described in this arti-
cle was reviewed by the EPA and ap-
proved for publication. Approval does
not signify that the contents necessar-
ily reflect the views and policy of the
agency.
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Dennis Schuetzle is a principal re-
search scientist and head of the
chemical research department of
Ford Motor Company. He received
his B.S. degree in chemistry in
1965 and interdisciplinary Ph.D.s
in analytical chemistry and envi-
ronmental engineering at the Uni-
versity of Washington. His pri-
mary research interests include
environmental analytical chemis-
try, surface analysis, and process
analytical chemistry.
Joellen Lewtas is chief of the genetic
bioassay branch at the Environmen-
tal Protection Agency's Health Ef-
fects Research Laboratory. She re-
ceived a B.S. degree in chemistry in
1966 and a Ph.D. in biochemistry
from North Carolina State University
in 1973. Her research has included
evaluation of the mutagenicity and
carcinogenicity of diesel and gasoline
exhaust emissions and identification
of mutagenically active components
in these emissions.
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Volume 4, Number 4 Sept/Oct 1986
' 1
A Publication of the Natural Resources Defense Council
Settlement of Case Against GM Establishes
Clean Bus Fuel Research Program
A unique program to perfect an engine for city buses
powered by clean-burning methanol instead of diesel fuel
has been instituted by NRDC, the Center for Auto Safety,
the Environmental Protection Agency and General Motors.
The cooperative program settles a major Clean Air Act
enforcement case brought by NRDC against GM and EPA
in 1982.
Under the agreement GM will conduct research and
development over a three year period to improve the design
and performance of current methanol engines. GM has
agreed to give New York City, free of charge, six "first
generation" methanol-powered buses. When a "second
generation" of buses with improved engines are available,
GM will sell up to twenty-six of them to New York City at
the same price as a diesel bus.
Developing the methanol engine to replace the diesel is
one oh NRDC's highest priorities for protecting the health of
city dwellers. Each year diesel vehicles dump thousands of
tons of foul-smelling smoke and soot into urban air
nationwide —more than three thousand tons in New York
City alone. Diesel particles are inhaled into the deepest part
of the lung where they can cause or aggravate serious lung
diseases, including cancer. According to EPA data, present
levels of diesel emissions may be causing up to 350 cases of
Settlement of Case Against GM
lung cancer every year. Diesel particles also cause millions
of dollars in soiling damage to buildings, fabrics and other
materials, and sharply cut urban visibility If the meth.mol
program succeeds, a vastly preferable alternative mil soon
be commercially available.
The dispute that led to this settlement began in 1932
when the EPA decided to let GM avoid its responsibility to
recall and repair two models ol 1979 Pontiacs which failed
to meet emission standards. NRDC attorney David Doniger
objected to EPA's alternative plan, in which the company
would impose a marginally stricter standard on cars made
in future years in order to "offset" the pollution increase
Doniger doubted that the plan would in fact reduce
pollution because it appeared that even in the absence ot the
plan the future model cars would have met the same
pollution levels anyway. Moreover, allowing GM to avoid a
recall would destroy the incentive that the expense involved
provides to build durable emission control systems that will
List throughout a car's lifetime. NRDC and the Center for
Auto Sarety brought suit to block the GM-EPA agreement.
In 1984, the court or appeals ruled in our favor, holding that
tlie Clean Air Act requires the recall of offending vehicles.
The settlement instituting the methanol bus program
grew out of eighteen months ot negotiations hollowing
that decision.
NRDC was willing to settle the case with the methanol
bus program because the time consumed in litigation had
diminished the effectiveness of a recall, since very few of the
1979 cars would likely be reached now. Instead, NRDC
opted for the methanol program, which will accomplish
some concrete environmental results and, by requiring a
substantial expenditure from GM, will maintain the incen-
tive for auto emission control durability. But now that the
legal issue over recall is resolved, we say "never again."
NRDC will not support remedies for future auto emissions
violations other than recall.
-------
Engine Modifications to Meet
Future Diesel Standards
0 Fuel injection
0 Electronic engine controls
0 Combustion chamber modifications
0 Air handling characteristics
0 Reduced oil consumption
0 Turbocompounding
0 Reducing heat rejection
Thomas Baines
-------
Fuel Injection
Higher injection pressures decrease solid carbon
through improved spray quality
Unit injectors
Allow for very high injection pressures
* Typical current pressures under 10,000
psi
* Up to 16,000 psi achievable with pump
and line systems
* Up to 30,000 psi achievable with unit
injectors (most will operate at
20-25,000 psi)
-------
Unit injectors (cont'd)
Better control over injection timing and
profile through electronic control
Not generally considered for smaller engines
Some manufacturers claim there is little or no
benefit from unit injectors
-------
Fuel Injection (cont'd)
Reducing injector nozzle sac and orifice volumes
Reduced SOF by reducing unburned HC
Some designs being implemented in 1987-1988 MY
-------
Electronic Engine Controls
Ability to optimize operating parameters over entire
speed/Ioad map
Most manufacturers feel electronic control holds
much promise
Detroit Diesel already using DDEC system, others
close behind
-------
Combustion Chamber Modifications
Optimizing air swirl for better mixing
Re-entrant bowl - promising if durability
issues can be resolved
Intake manifold modifications
Eliminating dead space to eliminate unburned HC
Reducing top ring land clearance
Eliminating head/valve pocket
-------
Air Handling Characteristics
Turbocharging
Using exhaust heat energy to compress intake
air
Higher charge pressures reduce particulate
Approximately 90 percent of current engines
turbocharged
-------
Air Handling (cont'd)
Aftercooling
Using heat exchanger to cool compressed intake
air
Cooler charge reduces NOx
Approximately 70 percent of current engines
use aftercooling
Major trend from Water Jacket to Air to Air
-------
Air Handling (cont'd)
Much turbocharging and aftercooling already in use
Emphasis now on optimizing the system
Some naturally aspirated engines being dropped
-------
Reduced Oil Consumption
Up to 10 percent of participate from lubricating oi
Improved piston ring design lowers oil consumption,
but durability problems arise
Advanced reduced oil consumption technology still in
the lab shows much promise
Some current engine designs already include good oil
control
-------
Turbocompounding
Extracting exhaust heat energy and routing it into
drivetrain
Increase power output at same particulate output
thus reducing g/BHP-hr
Fairly expensive and would only be expected on large
engines
A longer term technology
-------
Reducing Heat Rejection
Reducing heat rejection allows for higher peak
temperatures and more efficient burning of fuel
Primarily achieved through ceramics
Opinions vary greatly on potential benefits of
ceramics
A longer term technology
-------
Conclusions
Engine out reductions are a high priority for the
manufacturers
Non-trap compliance with 1991 standards on some
engine lines is a possibility
-------
Diesel Particulate Control:
Emerging Control Technologies to Address A Serious
Pollution Problem
Presented by
Bruce I. Bertelsen
Executive Director
Manufacturers of Emission Controls Association
at the
Diesel Particulate Control/Alternative Fuels
Symposium
January 27-28, 1987
Chicago, Illinois
-------
I. Diesel Particulate from Motor Vehicles Pose a Serious
Threat to the Public Health and Welfare
Diesel particulates are extremely small, can be lodged
deep in the most sensitive regions of the lung, and are
suspected of contributing to or aggravating chronic lung
diseases such as asthma, bronchitis, or emphysema.
Moreover, up to 10,000 different chemicals, some of them
known to cause cancer in animals and suspected by many
health experts as causing cancer in humans, are absorbed
with the diesel particulate and deposited deep in the lungs.
Diesel particulates, because of their size and
composition, can greatly impair visibility. Studies
indicate that diesel-powered vehicles may be responsible for
significantly reducing visibility in major urban areas.
In addition, these particles soil public buildings and
private residences, and contribute to structural damage by
corrosion or erosion. Diesel exhaust also gives off a
pungent and offensive odor.
Diesel trucks, buses and cars together are a
significant and growing source of particulate emissions.
Such vehicles emit 30 to 70 times more soot know as
"particulate matter" than gasoline vehicles equipped with
catalytic converters. Diesel engines currently power the
majority of large trucks and buses, and by the late 1990's
virtually all of the new large trucks and buses will be
diesel powered. EPA predicts that unless controlled diesel
particulates from motor vehicles will more than double
current levels by 1995.
Diesel particulate emissions from motor vehicles are
particularly troublesome because they are emitted directly
into the breathing zone where we work and recreate.
II. Congress, EPA and California Responded to the Risks Posed
by Diesel Particulate
Congress recognized the risks posed by diesel
particulate and as part of the 1977 Clean Air Act Amendments
established specific, technology-forcing requirements for
controlling these emissions. The U.S. Environmental
Protection Agency) (EPA) in 1980 established particulate
standards for automobiles and light trucks. In 1985, after
nearly five years of unfortunate delays, EPA established
-------
particulate standards for heavy trucks and buses.
California, concerned that EPA standards would not
adequately protect its citizens, adopted its own set of
standards for passenger cars and light trucks.
Table I below summarizes the diesel particulate
standards currently in effect.
TABLE I
PASSENGER CARS PARTICULATE
1986 Federal 0.6 gpm
1986 California 0.2
1987 Federal 0.2
1989 California 0.08
LIGHT TRUCKS (under 8,500 Ibs GVWR)
1986 Federal 0.6 gpm
1986 California 0.2
1987 Federal 0.26
1989 California 0.08
HEAVY DUTY TRUCKS (8,500 Ibs GVWR or over)
1988 Federal & California .6 g/BHP-hr.
1991 Federal & California .25
1994 Federal & California .1
URBAN BUSES
1988 Federal & California .6 g/BHP-hr.
1991 Federal & California .1
The progress made in developing diesel particulate emission
control since EPA first established standards for automobiles in
1980 has been dramatic. The remainder of this presentation will
describe the advanced control technologies being developed and
used in commercial application, and discuss the s.tatus of
applying those technologies to the various catagories of motor
vehicles.
An important factor to keep in mind in assessing the
progress in developing and applying this technology is that this
progress simply would not have occurred absent the presence of
technology-forcing standards. Particulate emission control is a
classic economic externality for the motor vehicle industry.
Without a regulatory incentive, it is unlikely that sufficient
pressure would be brought to bear on industry to aggressively
pursue development of needed control systems.
III. Diesel Particulate Trap Oxidizers Offer A Technological
Solution to Controlling Diesel Particulates
Manufacturers have had, and will continue to have,
success in reducing particulate emissions from motor vehicles
through vehicle and engine modifications. Since particulate
emissions are roughly proportional to the amount of work done by
-------
» i I
the engine, the total particulate emitted can be reduced by
reducing the amount of energy required to drive the vehicle.
Therefore, such things as reducing vehicle size and weight, and
changes in aerodynamic design have a positive effect in reducing
diesel particulate emissions. Changes in engine design features
such as combustion chamber design, fuel injection timing, fuel
injection rate, and fuel spray pattern can also reduce
particulate emissions. Even with such modifications, however,
particulate emission levels remain high.
In order to achieve low levels of particulate emissions,
manufacturers have turned to aftertreatment devices, that is,
devices added to clean up the exhaust after it leaves the engine.
The most promising of these aftertreatment devices is the trap
oxidizer control system. Trap oxidizers systems have
demonstrated particulate control efficiencies in some instances
of over 90 percent.
A. Trap Oxidizers - How They Work
The trap oxidizer system consists of a filter positioned in
the exhaust system designed to collect a significant fraction of
the particulate emissions while allowing the exhaust gases to
pass through the system. Since the volume of particulate matter
emitted is sufficient to fill up and plug a reasonably sized
filter over time, some means of disposing of this trapped
particulate must be provided. The most promising means of
disposal is to burn or oxidize the particulates in the trap, thus
regenerating, or cleansing, the filter.
A complete trap oxidizer system consists of three
components, the filter itself, the regeneration system and the
controls which bring about regeneration.
1. Filter Material
A number of filter materials have been tested, including a
monolithic ceramic trap, wire mesh, foam, mat-like ceramic
fibers, and woven silica fiber coils. Collection efficiencies of
these filters range from 50 percent to over 90 percent.
The ceramic cellular monolith filter is similar in
construction to monolith catalyst supports used in gasoline
engines. It is modified by blocking alternate channels in a
checkerboard fashion on the entrance face. The opposite or exit
face is similarly blocked, but one cell removed so that the gas
cannot flow directly through a given channel. The entering
exhaust gas is thus forced through porous walls to exit through
an adjacent cell. The ceramic walls forming the cells serve as
the filter medium.
The wire mesh trap oxidizer filter design is composed of
knitted stainless steel mesh to which a high surface area alumina
-------
supported precious metal catalyst coating is applied. The
presence .of a catalyst in addition to oxidizing gaseous HC and CO
facilitates the regeneration of the filter by catalyzing the
oxidation of the collected material.
Another filter type is composed of sintered mullite fibers
and silica alumina clay in a nearly 80% porous body. It is
formed in a honeycomb configuration with plain and corrugated
sheets joined together. Alternate cells are plugged similar to
the ceramic wall flow design described above to form a filter
element.
Silica carbide fibers can be adapted to be a filter in a
densely packed tube form. Using radial flow from the outside to
the inside, the particles are trapped in the body of the tube as
well as on the outside surface.
Yet another trap oxidizer scheme being developed in Europe
and specifically designed for heavy duty applications consists of
treated silica fiber yarn woven in a number of porous metal
tubes. The exhaust gas flows into a container through the walls
of these "candles" and exits through the center of the tubes
depositing its particulate content on the yarn.
Finally, ceramic foams such as those used as filters in the
processing of metals are being examined as filter material for
trap oxidizers.
2. Regeneration
The exhaust temperature of diesels is not always sufficient
to bring about regeneration in the trap. A number of systems are
being developed to bring about regeneration of traps. Some of
these methods include:
o Throttling the air intake to one or more of the
cylinders thereby increasing the HC and CO concentration
in the exhaust.
o Using a catalyst coated trap. The application of a base
or precious metal coating applied to the surface of the
filter reduces the ignition temperature necessary for
thermal oxidation.
o Using metallic fuel additives to reduce the temperature
required for ignition of the accumulated material has been
successfully demonstrated;
o Throttling the exhaust gas downstream of the trap. This
method consists of a butterfly valve with a small orifice
in it. Manually operated, the valve restricts the flow
adding back pressure to the engine thereby causing the
temperature of the exhaust gas to rise. Special controls
of fuel input to the engine are also made at time of
-------
regeneration; and
o Using burners or heaters to heat the incoming exhaust gas
to a temperature sufficient to ignite the particulate.
o With two cycle engines frequently found in transit buses a
concept of bleeding predetermined amounts of scavenger air
has shown very encouraging regeneration results.
The diversity in filter materials and regeneration
systems being developed and employed illustrates the breadth of
commitment to develop technological solutions. It also suggests
that vehicle manufacturers will have choices available in
selecting the control system that can best be applied for their
particular vehicles and engines.
An alternative to trap oxidizers being evaluated by several
diesel engine manufacturers is the conventional catalytic
converter similar to that found in today's gasoline-powered
engines. The catalytic, converter has been found useful for
applications where a small amount of particulate reduction is
required to meet standards. The catalyst oxidizes the soluble
organic fraction of the particulate and does not actually perform
as a trap or filter.
B. Affects of Trap Oxidizers on Engine and Vehicle
Performance
The engineering goal of optimizing a trap oxidizer system to
a particular application is that any adverse affects from its
presence on vehicles and engine performance be eliminated or
minimized to acceptable levels. Work to date with trap oxidizer
development suggests these goals should be attainable. Several
specific affects are discussed below:
1. NOx, Hydrocarbons, and Carbon Monoxide Emissions -
Non-catalyzed traps appear to have little or no affect on
NOx or CO emissions, but a trap using a monolith «wall flow
ceramic filter did demonstrate the capability of reducing HC
emissions by as much as 30 percent. Experience with the
catalyzed wire mesh traps indicates that HC and CO emissions have
been reduced to a considerable degree (in the range of 60-90
percent) with no adverse impact on NOx emissions.
