EPA-AA-TSS-PA-88-1
                  Technical Report
      Derivation  of  Technology  Specific  Effects
      of the Use of Oxygenated Fuel Blends on
           Motor  Vehicle  Exhaust  Emissions
                    October,  1988
                       NOTICE

Technical Reports  do not  necessarily represent  final  EPA
decisions  or  positions.    They  are  intended  to  present
technical   analysis   of    issues   using   data   which  are
currently available.   The purpose  in the  release  of such
reports   is   to  facilitate  the   exchange  of  technical
information   and   to  inform   the  public   of  technical
developments  which  may  form  the  basis  for  a  final  EPA
decision, position or regulatory action.

               Technical  Support Staff
         Emission  Control  Technology Division
               Office  of Mobile  Sources
             Office of Air and Radiation
        U. S. Environmental Protection Agency

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1.0  INTRODUCTION

     In  the  past  decade  there  has  been  a  large  amount  of
research into  the  effects of fuel composition on  the emissions
of motor vehicles.  Blends  of  gasoline with oxygenates  such  as
alcohols and ethers  have received particular  attention,  and  it
has  been widely  demonstrated  that   use  of  these  blends  can
reduce  emissions  of carbon  monoxide  (CO).   Some  organizations
have proposed  that  this  beneficial  effect could help alleviate
CO  air   quality  problems which  have  been  experienced  in  some
areas.   It  has  also  been  shown that  such  blends   can  affect
exhaust  and evaporative  emissions of volatile organic compounds
(VOC) and  exhaust  emissions of  oxides of nitrogen  (NOx).   The
blends  generally  cause  small  increases  in  NOx emissions,  and
they can cause  increases or  reductions in the net emissions  of
VOC, depending on  the  blending  components and volatility of the
final  product.   State  and  local   governments  have  proposed
including  programs  of  increased use  of  these blends  in  their
plans in order to help  local  areas   meet  the National  Ambient
Air Quality Standard for CO.

     To  assist  local  and  state planners  in considering  this
issue, EPA has  developed guidance  for estimating  the fleetwide
effects  that these  fuels can have on vehicular emissions of CO,
VOC,  and NOx.    The  technical  report,  "Guidance  on  Estimating
Motor Vehicle  Emission  Reductions from the Use of  Alternative
Fuels   and   Fuel  Blends"1,  discusses   EPA's  procedure-  for
estimating  these  fleetwide  effects.   A draft of the  report was
released  for  public   comment   in  July,  1987,   and  the  final
version was released in January, 1988.

     The procedure is  based  on estimates  of  the   effects  on
emissions that gasoline/oxygenate blends  can  have on groups  of
vehicles within  the fleet.   This  report discusses  the methods
and  data which EPA used in calculating  these  estimates.   Only
the  data used  in  the  development  of  the  guidance  report  are
discussed  here;  no additional  data   have been  included.   Some
errors  in  calculation  (Data were duplicated  on more  than one
reference)  were discovered  and  corrected  after  the  guidance
report   was   released.   Therefore,   the  effects   which   are
presented here are  different from those listed in the guidance
report.   These differences are small.

     It  should  be noted  that  all  of  the  calculation  steps
presented  in  this  report  are  intermediate  steps   in  a  larger
calculation described  in the  Guidance Report.   To  prevent the
proliferation  of  truncation errors,   numerical  figures  are  not
truncated to  their known number of significant digits.

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                              -2-

1.1  Effects of Fuel Oxygen Content;  a General Discussion

     Most  vehicles  meter  fuel  by   volume   with  the  goal  of
controlling the ratio of air to fuel.  A  useful  reference point
in discussing  air/fuel ratios  is  the stoichiometric  point,  at
which all of  the  fuel can  theoretically  react with  the oxygen
in the air.  When  the fuel control system of a vehicle puts too
much  fuel  into  the  engine  at  a  time  (a  condition known  as
"running  rich"),   there   will   not  be  enough oxygen to  allow
complete combustion of the  fuel.   The result will be increased
amounts of  the products  of  incomplete combustion, CO and VOC,
in the exhaust.  Most gasoline  fueled engines run rich  some  of
the time, and  it  is during this time that much of the emissions
of these pollutants occur.

     The feature  of gasoline/alcohol  and  gasoline/ether blends
which  has  the  largest  effect  on  emissions  is  oxygen content.
When these  fuels  are  used,  the oxygen  in the fuel  reduces the
amount of  air  needed to  burn  a  given  amount  of  fuel   in two
ways.  It increases the amount of  oxygen  which is  available for
combustion,  and it  displaces  some  of the  carbon which would
otherwise consume oxygen.  This effect  is called "enleanment."
A vehicle which uses  a gasoline/oxygenate blend fuel will spend
less  time   running  rich,  and  will  have  less   severe  richness
during that time  than when  it  uses a non-oxygenated fuel.   A
vehicle which spends a large portion of its  operating time in a
rich mode  will have  higher base emissions  than  another  vehicle
which  is  seldom  running  rich.   The use  of oxygenated  blends
will  cause  a  larger  reduction in the emissions of  the former
vehicle than the latter.

