EPA-420-S-83-101
THE ENVIRONMENTAL IMPACTS OF THE USE OF
METHANOL AS A MOTOR VEHICLE FUEL
Presented before the
First International Conference on Fuel Methanol
on
May 10, 1983
Charles Gray, Jr.
Jeff Alson
Office of Mobile Sources
Environmental Protection Agency

-------
Introduction
The Office of Mobile Sources within the Environmental
Protection Agency has studied and evaluated alternative
transportation fuels since its formation in 1970. EPA's
responsibilities under the Clean Air Act also have necessitated
a significant regulatory role dealing with transportation
fuels. In particular, Section 211 of the Clean Air Act
requires EPA to play a key role in the introduction of new
fuels and fuel additives. Perhaps most visible was EPA's role
in the introduction of unleaded gasoline to permit the use of
catalytic converters on 1975 and later model year automobiles.
More recently EPA has responded to a growing interest in the
use of oxygenates (in particular methanol) for use in motor
vehicles and for blending with gasoline.
From a technology assessment perspective, EPA has been
motivated to investigate alternative transportation fuels
because of concerns over diesel engine emissions. Diesel
engines, which are becoming more numerous in both passenger
cars and trucks due to their significantly higher efficiencies,
produce relatively high levels of particulate matter and oxides
of nitrogen. In a sense, fuel modification can be considered
as an emission control technique.
EPA studies have suggested that neat or near-neat methanol is
one alternative fuel which can provide the relatively low
particulate and oxides of nitrogen emission levels
characteristic of current technology gasoline-fueled vehicles
while yielding improved energy efficiencies similar to those of
diesel vehicles. In addition, only minor engine design
modifications are necessary in order to produce vehicles which
could successfully utilize pure methanol fuel. Studies by
others in both the private and public sectors have shown that
methanol can be produced from a wide variety of feedstocks
which are distributed throughout the U.S., that the
technologies to produce methanol from several feedstocks are
available today, and that the overall economics of methanol
production and usage appear favorable compared to other
candidate alternative transportation fuels. EPA has recently
published a report to Congress assessing the environmental and
economic impacts of methanol and other coal liquids [1]. As a
result of the increasing interest in methanol, EPA has recently
completed several emission characterization test programs in
order to better understand the emission impacts of methanol

-------
utilization. EPA is currently in the process of projecting
probable air quality impacts and health effects of methanol
combustion.
Interest in the use of methanol in gasoline blends to extend
petroleum supplies and raise octane ratings has accelerated
during the last two years. Section 211 of the Clean Air Act
requires EPA to approve methanol/unleaded gasoline blends and
several companies have filed for fuel waivers. Many of the
waiver applications have been approved and a few have been
denied. EPA expects additional fuel waiver requests in the
future.
This paper will examine the use of methanol as an automotive
fuel both as a blending component and as a neat fuel. The
focus of this paper will be on expected end-use environmental
impacts of pure methanol combustion, and any resulting health
effects, based on data from EPA test programs. It will also
discuss possible environmental impacts associated with the
transport and handling of methanol and safety concerns related
to its use. It should be emphasized that any conclusions
regarding the relative impacts of methanol usage must at this
time be considered preliminary. Research is ongoing at EPA and
other public and private organizations to better define the
likely environmental impacts (and ways to ameliorate these
impacts) of methanol usage.
-2-

-------
Methanol as a Motor Vehicle Fuel Component
Methanol, usually along with cosolvents and sometimes certain
inhibitors, is being seriously considered as a motor fuel
component. Most of the current attention deals with methanol
as a gasoline component, although EPA has performed some
preliminary investigations into the use of methanol as a diesel
fuel component [2J. Methanol concentrations in gasolines of up
to about 10 percent are being considered. Clearly there are
certain advantages of such blends, such as an economical means
of extending petroleum reserves, higher octane ratings, and
lower carbon monoxide emissions. However, there are several
potential problems with methanol/gasoline blends including: 1)
higher evaporative emissions, 2) poor vehicle driveability due
to an enleanment effect, 3) material compatibility problems, 4)
phase separation potential and 5) further stress on distillate
availability.
Higher evaporative emissions may be a result of short-term or
long-term effects. Higher short-term evaporative emissions
would likely result from methanol blends due to the increased
low-end volatility characteristics of methanol blends, unless
appropriate volatility adjustments are made. Long-term
evaporative emission concerns are associated with the
possibility that methanol may reduce the effectiveness of the
charcoal canister in the evaporative emission control system.
Poor vehicle driveability may be experienced with some vehicles
calibrated near to or lean of stoichiometric due to the
additional enleanment effect of methanol/gasoline blends.
While certain 1981 and later model year vehicles have
closed-loop fuel control and may avoid lean driveability
problems, concern remains i'>!' for the other vehicles. The
materials compatibility concern stems from methanol's
deleterious effect on certain metals and elastomers. The
materials compatibility problem can be either a short-term or a
long-term concern. The tendency of phase separation in
methanol/gasoline blends is well known, and can be initiated by
small amounts of water. In addition to possible safety
problems (i.e., vehicle stalling), phase separation would also
worsen materials problems for those materials in contact with
the methanol phase. Finally, using methanol in gasoline may
exacerbate a potential future problem of distillate
availability. Extending gasoline supplies alone would reduce
the amount of oil refined and thus reduce distillate
-3-