2. Unregulated pollutants -
Though difficult to quantify, one manufacturer has found
that ceramic traps significantly reduced aromatics, and also
reduce S04 and noise. The experience with a catalyzed wire mesh
trap indicates that there is a virtually complete reduction in
odor and in the organic particulate fractions of the particulate,
but some increase in sulfate emissions. Companies utilizing
catalysts to provide regeneration for their traps are modifying
-------
catalyst formations to reduce any sulfates emitted to an
acceptable level.
Reducing the sulfur content of gasoline -- (as has been done
in parts of California) — in addition to reducing pollution and
engine wear, would help eliminate any problem with sulfate
emissions from catalyzed traps. The U.S. EPA is currently
considering a requirement for low sulfur fuel.
Trap systems which replace mufflers in retrofit applications
have been shown equal sound attenuation to a stock muffler.
3. Fuel economy
A slight fuel economy penalty has been experienced with trap
oxidizer technology which is attributable to the back pressure of
the system. Some forms of regeneration involve the use of
fuel, and to the extent those methods are used, there will be
additional consumption of fuel. It is expected that the systems
can be optimized to minimize, or in some cases possibly
eliminate, any noticable fuel economy penalty.
4. Engine Wear and Vehicle Maintenance --
Trap systems do not appear to cause any engine wear or
affect vehicle maintenance. Concerning maintenance of the trap
system itself, manufacturers are designing systems to minimize
maintenance requirements.
5. Vehicle acceleration and driveability --
Various trap oxidizers have been or likely can be designed
so that driveability should not be affected, or at least can be
minimized most notably by limiting back pressure.
6. Safety —
Safety is a paramount consideration in developing a trap
system. In establishing the particulate standards, EPA expressed
its belief that safe systems could be developed. Trap system
manufacturers likewise are confident that safe systems can be
developed.
C. Status of Trap Oxidizer Development
1. Light Duty Vehicles
Quite understandably the greatest advances in trap oxidizer
technology have ocurred in light-duty vehicle application. Trap
equipped passenger cars are now being sold by Daimler Benz
(Mercedes). Mercedes first offered trap equipped vehicles in
1985 in several western states including California. A measure
of the success of Mercedes' program is that for the., 1987 model
year, all but the Model 190 diesel powered vehicles are trap-
-------
equipped. Other passenger car manufacturers have met EPA's 0.2
gpm particulate standard without traps.
No light duty truck manufacturer currently markets trap-
equipped vehicles. Nevertheless a number of promising systems
are being developed.
Several years ago General Motors Corporation conducted a
cross-country test with a fleet of trap-equipped vehicles. While
the test program revealed a number of engineering challenges to
be addressed, the overall results were encouraging.
Mitsubishi Motor Corporation reported at last year's Society
of Automotive Engineers International Congress on tests of a trap
oxidizer system consisting of a ceramic foam filter coated with a
catalyst for regeneration, a back-up regeneration device (which
senses particulate loading and increases exhaust temperature to
cause incineration by catalytic reaction), and an emergency
regeneration system which alerts the driver by means of a warning
lamp to activate the regeneration device with a switch in the
vehicle compartment. The system also included an odor reducing
catalyst.
Two light-duty trucks powered with 2.3 liter turbocharged
diesel engines were durability tested for 50,000 miles on the AMA
cycle with the Mitsubishi system. Both vehicles completed 50,000
miles while maintaining tailpipe particulate levels of about 0.15
grams per mile. Mitsubishi reported during the durability
testing that it was unnecessary to operate the manual
regeneration device on either vehicle. Mitsubishi concluded that
the catalyst coated trap filter system while not completely
satisfying all the parameters of trap efficiency, cost, fuel
economy, vehicle performance, practicability, reliability, and
safety, did satisfy many of these demands and overall was an
acceptable system.
2. Heavy Duty Vehicles
With EPA's and California's heavy-duty particulate standards
now in place, engine manufacturers, trap manufacturers and others
have turned their attention to the heavy duty application of trap
oxidizers. Although EPA's standards have been in effect for less
less than two years, the progress made is extremely encouraging.
Engine manufacturers throughout the world are subjecting
prototype trap systems to a full range of testing. In addition,
devices have been or are being evaluated by other parties
interested in diesel particulate control, including: The Ontario
Research Foundation; Southwest Research Institute; Michigan Tech
University; Ricardo Consulting; the National Coal Board
(England); and FEV (Aachen, West Germany). Of particular note,
the Engine Manufacturers Association is sponsoring a program by
an independent contractor to develop and evaluate a generic trap
system.
-------
One of the early successes of heavy duty trap application
was a Daimler Benz trap-equipped bus which operated for 100,000
miles. Both Daimler Benz and Volvo White advised EPA during its
standard setting process that trap equipped trucks and buses
should be available in the early 1990's.
Heavy duty application of trap oxidizer presents special
engineering challenges. While the basic technology to ensure a
high trap collection efficiency has been established, the
durability of a trap system in heavy-duty application--
particularly in light of the longer useful life requirements,
rugged use, volume of particulate emitted, and higher exhaust
temperatures -- needs to be demonstrated.
Given the tremendous progress realized to date and the
considerable combined research and development efforts of
equipment and engine manufacturers, the prospects for addressing
the remaining engineering challenges and having trap-equipped
heavy duty vehicles in the early 1990's is excellent.
3. Retrofit Applications
Heavy duty vehicles meeting EPA's particulate standards will
have greatly reduced particulate emissions. However, the EPA 0.1
g/BHP-hr. particulate standard for buses does not take effect
until 1991 and for trucks not until 1994. We will be well into
the next century before the fleet of clean burning diesel
vehicles turns over completely.
Particulate emissions from transit buses in urban areas are
of particular concern. Indeed, diesel pollution from buses is
clearly the most talked about motor vehicle pollution problem.
Buses have a life span of up to 20 years. As a result, many
localities are exploring the possibility of retrofitting buses
with diesel particulate controls.
Trap manufacturers and others have separate development
programs targeted for trap retrofit applications. Demonstration
projects have been or are underway in the Netherlands, Great
Britain, Munich, Athens, California, Philadelphia, and Tucson. A
number of other demonstration projects are being planned. Two of
these demonstration projects illustrate the significant progress
and encouraging results that have been achieved.
The first program is in Athens, Greece. The City of Athens
has one of the more serious air quality problems in the world.
Diesel exhaust emissions are the major contributor. Two Athens'
city public transit company buses have been equippped with trap
oxidizer systems. The system is a ceramic wall flow filter with
regeneration by means of exhaust throttling. The buses operate
under real conditions on Athens' urban^ bus routes and have
successfully operated for two years. " In the near future, the
-------
A I
program will expand to 25 buses. -
The second program is taking place in Phladelphia. The
Southeastern Pennsylvania Transit Authority (SEPTA) retrofitted a
6-V71 diesel engine-powered transit bus with a wire mesh
catalyzed trap oxidizer. The bus has accumulated well over
40,000 miles in 20 months of revenue service.
Video recordings and visual inspections indicate that the
bus had totally invisible exhaust under all revenue service
operating conditions. SEPTA has reported no maintenance,
performance, fuel or oil consumption problems and it has found
that the system has gone largely unnoticed by the various drivers
who have operated the bus. SEPTA reported the trap also
appeared effective in controlling odor. SEPTA will continue to
evaluate the trap's performance in order to identify capital and
operating costs of such a system vis-a-vis using alternative
fuels and other emerging methods for controlling diesel
particulates.
CONCLUSION
Diesel particulate emissions from motor vehicles pose a
serious health and welfare threat, but diesel particulate
trap oxidizers represent a technology that can greatly
reduce particulate emissions from motor vehicles.
Substantial progress has been made in developing and
applying trap oxidizer technology since EPA first adopted
particulate standards in 1980. In 1987 trap equipped
automobiles are being marketed nationwide.
Trap oxidizer applications to heavy duty vehicle offers
special engineering challenges. Engine manufacturers, trap
manufacturers and others, however, are engaged in worldwide
development efforts to refine trap oxidizer technology for
heavy duty application and the prospects for meeting those
challenges and having trap-equipped heavy duty vehicles in
the 1990's ajjpear excellent.
The significant progress in developing trap oxidizer
technology is a direct result of technology forcing
standards established by the U.S. Environmental Protection
Agency and the State of California. If progress is to
continue, it is essential that these technology-forcing
standards remain in effect.
Existing heavy duty diesel powered vehicles, particularly
buses operated in urban areas, pose a special problem to the
air quality of our nation's cities. A number of development
and demonstration projects involving retrofit trap
application to transit buses are underway and the results to
date have been extremely encouraging. Retrofit application
of diesel particulate traps offers a unique opportunity for
local governments, engine manufacturers, and device
manufacturers, to work together to find solutions to this
problem.
9
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Status of Exhaust Aftertreatment Projects
0 Overview of Projects
+ - EPA
Heavy Duty Engine Manufacturers
Equipment Supplier Industry
Research Institute
0 Status Summary
Trap Oxidizer Concepts
Trap Oxidizer Regeneration
Oxidizing Catalysts
Thomas Baines
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EPA Exhaust Aftertreatment Projects
1, Concepts development
Performed on light duty diesels
Most promising will be applied to heavy duty engines
Current work
Face heated ceramic wall-flow monolith
Electrically conductive substrate (Fogarty)
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2, Heavy Duty Technology Evaluation
Caterpillar 3208 with Mercedes-Benz LD Traps
Law cost wire mesh
Catalytic converter
Johnson Matthey
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Heavy Duty Engine Manufacturers
Manufacturers main emphasis is on engine-out
participate reductions
All manufacturers also have a trap program
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0 Mostly proprietary information
0 Some work is still in the lab but there are some
vehicle demonstrations
0 Main concepts:
Ceramic monolith
Catalyzed wire mesh
Ceramic fiber coi
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Equipment Supplier Industry Projects
Corning support role
Supply Daimler-Benz LOO Traps
40 buses in Europe
Product being tested by all HDD manufacturers
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Johnson Ma(they
Light duty diesel research
Apply promising concepts to HD catalyst
formulations trapping media
Field Durability Trials
- SEPTA (Philadelphia)
(Tucson)
Product being tested by some HDD manufacturers
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Muffler Manufacturers
Donaldson, Nelson,
Traps may replace mufflers
They may produce a complete system
Tread towards distributing costs
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Research Institute Projects
1, Southwest Research Institute
EPA Trap-equipped bus
CAfiB bus engine work
Internal Funding
. - Silica foam
Silicon carbide foam
Consortium Multi-client
Fundamentals of regeneration and control
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2, Ontario Research Foundation
EMA funded joint research
Burner-assisted regeneration
Ceramic wall flow monolith
Ontario Government project
Demonstrate trap on a local bus
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Trap Oxidizer Concepts
1, Ceramic monolith
Most prominent and likely trapping concept
High efficiency (up to 90 percent)
Much promise if durability problems
(melting/cracking) can be solved through better
control of regeneration and/or ceramics with better
thermal properties
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2, Catalyzed wire mesh
Low trapping efficiency (40-60 percent)
High reduction of SOF
Increased sulfates
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3, Ceramic fiber coil trap
Developed by Daimler-Benz
Good durability
Medium trapping efficiency (60-80 percent)
Hard to regenerate
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Trap Oxidizer Regeneration
1, Active Regeneration - May be a prefered approach for HD
application
A, Fuel burner system
Generally involves exhaust bypass
Problems with maintaining proper oxygen
concentration and good heat distribution
Some safety concern (accident while burner is
on)
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B, Electric Heater System
Face heater or (more recently) use of conductive
substrate
Good control of heat distribution
Can involve large electricity demand
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2, Passive Regeneration
Exhaust temperatures generally too low for
successful passive regeneration
Catalysts which lower participate regeneration
temperatures are primary path for passive
regeneration
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Catalysts applications
Coating on traps
i
,i
Fuel additives (pre or post engine)
* Problems with additives eventually
plugging trap
* Safety concerns include emissions of
catalyst and handling of leftover
catalyst when vehicle is scrapped
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i. I
Fuel sulfur a problem for most catalysts (sulfate
formation)
Unless sulfur is reduced or more selective catalysts
can be found it is unlikely that their use as a
passive regeneration method will be widespread in
the future
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Oxidizing Catalysts
Oxidizes SOF {80-90 percent efficient)
15 to 35 percent reduction in total PM
If engine levels are close to standard this may be a
feasable approach
Fuel sulfur a problem (sulfate formation for many
catalyst formulations)
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Fuel Quality Control Issues
Advantages:
- Potentially significant participate emission
J reductions
SO, secondary participate reductions
Possible engine wear reduction
Potentially lower engine price increases due to less
costly exhaust treatment devices
Disadvantages:
Fuel price increase
Fuel economy decrease (due to aromatics reduction)
Timothy Sprik
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Sulfur Content
0 ASTII Limit: 0.50 wt. I
0 Current Level: 0,27 wt, X
0 South Coast Air Basin Standard: 0,05 irt, I
0 Survey data shows sulfur content is increasing
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Aromatic Content
ASTM Limit: None
Current Level: 293! by volume
Levels expected to increase as cheaper crudes are used
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Effect of Sulfur on Engine-Out Emissions
Participates
Sulfates: Typically 2-6% of sulfur in the fuel is
converted
Bound HO: Roughly 1,3 x sulfate at SOX humidity
SOF; Possibly a weak correlation
Sulfur Dioxide (SO)
2
Typically 94-98% of fuel sulfur
Between 30 and 70% of SO is converted to sulfate
2
in the atmosphere
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EFFECT OF FUEL SULFUR INCREASE
ON TOTAL PARTICULATES
AND INDIVIDUAL FRACTIONS
AT1400RPM/112BHP
V.7
0.6
.5
0.4
a
5
*B)
0.3
0.2
0.1
0
Assume Bound H20
Percentage of Change
— Due to Sulfur Addition
SOLC 8%
SOF 34%
S04= 25%
U.O T?o/.
— n2W O*9/0
100%
MM*
••••M
MM»
SOLC
SOF
(0.050)
SO4=
(0.034)
y». •***-* f
Bound
(H20)
SOF
(0.131)
SO4=
(0.095)
Bound
(H20)
SOLC
OF 2
(0.20% Sulfur)
DF 2 * DTBOS
(0.55% Sulfur}
(Presentation to EPA "Fuel Composition Effects on Diesel
Particulate Emissions", Chevron Research Conpany, 8/21/84}
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Effect of Change from 0.27 I to 0.05% Fuel Sulfur on Emissions
1 Direct Emissions
Total Participate: Reduced ~ 0,10 g/BHP-hr .