1.2  Quantifying These Effects

     It is  difficult  to  quantify the effects of fuel  oxygen  on
exhaust  emissions  both  in terms  of predicting  the  effects  on
the  emissions   of  a  vehicle  and  in  terms   of  predicting- the
effects  on  the   emissions   of  a  fleet  of  vehicles.   This
difficulty  stems  from the wide  variety  of  other  factors which
affect emissions  and can  interact with  fuel oxygen  content  to
further  affect emissions.  Such   factors  include,  but  are not
limited  to  the  age  of  the  vehicle,   the  emission  control
technology used in  the vehicle  design, the  maintenance  history
of the vehicle,  the ambient operating temperature, the altitude
of  operation,   the  initial  calibration   of   the  fuel  metering
system, and  the  fuel  volatility.   A  further complicating factor
is the wide range of  emission levels  from different  vehicles  in
a  given  fleet  and  the non-normal  distribution of  these  levels.
These issues are discussed in more detail in Section 3.

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     EPA has examined many studies in an  attempt  to  predict the
effects  that  gasoline/oxygenate  blend   fuels   will  have  on
vehicle emissions.   This document presents  in  a  consistent form
all  available  and  relevant  data which  EPA  has used in  its
examination  of  this  issue.   Also  discussed  are  the  methods
which  EPA  used  to  evaluate  these  data,  and the  conclusions
which EPA has drawn from this  effort.

2.0  THE DATA BASE

     EPA applied  a number  of criteria  to  the  data  from each
known  vehicle test  program  before  including  it in  the  data
base.   To  be included,  each  program  had  to  report  emissions
data  from  Federal Test  Procedures  performed on  vehicles  using
at  least two different  fuels.   Preferably,  one  of  these  fuels
would   be    similar   to   non-oxygenated   gasolines   currently
available  at retail  outlets, while  the other  fuel(s)  would
represent  a  gasoline/oxygenate  blend which  could be  sold  at  a
retail  outlet.   EPA  excluded data  on vehicles  using  certain
fuel  blends, such  as  blends of  ethanol  in  greater  than  10
percent  concentrations,  blends   of  methanol in  greater than  5
percent  concentrations,  and   blends   of   methanol   without
cosolvents.   In  one  case a low  level methanol/cosolvent  blend
was  excluded because  it had  an unrepresentatively  low RVP of
8.0  psi.   The  data  include  test  results  from high   and. low
altitude facilities,  results  of  tests on light  duty  and  heavy
duty  gasoline fueled  vehicles   and  trucks,   results  of  tests
using   blends    of    gasoline    with    ethanol,   MTBE,    and
methanol/cosolvent.    No  data  from  low  temperature  emission
tests  are  included.   The resulting data  base  includes tests of
about 350 vehicles in 21 studies.

2.1  Sources

     EPA  has considered data   which  were  found  in   its  own
extensive  literature searches, as well  as all of the data  which
were brought  to  light  by commenters to the  July 1987  draft, of
the  report,  "Guidance  on  Estimating  Motor  Vehicle  Emission
Reductions  from the Use  of  Alternative  Fuels  and Fuel Blends".
The  data  were   gathered  by   State  and  Federal  governmental
testing  programs,   programs  conducted  by  the  petroleum- and
automobile  industries,  and   independent  testing laboratories.
Two organizations offered  large  lists  of  additional  sources of
data.

     Energy  and  Environmental Analysis,   Inc.  (EEA)  submitted a
report  which  it  prepared  for   the  Maricopa  Association  of
Governments,  "Feasibility  of  Using  Alternative Fuels  as an Air
Pollution  Control  Strategy,"2   which   contains  a   list  and
grouped  analysis  of  thirty-two studies.   Some of   the  data

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contained  in   these  studies  were  excluded  from  EPA's  final
analysis because of the characteristics  of  the fuels which they
used,  as was discussed previously, but other  studies referenced
in this list provided EPA  with  additional information about the
effects of  blends  at  high  altitudes  and emissions  of  vehicles
using   fuels  with intermediate  levels of  oxygen content.   (An
oxygen content  of 3.7% by  weight is the  maximum allowable under
existing  regulations.   Some  blends,  especially  those  which
contain MTBE,  have oxygen  contents close to 2.0%.)   Nine of the
studies cited  by EEA  are  directly included in  EPA's data base.
Several others  are referenced in a summary study  which  EPA also
included.

     The Ad Hoc  Ethanol  Committee submitted  extensive  comments
including a  list of  thirteen studies.   There  was  considerable
overlap  between  this  list  and  the  references  of  the  EEA
report.   The  EPA  data   base  was   expanded   to  include  six
additional  studies  from  this  list.   Most of  these compare  a
blend of 10% ethanol with  gasoline.   A large proportion  of the
vehicles covered have  open loop  fuel  control.

     EPA received additional  data from  the  Colorado Department
of  Health   (CDH)5  during   the  comment   period,   some  of  which
were also  referenced  in  the  EEA report.  The  testing  programs
of CDH have provided  the  majority of EPA's information  on the
effects of blends at  high  altitude.   They cover a wide range of
vehicle technologies  and  fuel types.