-------
production. There is a possibility, with the increased use of
diesel engines in transportation and other demands on
distillate fuels, that extending gasoline supplies through the
use of methanol blends may be counterproductive.
EPA's involvement in considering these potential problems is
limited to the provisions of Section 211(f)(1) of the Clean Air
Act which prohibit the introduction of any new fuel or fuel
additive for general use in 1975 and later model year
automobiles, unless the EPA Administrator waives the
restriction by determining that the new fuel or fuel additive
will not cause or contribute to a failure of the vehicle
emission standards. EPA's role in research pertaining to the
issues involved with blends has necessarily been somewhat more
limited than research associated with the impacts of utilizing
pure methanol fuel. This is primarily due to the fact that
there are an infinite number of possible methanol/gasoline
blends, given varying concentrations of methanol, cosolvent
alcohols, and other additives which might be used for other
purposes such as inhibiting corrosion. Accordingly, it is not
possible for EPA to design a test program to resolve all of the
concerns associated with the entire range of possible blends.
EPA's role is thus one of reacting to specific fuel waiver
applications. Further, because of the number of waiver
applications we have received in the past and expect to
continue to receive in the future, EPA cannot carry out a
comprehensive evaluation of each blend. Thus, we have
generally relied on applicant data to resolve emissions,
driveability, and materials compatibility concerns.
EPA has granted several methanol/gasoline waivers. Those
waiver applications which have been denied have generally
involved insufficient data being submitted by the applicant.
EPA intends to continue to work with interested parties to help
define the constraints on the appropriate use of methanol as a
motor fuel component.
-4-

-------
PureMethanol as a Motor Vehicle Fuel
Methanol has long been recognized as a fine fuel for automotive
engines. Many of its distinctive properties, such as its high
octane number/ high flame speed, and high heat of vaporization,
make it an especially attractive fuel for Otto-cycle engines.
Because of its low cetane number, methanol had traditionally
been considered a poor diesel-cycle fuel. Recent developments
have produced some promising concepts for methanol combustion
in diesel engines, such as spark ignition and glow plug
assisted ignition. EPA has reviewed the results of previous
methanol research projects which indicated that methanol had
the potential to produce improvements in emission levels and
energy efficiency [3,4]. The next section of this paper will
focus on EPA's own efforts to characterize the emissions from
methanol-fueled vehicles.
Emission Characterization Programs
In order to assess the emissions and energy efficiency
performance of pure methanol fuel combustion, EPA obtained
three state-of-the-art methanol-fueled vehicles: Volkswagen
Rabbit and Ford Escort passenger cars and a MAN heavy-duty
engine designed for intracity bus operation. Gasoline-fueled
versions of the Rabbit and Escort were tested at the same time
for comparative purposes, as was a Volvo heavy-duty diesel
engine (recently we have obtained some comparative data from a
MAN heavy-duty diesel engine from the company). The primary
differences between the methanol and gasoline-fueled passenger
cars were the higher compression ratios used on the methanol
versions. All of the Rabbits and Escorts utilized three-way
catalytic converters. The MAN heavy-duty methanol engine is
based on a diesel-cycle engine design with the addition of
spark ignition to facilitate methanol combustion. The MAN
methanol-fueled engine utilized an oxidation catalyst while the
Volvo diesel engine did not (nor did the MAN diesel engine for
which data have been obtained) .
Each of these vehicles was subjected to a comprehensive
emission characterization program at the Southwest Research
Institute. Tables 1 and 2 summarize the test results from
these characterization programs. EPA has reported the results
in greater detail elsewhere (5,6,7). Although these are early
prototypes and are basically straightforward conversions of
their gasoline/diesel counterparts, they do provide EPA with
-5-

-------
the opportunity to perform a preliminary assessment of the
exhaust composition of methanol-fueled vehicles. Exhaust from
each of the light-duty vehicles and heavy-duty engines tested
in these programs was analyzed for each of the currently
regulated pollutants: hydrocarbons, carbon monoxide, oxides of
nitrogen, and particulate. Tests were performed for a range of
other organic compounds such as methanol, formaldehyde, other
aldehydes and ketones, and some individual hydrocarbons. In
addition, several other unregulated pollutants (nitrosamines
and total organic amines, ammonia, cyanide, and methyl nitrite)
were measured during tests on one of the light-duty vehicles.
Phenols, smoke, sulfate, and benzo{a)pyrene were also analyzed
from the heavy-duty engines. The basic intent was to identify
any possible emission surprises as early as possible with
respect to methanol-fueled engines. The results of the test
programs compare well with what was expected based on previous
methanol research projects.
One of the most important classes of emissions from motor
vehicles is composed of fuel-related emissions, which will be
referred to as organic emissions in this paper. The great
majority of fuel-related emissions from gasoline and
diesel-fueled vehicles are hydrocarbon compounds, and the
custom has been to use the term hydrocarbons to include all
organic emissions measured by the EPA test procedure, which
utilizes a flame ionization detector (FID). Since methanol¦is
an oxygenated hydrocarbon itself, the emissions from
methanol-fueled vehicles are predominantly oxygenated
hydrocarbons such as unburned methanol and formaldehyde.
Because of the inability of the FID to accurately measure
oxygenated hydrocarbons, the organic compounds in
methanol-fueled vehicle exhaust were determined by individual
measurement procedures. Tables 1 and 2 give the total
hydrocarbon, individual hydrocarbon, and oxygenated hydrocarbon
emission results. It must be emphasized that the hydrocarbon
values in Tables 1 and 2 include emissions also listed under
the individual and oxygenated hydrocarbon values.
To make the data more understandable, Tables 3 and 4 show a
more accurate breakdown of the total and individual organic
emissions for the vehicles tested. The total organic emission
is the sum of the individual organic components. For the
gasoline and diesel-fueled vehicles, the hydrocarbon data are
basically the FID-measured hydrocarbon results. For the
methanol-fueled vehicles, the hydrocarbon data are the total
individual hydrocarbon results. The oxygenated hydrocarbon
values are listed separately.
-6-