SuI fates: Reduced 0,04 g/BHP-hr (based on
3X conversion)
Bound H 0: Reduced 0,05 g/BHP-hr
SOF: Possible reduction 0,01 g/BHP-hr
- SO : Reduced 0,84 g/BHP-hr
1 Indirect Emissions
Secondary Sulfate: Reduced 0,38 - 0,88 g/BHP-hr
(dependant on atmospheric conversion)
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Effect of Aromatics on Engine-Out Emissions
Participates
Fuel aromatics correlated with carbonaceous portion
and soluble organic fraction (SOF) of particulates
Gaseous Emissions
Can be correlated with HC and NOx emissions
Effect uncertain and probably highly engine specific
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04'
0.7-
0.8-
r o.s -
0.* -
OJ-
0.2
• SUMy-Slau
B Tnnmnt
1S 20 35 30 15 40 «S 50
Aromatic Carrtwn. VW H
Figure 18
AROMATIC CONTENT EFFECT
ON PARTICULATES
(SAE #852073, Barr/ et alia, 1985)
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Effect of Change from 29% to 20% Aroma tics on Emissions
Participates
Carbonaceous: Reduction of about 0,10 g/BHP-hr on
existing engines
SOF: Possible slight reduction (< 0,05 g/BHP-hr)
Gaseous Emissions
Possible reductions in HC, NOx
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Effect of Fuel Sulfur on Exhaust Aftertreatment Devices
Ceramic Monolith
Su I fates can lead to problems by plugging monolith
walls !
Catalyzed Wire Mesh
Catalyzed traps increase conversion of SO to
sulfate participates
Oxidizing Catalysts
Significant increase in sulfate formation
Infeasible unless highly selective catalyst is found
or fuel sulfur is reduced
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Cost of Sulfur Reduction to 0.05% Through Hydrodesulfurization
5 CARB: 2,6-7,4 c/gal, (survey results)
} ERC/Sobotka: 1,2 $/gal, (refinery modelling)
achieved through segregation of diesel and
distillate burner fuel
~ 8 vol % decrease in aromatics would result from
desulfurization
1 Bonner & Moore Model I ing (Sponsored by EPA):
quality of off-highway distillate fuel maintained
various degrees of segregation considered
preliminary results expected in Spring 1987
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Cost of Aromatics Reduction through Hydrotreating
Method: Severe hydrotreating, similar to
hydrodesulfurizing
CARB: 5,7t/gal, (from 33 to 10 vol %)
ERC/Sobotka: Reduction to 20 vol I achieved as side
effect of desuifurization via blending and product
segregation (Further reduction to 17 vol % acheived at
0,4$/gal)
Bonner & Moore: Currently investigating cost of reducing
aromatics to 20 vol I
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Engine Durability Effects of Fuel Sulfur
0 Increased sulfur levels in fuel cause corrosive wear
problems
0 ERC Report claimed a M reduction in wear rates resulting
from desulfurization based on locomotive test data
0 Comments from manufacturers claim reduction in wear will
be minimal
0 Testing by Daimler-Benz hows fuel sulfur has minimal
effect on wear at normal operating temperatures
0 Southwest Research Institute currently is evaluating lube
oil analysis from Southern California fleets
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EPA Action
EPA contractor report by ERC/Sobotka has been released for
public comment
Meetings with representatives of the oil industry and
engine manufacturers to coordinate further modelling work
and investigation have taken place
EPA currently developing comprehensive environmental and
economic impact study to be released in the near future
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THE ENVIRONMENTAL PROTECTION AGENCY VIEW OF METHANOL
AS A TRANSIT BUS FUEL
Presented at the Headway '85 Transit Conference
in Kansas City, Missouri on November 4, 1985
Jeff Alson
Assistant to the Director
Emission Control Technology Division
Office of Mobile Sources
Environmental Protection Agency
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Environmental Protection Agency (EPA) interest in transit
buses has increased significantly in the last few years.
Concerns over existing diesel bus pollution and enthusiasm over
the potential of methanol to alleviate these concerns have both
contributed to this increased interest. This paper will give
an overview of the transit bus issue from an EPA perspective,
summarizing our current outlook on diesel buses, discussing
methanol as a general motor vehicle fuel, and focusing on the
benefits of methanol as a future transit bus fuel.
A Reassessment of Diesel Bus Pollution
Historically, transit buses have not been considered to be
a significant environmental problem. In any urban area, the
number of transit buses is only a minute fraction of the total
number of motor vehicles. Powered by diesel engines, which
inherently produce low levels of hydrocarbon (HC) and carbon
monoxide (CO) emissions, total mass emissions of most
pollutants from transit buses are dwarfed by aggregate
emissions from passenger vehicles, large trucks, and stationary
sources such as power plants and factories. In addition, from
a technical perspective, there has not been a promising bus or
truck alternative to the diesel cycle engine operated on diesel
fuel. Accordingly, EPA regulation of heavy-duty trucks and
buses has lagged behind that of passenger cars and light
trucks, and current EPA standards require only token control
measures on new heavy-duty diesel engines.
A number of developments have forced EPA to reexamine the
diesel bus issue. As EPA has reduced emissions from other
sources (for example, new passenger car HC and CO emissions
have been reduced by over 90 percent in the last fifteen
years), bus emissions have become proportionally more
important. Public health concerns with diesel particulate
matter (PM) and oxides of nitrogen (NOx) emissions have
increased, the former because of evidence that it contains
carcinogenic compounds and the latter because air quality
projections show that certain areas of the country will exceed
EPA's ambient standard during the 1990s, and both of these
pollutants are emitted in relatively large amounts by diesel
engines. As our ability to analyze motor vehicle emission
impacts has become more sophisticated, we have determined that
public exposure to transit bus pollution is much higher than to
many other pollution sources, on a per* unit mass basis: buses
are operated exclusively in urban areas, typically over the
busiest roadway corridors with maximum population exposure, the
pollution is emitted at ground level directly into the human
breathing zone, and EPA and local environmental officials
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receive a high frequency of complaints about bus pollution and
odor. Finally, recent EPA testing has indicated that actual
diesel bus emissions of certain pollutants, such as CO and PM,
are much higher than previously thought.
Table 1 lists the current and future emission standards
which have been established for new engines to be utilized in
transit buses, as well as ranges for the emissions of current
technology engines. It can be seen that current diesel bus
engines are comfortably below the .current HC and-CO standards
of 1.3 and 15.5 grams per brake horsepower-hour (g/bhp-hr),
respectively, and that these standards are not expected to
change in the future. The situation with NOx and PM standards
is in a state of flux, however. We currently have a NOx
standard of 10.7 g/bhp-hr, which represents very little
control, if any, and no PM standard (there is a smoke standard
which constrains PM emissions somewhat). On March 15, 1985,
EPA promulgated new rules which will, for the first time,
require meaningful NOx and PM reductions from heavy-duty diesel
truck and bus engines. Interim standards beginning in 1988
will require minor improvements on some engine models. By
1991, new diesel bus engines will be subject to a NOx standard
of 5 g/bhp-hr, similar to a standard already in effect in
California. This will require some type of engine modification
on most new bus engines. Also beginning in 1991, new bus
engines will have to meet a 0.1 g/bhp-hr PM standard. This is
a very significant reduction in allowable PM emissions, and
will likely require the application of trap oxidizers, exhaust
aftertreatment devices which continuously filter and
periodically oxidize PM.
The lower diesel bus emission standards in 1991 have
certainly contributed to the interest of diesel engine
manufacturers in alternative fuels. The application of trap
oxidizers " and NOx controls will undoubtedly raise the initial
purchase price, and probably the fuel consumption as well, of
transit bus engines. A second motivation is simply the
realization that we will not have abundant supplies of cheap
diesel fuel forever, and that an alternative fuel will
ultimately be necessary.
Methanol; The Transportation Fuel of the Future
Whether examined from an energy, environmental, or
economic standpoint, methanol is a very promising alternative
motor vehicle fuel. Of course, the historical context for
interest in methanol, and all alternative liquid fuels,
involves the oil price shocks of the 1970s. American society
had prospered on cheap and plentiful oil, and.it was only after
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the OPEC oil embargo of 1973-74 that we realized that petroleum
was a finite and valuable resource. Our vulnerability with
respect to energy security was reinforced in 1979-80 when a
relatively minor cutoff of crude oil from Iran caused major
havoc with world oil prices. Prices rose from $3 per barrel in
the early 1970s to nearly $40 per barrel in 1981. Oil import
payments, which peaked at $80 billion in 1980, became a major
drain on American capital, and contributed to a decline in our
international trade balance.
Although the present world oil price and supply situation
is much improved, with plentiful supplies and falling prices,
we cannot afford to become overconfident. Domestic oil
production, which has been constant for several years, is
projected to decline in the late 1980s, as shown in Figure 1.
The combination of lower domestic oil production and increased
economic growth is expected to significantly increase our
appetite for imported oil. In addition, world economic
recovery and growth and falling crude production in other
non-OPEC areas are expected to significantly increase world oil
prices in the 1990s. It is expected that our oil import bill
will exceed $100 billion per year by the early 1990s if a
satisfactory liquid fuel substitute is not found. Figure 2
indicates that our cumulative international trade deficits are
increasing at a high rate, due to record merchandise trade and
current account deficits in 1984. Higher oil import bills in
the 1990s can only worsen our trade difficulties. Since, as
shown in Figure 3, approximately 60 percent of U.S. petroleum
consumption is in the transportation sector, it is clear that
the U.S. will ultimately require a liquid fuel alternative to
petroleum which can be produced from domestic energy resources.
From an energy perspective methanol is an attractive
alternative. It can be produced in very large volumes from a
variety of domestic feedstocks such as natural gas, biomass,
and, most importantly, all types of coal. Our huge domestic
reserves of coal, evidenced in Table 2, will undoubtedly be a
feedstock for alternative liquid fuels in the future. The
production. technology for coal-to-methanol plants is
technologically proven as both the coal gasification and
methanol synthesis processes are in use today. The fact that
coal would go through a gasification step would permit any'
sulfur in the' coal to be easily removed allowing the use of
high-sulfur coal. As a liquid fuel, methanol would generally
be compatible with existing vehicle and distribution systems.
Finally, it has been known for decades that methanol is a very
efficient-, high-octane motor vehicle fuel. From an overall
energy efficiency perspective, methanol would likely provide
the maximum number of vehicle miles per ton of coal feedstock.
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Methanol has always been considered to be a very
clean-burning fuel; in fact, its low emissions, especially of
nitrogen oxides, was a primary impetus for many of the initial
methanol research projects of the early 1970s. Of course, we
now have much more stringent passenger car emission standards,
and sophisticated emission control technologies have been
developed to control emissions from gasoline-fueled cars.
Compared to gasoline-fueled vehicles, methanol vehicles would
likely emit lower levels of reactive hydrocarbons, leading to a
projected decrease in photochemical, oxidant levels-. Engine-out
nitrogen oxide levels would also be lower, though whether
vehicle emission levels would be lower would depend on the
emission control system used (i.e., manufacturers might choose
to use a lower cost catalyst).
The environmental benefits of methanol are most evident
when considered as a substitute for diesel fuel. Diesel
engines inherently emit high levels of particulate and nitrogen
oxide emissions, and trucks and buses are major sources of
these pollutants in many urban areas. Methanol engines tend to
emit very low levels of both of these pollutants. Methanol
substitution for diesel fuel would also reduce reactive
hydrocarbon and sulfur dioxide emissions as well. From an
environmental perspective, the use of methanol provides the
opportunity for vehicle manufacturers and consumers to achieve
the energy efficiency of a diesel engine but with exhaust
emissions comparable to or better than the cleanest gasoline
engine. Bus emissions will be discussed in more detail later
in this paper.
Of course, fuel economics will be vital to the viability
of any alternative liquid fuel. EPA has studied this issue
extensively and concluded that methanol would be the most
cost-effective liquid fuel, on a dollar per mile basis, of any
of the candidate fuels which can be produced from coal. When
methanol would be competitive with petroleum fuels is very
dependent on world oil prices. Our studies indicate that
methanol would be competitive with gasoline from $35 per barrel
oil and competitive with diesel fuel when crude oil prices
reach $45 per barrel. Even assuming that there will be no
world oil supply disruptions, most forecasts are that world oil
prices will rise above these levels In the 1990s.
There is a growing consensus that methanol is our most
promising alternative transportation fuel. Both Ford and
General Motors have active methanol vehicle development
programs and various foreign manufacturers are also involved in
the area. Many energy and chemical industry firms have studied
the economic feasibility of coal-to-methanol production plants,
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though plans are presently on hold due to the large methanol
surplus and falling world oil prices. Methanol vehicles are
currently being evaluated by private and public sector fleet
operators throughout the U.S., such as the Bank of America and
the California Energy Commission.
Interest in methanol development has reached the highest
levels of our federal government - and both major political
parties. The Administration has formed a Methanol Working
Group composed of representatives of 15 different executive
agencies and White House staffs. ' The primary purpose of the
working group is to review regulatory requirements which might
inhibit consumer use of methanol. Various pieces of proposed
legislation have attracted bipartisan support in Congress
including federal fleet demonstrations, explicit appropriations
for methanol bus purchases, the establishment of a formal
interagency commission on methanol, and changes in methanol
fuel taxation. Given the interest by high-ranking members of
both parties, it is expected that such proposals will continue
to be considered.
Thus, with respect to environmental, energy, and economic
considerations, we believe methanol is the most promising
alternative transportation fuel. The conversion of our
national vehicle fleet to pure .methanol could eliminate our
need for oil imports with concomitant benefits such as an
improved balance of trade, insurance against the economic
dislocations caused by another oil price shock, and increased
national security. The redirection of the U.S. wealth now
going for oil imports into domestic coal-to-methanol production
could increase domestic economic growth and employment and
would provide a needed market for high-sulfur coal. And, at
the same time, the use of methanol in motor vehicles would
improve urban air quality.
The Potential for Methanol as a Transit Bus Fuel
While we believe methanol has the potential to ultimately
displace petroleum fuels in all motor vehicle applications, it
is particularly attractive at the present time for use in
transit buses. There are several reasons why methanol transit
buses could be implemented much more easily than could a
general fleet transition to methanol. First, because most
transit authorities are public agencies, they should be
sensitive -to public complaints about the environmental problems
of diesel buses and the benefits to be gained from operating
methanol buses. Transit agencies typically receive operating
subsidies from local units of government, and this provides a
leverage point for citizens interested in reducing air
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pollution. Even more directly/ since the federal government
provides up to 80 percent of the funds used to purchase new
urban buses, it could directly promote interest in methanol
buses by providing financial inducements for technology
transfer or by simply requiring that all federal monies be used
for methanol bus purchases. Second, transit authorities have
centralized fueling sites which could be modified to store and
dispense methanol fairly easily. This means that a methanol
bus implementation program would be largely immune from the
distribution problems which would be associated with the
widespread transition to a fuel like methanol, with its
different chemical properties, requiring that scores of
thousands of private service stations be capable of storing and
dispensing it. Finally, because transit systems also have
centralized maintenance facilities, there would be far fewer
concerns over the proper maintenance and repair of a "new" or
at least different engine technology. Thus, urban buses are
probably the most appropriate vehicles to be initially fueled
with methanol.
Several heavy-duty engine manufacturers are now involved
in methanol research programs. Despite the fact that research
into the use of methanol in diesel engines is a fairly recent
phenomenon, manufacturers have already achieved considerable
progress. Three manufacturers have developed methanol-fueled
diesel-cycle bus engines: M.A.N., Mercedes-Benz, and General
Motors. M.A.N.'s involvement in the German Alcohol Fuels
Project led them to modify an existing 11.4-liter,
six-cylinder, direct-injected, naturally-aspirated, four-stroke
diesel engine for pure methanol combustion. The two key
aspects of the modification were the addition of spark ignition
and the functional separation of fuel injection and mixture
formation through wall deposition of the methanol. M.A.N. is
now developing a turbocharged version of this same methanol bus
engine.
Mercedes-Benz has designed a 11.4-liter, six-cylinder,
spark-ignited engine to operate on gaseous methanol, in order
to take advantage of methar.ol's relatively low boiling point
(permitting vaporization) and high heat of vaporization
(increasing usable energy). The engine, adapted from a design
originally intended for operation on natural gas and propane,
features a fuel vaporizer which utilizes heat energy from
engine cooling water.