     The  CDH   laboratory   and  more   recently  EPA's  Office  of
Mobile  Sources  have  conducted  testing  programs  on  the effects
of  long  term  use  of  gasoline/oxygenate  blends  in  late  model
vehicles  with   "adaptive   learning   systems."    These   systems
increase the  control  of  vehicle  designers  over  the  air/fuel
ratio  during  the  operation  of  the  vehicle.   Some  vehicle
manufacturers  have   claimed  that  these   systems   can  almost
completely  negate  the  effects   of   fuel   oxygen  content  on
emissions after  the  vehicle  has  used   a  blend  for a  certain
amount  of  time.  These   two   laboratories  have  been  testing
vehicles equipped with  such systems,  and the  results  of these
tests  are also  included in this  analysis.

3.0  ISSUES IN ANALYSIS OF DATA

     EPA considered several issues in the  process  of analyzing
the data.   Since the  database includes information  from so many
studies of  different  fuels and vehicles, care  must  be  taken to
combine  the results  in  a  manner which will  give  the  best
approximation  of the  fleetwide  effects   of  a  particular  fuel.
It  is  also  important  to  separate   groups  of  data  in  which
vehicles could  be expected to respond in different  ways to the
presence of oxygenates in  fuel.   Factors which were considered
when forming these groups  are discussed later in this report;

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                              -5-

3.1  Choosing a Model for Effects on Emissions

     A  model  must   be  developed  which predicts  the  emission
effects  of  oxygenated  fuel blends  within  each  appropriately
segregated vehicle  group.   These  effects  will be weighted  and
combined as  described  in Appendix D  of the  Guidance  Document.
There  are  several  ways   in   which   these  effects  could  be
modeled.  The  simplest  of these  is  to  assume  that  a  given
oxygenated blend  causes  an offset, in grams  per mile,  above or
below the base emission  level.   This model  is easy to  develop
and  apply,  but,  as has  been   discussed  before,  vehicles  with
already low emissions should not,  theoretically, see as  much.of
an absolute reduction as  a group of high emitters.

     Another simple model  could  predict  emissions  changes  in
each group as  a  constant  percentage  of  the base emissions.   In
this  model,   high  emitters would achieve   a  larger  absolute
change than  low  emitters.   This model is consistent with  other
models  which  have  been  developed4,  but it  does not  allow  for
the  possibility  that vehicles  with already  very low  emissions
would  see  little or  no  benefit  from the  enleanment  effect of
blends.

     It has  been proposed2 that  quadratic  or other  non-linear
models could be  used to  describe  the effect  of oxygen content
on emissions.  There are  two problems with this approach.   The
first  is  in  developing the model;  there is  so much  scatter in
the data that  deciding which  model to  use and determining >the
parameters of  such  a  model can  be  a  difficult and  arbitrary
procedure.  The  other problem with non-linear models  (and-even
linear  but  non-proportional models)  is that  their  application
to  a fleet  is  a complicated  process.   To  apply  a  non-linear
model  properly  it  is necessary  to  know   the distribution  of
emissions within a given  group  and integrate  the results  of  the
model  over  the  whole group.   It  would be  very  difficult  to
predict  and  to  use  the  emissions  distributions  of  the  many
groups  that  would  be required to obtain  a  fleetwide  effect.
EPA's  emission  factor model,  MOBILE3,  does  not  provide  such
distributions.

     EPA  has  elected to  use  the  model of  percentage changes.
The  average  emission reduction for the  portion of  the  vehicle
fleet of  a  given type is  taken to be a constant percentage of
those  vehicles'   base   emissions   on  oxygen   free   gasoline,
regardless of average base  emissions,  age,  odometer,  speed,  and
ambient temperature.  The  constant percentage is calculated as
described below  from the  available test  data on vehicles of the
given  type.    This  model  fits observed  patterns  in  the  data
better than the  constant  mass  reduction model, and  it  is easier
to apply than a non-linear model would be.

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     Most analyses of emission  data  have used the  technique  of
comparing  means  to  report  emission  changes.   At  least  one
report (EEA) has used regression techniques  to  make predictions
of  emissions  changes  which   depend   on  the  base  emissions
themselves.    EPA  recognizes  the  advantages  that  regression
techniques  can  offer  in such analyses,  such as  the separation
of the effects  of  several  independent  variables.   However,  the
results  present among  the  studies  which  EPA considered  were
widely scattered  and  not  normally  distributed.  Curve  fitting
techniques  are  less  convincing when  applied  to  data  such  as
emissions results  which are not normally distributed and  have
large  amounts  of  scatter.   Therefore,  EPA  has elected  to  use
the simpler technique of finding changes in mean results.

     The  primary  drawback  to this method is that  there  is  no
way  to perform statistical  tests of  significance.   Since  the
data  are lumped  together  in  groups  of  different sizes  (the
number  of  vehicles  tested  in  each study  varies  widely),  and
since  many  of  the  study  wide  means  are  reported  without
information  about  their respective  variances,  there  is  no  way
to examine  the  distribution  of individual  points  in the  data
base.  Therefore,  the  interpreted  significance of  many  of  the
effects which will be discussed in this  report  must be based on
engineering  judgement.   It is  likely  that  such judgement would
be equally  important  even  if all of the  individual  data points
were   known,   because   of   the   non-normality  of  emissions
distributions and  the wide  ranges of  emissions  from  different
vehicles, which would  make  statistical  tests  less valid  than
they would otherwise be.