-------
Certain trends are apparent in Tables 3 and 4. Organic
emissions from the gasoline and diesel-fueled vehicles are
nearly all hydrocarbons with only trace levels of other classes
of compounds. The methanol-fueled vehicle exhausts are
dominated by unburned methanol emissions but contain small
amounts of formaldehyde and hydrocarbons. The heavy-duty
methanol engine contained very low levels of aldehydes and
hydrocarbons, though it must be remembered that it was equipped
with an oxidation catalyst. The environmental impacts of these
different organic emissions will be discussed in a later
section of this paper.
Both the CO and NOx results were mixed from the light-duty
vehicle tests (Table 1), with methanol sometimes increasing and
sometimes decreasing these emissions. However, all of the
gasoline-fueled and methanol-fueled vehicles emitted very low
emission levels, as they were all calibrated to meet the very
stringent future California emission standards. Therefore,
considering the level of control, the differences observed are
quite small in absolute terms. One significant observation is
that a trade-off seemed to be occuring between NOx emissions
and energy efficiency. Although optimum methanol combustion
would be expected to occur at very lean operation, both of the
methanol light-duty vehicles utilized three-way catalytic
converters and thus were forced to operate at very near
stoichiometric conditions so that the NOx reduction catalyst
would perform well. The methanol-fueled Escort showed no
significant difference in energy efficiency at very low NOx
levels, while the methanol-fueled Rabbit showed a significant
increase in efficiency but at higher NOx levels. The
methanol-fueled Escort was calibrated with more spark retard
setting than the Rabbit thus resulting in low NOx and relative
efficiency. Both CO and NOx emissions were lower with the
methanol-fueled heavy-duty engine compared to the heavy-duty
diesel engines. The low CO emissions were due to both low
engine-out emissions and effective catalytic aftertreatment.
The lower NOx emissions were expected, as NOx levels from
heavy-duty diesels are typically relatively high and the lower
flame temperature of methanol should provide lower NOx levels.
Emissions of particulate and unregulated compounds such as
ammonia, cyanide, and organic amines are consistently lover
from the methanol-fueled light-duty vehicles than from the
gasoline-fueled vehicles. The very low level of particulate
emission from the heavy-duty methanol engine is very impressive
¦compared to the particulate levels of the two ciesel engines.
It can also be seen that smoke, sulfate, and benzo (ajpyr ene
levels were all lower from the methanol engine than from the
Volvo diesel engine. No surprises appeared in these extensive
-7-

-------
methanol characterization programs. However, the optimum
emissions and efficiency configurations for methanol-fueled
vehicles may very likely be different from the vehicles tested
in this program.
In addition to the test programs which have been described, EPA
has several contracted methanol engine optimization programs
currently underway including projects with Ford Motor Company
to optimize the Ford PROCO engine with methanol and with
Ricardo Consulting Engineers to evaluate methanol performance
with the Ricardo HRCC (high compression ratio, compact chamber)
combustion system when fueled with methanol, as well as an
in-house program at the Ann Arbor laboratory. While the
in-house program is only a modest effort, preliminary results
from the program are encouraging. The in-house program is
first focusing on the determination of optimum engine
efficiency and emission configurations, with the second phase
involving final emission control system integration and vehicle
testing. A parallel methanol exhaust aftertreatment project is
also underway and preliminary results from this effort will be
presented later. It is also important to point out that
development/optimization activities for methanol engines are in
a very early phase, as compared to gasoline and diesel
engines. Therefore, it is reasonable to expect additional
significant improvements in any methanol efficiency or emission
results that are now available.
Figures 1 and 2 present thermal efficiency values at two
different power settings from one of the engines being
evaluated in the EPA in-house program (the Nissan NAPS-Z)
compared to several advanced technology passenger car engines.
(Other in-house engines show similar results with methanol, but
the NAPS-Z engine has more versatility in parameter control and
is receiving most of our experimental focus.) The NAPS-Z
engine represents an advanced technology Otto-cycle engine,
having both low friction and fast burn characteristics. The
Volkswagen Rabbit turbocharged diesel engine is presented to
represent state-of-the-art indirect injection passenger car
engine technology. The turbocharged, direct injection Sofim
diesel engine is representative of the best efficiency
characteristics in research passenger car diesel engines. As
can be seen, the methanol NAPS-Z is more efficient than any of
the other advanced technology engines shown. The methanol
results from the NAPS-Z engine, while very impressive,
represent only simple compression ratio changes from the
gasoline engine and parameter optimization for methanol fuel.
Several alternative configurations are being evaluated for
methanol which include water/methanol blends for reduced N Ox
emissions and possibly improved efficiency and specific power,
-8-