General Motors has only recently become involved in
methanol bus engine research. GM selected its 9.0-liter,
six-cylinder," direct-injected, turbocharged, two-stroke diesel
engine, used in most new U.S. transit buses, as its baseline
engine. It was found to be surprisingly easy to autoignite
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pure methanol in the two-stroke engine at normal engine
operating temperatures by controlling the exhaust gas
scavenging process to produce the requisite in-cylinder
conditions at the time of fuel injection. In effect, much of
the exhaust gas is maintained in the cylinder thus providing
sufficient temperatures for methanol ignition. Glow plugs were
added to the engine for use in cold starting and light-load
operation.
Each of these three manufacturers now has methanol buses
in various demonstration programs throughout the world.
Prototype methanol buses are now operating in revenue service
in San Francisco (GM and M.A.N.), Berlin (M.A.N. and Mercedes),
Auckland, New Zealand (M.A.N. and Mercedes), and Pretoria,
South Africa (Mercedes) . Each bus has had some problems, but
none appear to be insurmountable. Both the engine
manufacturers and the demonstration sponsors have been pleased
with each of the programs.
The most critical ongoing demonstration program for U.S.
policymakers, both because of the manufacturers involved and
its accessibility, is the one in San Francisco sponsored by the
California Energy Commission. Two GM and M.A.N. methanol
buses, which went into service for the Golden Gate Bridge,
Highway, and Transportation District in January and July of
1984, respectively, will be operated in normal revenue service
until the end of 1985, at which time it is likely that
additional funding will be sought to continue the
demonstration. The program has been designed to provide
important information with respect to operating cost, fuel and
oil consumption, emissions, maintenance, driveability,
durability, and consumer and driver reaction. Experience
gained from this program will be very helpful in planning for
more comprehensive demonstrations in .the future. In general,
the San Francisco demonstration has been very successful in
proving the feasibility of methanol transit buses. The M.A.N.
bus has been particularly impressive with very few maintenance
problems and an energy efficiency equivalent to its diesel
counterpart both in service and on track fuel economy tests.
As of October 1985, the M.A.N. bus had accumulated 37,000
miles. The GM bus was beset with some problems early in the
program, but is now running well and has accumulated 27,000
miles. The GM bus has not yet reached an energy efficiency
equivalent to the diesel. Both of the buses have exhibited
performance equivalent to diesel buses. For more detailed
information on this program, the reader should consult Society
of Automotive Engineers paper number 850216.
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A. second U.S. demonstration, sponsored by the Florida
Department of Transportation and UMTA, is also ongoing. Its
purpose is to determine the costs and benefits of retrofitting
in-use GM 71-series diesel bus engines to methanol. Three
engines have been converted in 1985 and will be put into
service in Jacksonville, Florida for six months in early 1986.
This program is more fully described in Society of Automotive
Engineers paper number 841687.
Based on the promising results to date; additional
demonstrations, involving larger numbers of buses and the
active interest and participation of individual transit
authorities, are being planned. Seattle Metro Transit has
signed a contract to purchase 10 M.A.N. methanol buses,with
delivery expected in late 1986. The Southern California Rapid
Transit District is expected to solicit bids for 30 methanol
buses in the near future. Officials in several other cities,
such as New York and Denver, have also expressed interest.
It is becoming increasingly clear that environmental
considerations comprise the primary driving force toward the
use of methanol in transit buses. While interest in
alternative fuels is generally a function of oil prices and
availability, the enthusiasm for methanol buses has grown
significantly in the last two years despite a world oil glut
and falling oil prices. Our discussions with local
environmental officials and individual transit authorities have
indicated that there would be a high value associated with a
transit bus fuel which was cleaner than diesel fuel. What
would be the environmental implications of substituting
methanol buses for diesel buses?
EPA has tested many diesel bus engines down through the
years. Until very recently EPA has relied exclusively on
engine dynamometer testing which simplifies the laboratory
expense of characterizing an engine which may be used in a
number of truck and bus chassis applications. In addition, an
engine dynamometer can be smaller and cheaper than a chassis
dynamometer. Data collected prior to the late 1970s was
generated over steady-state engine testing which is not
considered to be very representative of in-use transit bus.
operation. Much of the more recent data was generated over the
EPA heavy-duty transient engine test procedure, which is used
for official EPA certification purposes. This involves
operating an engine over a test cycle that consists of engine
speed and load transients which were designed to simulate
intercity truck usage (truck operation was selected for the
cycle design because trucks outnumber buses). The first column
in Table 3 gives the average engine emissions data for three
new diesel bus engines which EPA has tested over our
certification transient engine test cycle.
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Of course, the relevant information for air quality models
is the grams per mile (g/mi) that a vehicle is emitting.
Historically, EPA has typically used a "conversion factor" of
between 3 and 4 to convert engine emissions in g/bhp-hr to
vehicle or chassis emissions in g/mi. Recently, EPA has tested
7 diesel buses pulled directly from operating service and
operated on a chassis dynamometer over emission test cycles
designed to simulate transit bus operation. Three of these
buses were CMC RTS II buses from the Houston bus fleet which
were equipped with DDAD 6V-92TA diesel engines. -Four CMC RTS
II buses with DDAD 6V-71 diesel engines from the San Antonio
transit authority were also tested. These buses had
accumulated between 55,000 and 247,000 miles prior to testing.
Two chassis test cycles were used, an EPA bus driving cycle and
the central business district phase of the SAB Type II Fuel
Consumption Test Procedure for buses. Both of these chassis
cycles involve transient operation with low average speeds and
high acceleration rates, and both cycles have yielded fuel
economy values which correlate well with field data. The
second column in Table 3 gives the average emission data for
these 7 buses. It can be seen that multiplying the engine data
by a conversion factor of 3 or 4 is pretty reliable for HC and
NOx emissions, but that this methodology does not hold for CO
and PM emissions. The CO and PM emissions for in-use diesel
buses were much higher than predicted by the engine data. The
discrepancies reflect some combination of engine aging and
wear, maladjustment, or more realistic test cycles. In any
case, EPA has concluded that previous projections of diesel bus
emissions have been underestimates, and that chassis testing is
necessary for accurate quantification of bus emissions.
Nevertheless, until recently there was no methanol bus
chassis data, only methanol engine data. Table 4 compares the
diesel bus engine emissions data from Table 3 with engine
emissions data for the M.A.N. and GM methanol engines. All of
these engines were new or nearly new. The M.A.N. methanol
engine was tested by the Southwest Research Institute under
contract to EPA. The engine was equipped with an oxidation
catalytic converter and tested over the EPA transient engine
test cycle. The GM methanol engine was tested by GM over the
older EPA 13-mode steady-state engine cycle. It did not
utilize a catalytic converter. As can be seen, CO and HC
emissions were not reported by
The engine data in Table 4 show clearly that methanol,
because of the absence of carbon-carbon bonds and fuel
impurities such as lead and sulfur, produces very low levels of
PM. Besides being a critical environmental benefit in and of
itself, the low particulate levels also permit the utilization
-------
* I
-10-
of catalytic converters which, as shown by the M.A.N. data,
reduce total organics and CO levels as well. The NOx data is
mixed. While methanol is considered a low-NOx fuel because of
its low flame temperature, the M.A.N. methanol engine actually
emitted slightly more NOx than the diesel engines. On the
other hand, the NOx emission level from the GM methanol engine
is the lowest ever reported to EPA for a heavy-duty engine.
•*
One of the most interesting issues with respect to
methanol fuel is organic (or fuel-related) emissions. Organic
emissions from diesel (and gasoline) vehicles are comprised
almost exclusively of HC compounds (with small amounts of other
compounds such as formaldehyde) , and EPA regulates these with a
single HC standard. Organic emissions from methanol combustion
are typically 90 percent (or more) unburned methanol with the
remaining fraction being primarily formaldehyde with low levels
of HC. As the data in Table 4 show, methanol engines emit
considerably lower HC emissions, much greater methanol
emissions, and similar levels of formaldehyde compared to
diesel engines. Even if overall mass organic emissions were
similar, methanol is considered to be less photochemically
reactive than most HC compounds. Thus, methanol substitution
could reduce the photochemical reactivities of urban
atmospheres, resulting in lower ozone levels. Preliminary
computer modeling simulations have projected reduced
reactivities, and EPA is now in the process of validating these
results with smog chamber research.
Just this last summer EPA completed a comprehensive
methanol chassis emission test program at Southwest Research
Institute with the M.A.N. and GM methanol buses from the San
Francisco demonstration program. This is the first such
testing of methanol buses anywhere in the world and permits us
to directly compare diesel and methanol bus emissions. This
comparison is given in Table 5. The diesel bus data, involving
7 in-use GM buses with both 71-series and 92-series engines,
are repeated from Table 3. All of these buses were operated
over the EPA bus and SAE central business district test
cycles. The M.A.N. methanol bus utilized a. catalytic
converter, while the GM methanol bus (and, of course, the
diesel buses) did not. The chassis data in Table 5 generally
confirm the engine data in Table 4. The methanol chassis
emissions data are particularly impressive for PM and NOx, the
two primary pollutants of concern from diesel buses. Both
methanol 'buses yielded PM and NOx reductions compared to the
diesel baseline, with the M.A.N. bus especially low *on
particulate and the GM methanol bus very low on NOx. The
M.A.N. bus also emitted low levels of CO and organics as well,
due to both an efficient combustion process and the presence of
-------
-11-
a catalytic converter. Of particular significance is that
aldehyde emissions from the M.A.N. bus were lower than from the
diesel buses. The GM methanol bus produced extremely high CO
and organics emissions,with the very high methanol (i.e.,
unburned fuel) emissions an indication that there is still the
need for considerable fundamental engine design work to be done
with this engine. This should not be surprising since this is
the very first methanol bus built by GM. The application of a
catalyst would also lower CO and organics emissions (and likely
PM as well, since most of the particulate is organic, formed by
the combustion of small amounts of lubricating oil).
In summary, initial tests of raethanol-fueled diesel
engines and buses confirm theoretical expectations that the
substitution of methanol for diesel fuel could provide
significant emission benefits. PM emissions would be greatly
reduced, and would likely be near zero for some engine designs.
NOx emissions would be reduced by at least 50 percent.
Methanol engines would likely be able to meet any future, more
stringent, PM and NOx standards without requiring additional
emission controls. Assuming the use of an exhaust catalyst,
which EPA believes should be mandatory, methanol engines would
also provide reactive HC reductions, with concomitant
improvements in atmospheric ozone levels, and CO reductions as
well. Present data indicate that catalysts would reduce
aldehyde emissions to levels equivalent to oc below those of
current diesel engines. The only pollutant which would be
increased would be unburned methanol although catalysts would
reduce it to acceptable levels.
Of course, whether methanol buses become a realistic
alternative is in large part dependent upon fuel costs. It is
very difficult to project the future operating costs for
methanol and diesel buses with a high degree of confidence.
Prices for both fuels are currently depressed because of excess
capacities, though it is unclear how long these surpluses will
continue. Diesel fuel prices are particularly difficult to
project given their dependence on world oil prices.
Nevertheless, given the vital importance of fuel costs in the
operation of a transit authority, it is important to have some
idea of the relative operating economics of methanol and diesel
fuels.
EPA has performed an analysis to determine when methanol
fuel might become competitive with diesel fuel for use in
transit buses. Our analysis utilized the following
assumptions: 1) Methanol buses will need only the addition of
a catalytic converter to meet the 1991 emission standards, 2)
The addition of a converter and a larger fuel tank will raise
-------
-12-
the cost of a methanol bus by approximately $1000, 3) Methanol
buses would achieve energy efficiencies equal to today's
uncontrolled diesel buses, 4) Delivered methanol fuel cost to
transit authorities in the 1990s would be $0.60 per gallon,
based on the large surpluses projected to exist, and 5) Diesel
buses would require particulate traps and NOx emission controls
to meet the 1991 standards, which will raise the cost of diesel
bus engines by $1000 to $3000 and will decrease fuel economy by
from 3 to 9 percent.
Based on these assumptions, the "break-even" diesel fuel
price would be in the range of $1.23 to $1.33 per gallon. In
other words, if diesel fuel cost more than $1.33 per gallon,
then methanol fueling would be cheaper. If diesel fuel cost
less than $1.23 per gallon, then diesel would continue to be
cheaper. Average diesel fuel prices between $1.23 and $1.33
per gallon could result in either methanol or diesel fueling
being more efficient depending upon various factors. Energy
experts still expect world oil prices to climb in the early
1990s, and diesel fuel prices could certainly exceed $1.33 per
gallon by the mid 1990s.
Conclusion
Evidence is mounting that diesel transit bus emissions are
of much greater public health concern that previously
believed. In view of the relatively high public exposure of
urban residents to diesel bus emissions, as well as
Congressional directives to control such emissions, EPA has
promulgated much more stringent emission standards to take
effect in 1991. For the first time, there is a real
alternative to the diesel bus which offers several
environmental advantages. It appears that methanol buses would
provide significant reductions of particulate, smoke, and NOx
emissions, and would likely reduce the ozone-formation
potential of urban atmospheres. Methanol bus engine
efficiencies are expected to equal, and possibly exceed, those
of diesel bus engines, and based on current energy price
projections methanol buses could be cheaper to operate by the
mid 1990s. EPA supports methanol bus research by the
automotive industry and strongly urges that transit authorities
consider methanol as one alternative for the 1990s.
-------
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-------
Table 1
EPA Transit Bus Engine Emission Standards
PM
Current engines 0.5 to 1.0 1 to 5 5 to 9 0.4 to 0.8
1985-1987 standard 1.3 15.5 10.7 none
1988-1990 standard 1.3 15.5 6.0 0.6
0.1
(g/bhp-hr
»s
idard
idard
: standard
over EPA transient engine test)
HC
0.5 to 1.0
1.3
1.3
1.3
CO
1 to 5
15.5
15.5
15.5
NOx
5 to 9
10.7
6.0
5.0
-------
Table 2
Recoverable Fossil Fuel Resource Distribution in the United States
Percentage' of Total Percentage of Total
Recoverable Fossil Recoverable Fossil
Resource Fuel Energy* Fuel Energy*
Coal 91.2 81.7
Oil Shale 2.8 12.9
Crude Oil 2.2 2.0
Conventional Natural Gas 2.2 2.0
Unconventional Gas 1.6 1.4
*Including only those oil shale resources containing over 30
gallons of oil per ton.
•(•Including only those oil shale resources containing over 15
gallons of oil per ton.