3.2  Combining Many Studies in a Single Database

     EPA  has attempted  in  this  analysis to  combine  the  results
of as  many  studies as  possible in  a  consistent  manner  so that
the  aggregate  could  be extrapolated  to  in-use  vehicles.   In
this process, EPA  was careful to consider the differences among
the studies and between the studies and in-use conditions.

     The  emission  levels  of  the vehicles used in  many  of  the
individual  studies are  not  representative  of emissions  which
occur with  in-use  vehicles.   Table  1 shows  the emission levels
which  EPA's  mobile  source  emission  factor  model  (MOBILES)
predicts  for vehicles operating at low  altitude  in  1990.  Three
vehicle classes are shown:  light duty  gasoline fueled vehicles,
and two classes of light  duty gasoline  fueled  trucks.   (Trucks
in the  LDGT1 class weigh  6000  Ibs  or  less,  and  LDGT2 includes
trucks which weigh between  6000 and  8500  Ibs.)    Within  each
vehicle  class,  the  vehicles  are  split  into  groups  by  model
year, to  represent  the  different emission  control  technologies
which have been most common in different model years.

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                             Table  1

              Emissions  of  In-Use Vehicles  in  1990*
LDGV
   Model yrs
   HC (g/mi)
   CO (g/mi)
   NOx (g/mi)
LDGT1
   Model yrs
   HC (g/mi)
   CO (g/mi)
   NOx (g/mi)
LDGT2
   Model yrs
   HC (g/mi)
   CO (g/mi)
   NOx (g/mi)
   NO
Catalyst

1968-74
   6.15
  80.44
   3.98

1968-74
   6.94
  89.58
   4.13

1968-78
   9.02
  99.94
   5.61
Oxidation
Catalyst

1975-80
   4.16
  47.90
   3.36

1975-83
   5.41
  58.05
   3.88

1979-83
   5.01
  51.21
   3.83
Closed
Loop/3way

1981-83
   1.57
  21.97
   1.71

1984-87
   1.82
  20.12
   2.54

1984-87
   1.86
  20.52
   2.58
Recent Cl
Loop/3way

1984 +
   0.66
   8.97
   1.04

1988 +
   1.00
  12.08
   1.38

1988+
   1.01
  12.19
   1.39
     As  predicted by  MOBILES  for  vehicles  operating  at  low
     altitude with  no  I/M or  anti-tampering  program in effect.
     High altitude  operation causes  increased  emissions  of. HC
     and CO.   I/M and anti-tampering  programs  cause the levels
     of HC and CO emissions to be lower.
     Many of  the studies which EPA  examined  had vehicle groups
with average CO emissions close to 2 grams/mile.  The emissions
measured  in  these  studies  clearly  do  not  represent  in-use
distributions.   Table  1  shows  that  even  among  relatively- new
vehicles  the  average  emissions  are  close  to or higher  than 9
grams/mile.    However,   under  the   percentage  change   model
selected  by  EPA,  the  base  emission  level should not,  strictly
speaking,  affect  the   percentage  change.   Given  the  extreme
differences between  the emissions of  the  test  samples  and the
in-use  vehicles  they  are taken to  represent  for  purposes  of
calculating  percent   changes,  EPA   kept   alert  for  possible
contradictions as it proceeded through the analysis.

     EPA  considered  whether to use  individual test  results  or
to  find  some way   to  group  the  data  before  performing  any
statistical   observations.    For  example,   the   EEA   summary
report2  used  as  the basic  unit  of  observation the  percentage
reduction  in  the  average  emissions  of  a given  vehicle  when
using  a  given fuel  blend.   While  many of  the reports  included
individual test  results,  some  included only averages.   Using

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the  results  of  individual  tests  would  require  that  data from
some  testing  programs  be  eliminated   from  the  data  base.
Entering  all  of  the  available  individual  test  results  into a
data  base would  have  required   a  large   effort while  adding
little  additional  information.   As  will   be discussed  in the
next  section,  EPA divided the total data  base  into subgroups,
based  on  technology   features  of   the  vehicles  and  the  test
programs  in which the data were  gathered.    EPA  elected  to use
study-wide  reductions  in  the average emissions of  groups  of
vehicles  operating on  a  given  fuel.   In  other words,  these
reductions  were   recorded,    and   statistical   analyses   were
performed on the  groups' reductions.   To  give extensive studies
a  larger effect  on the final results than  more limited ones,
each  study is  considered to have  a weight within a technology
group equal  to  the number  of vehicles of  that  group which were
used  in the program.

     To  summarize  the  procedure,  the data  are divided  into
groups,  as  will be explained in Section 3.3.  The emissions of
vehicles which are in the same study  and group  are averaged for
all  cases in which they  use  the  same  fuel.  The  averages of
vehicles  using  an  oxygenated  fuel  blend  are  compared  to the
averages  of the  same  vehicles  when operating on  an HC-only fuel
and expressed as  a percentage change.  Each of  these percentage
changes   are   normalized  to   represent   fuels   with  matched
volatilities and  constant  oxygen  content,  as will  be  shown in
Section  3.3.4.   When  vehicles  in  the  same  study  used more than
one   oxygenated   fuel   blend,  the  percentage    reductions  are
averaged  over   all of  the  fuel   blends  for  that  study.   The
resulting changes are averaged over an  entire group,  with the
results   of  each  study  weighted  by the  number of  vehicles
represented in the group.