-------
partial methanol dissociation for increased efficiency and
reduced emissions, and turbocharger optimization. The
methanol-fueled NAPS-Z engine also produces about 25 percent
more power than its gasoline configuration.
Figures 3 and . 4 present preliminary results from the
EPA/Ricardo contract. These results come from a 1.5 liter HRCC
engine Ricardo prepared for EPA. The engine has a 13:1
compression ratio, with methanol results being generated with
the engine equipped with a very simple single barrel carburetor
while the gasoline results are taken from the same engine
fitted with an improved two barrel carburetor. The part-load
conditions presented are within the range of operating
conditions commonly encountered in a normal vehicle
application. Although these results are from the same engine,
methanol operation generally produced efficiency improvements
of 4 to 6 percent over the gasoline fuel. These gains may be
due to the effects of lower combustion temperatures when using
methanol/ the greater number of moles of combustion products
per mole of fuel for methanol, and/or the faster combustion
characteristics of methanol (higher flame speeds). The NOx
emissions from methanol are significantly lower than with
gasoline, and achieve very low levels at lean equivalence
ratios where methanol combustion still appeared stable. In
contrast, even with the HRCC engine, gasoline combustion
appeared unstable at equivalence ratios lean enough to get
significantly lowered NOx levels. A significant issue for
methanol-fueled engines designed for very low NOx levels will
be whether good vehicle driveability can be achieved when
operating at an equivalence ratio near 0.7.
Another interesting result of the Ricardo study is the
assessment of idle performance. Figure 5 presents idle fuel
consumption and hydrocarbon emission results for several
engines. The curves for each engine represent different spark
timing and equivalence ratio settings. Of significance here is
that the methanol-fueled HRCC engine idle fuel consumption is
one-half that of the standard production gasoline engine, and
within the range for production diesel engines.
If methanol-fueled engines can operate satisfactorily at lean
equivalence ratios for optimum efficiency and very low NOx
emissions, then oxidation catalysts (perhaps with some EGR) may
be sufficient to meet stringent emission standards. There is
also the possibility that the exhaust catalyst could be of the
base metal variety, such as copper, chromium, or nickel, and
not require noble metals, such as platinum and palladium.
Unlike gasoline, methanol does not contain any sulfur or trace
lead, which degrade base metal catalysts. This could
-9-

-------
significantly reduce the cost of the catalytic converter
system. This change could also improve the country's balance
of payments, since all noble metals must currently be
imported. While some base metals are also imported, their
value would be significantly less and the result would still be
a net decrease in imports. Of course, it may also be possible
that a noble metal catalyst with significantly less noble metal
loading could still be effective. In either case, a
significant potential exists to use a lower cost catalyst with
methanol-fueled vehicles. The in-house test program evaluating
alternative catalysts is using the methanol-fueled Volkswagen
Rabbit, characterized in its stock configuration in Table 1.
Table 5 presents preliminary summary data on several
alternative catalysts. Early results are encouraging.
Environmental Concerns of Pure Methanol Use
Several studies have been performed which assess the overall
environmental effects of synfuel use [1,8,9]. However, while
EPA is continuing to evaluate the environmental effects of the
various alternative transportation fuels production processes,
this discussion will focus on the concerns with the use of
methanol as a motor vehicle fuel. The discussion will address
specific exhaust emission concerns as well as general health
and safety concerns associated with the handling and use of
methanol.
Emission-Related Issues
Based on the results of the EPA test programs described above,
as well as data from previous methanol research projects, it
appears that pure methanol combustion would likely result in
lower emissions of currently regulated pollutants. The
hydrocarbon/organic emission comparison is difficult to make
because of the different classes of compounds involved, and
will be discussed in greater detail below. With respect to CO
emissions the available data indicate that methanol-fueled
vehicles will produce about the same levels as current
vehicles. It is with respect to NOx and particulate emissions
that methanol-fueled vehicles offer the greatest benefits.
Although current unleaded gasoline-fueled vehicles emit very
low levels of particulate and generally have fairly low NOx
levels as well due to three-way catalytic converters, diesel
vehicles emit relatively high levels of both pollutants. As
petroleum prices have risen in the last five years, so has the
popularity of diesel vehicles. Furthermore, it is expected
that diesel fuel quality will continue to worsen in the future
which would likely result in even higher diesel emissions.
Methanol utilization may be one alternative for achieving the
-10-

-------
energy efficiency of the diesel while maintaining very low NOx
and particulate levels. Methanol would also produce lower
levels of heavy organics and sulfur-bearing compounds.
There are three remaining emission-related issues of methanol
use: the impact on photochemical oxidant levels, ambient
methanol levels, and ambient formaldehyde levels.
As was shown in Tables 3 and 4 above, the methanol-fueled
light-duty vehicles emitted somewhat more, and the
methanol-fueled heavy-duty engine emitted somewhat less, total
organics than did the gasoline and diesel-fueled baseline
vehicles. But the primary justification for the regulation of
organic emissions is not direct health impacts associated with
the specific organic compounds themselves, but rather is their
role as photochemical oxidant precursors in urban atmospheres.
It is well known that different organic compounds have varying
impacts on the photochemical oxidant process. Therefore, the
relative masses of organic emissions in gasoline, diesel, and
methanol exhausts are not as important as the relative
photochemical reactivities of the species involved.
Methanol-fueled vehicle exhaust is composed primarily of
unburned methanol with the remainder almost entirely
formaldehyde. While formaldehyde is known to be very
photochemically reactive, unburned methanol itself is generally
considered to be of low reactivity. Methanol exhaust contains
almost no alkenes, aromatics, or nonmethane alkanes which are
the major reactive components of gasoline and diesel exhausts.
It has been suggested that because of the dominance of unburned
methanol, with its apparently low reactivity, in
methanol-fueled vehicle exhaust that there is less potential
for oxidant formation than with gasoline and diesel-fueled
vehicles. There is little empirical evidence for this,
however, and considerable atmospheric modeling and smog chamber
work should be conducted to resolve this issue. EPA will be an
active participant in this research.
Clearly the use of pure methanol fuel would result in a large
increase in ambient methanol levels. The determination of the
possible health impacts of likely ambient methanol levels is a
primary objective of EPA research in this area. Because of our
need to be able to determine the possible health impacts of
motor vehicle pollutants in general, EPA, through a contract
with Southwest Research Institute, has developed a methodology
which identifies whether expected levels of pollutants are of
possible public health concern or not [10]. The methodology
uses mathematical models to predict ambient concentrations of
mobile source pollutants for exposure situations such as
-11-