-------
Table 3
Diesel Bus Engine vs. Chassis Emissions
Pollutant
HC
CO
NOx
PM
(EPA transient test procedures)
New Diesel In-Use- Diesel
Bus Engines Bus Chassis
(g/bhp-hr) (q/mile)
1.51
3.22
6.25
0.57
3.35
51.9
26.1
5.52
-------
Table 4
New Diesel vs. Methanol Bus Engine Emissions
Pollutant
PH
NOx
CO
Organics
HC
Methanol
Aldehydes
(g/bhp-hr)
Diesel MAN, Methanol
Bus Engines Bus Engine
0.57
6.25
3.22
1.61
1.51
0
0.10
0.04
6.60
0.31
0.68
0.001
0.68
0.001
GM Methanol
Bus Engine
0.17
2.20
-
1.28
1.13
0.15
-------
Table 5
In-Use Diesel vs. Methanol Bus Chassis Emissions
Pollutant
PM
NOx
CO
Organics
HC
Methanol
Aldehydes
Diesel Bus
Chassis
5.52
26.1
51.9
3.88
3.35
0
0.53
(g/mile)
MAN Methanol
Bus Chassis
0.09
13.6
0.65
1.40
0.09
1.16
0.15
GM Methanol
Bus Chassis
1.09
7.90
107
120
1.15
116
2.33
-------
" — — - The Engineering
Resource For
400 COMMONWEALTH DRIVE WARRENDALE. PA iso96
SAE Technical
Paper Series
860305
Emissions from Two Methanol-Powered Buses
Terry L. Ullman
and Charles T. Hare
Southwest Research Institute
Sen Antonio. TX
Thomas M. Balnes
Environmental Protection Agency
Ann Arbor, Ml
Internitionil Congress ind Exposition
Ootrott. Mlehlgin
Fsbruiry 24-211986
-------
860305
Emissions from Two Methanol-Powered Buses
Terry L. Ullman
and Charles T. Hare
Southwest Research institute
San Antonio. TX
Thomas M. Baines
Environmental Protection Agency
Ann Arbor. Ml
ABSTRACT
Emissions fro n the two methanol-powered
buses used in the California Methanol Bus Demon-
stration have been characterized. The M.A.N. SU
200 bus is powered by M.A.N.'s 02566 FMUH meth-
anol engine, and utilises catalytic exhaust aftertreat-
rnent. The CMC RTS II 04 bus is powered by a first-
generation DDAD 6V-92TA ,-nethanol engine without
exhaust aftertreat nent. Emissions of HC, CO, NOX,
unburned methanol, aldehydes, total particulates, and
the soluble fraction of particuUte were determined
for both buses over steady-state and transient chassis
dynamometer test cycles. Emission levels from the
M.A.N. bus were considerably tower than those from
the CMC bus, with the exception of NOX. Compari-
son of emission levels fro n methanol-and diesel-
powered buses indicates that substantial reductions in
emissions are possible with careful implementation of
methanol fueling.
DIESEL ENGINES have been used with petroleum
fuels for nearly a century, yet in some applications,
high levels of particulate and NOX emissions persist
along with nuisance emissions of smoke and odor.
Diesel-powered buses are one of the prime examples
of a diesel engine application which has come under
scrutiny due to concerns about emissions. In the
interest of reducing emissions and dependence on
imported oil, the California Energy Commission
(CEO has undertaken demonstrations of advanced
fuel technologies with particular emphasis on the use
of methanol, a clean burning and efficient transpor-
tation fuel which can be produced from a variety of
U.5. feedstocks.
One of these demonstrations involved two neat
methanol-powered transit buses, with one bus
developed by Maschinenfabrik Augsburg-Nurnberg
(M.A.N.) of the Federal Republic of Germany and the
other by General Motors Corporation (CMC). Both
methanol buses were placed in revenue transit
service by the Golden Gate Bridge Highway and
Transportation District, to demonstrate the feasi-
bility of operating methanol-fueled buses in suci
service. The objective of this work was to charac-
terize the emissions behavior of these'two methanol-
fueled buses during chassis dynamometer operation at
four steady-state conditions and on two transient test
cycles on behalf of EPA.(l)*
ANALYTICAL PROCEDURES for emission measure-
ments were based on procedures established for the
1984 transient testing of heavy-duty engines(2), and
on procedures outlined in EPA's "Recommended Prac-
tice for Determining Exhaust Emissions from Heavy-
Outy Vehicles Under Transient Conditions'^) for
heavy-duty chassis dynamometer testing of vehicles.
A large single-dilution CVS was used to obtain mass
proportional emissions samples. Extremely low par-
ticulate rates were expected, so the CVS dilution
tunnel and the associated sampling systems normally
used for diesel engine emissions sampling were
cleaned to reduce the potential for particulate
sample interference due to tunnel background partic-
ulate.
Total hydrocarbons were determined over each
test cycle by integration of continuous hydrocarbon
measurements of the CVS-diluted exhaust. These
hydrocarbon concentrations were measured using a
Beckman 402 heated flame ionization detector
(HFID), calibrated on propane. Normally, the heated
sample train is maintained near 375°F. However,
since methanol undergoes increased dissociation into
hydrogen and CO at temperatures above 250°F,(4)
the continuous HC sample train was maintained near
175°F for this program. Total hydrocarbon emissions
are generally assumed to be of the same general
composition as the fuel used, and therefore it is
assumed here that all of the gaseous "hydrocarbons"
are methanol vapor. Thus, a HC density of 37.7 g/ft3
was used in computation of HC mass from concentra-
tion (ppm C) levels obtained by HFID analysis.
Results obtained using the measured concentrations
were increased by a factor of 1.25 to account for the
•NurnberslrTparentheses designate references at the
end of the paper.
014I.7191/86/Q2244306M230
Copyright 19M Society of Automotive Enfirw«n, Inc.
Ullm«n/H*r«/Bain«s
-------
860305
0.80 response of the HFID to rnethanol (based on a 90
ppm methanol-in-air gas). The mass emission of
"HC" represents the methanol molecule and includes
the mass of oxygen associated with methanol. To
differentiate this value from individual hydrocarbon
species (discussed later), the term "FID HC" will be
used for total HFID measured hydrocarbons.
Unburned methanol samples were collected by
bubbling CVS-diluted exhaust gases through distilled
water. Concentrations of unburned methanol were
determined with a gas chromatograph using an FID
specifically calibrated for quantitative purposes. In
addition, proportional bag samples of dilute exhaust
gases were analyzed for selected individual hydrocar-
bons (IHC) including methane, ethane, ethylene, acet-
ylene, propane, propylene, benzene, and toluene.O)
The 2,4-dinitrophenylhydrazine (DNPH) method(5)
was used to determine levels of formaldehyde, acet-
aldehyde, acrolein, acetone, propionaldehyde, isobu-
tyraldehyde, methylethylketone, crotonaldehyde,
hexanaldehyde, and benzaldehyde. The emission
rates of these individual hydrocarbon and aldehyde
species were then summed to yield total IHC and
total aldehyde emissions, respectively.
Concentrations of CO and CO2 in proportional
dilute exhaust bag samples were determined by non-
dispersive infrared (NDIR) instruments. NOX emis-
sions were determined from integration of continuous
concentration monitoring of the CVS-diluted exhaust
by use of a chemiluminescence (CD instrument. NOX
correction factors for intake humidity were applied
as specified in the 1984 transient FTP.(2)
Emission levels for HC, CO, CO2, and NOX
were processed along with CVS flow parameters and
bus operating parameters to compute mass emissions
on the basis of distance and fuel usage. These
computations were based on the equations specified
in the Federal Register for exhaust emissions from
gasoline or diesel exhaust.(2) However, the equations
were modified per "Calculation of Emissions and Fuel
Economy when Using Alternate Fuels" (EPA Report
No. 460/3-83-009X6) in order to account for the use
of an oxygenated fuel. Using these modified equa-
tions, fuel consumption was computed on the basis of
carbon balance.
Paniculate emissions were determined from
dilute exhaust samples utilizing various collection
media and apparatus. Total particulate mass samples
were collected on 47 mm Pallflex T60A20 fluorocar-
bon-coated glass fiber filter media, by means of a
single-dilution technique. A sample of total particu-
late matter was collected on a 47 mm Fluoropore
filter for the determination of metals and other
elements by x-ray fluorescence. To determine the
soluble organic fraction (SOF) of the total particu-
late, large particulate-laden filters (20x20 inch Pali-
flex T60A20) were extracted with methylene
chloride. The boiling point distribution of the SOF
was determined using a high-temperature variation of
ASTM-D2887-73 (a gas chromatograph method).
CHASSIS DYNAMOMETER TEST PROCEDURES used
in this program were based on procedures outlined in
EPA's "Recommended Practice for Determining
Exhaust Emissions From Heavy-Duty Vehicles Under
Transient Conditions."(3) The chassis dynamometer
used in this program was a tandem-axle Clayton
heavy-duty unit modified by the addition of eddy
current power absorbers and directly coupled inertia
wheels. Selective coupling of inertia wheels provided
appropriate inertia simulation. Electronic program-
ming of the system enabled application of the
computed road-load speed-power curve (based on
previous documentation^)).
Both methanol buses were tested over six
chassis cycles or operating conditions. Steady-state
operation included cold idle, 20 kilometer per hour
(kph), 40 kph, and hot idle conditions. Transient
operation included the DOT central business district
(CBD) cycle and the EPA bus cycle. All test work
was conducted with the air conditioning and all other
normally controlled accessories turned off.
The cold-idle steady-state was conducted with
the transmission in neutral position. Emissions
sampling commenced with engine cranking and start
of the engine. The engine was allowed to idle in
neutral and emission samples were taken for 15
minutes. Although it is unlikely that a 15-minute idle
in neutral would occur in field operation, the
prolonged idle was used to accumulate adequate
samples for analysis. The term "cold," as it is used in
this report, refers to the engine being allowed to
stand overnight in an ambient temperature between
20 and 30°C (68 to 86°F) prior to and during engine
start-up. No attempt was made to cause fast engine
warm-up over the "cold-idle" period.
After completing cold-idle emissions sampling,
the bus was operated in a warm-up mode, then held
at 80 kph to check the dynamometer load setting.
Once the load was confirmed, emissions testing pro-
ceeded with the 20 kph steady-state, then the 40 kph
steady-state and finally the hot-idle steady-state.
The hot-idle steady-state was conducted with the
transmission in "drive" and the brakes set. Emission
samples were collected over a 15-minute period at
each condition to allow adequate time for sample
accumulation (although a 15-minute idle may not
occur in actual use, the emission rate determined
from this testing should be valid for shorter idle
periods).
Emission samples were also taken over the CBD
and bus cycles. The CBD cycle is one of four transit
coach operating profile duty cycles adopted by the
Urban Mass Transportation Administration of the
U.S. DOT for evaluation of bus operation and fuel
economy.(8) For this work, the CBD cycle was
composed of 14 repetitions of the basic cycle, which
included idle, acceleration, cruise, and deceleration
modes. An example of this basic cycle is given in
Figure 1, and it was repeated 14 times for a chassis
driving cycle time of 580 seconds and a distance of
2.0 miles (3.2 km).
Data accumulated from bus operation (CAPE-
21X9) were used by EPA to develop a "heavy-duty
chassis bus driving cycle."(10) The driving schedule
shown in Figure 2 was used in this program and called
the "Bus Cycle." Of the 1191-second duration of the
cycle, a total of 394 seconds are at idle with the
transmission in "drive." The distance of the bus cycle
is 2.90 miles. The maximum speed called for by the
cycle is 36 mph. The bus cycle contains many sharp
accelerations and decelerations requiring full accel-
-------
860309
30
20
I 10
CA
_L
I
0 10 20 30 40 50
Time, Seconds
Figure 1 - One segment of the CBD test cycle
erator pedal deflection one moment and braking the
next.
BOTH METHANOL POWERED BUSES were tested
for emissions after approximately two years of rev-
enue service in the San Francisco area. The metha-
nol buses were transported to and from California by
truck-trailer due to the lack of maintenance support
and fuel supply enroute. Both buses were received
with on-board tanks full of "fuel quality" neat metha-
nol provided from the bulk supply fuel point at the
Golden Gate Transit garage. Upon arrival, each bus
was off-loaded, and a basic operational check was
performed, allowing the driver to become familiar
with the controls. Each bus was driven to a public
scale for weight determination and returned to the
laboratory for dynamometer set-up. Some of the
pertinent descriptive information on both buses is
given in Table 1.
100
80
60
Table 1 - Methanol Bus Specifications
and Test Weights
Manufacturer
Model
Length, m (ft)
Passanger Cap. (seated)
Transmission Model
Aiie Ratio
Tire Sue
Engine Modal
Displacement, liter
Rated Power, k» Q rpm
Engine Cycle
Compression Ratio
Ignition System
Intake Air
Service Accum., km (miles)
Cur. Weight*, kg (IM
Teat Inertia, kg life)
M.A.N.
SU 2*0
II.tOI)
Voitti 0 13*
J.»3«
IIR 22.* i2A
VLA.N. 025*4 FMUH
1*7 9 2200
(-Stroke
Ilil
Spark
Naturally Aspirated
• 3.300 (21,300)
11.100 (2*.300)
12,100 (21,300)
CMC
RTS II 0*
12.2 <*0)
*3
Allison V7300
12.3 i 22.)
DDAO »V-»2TA Metnanol
207 3 2100
2-Stroke
Compression6
Turbo * Blower
30.300 (U.»00>
13.000 (21,700)
1»,IOO (32.MO)
••eight as received with fusri tanks filled, bus empty
•With glow plug assist at light Idada plus scavenging air management
THE M.A.N. METHANOL BUS, shown in Figure 3, is a
model SU 2*0 powered by a M.A.tf. D2566 FMUH
engine developed for consuming a variety of low-
cetane fuels. The methanol engine is based on a
M.A.N. diesel engine design and has an 18:1 compres-
sion ratio. Ignition of the methanol is accomplished
by a timed spark ignition system.(11) This naturally
aspirated, four-stroke, in-line 6-cylinder engine is
essentially the same as that tested on an engine
dynamometer in an earlier EPA program.(12) Figure 4
shows the engine compartment of the M.A.N. SU 240
methanol bus with the horizontal configuration of the
engine. Power for air conditioning on the bus is
supplied by a small auxiliary diesel engine.
The M.A.N. bus uses a catalyst for exhaust
af tertreatment to reduce emission of unburned meth-
anol and aldehydes. The catalyst formulation was
provided by Engelhard, and was designated as a
"diesel oxidation catalyst containing 1770 g/m^ of
platinum." The catalyst assembly utilized Corning
M 20/400 ceramic monolith substrate, and has a
volume of 5.7 liters. Prior to transport, a new
catalyst assembly was installed to replace one which
had failed due to loss of spark ignition. After routine
maintenance, operation and driveability of the bus
were deemed typical and acceptable before shipment
for testing.
SO
40
20
10
0
1200 1100 1000 900 800 700 600 500
TiM, Seconds
400
300
200
100
Figure 2 - Heavy-duty chassis bus driving cycle
-------
860305
Figure 3 - M.A.N. SU 2*0 methanol bus positioned
for emissions testing
Figure » - Engine compartment of the M.A.N. SU 2*0
methanol bus with exhaust routed to CVS
The M.A.N. was received with approximately
45,500 km (28,300 miles) accumulated usage. After
familiarization and a check that all spark plug wires
were in place, the driver started the bus according to
the start-up procedures outlined in the instructions
(essentially to turn on the power to the fuel pumps,
wait 5 seconds, and start the engine with the foot
throttle depressed). The M.A.N. was driven to a
public scale and weighed (2*,*70 Ib total). Overall
performance of the M.A.N. methanol bus was good.
The inertia wheels of the dynamometer were
set for a simulation of 12,33* kg (28,300 Ib), repre-
senting approximately 25 passengers and a driver.
Total road load power at 80 kph (50 mph) was
computed to be 58 kW (78 hp); 31 kW (*2 hp) due to
air resistance, and 27 kW (36 hp) due to rolling
resistance. The dynamometer controls were adjusted
to approximate the computed road load curve of the
bus.
Cold-start of the M.A.N. methanol engine went
well, and "good" engine idle quality was observed.
Engine operation was "good" over all operating test
conditions. The driver was able to follow both the
CBD and bus cycle transient driving schedules in a
satisfactory manner.