3.3   Subdividing  the Data Base

      There  are  factors  which  change  the  way  the  presence  of
oxygenates  in   vehicle  fuel affects emissions.   These factors
fall  into three  categories;  features of  the vehicle  (such as
emission  control  technology  and  fuel  delivery   system),  fuel
attributes   (volatility  and  oxygen  content),    and   ambient
conditions  (altitude  and temperature).  EPA  decided to examine
the  interactions  between  these  effects  and  to   subdivide the
data  base  when  appropriate  so  that  the  effects  could  be
calculated  separately.   EPA  has  been careful   keep   the  data
groups as large  as  possible;  conclusions drawn on small samples
of  emissions data may not  be very accurate because  of  the wide
variation in emission levels from different vehicles.

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                              -9-

3.3.1 Technology

     Perhaps the most important  subdivision  in this database is
based on  the  vehicle technology.   Since 1970  there have  been
several developments  in emission  control technology which  may
interact with the way oxygenated fuel blends  affect emissions.
The  introduction  of the oxidation  catalytic converter  in  1975
and  then  the  widespread   use   of  the  three-way  catalytic
converter,  starting  in  1981,  are  examples.  Since oxygenates
have different products  of  combustion at  a given  air/fuel ratio
than  gasoline  and  since   they  tend   to   burn  at  different
temperatures,   it  is  reasonable  to  assume   that  a  catalytic
converter might behave  differently in the exhaust  stream of. a
blend fueled  vehicle  than  in the  exhaust of  the  same  vehicle
fueled with gasoline.   EPA has  chosen to examine the emissions
of vehicles equipped with  catalytic converters  separately  from
those not so equipped.

     A   further   development   in  technology   has  been   the
introduction of closed  loop fuel control  systems.   Such systems
readjust  the  air/fuel   ratio  during  some  phases  of  vehicle
operation based on measurements  of  the  oxygen concentration in
the exhaust.  Too much  oxygen in the exhaust indicates that the
mixture  is  too lean, while too  little   oxygen  in  the  exhaust
indicates that  the  mixture is rich.  Closed loop fuel  control,
by maintaining  a  mixture that is  close  to  stoichiometric,  has
been  very effective  at controlling  emissions.    Most  vehicles
which  have three-way  catalysts  also  have   closed  loop-  fuel
control,   and   vice-versa.    Such   systems   can,   in   theory,
counteract the enleanment effect  of  the  fuel oxygen content by
adding  more  fuel.   EPA  has chosen  to  examine  the  effects  of
blends on the emissions  of  these systems separately from those
of open  loop  (fuel  controlled without measurements of  exhaust)
systems.

     Some  studies   have  separated  vehicles  with  three-way
catalytic  converters  and  open  loop  fuel   control  from  other
groups.   EPA  considered  this course  of   action  and  noted  that
three-way catalysts  are  similar  to  oxidation catalysts in their
effect  on VOC  and   CO.   Oxidation  catalysts  often  use  some
formulation  of   platinum    and   palladium   as   the  catalytic
material.   Three-way   catalysts   usually   have   platinum   and
rhodium,  and  perhaps  some  palladium.  Based on  this similarity
and the  small  amount of data on vehicles with  open loop  fuel
control  and  three-way   catalytic  converters,  EPA  decided  to
group  such vehicles  together  with  open  loop   vehicles  with
oxidation catalysts.

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                              -10-

     Closed  loop  systems  operate in  an open  loop mode  under
certain  circumstances,   such  as  cold   starting,   idling,   or
extreme acceleration, depending on the  design.   In such a mode,
the air/fuel mixture  is  controlled  based on  some  predetermined
value,  rather  than  a measurement  of  oxygen  in  the  exhaust.
Most  closed  loop  vehicles use  only fixed  calibrations  to  set
the  air/fuel  ratio  when  operating  in  an  open  loop  mode.
However, some  new  systems (available since  about   1984)  adjust
the  mixture during   open  loop  mode based  on  electronically
stored  values  from  previous closed  loop modes.  These  systems
are said to  have  "adaptive  learning"  algorithms.  Manufacturers
do not  routinely  identify individual vehicles  or   even  vehicle
models  as  being  equipped with  an  adaptive learning  feature.
Not all vehicles are, even  in the latest model year.   EPA  has
assumed that the mix of  1984 and later  vehicles that  have been
tested  in  the  various studies adequately represent the  mix  of
adaptive and non-adaptive  models in  recent  and   future  model
years.

     In theory, vehicles  with  adaptive   learning systems should
be  less affected by oxygenates   in  the  fuel  than older  style
closed  loop systems.   In actuality,  the  proof must  be  sought  in
data,  since vehicle designers  have implemented  the  adaptive
learning concept in different ways.

     The last  issue  with respect  to   technology  division  was
whether all  closed  loop vehicles that  have been  tested should
be  grouped  together to  represent  the  entire  population  of
closed  loop  vehicles,  including  those from  the most  recent and
future  model  years.   The  alternative  would be to divide  the
closed  loop  test  sample  into  "old  technology"  and  "adaptive
learning"  (or "new technology"  more generally)  and  use  only the
latter  to  represent  the  latest and  future  production vehicles.
To  test the emissions  of  such  vehicles  when  operating on  a
gasoline/oxygenate   blend   fuel,   it  is   important   that  the
vehicles be operated with the fuel for a  certain amount  of time
(which  may vary  for different  vehicle  designs)  prior  to  the
test.