-------
expressways, street canyons, roadway tunnels, and personal and
parking garages based on emission factors for various vehicle
categories. Two scenarios, representing "typical" conditions
and "severe" conditions, are utilized in most of the exposure
situations. EPA utilizes health effects literature searches to
suggest a range of concern for the pollutant in question. The
upper level of the range of concern is that value above which
the studies show that the pollutant causes serious health
effects. If the exposure situations are projected to result in
ambient concentrations in excess of the upper level of the
range of concern, then the pollutant is considered to be a
"high risk" to human health. The lower level of the range of
concern is the lowest level at which there is some suggestion
of adverse physiological effects. If the projected ambient
concentrations of all the exposure situations are below the
lower level of the range of concern, then the pollutant is not
considered to be a serious health risk. The region between the
lower and upper levels of concern is the "range of concern"
which indicates the bounds of uncertainty of adverse
physiological effects based on the different health effects
studies in the literature. If the exposure situations are
projected to result in ambient concentrations within the range
of concern for a particular pollutant, then the use of the
particular technology/fuel should be subject to closer scrutiny.
EPA recently performed a preliminary study of the health
effects of methanol based on a comprehensive literature search
[11]. It considered the three primary methods of methanol
intake: inhalation, ingestion, and skin absorption. Inhalation
will be discussed in this portion of the paper, since it is
related to the issue of methanol combustion emissions.
Ingestion and skin absorption will be discussed later in the
paper.
Inhalation studies reported in the literature have shown a wide
range of effects. Headaches have been reportedly caused from
inhaling methanol concentrations as low as 22 milligrams per
cubic meter (mg/m^). The odor threshold may be as low as 5
mg/m^, although some studies indicate that the odor threshold
is much higher. The OSHA work place standard for methanol is
200 mg/m^ maximum. The threshold limit value (TLV) is 260
mg/m^, with a 310 mg/m-3 short-term limit.
EPA will utilize the methodology described above to identify a
range of concern for ambient methanol concentrations and to
calculate projected ambient concentrations under various
exposure situations. The contractor report on methanol health
effects has suggested that a range of 1.0 to 3.0 mg/m^ be
considered for the lower limit of the range of concern for
-12-

-------
ambient methanol concentrations [11]. EPA has performed some
very preliminary air quality projections for various exposure
scenarios assuming that the entire vehicle fleet were operating
on methanol with 75 percent of the fleet involving successful
catalytic converter operation and 25 percent of the fleet
lacking effective aftertreatment (due either to no catalyst or
an inoperative one). These early results indicate that under
most of the worst-case exposure situations the ambient methanol
concentrations would likely be below 3.0 mg/m^, but that the
most severe worst-case scenarios, such as the severe roadway
tunnel and personal garage situations/ might well be above that
level. These are tentative results and EPA will be refining
this analysis in the future.
The use of methanol fuel would also increase formaldehyde
emissions. Table 6 lists formaldehyde emission levels for a
variety of passenger cars that EPA has tested. It can be seen
that formaldehyde emission levels from catalyst equipped
methanol-fueled vehicles are similar to formaldehyde levels
from non-catalyst equipped gasoline-fueled vehicles, but higher
than the levels from catalyst-equipped gasoline-fueled
vehicles. EPA is using the same methodology described above to
define the possible health impacts of increased formaldehyde
emissions. A preliminary formaldehyde health effects study has
been performed based on a review of the literature [12].
Formaldehyde is a strong irritant of the human eye, nose, and
throat and is capable of causing allergic sensitization. Acute
human exposure to concentrations of 1.0 mg/m^ have resulted
in such irritation, as well as other effects such as changes in
breathing rhythms and alpha-ryhthms. Slight irritation has
been observed at levels as low as 0.2 mg/m3. Odor thresholds
range from 0.4 to roughly 0.01 mg/m^ for sensitive subjects.
The threshold limit value for formaldehyde is 3.0 mg/m^.
Based on the formaldehyde health effects literature review, our
contractor has suggested that the lower limit of the range of
concern for ambient formaldehyde concentrations be either 0.06
or 0.2 mg/m3. It recommended 0.2 mg/m^ as the "most
defensible choice" since formaldehyde levels as high as 0.1
mg/m^ have been detected in the human breath of both smokers
and non-smokers [12]. Again assuming that all motor vehicles
were utilizing methanol fuel, with successful catalytic
aftertreatment on 75 percent of those vehicles, our preliminary
analysis indicates that most of the exposure situations would
result in formaldehyde concentrations below 0.2 mg/m^.
Concentrations under the severe roadway tunnel and personal
garage scenarios could exceed 0.2 rng/rn-^. It must also be
emphasized that this analysis is still in its infancy and much
further work is necessary.
-13-