THE CMC METHANOL BUS, shown in Figure 5, is a
model RTS II 0*, which is typical of the majority of
city transit buses used in the United States. The
methanol engine was developed from the CMC
Detroit Diesel Allison Division (DDAD) 6V-92TA
diesel engine. The DDAD 6V-92TA (turbocharged,
aftercooled) methanol engine shown in Figure 6 is of
two-stroke design and depends on compression igni-
tion of methanol. Compression ignition of methanol
occurs unassisted during high load conditions. The
Figure 5 - CMC RTS D 0* methanol bus positioned
for emissions testing
Figure 6 • Engine compartment of the CMC RTS tt
04 methanol bus with exhaust routed to CVS
-------
•60305
design relies on control of scavenging air to maintain
ienition during moderate and light loads. In addition,
•low plugs are used to assist light load, idle and
start-up oper»ti°n ol the GMC metn*no1 engine. The
methanol engine utilizes electronically controlled in-
jectors. The CMC methanol bus uses an on-board
• computer to vary scavenging air, glow plug operation,
fuel delivery, and injection timing relative to throttle
demand and engine parameters.(13,U)
No catalyst aftertreatment was used on the
CMC methanol bus. Prior to shipment, preventive
maintenance was conducted on the GMC methanol
bus, including checks of the glow plug voltages and
the parameters monitored and used by the on-board
computer. Operation and driveability were deemed
typical and acceptable before shipment for testing.
The CMC bus was received with approximately
30,*00 km (1S.900 miles) accumulated usage. After
familiarization, the CMC methanol bus engine was
started according to the instructions provided. The
starting procedure basically called for turning on the
flow plugs for approximately 1-2 minutes, then en-
gaging the starter. If a false start was encountered,
the sequence was repeated. Once the bus was
started, the engine was under the control of the on-
board computer and would not respond to accelerator
pedal movement until after about 2 to 3 minutes.
Idle quality was very rough until the engine oil
warmed up. After about 15 minutes of low speed
idle, engine idle quality Improved. Initially the
improvement in idle quality was not as good as
expected, and it was determined that one of the glow
plug connections was faulty. The warm idle quality
improved when all the glow plugs were working
properly.
The bus was weighed at the public scale (2ft,650
tb total), then driven back to the laboratory. Inertia
wheels of the dynamometer were set for a simulation
of 1»,7S» kg (32,600 Ib), representing approximately
25 passengers with a driver. Total road load power at
SO kph (50 mph) was computed to be «0 kW (SO hph »
kW (39 hp) due to air resistance and 31 kW (*1 hp) due
to rolling resistance. The dynamometer controls
were adjusted to approximate the road load curve
computed for the CMC methanol bus.
The CMC bus was equipped with a diagnostic
data link (DDL). Some of the outputs from the DDL
reader were recorded during steady-state operation
and are summarized in Table 2. "Pulse width*
Table 2-CMC Methanol Bus Diagnostic Data LHc
(DDL) Reader Output*
•MO
».»
IS
ti»*» ua-ari
>o >»
«JML> SM4
n
UM
Jt«J
in SH i« i»»
IM S» Bt Ml
u» sit tn iio
in st» in in
s» MI «*i SM
1ST M in Ul
information (the number of crank tngle decrees that
the injectors are supplying fuel) indicated more fuel
was iniectedI during the cold-start idle inWtrS than
was injected during the hot idle in drive. F«E
"beginning of Injection- (injection timing In de™
BTDC) information, it appears that the^ethanff bus
engine timing was substantially retarded from that
reported by Toepel, et ai, during development work
on the CMC methanol engine.U3l Exhaust tempwa-
ture data indicated cylinder-to-cylinder combustion
imbalance on this prototype engine.
The CMC bus performed reasonably well with
the exception of cold idle in neutral. Cold start-up
was accomplished with no problem, and the engine
did not stall. Aside from the rough idle during warm-
up, the general performance was regarded as "accep-
table" by the driver. The driver was able to follow
both the CBD and bus cycle transient driving
schedules in a satisfactory manner.
EMISSION RESULTS from the M.A~N. and the GMC
methanol buses are summarized in Tables 3 and *,
respectively. Cold idle emissions included engine
start-up and low speed idle operation with the trans-
.mission in neutral for a total of 15 minutes. FID
hydrocarbon levels during cold idle operation of the
M.A.N. were relatively high for a short time (1-3
minutes) after start-up, then tapered off and stabi-
lized. Based on very low FID HC levels observed
during the warm engine/warm catalyst operation that
followed, it appears that the M.A.N. catalyst was not
functioning during the cold idle conditions. Even so,
cold-idle emission levels of FID HC, CO, and panic-
ulate from the MAM. were significantly lower than
for the CMC bus.
Cold-idle FID HC •missions from the CMC
methanol bus were also very high during the Initial 2
to 5 minutes after engine start, when the engine idled
very roughly. The FID HC level tapered down to-
about half the initial peak level and remained stable
4or II to 15 minutes, coinciding with improved but
still somewhat erratic idle quality. After 13 to 15
minutes the idle quality smoothed and the FID HC
level dropped again. These changes in FID HC levels
and idle quality corresponded with changes in engine
operation controlled by the on-board computer.
The high levels of FID HC emitted by the CMC
(6 times those from the M.A.N.) during the cold idle
represent a significant portion (about 20 percent) of
the fuel consumed. In addition, the extremely low
emissions of NOX from the CMC during cold Idle
operation were likely due in part to poor combustion.
Cold-idle paniculate emissions for the M^.N. were
vary low. Cold-idle particulate levels for the CMC
were higher than expected on the basis of consuming
neat methanol. It is likely that engine lubricating oil
was scavenged out into the exhaust and caused the
higher-than-antidpated particulate emissions. Emis-
sion results from warm engine testing of the M^.N.
and CMC were significantly different from those
achieved in ooM idle testing.
MJLN. METHANOL BUS FID HC emission levels
during warm engine testing were very low at about 1
g/kg fuel, or less than 1 f/km. Carbon monoxide
emissions were essentially negligible. Low levels of
-------
860305
Table 3 - Summary of Emissions from the M.A.N. SU 2*0 Methanol Bus
Chassis
Test Procedure
Hydrocarbons,* FID HCd
g/km, (g/hr),[ g/kg fuel]
Carbon Monoxide, CO ' '
g/km, (g/hr),[g/kg fuel]
Oxides of Nitrogen, NOxd
g/km, (g/hr),(g/kgfuel]
Fuel Economy**
km/kg, (kg/hr)
Diesel Fuel Equivalent0
km/kg, (kg/hr)
Total Individual HC
mg/km, (mg/hr), [mg/kg fuel ]
Total Aldehydes
g/km, (g/hr),[g/kg fuel]
Unburned Methanol
g/km, (g/hr),[g/kg fuel]
Total Particulate
g/km, (g/hr),[g/kg fuel]
Soluble Organic Fraction
g/km, (g/hrUg/kg fuel]
Steady-State Operation
"Cold id'ie
(225)
[32]
(56)
(s.ol
(07)
[6.6]
(7.0)
(3.2)
(840)
[120]
(U)
[2.0]
(230)
l«]
(0.58)
(0.081
(0.58)
[0.08]
Hot Idle
(4.6)
(0.65 ]
(2.3)
[0.31
(67)
1 9.4]
(7.2)
(3.3)
(41)
[3.7]
(2.1)
[0.30]
(S.5)
[1.2]
(0.81)
[0.11 1
(0.09)
[0.011
20 kph
0.63
[0.93]
0.31
[0.4]
3.3
[4.8]
1.5
3.2
43
[65]
0.18
[0.28]
1.6
[2.4]
0.04
[0.05]
0.01
[0.01]
40 kph
0.45
[l.U
0.21
[0.5]
2.4
15.5]
2.3
5.1
4.0
[9.3]
0.039
[0.092]
0.49
[1.1]
0.02
[0.06]
0.01
[0.02]
Transient Cycles
CBD
0.53
[0.54 ]
0.48
[0.5]
8.8
[8.9]
1.0
2'2>
79
[80]
0.10
[0.10]
0.35
[0.36]
0.06
[0.06]
0.02
[0.02]
Bus
0.85
[1.00]
0.33
[0.4]
8.1
[9.5]
1.2
2.6
28
[32]
0.084
[0.098]
1.1
[1.5]
0.04
[0.05]
0.02
[0.02]
*HC emissions have been increased to account for the 0.8 response factor of the FID to
methanol, and are based on a molecular weight of 32
bFuel consumption figures were computed by carbon balance, km/kg methanol may be converted
to mi/gal methanol by multiplying by 1.86
cDiesel fuel equivalent was computed using a heating value ratio of 2.17
^Based on continuous measurement
both FID HC and CO indicate that the engine/
catalyst • package was working well. It should be
noted that emissions during the hot idle in "drive"
were stable, and indicated that the catalyst
continued to function steadily for a relatively long
idle period. Emissions of NOX from the M.A.N. over
all test operation ranged from 4.8 to 9.5 g/kg fuel, or
3.3 to S.8 g/km. Particulate emissions from the
M.A.N. for all tests were very low, ranging from 0.05
to 0.11 g/kg fuel, or 0.02 to 0.06 g/km. These levels
were in the same range as noted for the M.A.N.
D2566 FMUH methanol engine tested on behalf of
EPA by SwRI in 1982.U2)
The highest average level of unburned methanol
emitted for the M.A.N. was 33 g/kg of methanol
during the cold-idle, representing 3.3 percent of the
fuel consumed. During the warm engine operating
conditions with the M.A.N., where the catalyst was
known to be working, the unburned methanol levels
were substantially lower and represented less than
0.2 percent of the fuel consumed.
For the M.A.N., methane was the predominant
individual hydrocarbon emitted; and it was greatest
during the cold idle. Methane was also noted to a
lesser extent over the CBD, 20 kph, and bus cycle
operations. Small concentrations of ethane were
noted along with an indication that ethylene and
propane may be present over some conditions. Form-
aldehyde was the predominant individual aldehyde
emission for the M.A.N. bus, essentially representing
the "total aldehydes.*
For the M.A.N, the SOF portion of the total
paniculate accounted for essentially all of the par-
ticulate emissions during the cold idle condition. For
warm engine/catalyst operation of the M.A.N., the
SOF ranged from about 10 to 50 percent of the total
paniculate.
-------
r
860305
Table * - Summary of Emissions from the CMC RTS D 04 Methanol Bus
Chassis
Test Procedure
Hydrocarbons,3 FID HCd
g/km, (g/hr), [g/kg fuel]
Carbon Monoxide, CO
g/km, (g/hr), [g/kg fuel]
Oxides of Nitrogen, NOxd
g/km, (g/hr),[g/kg fuel]
Fuel Economy'*
km/kg, (kg/hr)
Diesel Fuel Equivalent0
km/kg, (kg/hr)
Total Individual HC
mg/km, (mg/hr), (mg/kg fuel ]
Total Aldehydes
g/km, (g/hr),[s/kg fuel]
Unburned Methanol
g/km, (g/hr),[g/kg fuel]
Total Particulate
g/km, (g/hr), [g/kg fuel 1
Soluble Organic Fraction
g/km, (g/hr), [g/kg fuel ]
Steady-State Operation
Cold-Idle
(2,900)
[230]
(440)
135]
(19)
11.3]
(13)
(6.0)
(3,000)
[230]
(35)
[2.7]
(2,700)
[210]
(6.8)
10.52 1
(5.7)
[0.44]
Hot-Idle
(660)
[100]
(290)
[46]
(3.6)
[0.6]
(6.5)
(3.0)
(1,600)
[250]
(23)
[3.5]
(380)
[58]
(3.8)
[0.58 1
(3.0)
[0.47]
20 kph
150
[180]
32
[38]
1.3
[1.6]
1.2
2.6
170
[200]
2.4
[2.9]
110
[170]
0.33
(0.391
0.28
(0.331
40 kph
140
1190]
27
[38]
1.6
[2.3]
1.4
3.1
110
[160]
1.2
[1.8]
120
[170]
0.19
(0.271
0.16
( 0.221
Transient Cycles
CBD
75
153]
55
[39]
4.9
(3.51
0.71
1.5
606
[450]
1.2
[0.89]
62
[44]
0.96
(0.69 1
0.84
(0.601
Bus
92
[611
78
[51]
4.9
[3.2]
0.65
1.4
820
(540J
1.7
[ 1. 11
S2
[54]
0.39
(0.251
0.33
(0.21]
aHC emissions have been increased to account for the 0.8 response factor of the FID to
methanol, and are based on a molecular weight of 32
''Fuel consumption figures were computed by carbon balance, km/kg methanol may be converted
to mi/gal methanol by multiplying by 1.86
cDiesel fuel equivalent was computed using a heating value ratio of 2.17
dBased on continuous measurement
THE CMC METHANOL BUS did not utilize a catalyst
for exhaust aftertreatment. FID hydrocarbon emis-
sion levels from warm engine testing of the CMC
methanol bus were very high compared to the
M.A.N.. The conditions of cold idle, 20 kph, and 40
kph all had notably higher levels of FID HC than the
hot idle in "drive," bus cycle, or CBD cycle. Carbon
monoxide from warm engine operation of the CMC
methanol bus ranged from 38 to 51 g/kg fuel. Warm
engine emissions of NOX were extremely low for the
CMC bus, ranging from 0.6 to 3.5 g/kg fuel. Lower
NOX emissions is one of the potential emission bene-
fits when using methanol as an engine fuel. However,
low NOX emissions can also be indicative of poor
combustion quality. Particulate emission levels for
the cold idle, hot idle, and CBD cycle were higher
than for the 20 kph, 40 kph, and bus cycle operations.
The soluble portion of the total particulate from the
CMC methanol bus ranged from 80 to 90 percent over
all test conditions.
Characteristics of this two-stroke cycle engine
allow a certain amount of engine oil to be scavenged
out into the exhaust. During prolonged idle, oil can
accumulate in the air box. Much of this oil accumu-
lation can be emitted during moderate to hard accel-
erations as condensible hydrocarbons, which can be
collected as total particulate (SOP) and are often
noted as smoke. Visible smoke was not measured
during this program, mainly because no smoke emis-
sions were expected. However, in observing the CMC
methanol bus enroute to the loading point, low levels
of visible smoke were noticed. The smoke levels
were judged to be near 5 percent opacity, and were
noted for a brief time (1 to 2 seconds) whenever the
bus accelerated from a stop. (No other visible smoke
was noted from either methanol bus.)
Similarities in the boiling point distributions of
the SOP and engine oil, along with similarities in the
metals content of total particulate samples and
engine oil, indicate that a major portion of the total
particulate emissions from the CMC methanol bus
was engine oil.
-------
I I
8
For the CMC, the highest level of unburned
methanol {0.21 kg/kg of fuel) was found at the cold
idle condition, representing 21 percent of the fuel
consumed. Levels of 4.4 to 5.8 percent of the fuel
supplied were emitted by the CMC over the hot idle,
CBD, and bus cycle operations. About 17 percent of
the fuel supplied was emitted during the 20 and 40
kph cruise conditions. Methane was the predominant
individual hydrocarbon found for the CMC, and was
greatest during the bus and CBD cycles. Ethylene
emissions were also noted over the six test condi-
tions, averaging about 46 mg/kg fuel, with the
highest levels noted for hot idle and CBD operation.
Lesser levels of ethane, propane, propylene, benzene,
and toluene were found, but the variabilities for
these determinations were relatively high, indicating
only that these species may be present under some
conditions.
Formaldehyde accounted for 90 to 97 percent
of the total aldehyde emissions from the CMC meth-
anol bus. Levels were greatest for the CMC at hot
idle, followed by lesser amounts for 20 kph, cold idle,
40 kph, and finally transient operation. Acetaldehyde
was noted along with lesser levels of acetone, benz-
aldehyde, and isobutyraldehyde and methylethy Ike-
tone as a group. The greater numbers of hydrocarbon
and aldehyde species noted for the CMC methanol
bus are likely attributable to engine crankcase oil
entering into the combustion process. High unburned
methanol emissions may make it difficult to apply a
catalyst for exhaust after-treatment on this engine.