     EPA has examined separately the tests  of vehicles  of  the
1984  and  later  model   years   which   were  tested  with  this
preconditioning.   The results  of this  comparison  are shown  in
Table 2.   EPA  could not  determine  in  all cases which vehicles
actually did have adaptive  learning  systems  and to what extent
the systems operate during test conditions.

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                              -11-

                            Table  2

                     Comparison of Effects;
          Preconditioned*  1984  and  Newer Vehicles Versus
     Unpreconditioned  and/or Pre-1984 Closed Loop Vehicles

Vehicle Group/       Emissions Changes on Oxygenated Fuels**
  References            N       HC        CO        NOx

Preconditioned         50     -11.1%    -24.6%    +10.6%
1984 and Newer
B, G

Other Closed Loop      88      -2.3%    -19.5%     +8.0%
C, E, J, S, U, V,
W, X, Y, Z, AA, AB
*    Preconditioning consists  of  use of a  particular  fuel in a
     vehicle for a  certain  amount  of time  (perhaps  several LA4
     test   cycles)   prior   to  the  actual   emissions   test.
     Preconditioning  procedures  are those  recommended by the
     vehicle manufacturers to each study's project manager.

**   Results  include  high  and  low  altitude  data.    Results
     normalized to matched RVP and 3.7% oxygen content.
     Though  the variance  of  the emissions  was  too  large  to
perform statistical tests  comparing  the  two groups  in  Table  2,
it  is  possible  to  draw  a  meaningful  conclusion  from: it.
Theoretically,  a  vehicle  with  adaptive  learning  should  be
affected  less by  fuel  oxygen  content  than a  vehicle  without.
Thus, the  null hypothesis would  be  that  the  vehicles  without
adaptive learning  are not  affected  more  than the vehicles-which
have  such  algorithms,   and the  data confirm   this  hypothesis.
EPA  concludes  that to  whatever  extent  adaptive  learning, is
being used  in  production,  it does not  cause  a  significant
change in the response to oxygenated fuels.

     Though not a  new technology,  the use of fuel injection has
become more common  in  new vehicles  in  recent  years.   Since  it
is  difficult  to   separate data  regarding  vehicles with  fuel
injection  from  vehicles  with  carburetion  (many of  the  studies
do not  record that information)  and since engine control logic
is probably  more  important  than the  mechanical  approach,  EPA
elects to  consider vehicles  with both types of fuel systems  as
part  of  the  same  group  in its analysis  of exhaust emissions.
It should  be noted, however,  that  the fuel  delivery system is
important in the analysis of  evaporative  emissions.

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                              -12-
3.3.2 Altitude

     The data may  also  be subdivided  by  the altitude  (high or
low) at which  they were collected.  There is a  large amount of
information available on both altitudes,  so  sample  sizes remain
sufficiently  large.   At  high  altitude,  a  given volume  of air
contains  less  oxygen.   Vehicles  operating  at  high  altitudes
must compensate  for the  lack of  oxygen,  or they will  run rich
for  a  larger  portion  of  their  operating time  than when  they
operate at  low altitudes.  The introduction of  extra oxygen in
the  fuel  can  mitigate   this  effect.   Fuel   oxygen  content
theoretically  should  have an absolute effect on high  altitude
emissions that is  greater  than  or equal  to  the effects  at low
emissions,  but the  percentage  effect may  be  about the same.
EPA  has  analyzed  separately the  data  taken at high altitude.
However,  no   studies   are  yet   available   which  compare  the
emissions of the  same  vehicles  at  both high and low altitudes
with oxygenated fuel blends.

                             Table  3

                Emission Changes with Oxygenated
             Blend Fuels*  at High  and  Low Altitude

Vehicle
 Group

No **
Catalyst

Oxidation
Catalyst

Closed
Loop
Altitude
High
Low
High
Low
High
Low
Number of
Vehicles
24
24
63
76
46
76
Effect of
HC
-11.3%
+0.4%
-15.8%
-15.3%
-1.9%
-4.2%
Blend on
CO
-23.9%
-25.0%
-31.4%
-37.3%
-18.4%
-20.6%
Emissions
NOx
+8.1%
+3.8%
+6.5%
+2.2%
+5.8%
+11.6%
**
Results  normalized  to represent  matched  RVP fuels  with
3.7% oxygen.

Appendix A  contains  complete  listings  of  the  references
used in generating this table.
     As  with  the   results  listed  in  Table  2,   it  would  be
difficult  to disprove  a  null  hypothesis  that  the  percentage
effect at  high  altitude is  larger  than that  at   low  altitude,
because of  the  large variance  in  the data.   However,  the fact
that the average effects on  CO  are larger for  the  low  altitude
tests of each vehicle  type tends  to confirm the null hypothesis
for  CO.   Similarly, the  hypothesis can  be confirmed  for  all
three pollutants from closed loop  vehicles.

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                              -13-

     EPA  believes  that   the  data  do  not  show a  significant
difference between  the  effects of  fuel  oxygen  content  at high
and low  altitudes,  especially for CO which  is  of  most interest
to planners  considering  oxygenated fuels.   EPA has  elected  to
use data gathered at high and low altitudes together.