-------
The methodology described above will focus only on the
toxicological and non-carcinogenic effects of formaldehyde. In
addition, formaldehyde has been shown to cause cancer in
certain animal tests. The federal government is currently
developing a general policy for use by federal agencies in
regulating carcinogens. Thus, it is not now possible to
predict the impact of any cancer-related regulation on
methanol-fueled vehicles.
Because of the toxicological and carcinogenic concerns over
formaldehyde, as well as its high photochemical reactivity, it
is clear that formaldehyde emission control will be an
important consideration for automotive manufacturers. Research
testing of current technology catalytic converters has shown
that they are able to remove up to and perhaps more than 90
percent of the formaldehyde from methanol-fueled vehicles.
Nevertheless, reducing engine-out formaldehyde emissions and
optimizing catalytic reductions will undoubtedly be high
priorities if methanol-fueled vehicles are to come into general
use.
Non-Emission-Related Issues
The previous section analyzed those environmental impacts which
would be expected due to the emissions from methanol-fueled
vehicles. This section will discuss other health and safety
concerns associated with the handling, transport, and usage of
methanol fuel. The following concerns have been identified: 1)
ingestion and skin absorption of liquid methanol, 2) the
near-invisible flame of methanol fires, 3) the fact that
methanol vapors inside a fuel tank are likely to be ingitable,
and 4) the impacts of a large methanol spill.
Methanol is highly toxic in heavy exposures, leading to
blindness or death. Much of its notoriety in this area is due
to people confusing it with ethanol and drinking it in large
quantities. Hydrocarbon fuels, while also being toxic, do not
suffer from this confusion and are not often taken internally.
The absorption of methanol through the skin is also hazardous,
more so than gasoline (though the presence of benzene in
gasoline complicates this issue). Given the public's rather
careless use of gasoline, widespread use of methanol would pose
some concerns in this area. EPA's recent study on the health
effects of methanol also considered ingestion and skin
absorption of methanol [11], and results from that study will
be summarized here.
Methanol was a frequent component of liniments, perfumes, and
some patent medicines well into this century. It has seen
widespread use as a solvent and as a high volume chemical.
-14-

-------
While bioassay studies with methanol are limited, current
results suggest that methanol is not mutagenic. Defining safe
exposure and dose levels is extremely difficult because of the
very large variability in individual response. In addition,
the toxic effects are generally delayed (twelve to eighteen
hours after dose) and may be as severe as blindness and even
death. If death does occur, it is generally attributed to
respiratory failure. To illustrate the wide variability and
individual sensitivity to methanol ingestion, one death was
reported in the literature from a dose of only 6 milliliters
(ml) of methanol (about 1 teaspoon)* while recovery has been
reported for a 500 ml dose. ; I Receiving a significant methanol
dose through skin absorption is a real concern as the skin
absorption rate is reported to be 0.2 milligrams per square
centimeter per minute.
Based on the data available in the literature, a lower limit
for the range of concern for methanol ingestion of between 0.1
and 1.0 ml has been suggested by our contractor [11]. Skin
contact should also be avoided as 0.1 ml corresponds to
approximately two drops of methanol. While some treatment is
available for methanol ingestion, it seems prudent that every
reasonable effort should be made to avoid methanol ingestion
and skin contact. Several actions can be taken to address
these concerns. A major public education campaign emphasizing
the risk of methanol exposure would be fundamental. Use of the
term methyl alcohol should probably not be permitted; perhaps a
non-alcohol fuel name would be wise. Warning labels on
dispensers and containers would need to be reviewed for
effectiveness.
Another concern with methanol:juse is that the methanol flame is
essentially invisible in daylight. Although methanol flames
are cooler than gasoline flames and extinguish with water,
methanol/water concentrations down to about 26 percent methanol
are still flammable. On the other hand, methanol has a higher
flashpoint and ignition temperature than gasoline, thus in open
air it is considered less of a fire hazard than gasoline.
Due to methanol's volatility characteristics, the vapors in a
methanol tank would be expected to be flammable. However,
flame arresters in the tank filler neck or bladder tanks seem
capable of mitigating this concern. Also, the electrical
conductivity of methanol is higher than for gasoline which
reduces the problem of static discharge causing ignition.
The possibility of using additives with methanol should be
-.15-

-------
investigated to help alleviate these concerns. Methanol
additives should be sought which would: 1) cause vomiting if
ingested, 2) make ingestion# inhalation and skin contact
unattractive (e.g., unpleasant smell, or dye), and 3) provide a
visible flame.
A final point which deserves mentioning is the difference
between the impact of an oil spill and a methanol spill. The
effects of oil spills are well known. The effects of a
methanol spill are expected to be quite different, primarily
because methanol is soluble in wateir. While high levels of
methanol are toxic to fish and faunai a methanol spill would
probably quickly disperse to nontoxic concentrations and,
particularly in water, leave little trace of its presence
afterwards. Water life should be able to migrate back and
plant life should begin to grow back fairly quickly, though
complete renewal would take the time necessary for new plants
to grow.
-16-