FUEL ECONOMY values for both methanol buses
operated at 40 kph and over the CBD cycle were
860305
computed on the basis of carbon balance, and agreed
well with data obtained from road operation reported
by Jackson, et al.(14) For the M.A.N., carbon
balance versus road-measured fuel economy was 2.33
vs. 2.36 km/kg of methanol for the 40 kph condition,
and 1.01 vs. 1.06 km/kg of methanol for the CBD
cycle. For the CMC, carbon balance versus road-
measured fuel economy was 1.48 vs. 1.90 km/kg of
methanol for the 40 kph condition, and 0.71 vs. 0.75
km/kg of methanol for the CBD cycle. Road mea-
surements were generated in December of 1983. The
CMC methanol bus has undergone several engine/
control modifications, along with mileage accumula-
tion, since that time.
COMPARISONS OF EMISSION RESULTS obtained
from the two methanol buses indicate that the
M.A.N. methanol bus had significantly lower emission
levels than the prototype of the first generation CMC
methanol bus as already noted. A major question is,
"how do the widely different emission levels iro-n
these two methanol-powered buses compare to emis-
sion levels from diesel-powered buses?" For compar-
ison, emissions from three randomly-selected, in-
service, CMC RTS II 04 buses, powered by DDAD 6V-
92TA diesel engines, were determined over various
chassis dynamometer conditions on behalf of
EPA.U5)
The ranges of various emissions observed in
testing the three diesel buses over chassis test condi-
tions similar to those used for the methanol buses are
sum-narized in Table 5. Emission levels of
particulate, NOX (the two pollutants of most concern
from diesel engines), CO, and FID HC from the well-
Table 5 - Range of Emissions Noted from Chassis Testing of Three
CMC RTS II 04 Buses Powered by DDAO 6V-92TA Engines
Operated on No. 1 and No. 2 Diesel Fuel
Service, km
(Oil Use, km/* )
Chassis
Test Procedure
Hydrocarbons,3 FID HC
g/km, (g/hr)
Carbon Monoxide, CO
g/km, (g/hr)
Oxides of Nitrogen, NOxa
g/km, (g/hr)
Diesel Fuel Economy'1
km/kg, (kg/hr)
Total Aldehydes
g/km, (g/hr)
Total Particulate
g/km, (g/hr)
90,000 - 230,000
( 700 - 1,100 )
Steady-State Operation
Hot-Idle
(18-40)
(20-30)
(130-200)
(3.0-3.6)
(1.3-2.6)
(4.0-8.0)
20 kph
1.6-2.6
1.5-3.3
10-14
3.2-3.6
0.10-0.20
0.50-1.1
40 kph
1.0-1.2
1.0-1.2
7.3-9.3
4.1-4.6
0.05-0.10
0.40-0.50
Transient Cycles
CBD
1.7-2.5
10-13
14-19
1.8-1.9
ND
1.7-3.9
Bus
1.3-2.9
6-25
13-20
1.9-2.2
ND
1.3-3.9
ND * No Data
•Based on continuous measurement
''Fuel consumption figures were computed by carbon balance
-------
860305
developed M.A.N. methanol bus were significantly
lo*«r than those obtained from the three diesel
powered buses. Aldehyde emission levels from the
M.A.N. methanol bus were generally in the range or
slightly lower than noted fro'n the diesel buses. In
addition, fuel economy (on a diesel equivalent basis)
also was slightly better, and no visible smoke was
observed. It should be considered that the M.A.N.
bus design may not compare directly to the diesel bus
f data given in Table 5 since there are differences in
engine, chassis, and accessory, design which may
f affect emissions.
Levels of FID HC, CO, and aldehydes fro-n the
prototype CMC bus were significantly higher than
obtained from the diesel buses. However, the CMC
methanol bus particulate emissions were lower than
those from the diesel buses. The CMC methanol bus
NOX emissions were extremely low, but these low
levels, as well as the high levels of unburned meth-
anol and CO are thought to be in part the result of
poor combustion. Fuel economy of the methanol bus
(on a diesel equivalent basis) was worse than for the
diesel buses. These comparisons indicate that signifi-
cant development work on the first-generation 2-
stroke methanol engine is necessary before the bene-
fits of switching this engine to methanol fuel for
lower emissions can be realized.
ACKNOWLEDGEMENT
We would like to express our appreciation to
the California Energy Commission, Acurex, and the
Golden Gate Transit Authority for their cooperation
in providing the methanol buses. We also wish to
thank VIA Metropolitan Transit of San Antonio and
Houston Metropolitan Transit Authority for their
assistance and cooperation in the testing of the
methanol and diesel buses, respectively.
REFERENCES
1. Uliman, T.L., Hare, C.T., "Emissions
Characterization of Two Methanol Fueled Transit
Buses." Final Report EPA 460/3-85-011 to the Envi-
ronmental Protection Agency under Contract 68-03-
3192, Work Assignment No. 10,
2. Code of Federal Regulations, Title 40,
Part 86, Subpart N - Emission Regulations for New
Gasoline - and Diesel - Fueled Heavy-Duty Engines;
Gaseous Exhaust Test Procedure, Nov. 16, 1983.
3. France, C. 3., Clemmens, W., and Wysor,
T. "Recommended Practice for Determining Exhaust
Emissions from Heavy-Duty Vehicles under Transient
v Conditions," Technical Report SDSB 79-08, Environ-
* mental Protection Agency, February 1979.
- 4. Smith, L. R., "Characterization of
Exhaust Emissions from Alcohol-Fueled Vehicles,"
Final Report to The Coordinating Research Council,
Inc., May, 1985.
5. Smith, L. R., Parness, M. A., Fanick, E.
R>, and Dietzmann, H. E., "Analytical Procedures for
Characterizing Unregulated Emissions from Vehicles
Using Middle-Distillate Fuels," Interim Report, Con-
tract No. 68-02-2497, Environmental Protection
Agency, Office of Research and Development, April
1980.
6. Urban, C.M., "Calculation of Emissions
and Fuel Economy When Using Alternate Fuels,"
Final Report EPA 460/3-83-009, March 1983.
7. Urban, C. M., "Dynamomter Simulation of
Truck and Bus Road Horsepower for Transient Emis-
sions Evaluations," SAE 840340, International Con-
gress
-------
OPERATIONAL ASPECTS
OF THE CANADIAN
METHANOL IN LARGE ENGINES PROGRAM
JANUARY 27-28, 1987
THOMAS J, TIMBARIO
SYPHER:MUELLER INTERNATIONAL INC,
130 SLATER STREET
SUITE 1025
OTTAWA, ONTARIO
KIP 6E2
(613) 236-4318
-------
LARGE ENGINE DEMONSTRATION
, A LARGE SCALE NATIONAL FIELD TRIAL COVERING ENTIRE RANGE OF
HEAVY ENGINE APPLICATIONS IN THE CANADIAN OPERATING AND
ECONOMIC ENVIRONMENT
, TO DETERMINE AND DEMONSTRATE THE VIABILITY OF METHANOL FUEL IN
URBAN BUSES* INTERCITY BUSES/ INTERCITY TRUCKS AND LARGE URBAN
TRUCKS
. TO DOCUMENT THE TECHNICAL/ ECONOMIC AND SOCIAL FEASIBILITY OF
METHANOL
. TO PROVIDE A CLEAR UNDERSTANDING OF HOW/ WHERE/ WHEN AND AT
WHAT COST OR BENEFIT METHANOL WILL SERVE AS AN ALTERNATIVE
FUEL IN THESE MARKETS
-------
DEMONSTRATION OBJECTIVE
TO ASSESS THE TECHNICAL, ECONOMIC AND SOCIAL FEASIBILITY OF
USING METHANOL IN LARGE POWER OUTPUT ENGINES,
CONCERNS RE METHANOL:
, SAFETY, HEALTH AND ENVIRONMENT
, LIFE CYCLE COSTS
, INSTITUTIONAL AND REGULATORY CONSTRAINTS
, LACK OF INFRASTRUCTURE
, FUEL SUPPLY LOGISTICS
, COLD START AND ENGINE WEAR
. VEHICLE SYSTEMS AND OPERATIONAL REQUIREMENTS,
-------
OPERATIONS PLAN
DEVELOPMENT OF TRAINING AND STANDARD PROCEDURES
- VEHICLE OPERATIONS
- REPAIR AND MAINTENANCE
- DATA COLLECTION
- OIL SAMPLING
- SAFETY
- REFUELLING
- DRIVEABILITY OBSERVATION
LOGISTICS
REFUELLING STATIONS
COORDINATION/LIAISON WITH ENGINE/ LUBE AND FUEL SUPPLIES
-------
DATA REQUIREMENTS
INITIAL CONFIGURATION OF VEHICLES AND SERVICES
DAILY DATA
- FUEL CONSUMPTION
- DISTANCE TRAVELLED
- DRIVING CYCLE
- DRIVEABILITY
- ROAD CONDITIONS AND WEATHER
OTHER DATA
- VEHICLE MAINTENANCE RECORDS
- LUBE OIL ANALYSIS (WEAR METALS, CONTAMINANTS)
- EMISSIONS
- FUEL QUALITY
-------
COST DATA
FUEL
LUBRICANTS
ADDITIVES
DISTRIBUTION
INFRASTRUCTURE
SPARES
TRAINING
MAINTENANCE
ADMINISTRATION
-------
i I
PERFORMANCE DATA
FUEL CONSUMPTION
MILES TRAVELLED
LIFE CYCLE COSTS
DRIVEABILITY
DOWNTIME
-------
i I
CQMUNICATIQNS AND MARKETING
, LOCAL PUBLIC AWARENESS
, TECHNOLOGY DATA BASE
, TECHNOLOGY TRANSFER
, INFORMATION DISSEMINATION
-------
t I
• Regional Fleet Co—ordinators
• Project Office
4 Potential Demonstrations
— Control
Vancouver
Medicine Hat
LOCATION OF PROJECT OFFICE, REGIONAL OFFICES,
AND DEMONSTRATION FLEETS
-------
A I
ff
OPERATIONS
MANAGER
i
REGIONAL
FLEET
COORDINATOR
fegU BLJ iffigW
I
ELECTRONIC
TRANSFER
£ pnaacn
o
/
o
m
DATA ENTRY
BY FLEET
COORDINATOR
DATA COLLECTION AND TRANSFER PROCESS
-------
i i
FACTORS: TO CONSIDER
HEALTH EFFECTS:
o TJAlCiTY
SAFETY :
o FIRE/EXPLOSION
o SPILLS
o EHISSlOiiS
2
-------
HEALTH EFFECTS
OL CHARACTERISTICS:
o TQXICITY IS GENERALLY COMPARABLE TO OR
LESS SEVERE THAN TriAT UF GASOLINE,
PRECAUTIONS:
o SIMILAR TO THOSE FOR GASOLINE
o ADDITIONAL PRECAUTIONS FOR MILE
PROJECT
- AVOID SPILLS ON CLOTHING AND SKIN;
USE UF PROTECTIVE CLOTHING
- USE IN WELL VENTALATED AREAS
- HAVE WATER SUPPLY, SAFETY SHOWER AND
EYE WASH FACILITIES NEAR BY
- PRUPER/DISTINCT LABELLING
- SAFETY TRAINING FOK ALL OPERATING
PERSONNEL
-------
SAFETY
HETH/WOL CHARACTERISTICS:
o TOTALLY nISCiBLE Irt WATER
o riU ODOUR OR TASTE
o BURNS WITH CLEAR FLAnE
o WIDER FLATWABiLITY/EXPLUSlYE LIMITS
THAN THOSE OF GASOLINE
o HIGHER AUTOIbrtiTIOrt TtHPERATuRE THAii
THAT OF GASOLINE
-------
200 .
if 150
e
^p*
-------
I I
SAFETY
PRECAUTIONS:
o HAVE WATER SUPPLY AND PROPER FIRE-
FIGHTING FOArtS AVAILABLE
o FihEFiuHTlNu TrtAiNI.lG FOR ALL OPERATING
PERSONNEL
o ENSURE PROPER GROUNDING DURING VEHICLE
FUELLING
o DESIGN FUEL STORAGE T/WKS WITH PROPER
VENTING AHU
FENCING PROTECTION
o OUTDOOR FUELLING WHERE EVER POSSIBLE
o USE PRESSURIZED VEHICLE FUEL TANK CAPS
IF NECESSARY
o PLACE PROPER dARNING/INSTRuCTIONAL
SIGNS IN CONSPICUOUS AREAS
o INVESTIGATE FuEL FORiiULATIoN/ADDITiVE
TtChniUUES TO ENHANCE FuEL SAFETY
CnARACTERISITICS,
7
-------
EH VI RON HEN TAL
METHAilOL CHARACTERISTICS (SPILLS):
o TOTALLY fUSCIBLE IN WATER
o oPiLLS MRE bErtERALLY LESS DAriAGlNo TriA.J
6ASOLiN£
o SPILLED METHANOL/wATER nIXTURES ARE
FLAilfiAfiLE WASTES AND CiUST BE HANDLED
ACCORUINGLY
!€THA.^OL CHARACTERISTICS (EMISSIONS):
o CO, HC A.JD NOX LEVELS ARE GENERALLY
EUUAL TO OR LESS THAN THOSE FROM
GASOLINE OK DI ESEL FUELLED EN3IHES
o SI6HIFICAN7LY LOWER PARTICULATES THAN
FOR DIESEL FUELLED ENGINES
o SIGNIFICANT GREATER ALDEHYDE EMISSIONS
THAN FOR JlESEL OK GASOLlNt ENGINES',
-------
EiW'lRQNrll-NTAL
PRECAUTIONS (SPILLS):
o INSTRUCT PERSONNEL IN PROPER i
PRUCEUUKES
o CONSTRUCT IJIKE AROUNu FUELLING STATIUH AREA
TU CONTAIN SPILLS. HAVE ABSORBAi^T MATERIAL
NEAK BV
o DILUTE SPILL AREA HEAVILY HITH rtATEK
o MAKE ARRAiNGEHENTS FOR PROPER DISPOSAL OF
SPILLEJ ilATERIAL,
PRECAUTIONS (EHISSIONS):
o B^SURE PROPER VENTILATION w'HEl BRINES ARE
OPERATING
o INVESTIGATE EFFECTIVE MECHANISMS FOR
ALiiErtYuE COriTKuL/ t,G, b^ulwt riOUFiCATIONS/
FuEt FOKriuLMTiON iiuDlFICATIONS/ EXHAUST
CATALrSTS,
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FEDERAL bOVERNMENI POLICIES DM
USE OF ALTERNATIVE fRANSPDRTrtTION HJELS
E. EUGENE ECKLUNQ
OFFICE uF TRANiFQRTA'i JLiN 'i VST EMS
U. &. L-GPAh'niEtMl OF EMER3V
FF.-ESENTEl.i ;,
DJFSE!.. FARTICULATE COKirOL ,' ALTO!'! iP f 1 VE F LFLb 9 YMK'US ! UM
U. G, t-IMVIRJMHENTr.! FFuri'.ulIOM ALd i-,U
JANUARY
-------
FEDEKAL GOVERNMENT POL I : IFS ON USE OF ALTERNATIVE TRAN3POR TAT ION I-UEL'J
F.. Eugene EC k J. u nd
U.S. Oep ai t men t o f E nt r q •/
Presented to "Diesel Par t iculate Contro 1/A3. ternat i >-e
Fuels Svmposium" EPA Region 5, Chicago, January E7-PB* lc. 8'7
Although I he federal qo /er r.n.erit has sponsored research ,m -J dp-'*---lopfnent
OP. producing and i.cinq alternative fuF'l= for th'= tota] spectrum c,-r
app 11 ca t ici'is for well over a decsde, there are no policies that
spec if j.cal Iv addrc?=3 imp lenient at ion on a b~c -d '=<:ale. The d i'=••,.• tsr 101 /-.