3.3.3 Oxygen Content

     A  potentially  important  issue  is  the  difference  between
the effects of fuels with 3.. 7% oxygen content  and  those  with 2%
oxygen  content.   Blends  of  ethanol  in  gasoline  which  are
currently  sold  at  the  retail   level   contain  3.7%  oxygen.
Gasoline/methanol  blends  are  not currently  marketed  in  the
U.S.,  but  they  would  generally  be  expected  to contain  about
3.7% oxygen.   Blends of MTBE  in  gasoline may  contain up  to 2%
oxygen,  limited  by EPA's decision  that  MTBE  is "substantially
similar"  to  gasoline  and  as  such  may  be  added  in  limited
concentrations without a Clean Air Act waiver.   It  is generally
accepted   that   the  effects  of   fuel   oxygen  increase  with
increasing oxygen content,  but  the increase  is  not necessarily
a  linear  relationship.   Different studies  have shown different
trends in  this  respect.   One  may  show  that  the benefit  of the
lower  oxygen  content   fuel   is   larger  than  what  would  be
predicted by a proportional model, while  another shows that the
benefit  is  smaller.   After examining  the data, EPA elected to
assume  that  the effect  on  emissions   is   linearly  (in* fact,
proportionately)  related  to oxygen content  at  least  up  to the
3.7% oxygen  level,  and  the data  are  normalized to  represent a
constant  oxygen  content  over  the  entire  data  base  before
averages are computed.

     Planners  will  be  considering   as   a   pollution  control
strategy the  mandated  use  of  oxygenated  blends.  By specifying
the  amount   of   oxygen   which  will   be  required,   they  can
effectively  limit  or  allow  certain  blend  types.   By  some
measures,  the  cost  (in  terms  of  loss  of  consumer  choice,
vehicle  effects,  reduced  price  competition,  loss  of  highway
revenue  through  tax credits,  etc.)   of  restricting  the  retail
market  to  higher  oxygen  level  fuels is  high.  Planners will
want to  be sure  that sufficient  additional  emissions benefits
are needed before incurring these additional costs.

     More  data  exist  on   emissions  effects  with   3.7%  oxygen
fuels  than with  2%  oxygen fuels.   There are  several  studies  in
which  vehicles  were ,tested with  both levels of blends.   There
is enough  variability in  the  results  of these  studies  that the
shape  of  a  curve  which relates  oxygen  content   to  emissions
effects  could only  be  arbitrarily  determined.   Such a  curve
would  be based  on the  theoretical enleanment effects of the two
types  of  fuels.  The  2%  oxygen   fuel  will  provide  a  certain

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                              -14-

amount  of  enleanment  during  rich  modes  of  operation.   The
enleanment might  reduce the  richness  of  some modes  beyond  the
point  of  stoichiometry  (after  which  additional  enleanment  has
little additional effect).  The additional enleanment  of  a 3.7%
oxygen fuel will  only further reduce emissions during operation
modes that are  still  rich when using the 2%  fuel.   Thus,  there
would  be  some  levelling  off of  the benefits  at  high  oxygen
contents.   This argument  would  indicate  that  the 2% fuel  has  a
larger effect  than  simply 2/3.7 of the effect of  a  3.7% oxygen
fuel  (as  would be  predicted  by an oxygen proportional  model).
However,   given that  vehicles often emit  pollutants  at  higher
levels than their certification  standards  even when  using 3.7%
oxygen  fuel,   it  appears  that  there  are   still  significant
periods of rich operation.   It  seems reasonable to  assume that
most  of   the  significant  levelling  off  occurs  at  even  higher
levels of oxygen  content.   The  correct answer to  this question
could vary with vehicle  technology.   EPA  has chosen  to  assess
these  questions  by examining the emissions  of  vehicles  which
have been tested  with both fuels,  accounting  for other factors,
such as RVP,  which could otherwise affect the  results.

                            Table  4

          Comparison of Effects on RVP-Adjusted CO per
          Percent Oxygen; Two Levels of Oxygen Content

Vehicle Group/      N         Change from Base Emissions/%0x*
  References        vehs**       2.0% oxygen    3.7% oxygen

No Catalyst/         9             -7.8%          -4.9%
E, H, AB

Open Loop/          28           -10.5%          -8.8%
E, R, S,  U,  V, AB

Closed Loop/         25            -3.4%          -4.2%
E, S, V,  AB
* *
Effects listed are  the  actual effects after  adjustment to
to  a  constant RVP  divided  by  the oxygen  content  of  the
fuels, which demonstrates  the idea that  the effect  of  the
blend fuel is proportional to the oxygen content.

Includes vehicles tested on fuels of both oxygen levels.

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                              -15-

     Table  4  shows  the  ratios of  average CO  effects to  fuel
oxygen  content  for  three  different  technology  types and  two
different  oxygen   levels.    It  shows  that  for  vehicles  with
catalysts  (both open and closed  loop)/ the  ratio  stays roughly
the same,  regardless of  the actual  oxygen level.   The constant
ratio indicates that the  effect  of  oxygen on these vehicles can
be estimated  as  directly proportional  to  oxygen  content.   The
sample  size  of  the  vehicles without  catalytic  converters which
were tested on both  fuels  is small,  so  the comparison is  less
conclusive  in  their  case.   EPA  has  elected  to  extend  the
assumption  of  proportionality  to these  older vehicles.     The
null  hypothesis  that  the  ratio  stays the  same  regardless. of
total oxygen content could not  be disproved based  on  these  data
for any of the groups.