-------
References
1.	"Preliminary Perspective on Pure Methanol Fuel for
Transportation," Environmental Protection Agency,
Office of Mobile Sources, EPA-460/3-83-003,
September 1982.
2.	"Diesel Car Particulate Control Methods," Society
of Automotive Engineers Paper 830084, Charles M.
Urban, Larry C. Landman, and Robert D. Wagner,
March 1983.
3.	"The Utilization of Alcohol in Light-Duty Diesel
Engines," Contractor Final Report, Ricardo
Consulting Engineers, EPA-460/3-81-010, May 28,
1981.
4.	"A Brief Summary of the Technical Feasibility,
Emissions, and Fuel Economy of Pure Methanol
Engines," Internal Staff Report, Jeff Alson,
EPA-AA-SDSB-82-01, December 1981.
5.	"Emission	Characterization	of	an
Alcohol/Diesel-Pilot Fueled Compression-Ignition
Engine and its Heavy-Duty Diesel Counterpart,"
Contractor Final Report, Southwest Research
Institute, EPA-460/3-81-023, August 1981.
6.	"Characterization of Exhaust Emissions from
Methanol- and Gasoline-Fueled Automobiles,"
Contractor Final Report, Southwest Research
Institute, EPA-460/3-82-004, August 1982.
7.	"Emission Characterization of a Spark-Ignited,
Heavy-Duty, Direct-Injected Methanol Engine,"
Contractor Final Report, Southwest Research
Institute, EPA-460/3-82-003, November 1982.
8.	"Environmental Aspects of Fuel Conversion
Technology - VI, A Symposium on Coal-Based
Synfuels" (October 1981), EPA-600/9-82-017,
September 1982.
9.	"Effects of Synfuel Use," Masood Ghassemi, Rajan
Iyer, Robert Scofield, and Joe McSorley,
Environmental Science and Technology, August 1981.
10. "An Approach for Determining Levels of Concern for
Unregulated Toxic Compounds from Mobile Sources,"
Internal Staff Report, Robert J. Garbe,
EPA/AA/CTAB/PA/81-2, July 19 81.
-17-

-------
11.	"Methanol Health Effects," Contractor Final
Report,	Midwest	Research	Institute,
EPA-460/3-81-032, December 31, 1981.
12.	"Formaldehyde Health Effects," Contractor Final
Report,	Midwest	Research	Institute,
EPA-460/3-81-033, December 21, 1981.
-18-

-------
Table 1
Average Light-Duty Vehicle
Emission And Energy Efficiency Results
Over the Federal Test Procedure

Ford
Escorts
VW Rabbits

Gas[a]
Meth[b]
Gas
Meth
Hydrocarbons (FID), g/mi
0.37
0.42[c]
0 .11
0.39[c]
Carbon Monoxide, g/mi
4.49
6.03
1.08
0.88
Oxides of Nitrogen, g/mi
0.55
0.40
0.16
0 .68
Particulate, mg/mi
9.2
6.3
11.8
4.7
Methanol, mg/mi
ND[d]
407
ND
440
Total Aldehydes and




Ketones, mg/mi
0.2
33.6
ND
10.3
Formaldehyde, mg/mi
0.2
33.0
ND
10 .3
Total Individual




Hydrocarbons, mg/mi
155
50
40
5
Methane, mg/mi
96.1
48.3
14.0
4.8
Ethylene, mg/mi
8.7
0.3
4.8
0.2
Ethane, mg/mi
18.2
0.5
2.6
0.1
Acetylene, mg/mi
1.4
0.1
1.8
0.1
Propane, mg/mi
0.8
0.6
ND
ND
Propylene, mg/mi
6.1
ND
4.2
ND
Benzene, mg/mi
6.3
0.1
5.3
ND
Toluene, mg/mi
17.2
0.1
9.2
ND
Nitrosamines, mg/mi
ND
ND
ND
ND
Ammonia, mg/mi
[e]
10.0
[e]
[e]
Total Cyanide, mg/mi
[e]
ND
[e]
[e]
Total Organic Amines,
[e]
0.1
[e]
[e]
mg/mi




Methyl Nitrite, ppm
[e]
0-0.5
ND
0-1.1
Energy Efficiency,
2.16
2.25
2.10
2.46
mi/lO^ Btu




[a]	Gasoline-fueled.
[b]	Methanol-fueled.
[c]	Hydrocarbons as measured by the FID (flame
ionization detector) and expressed as methanol,
[d] None detected,
fe] Analysis not conducted.
-19-

-------
Table 2
Average Heavy-Duty Engine Emission
And Energy Efficiency Results Over
The Transient Federal Test Procedure
Hydrocarbons,[a] g/hp-hr
Carbon Monoxide, g/hp-hr
Oxides of Nitrogen,[b]
g/hp-hr
Particulate, g/hp-hr
Methanol, mg/hp-hr
Total Aldehydes and
Ketones, mg/hp-hr
Formaldehyde, mg/hp-hr
Total Phenols, mg/hp-hr
Total Individual
Hydrocarbons, mg/hp-hr
Methane, mg/hp-hr
Ethylene, mg/hp-hr
Ethane, mg/hp-hr
Acetylene, mg/hp-hr
Propylene, mg/hp-hr
Benzene, mg/hp-hr
Sulfate, mg/hp-hr
Benzo(a)pyrene, ug/hp-hr
Fuel Consumption
lb diesel equivalent/hp-hr
Volvo
Diesel
TC*
No Cat
0.85
3.01
8.34
0.52
[c]
10
10
26
97
11
78
1
2
6
1
28
2.8
Smoke, peak percent opacity 33
MAN	MAN
Diesel	Methanol
TC, IC*	NA*
No Cat	W/Cat
0.85
3.16
8.54
0.37
t c]
[d]
[d]
[d]
[d]
[d]
[d]
[d]
[d ]
[d]
[d]
[d]
[d]
0.476 0.451
[d]
0.04
0.31
6.61
0.04
680
1
1
0
[c]
0.01
0.538
[a]
tb]
[c]
[d]
NA = Naturally Aspirated, TC = Turbocharged, IC =
Intercooled; the brake specific fuel consumption is
directly affected by the technology employed with
improvements expected in going from NA to TC to IC.
Therefore, direct efficiency comparisons are not
possible.
Hydrocarbons as measured by the HFID (heated flame
ionization detector) and expressed as diesel-like
species.
No NOx correction factor used.
Does not apply.
No analysis performed.
-20-