Lutlciy c.cldre&'i h .chwa1-- tran ~.por tat i on ., and s lie rc-rna .1 rii i iiai aa^ a'- fa-.'inq the most me.-ani ngf ul dppec. 1 -'(.'id MppiM tuiutiet;,
Finallv> d-i scu^'i. j ci ri £ ddre'S'seti pol i<: v-rel.itet! ^rtioi s.
/
The.' world will not run c.-
United States,, Hone'v er , we do not have to run out to be in trouble.
i-'e need only to ha/(- world demctnd strain the- >-.,vai 1 ab i 1 j t\ of iupplv,,
Histc-ry has snoun that a djfference of -f-5% in the use • suppiv
-------
differential provides a cwinq frcrn fuel qlut to lines at rc"ci3l
stations or vice versa.
Until 1963, the U.S. provided over half the petroleum ever produced.
In 1970? U.S. oil production peaked and it has generally declined since
that time. From 1977 through 19853 U.S. discoveries of oil hci-, e
been only one third the amount produced. U.S. petroleum USB ha>=;
outs-cr ipped product K: n since the 19^Os. Use by transpor tat 3 on ha =
exceeded domes tic production since 1975. Mil of this has occurred
despite drillinc, M-0,000 to 100,000 new wells pier year for trie past 35
vear s .
The l.ist truly large petroleum discove-'-. in the U.S. was *-he North
Slope \ i n 197''V) which increased receiver air. , •-• reserves ov about- one
third. However H the U.S. appetite for oil. even with censes" vat i or,
'\i id fuel switching that occurred f o I lot-- ; , .q 1 9 '73 snd 1CJ7T •. '-,
brsruencr u-::; ., anJ the r- resent demand of 15 rr.il liL-n barrels p^-r dr-y wc>u;.c!
u~(7? UD <:iil of the o i iq trial North Slope crude' in two ,'e^rs if it we; r-
the o/ily =ourrt_- i_
-------
j. ncreas i nq . In iv3i> imports were about* 35 percent :• f consume1 1 ior: »
Experts predict tha-t L-- 1 9'?5 imports will re-r-tch li'O pc-r ::en to f 'ruppl^,
and rise to e>O— 7O percent in tht-:- decade? that follows.. Ir, view of th<-~
effsct of imports on the balance—of -pavinerri's <. this should be of gr^ve
concern. Also, a<= imports crrou c-~o will our r e } i a nc e or, OF EC and
Midcle East oil. The Middle East has 50 percent of the world"s
reserves? and by the year 200O will produce 50 percent of the world
supply. Vet this reqion is political I/ unstable and the r c-nsfioi" ta t ion is alrnos; totally (9" percent) 'lependei > '- on petroleum..
Further < trarispor tut ion nuw uses 63 percent '.if this total p.. te sma J 1 cars1 trunspc r ';>/ 1 i or, USE- !~
i i'C reaa 'i. nq . Phus in the e/t"?nt of another shortfall i ri pe^i'douiTt
E.t_!ppJv- t.-anspc r t a t ion will be-ar th» brunt •"> f th& shortaqp. M&sr,1? io
u<=t-'
-------
diesel fuel. Svnfuels c.ari serve as a direct substitute for petroleum
based fuels* and act in substantial s. y the s^me msni it-:-r L-,>I tho u t -?•!','-
anticipated surprises.. LP.'j, which is made during petroleum leMnmq •••(-
stipped from riatural £',*<*>* has long been used in fleet operations and a
million or more vehicles now operate on it. The techniques to u.h (djese^l has about 1O
oercent greater enerqv density than gasoline). These r.r.mucir I'-o'is hd^i
beeri made to qasc-line becc'U'se LPB« Tiatur^l qa-r ', or methanr'' aisd
alcohols are high nctane faels? providing ,-.• logical subst L tu t ic.n for
qjarvoliite. DiiB<=el fuel has low octane number H -tnd hi oh cetarit7/ number.
Let; an« numb e r i s the ap p r o n r i a t e r ^ b i nq n f d i >v -. 6.1 i q n i 11 C1 ri q < ta I 11 y •. a i id
fi..els with the h.iq'n c etane rating desirable fi-el engines, though er.qint? mod if n:t 11 onc;
are generally required. One of the reasons that the use of natural i;<-i =
-------
and alcohols in diesels is of interest 1-5 that lass harinful e, haust
emissions are ob tai necl . 'fhi."--.e lighter fuels r^
phc. tocnem i ca ] 1 v non — re^ct i ve . Unbuv ned alcohol fuels alr.::' h .< /•= lower
reactivity than petroleum hydrocarbon omissions* ^r.d aic_.. r a I •.=? ;htiU-= b tre<.xtmerit svsteois wort, rsiuch better on
petro l^urri comb istir.r, ---riiuu. tc than or, tho': e- fiom i ia tuir ...•• I qas . It
•£hca>ld brj rioted that altnouqt e.'it her ^tharml r-r methario.l i.ai, be burne*d..
ec.or.cm ins fo'i ethano i u'"'2 ar^- unt a /orab le •> -St.-
are djs^el cori, er 2 1011^ . Ho^f- /er , "-o-call d snufi-. ..-li-s i c. r.t:d ••} i v.."= 'i 11~
oper«rti.ng ori natural Q->-= r •,:-.-*_-? tone Liven uoei) in sJationar-,
app 1 ication'Sj and a f GW true).. cc'rive-ris ion:, havs b;?c?ri ,n.;ii'Jsr- in ttie
after-Tiiai ^ e?t . The numbt?r of the^e- is I'.'uqhl-. comparable lo th,:? number
n f diesE/L conver = i uns tor u'.-.e of alcohol. Little _i t tent i on r.^is b^en
paid t« natural Q.-v.-.i for dieselc by enqine manuf etc turei s n but a good
-------
many hcive been involved in alcohol e-per i men ta t ion. There are a
v a r i e t v o f o p t j. o n s - a v a i 1 a b ] e f" o r m o d i f L c a t1 r. n t • f a i c o h i <-. 1 f u & L s o , •
enqines to use alcohol s < appreciably more? than for natural qas . 11
techruca.. information and data base is available for _-i L i of th»
techniques? and all h-?ve been applied Co experimental veh ic Los. Thus
for alcohols* Mercedes arid Saab-Scam a buses ha/'e boRn oper at-ec! A.'I
Brar. a I and elsewhere on et Hanoi plus an advanced cet "irie- improver
additive. This additive requires smaller aniourr!:3 than u-.-.u,:-l ^nd l-.has
rtvduces the typically premium cost. Volvo has ooerated t«o hues'- i ri
revenue service Tor a couple of years that used d'jesel pilut fuel plu-..
roetharii i, achievinq >:bout an 8^' percent d ie'=el fuel rep !. ifCL^.ne-nt . MAN
hos opor-nted its m&djfied enqint.- with spari iqniticip \<, C.-i : for r, it ,
&t-'r fricuTv and ' l'3e'..Jhere. bptroit Oiesel AliiEori has t-rov tried 117
("t-chno Log / for ,-jasti-' heat cor.trc] and a qlow . ; uci in a t-jo -•- c is &• pq L re--?
a~. a means to use nt-at methantil. Dthoi" I i., S. man LI fac' urer s have
c-.tp-sr ii:iefit,*l mcidif i.ed f^nqinF de~iqns fo.' '.tc^' c i'! I! F '• .,
The b a'T i c - roli.- o i vcirious federal aaenc i. c~ \ .i c'ei • i-,f d t - their
i rid i v idua .1 missiovis. The role'; of tl-s/ Eriv i ruiii(i& it.-il i'-r c tec', j iri , nje-nt.-,
(E'f-'A > arid the Depai tinerit of Transpoi tatir^n (DOT > ^u <• pi i.m=tri]v
requ Ic? tor" y i dea1;''>q with TO. r quality a no safetv. DOT ^ thiouqi'i t!"i<-:/
U "ban Mas. •=• Trarispoi t^t-ion Adm ' n '. s fcr t iori ''UMTA;, dl-jo ccinti ibutu-s ~.o
techno loqv app 1 ira t ion aiid to support of local transportation ••j/
-------
Since termination of petroleum price control, the role of the
Department of Energy- < LDE ) has been primarily on technology' P&-D -. t-hi-nh
had been a major role since establishment. It is the policy of tre
present administration to reduce industry regulations* arid to dK-p-.-nr!
primarily on free market forces to determine change. Present _.,-
-------
a
to avoid problems related to premature exposure and/or overextended
efforts, Activities- are still in the development stage, thouqh one
manufacturer has expressed the view that production could start m
about four years following identification of an appropriate nii.vrl-. <~'i .
The Federal Government is substantially involved in matters that impact
fuel use? including energy? environment arid safety. Congressional
'"eqi.ii rnmeots for air quality and fuel economy have long existed? and
•although those are generic i n nature? their historv and makeup rente* on
petroleum products,, The government has sponsored research?
development? demons bra I u: n and forums to bring new technology,
consideration and discussion to the fore,, and has in a ruTiber :.• f wot,=
encouraged the poss ib i 1 .1 tv of using new fuels. However, AS long as
petroleum is in good supplv and economic*.-J little pubJ ic. i ntc-r r-i-r
exists. In this environmenb it is difficult at best for legislative
supoort for anv action that would require-'- investment of nover nmi^nt
funds. As earlier notsd-. the polic.v of the r\dm t nistrat i on is to rely
on f res-marl-et fcrces to institute changes and/or balance. This
strategy ot the administration is to rely or. balance a.Tioncj ener ~v
rpsc-urces.- A modest cushion against a petroleutio supp i * up~,et i ?
/
pi ovided by the E-traleqic Petroleum Re"er/e» I ii the area of
alternative transportation fuels? appreciable effort ha:; been e,:tendod
to ''level the pla/inci field' for methanol. This includes EPA's
proposed r e q u i r e m G r\ t B for c e r t i f i c & 11 o n of alcohol - f i' e 1 e d v e h i c 1 e s .
S'; i 1 3 5 agencies have not tat-en any significant action to clarify
-------
matters such as energy content of alternative fuels and their
relat lonsh ip to requirements such as corporate average fuel economy
(cafe). There are no long-term alternative fuels plans per se,
though the options for transportation have been well
identified. DOE? EPA and UMTA have all encouraged methanol fuel
application in various ways. DOE also recognizes that natural gas is
a good fuel and can play a role in the near future i r; niche
applications. which would include bus use. DOE has concentrated en
working wibh industry to assure its readiness to apply available and
appropriate technology when the market is read'/. EPA works with
industr/ as well* but concentrates on methanol as a means to improved
air Quality and apparently considers this a means for creating market
pull. UMTA has sought understanding of methanol bus f.i.eld operating
factors and answers to problems; through selected investigative
demons trat ions. At the state leveli California and New r'ork are tbe
or.l / ones that have significant enerav proqr jms in the transportation
area. California is a strong proponent of methanol. New York hac.
c o n c e ntr at ed o 1t n a t u r a i g a si b ut now has some ac 1t v i t v wi t h me t hano1„
Some members of Congress have conridered a more aggressive federal
approach .throuah legislation under consideration fch-at would provide-
/
incentives for use of specified alternative- fuels and rome additional
demonstrations (which are contrary to admi ni s fcat ion polic--.1. Concepts-
for commercial int.roduc.tion of methanol fuel into the market
have been proposed in printed documents b / personnel from both
EPA cind DOE. It IE this authors personal view that since a
-------
io
copious-, number of participants are necessary to achieve success, it is
essential that those who would participate must picl-; up on ~uch
ideas and shape them to meet the needs of their organ i. za Lions . Whpretr=
all of these attitudes are helpful. conditions are such that serious
movement toward commercialization, is dependent on free market forces
thab are not visible in the near term.
In nummary. there are several potential fuels to USP in place of
petroleum products* arid the more attractive ones. taking into account
energy and environment* are natural gas and met Hanoi. Natural qcnc! there is
probably sufficient informaticin to sort out the options. There has
been encouraqement for interest and use from federal quartersi
particularly for methanol. The government policy is to relv on free
-------
11
market forces? and the public shows little interest in petroleum
substitutes during this period of plentiful petroleum. Sines it tai.es
appreciable time to design vehicle systemsH test i evaluate emd
prove them, industry technological progress may pace the transition to
commercialization. If" a market were apparent to the industry» it would
take about four y-^ars (minimum) to achieve production. To encourage
this and to achieve wide spread interest, grass roots support from
those in the community that would be served is vital.
-------
K
U,S, PETROLEUM PRODUCTION
o OVER HAlf OF WORLD'S TOTAL UKTIL 1963
o PEAKED IN 1970
o 1977 - 1985 DISCOVERIES EQUAL 1/3 OF PRODUCTION
o USE GREATER THAN PRODUCTION SINCE 1940s,
o TRANSPORTATION USE GREATER THAN PRODUCTION SINCE 1975
o 40,000 - 100,000 WELLS DRILLED PER YEAR FOR 35 YEARS
o NORTH SLOPE (1970) INCREASED RESERVES BY 1/3
o NORTH SLOPE ALONE WOULD LAST 2 YEARS
o NORTH SLOPE PRODUCTION AT PEAK
Slide Presentation E. Eugene Ecklund
-------
FOREIGN OIL RELIANCE
o WORTS AT 35£ AND INCREASING
o 1995 WORTS 50fc
o FOLLOWING DECADE WORTS 60-7(1
o MIDDLE EAST RESERVES 50S OF WORLD'S
o MIDDLE EAST 2000 PRODUCTION 5QK OF WORLD'S
-------
TRANSPORTATION RELIANCE ON PETROLLUh
o PETROLEUM WKES UP 97% OF TRANSPORTATION FUEL
o TRANSPORTATION USES 635S OF U,S, OIL USE
o TRANSPORTATION WILL BEAR BRUNT OF SHORTFALL
-------
AVAILABLE SUBSTITUTES
o SYNTHETIC GASOLINE AND DIESEL FUEL
o LIQUID PETROLEUM GASES (1 Itl VEHICLES)
o NAT1JBAL_GA$_.(25,000)
o
o
EMISSIONS IMPROVED WITH NG OR ALCOHOLS
.TECHNOLOGIES
.JIT
4YEARS
-------
t I
FEDERAL INVOLVEMENT
o HMOS ENERGY, ENVIRONMENT AND SAFETY
o SPONSORED R&D, DEIWSTRATIONS AND FORUMS
o FREE-WET POLICY
o RELY ON BALANCED ENERGY RESOURCES
o SPR PROVIDES PETROLEUM SUPPLY CUSHION
o ENCOURAGE LEVEL PLAYING FIELD
o NO SPECIFIC LONG-TERM PLANS
o DOE, EPA AND UMTA HAVE ENCOURAGED MEIWWL
o NATURAL GAS CAN SERVE NICHES
o SOME STATE DEMONSTRATIONS
-------
0
0
0
0
0
0
0
POTENTIAL FOR USE OF METHANOL AND NATURAL GAS
IcMS /ACTING BIS APPLICATIONS
fWJFACRJRERS ADDRESSING METWNOL DESIGNS
NO FEDERAL PLANS, BUT ENCOURAGEMENT
PRESENT RELIANCE ON FREE MARKET FORCES
INDUSTRY PROGRESS WY PACE USE
GRASS ROOTS SUPPORT IS VITAL
-------
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ratio; and glow plugs for starting and
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