-------
Table 3
Average Light-Duty Vehicle
Organic Emission Results Over the Federal
Test Procedure (g/mi)
Ford Escorts	VW Rabbits
Gas. Meth.	Gas. Meth.
Hydrocarbons [a]	0.37 0.05	0.11 0.005
Methanol	0 0.41	0 0.44
Formaldehyde	0.0002 0.033	0	 0.010
Total Organics	0.37 0.49	0.11 0.46
[a] For the gasoline-fueled vehicles, this is the FID value. For
the methanol-fueled vehicles, this is the sum of the individual
hydrocarbon data from Table 1.
-21-

-------
Table 4
Average Heavy-Duty Engine Organic Emission Results
Over the Transient Federal Test Procedure (g/bhp-hr)

Volvo
Diesel
TC*
No Cat
MAN
Diesel
TC,IC*
No Cat
MAN
Methanol
NA*
W/Cat
Hydrocarbons
0.82[a]
0.85
0.001[b]
Methanol
0
[c]
0.68
Aldehydes and Ketones
0.01
[c]
0.001
Phenols
0.03
[c]
0
Total Organics
0.86
0.85
0.68
* NA = Naturally Aspirated, TC = Turbocharged, IC = Intercooled.
[a]	From Table 2, hydrocarbons less phenols.
[b]	From Table 2, total individual hydrocarbons.
[c]	No analysis performed.
-22-

-------
Table 5
Methanol Catalyst Preliminary Summary
Catalyst
No Catalyst
VW Stock - 0% O2
VW Stock - 3% O2
A - 0%
°2
A - 3%
02
B - 0%
°2
B - 3%
°2
C - 0%
°2
C - 3%
02
D - 0%
02
D - 3%
02
E - 0%
°2
E - 3%
02
HC(FID)
CO
NOx
HCHO
g/mi
g/mi
g/mi
mg/mi
0.90
7.70
2.17
330
0.15
0.80
0.56
18
0.19
0.73
1.80
23
0.11
0.69
0.62
12
0 .12
0.39
2.01
16
0.13
0.77
0.76
11
0.13
0.40
2.05
14
0.15
1.47
0.85
30
0 .16
0.35
2.07
73
0.17
1.99
0.74
42
0.14
0.38
1.98
68
0.28
2.85
1.97
_*
0.28
2.05
1.95
-
Results not complete.
-23-

-------
Table 6
Comparison of Average FTP Formaldehyde Emissions
	for Various Light-Duty Vehicles	
HCHO Emissions
(mg/mile)
Gasoline-Fueled Vehicles
1981 3-way-catalyst equipped cars	1
1978, 1979 3-way-catalyst	2
equipped cars
1978 oxidation-catalyst equipped cars	3-11
1977 non-catalyst cars	16
1970 non-catalyst cars	51
Methanol-Fueled Vehicles
1981 3-way-catalyst equipped,
carbureted car (Escort)	33
1981 3-way-catalyst equipped,
fuel injected car (Rabbit)	10
-24-

-------
Figure 1
M » NAPS-Z N.fl.
METHANOL 12.8s ICR
2. OL

N»8

6 = NAPS-Z N.fl.
GASOLINE 8.5:ICR
2. OL

N»8
H m H M ¦¦ 1 II
S = SOFIM T/C 01
DIESEL
SAE 810481
2 . 5L

N = 7

V » VW
T/C ID I
O-IESEL
SAE 780634
1 . 5L

N»9

1500 2500 3500
1 000 2000 3000
RPM
4500
4000 5000
25

-------
Figure 2
(7OX POWER]
M » NflPS-Z N.fi.
METHANOL 12.8:ICR
2. OL
N«8	
G * NflPS-Z N.fl.
GASOLINE. 8. S: ICR
2. OL
N»8
S » SOFIM T/C 01
QIESEL SfiE 810481
2. 5L
N = 7 __
V » VW T/C 101
DIESEL SflE 780634
1.5L
N»9
26

-------
Figure 3
HRCC ENGINE RESULTS
20REV/S 1.5 BMEP BAR
X	X METHANOL
O-	-0 98 RON GASOUNE

-------
Figure 4
HRCC ENGINE RESULTS
60REV/S 4.0 BMEP BAR
*-
-X METHANOL
¦-€> 98RON GASOLINE





-* X
		
r 40
g|-20
x
o
100-1
50-
"35
O
O

0yi Jtt

\

r30
. j-20
"Bi
• S I"10
28—i
26-
24-
22-
#
LL
LU
-I
<
2
cc
111
X
K
LU
*
<
oc
CD
LEAN
EQUIVALENCE RATIO
i	i	i	i
RICH
0.5 0.6 0.7 0.8 0.9 1.0 1.1
I	I
1.2 1.3
28

-------
jgure
HRCC IDLE TESTS—900 RPM
A-
X-
1.5L HRCC engine—Gasoline
-A 1-61- Standard engine—Gasoline
-X 1-5L HRCC Engine—Methanol
(Gasoline Energy-Equivalent results)
1.5-2.5 L Diesel
Engines
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Fuel consumption (kg/h)
29

-------