     Since  the  time that  the  Guidance  Document  was  released,
EPA  has tested more than  sixty  vehicles  using  fuels of  two
different oxygen levels.  Data have become available from other
sources  as  well,   and  this  additional   information  will  be
considered in the  next revision of the Guidance Document.

3.3.4 Other Fuel  Related Factors;  RVP and  Oxygenate Species

     Fuel  related  factors  other   than oxygen  content  may  affect
emissions.  For example,  it is  well documented  that  the  Reid
Vapor  Pressure  (RVP)   of  the  fuel  can  affect  FTP  exhaust
emissions.  Since  the  RVP of any large group of  fuels forms a
continuous  spectrum,  EPA  has  found  no  appropriate  way  to
subdivide  the  data  base  to separate  the effects of  RVP  from
fuel oxygen content.   Instead  of  subdividing the data base, EPA
has elected to adjust emissions test  data  using  known relations
to  volatility when  RVP  of  the fuels  are  known  (or can  be
reasonably   assumed,   since   some   reports   do    not   include
volatility  information).  The  adjustment  takes  place before the
percent   changes   between   group  means   on   two   fuels   are
calculated.  The  adjustments  are based on  data  from variable
RVP  tests   in  EPA's   emission   factor  program.    They  were
determined using only  tests  with  gasoline,  but EPA assumes that
they  also  apply to  gasoline/oxygenate  blends.    Few  data  are
available  to  test  this  assumption,  however.   The  following
table  shows the  functions   which  EPA  applied  to  make  these
adjustments.

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                              -16-

                            Table 5

                 RVP adjustments from MOBILE3.9

Model Years 1971 - 1980 HC adjustment:

         HC = (HC @11.5 RVP) * (0.79622 + 0.01772(RVP))

Model Years 1981 and later HC adjustment:

         HC - (HC (§11.5 RVP) * (0.57112 + 0.03729(RVP))

Model Years 1971 - 1980 CO adjustment:

         CO = (CO @11.5 RVP) * (0.65094 + 0.03035(RVP))

Model Years 1981 and later CO adjustment:

         CO = (CO eil.5 RVP) * (0.18753 + 0.07065(RVP))


     MOBILE3.9  is  the  last  version  of  the  MOBILE3  emission
factor model.   It was  intended  to incorporate many of the ideas
which will  be  included  in  the MOBILE4  model  which is  still
under development as of this writing.

     The model  year  groups above separate those years  in which
open loop and closed loop  fuel  control  systems predominate.   In
the  analysis  of gasoline/oxygenate  blends,  the pre-1981  model
year  expression is  applied  to  open  loop  vehicles,  and., the
expression for  1981  and later model  years is  applied to closed
loop vehicles.

     The type of oxygenate used in a  fuel blend  might also have
an   effect   on   emissions.   There   are  significant  physical
differences between  the  various  oxygenates,  such   as polarity,
miscibility with water,  latent heat  of  vaporization, etc.  EPA
has  attempted  to  determine  the  effect  of  the  species  of
oxygenate  (ethanol,  methanol,  MTBE,  etc.) in  the  fuel  blend on
emissions  independent  of  total  fuel  oxygen  content.   This  is
directly possible  only for  comparisons  of ethanol  blends with
methanol  blends,   since   blends  with  MTBE  have  lower  oxygen
contents  than  most  blends  with methanol  or  ethanol.   This
comparison can be made in paired tests with  the  relatively very
few vehicles which  received emissions tests  using  both types of
fuels, as shown in Table 6.

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                              -17-

                             Table 6

             Paired Oxinol, TBA,  and Gasohol Tests*
 Vehicle
  Group

Oxidation
Catalyst
Closed Loop
 N
Vehs

 8
  Fuel
  Blend
10% EtOH
16% TBA
Oxinol

10% EtOH
16% TBA
Oxinol
 Changes  in  Emissions  **
 HC        CO      NOx
-35.4%
-30.2%
-33.9%

-28.8%
•29.7%
-19.7%
-47.3%   -4.5%
-47.5%  -10.6%
-49.6%  -13.1%

-49.0%   -3.8%
-51.0%   -7.0%
-29.2%  -10.8%
*    Data taken from ARCO waiver request for Oxinol.

**   Emissions   changes    are    relative    to   emissions
     non-oxygenated base gasoline.
                                                on
     The  theoretical  effect  of oxygenate  species  (independent
of  oxygen content  and  volatility)  is  not well  defined.   EPA
could  find  no  empirical   reason   to   separate  the  data   by
fuel-related factors other than volatility  and oxygen content.

3.3.5 Ambient Temperature

     Low  ambient temperatures  can extend the time that it takes
for  an engine  to  reach  operating  temperature.    During  this
ti«e,   catalytic   converters  operate   at   less   than  peak
efficiency, closed  loop  systems operate in open  loop mode,   and
fuel control systems  use a rich mixture to keep the engine from
stalling.   These effects may interact  with the  effects  of fuel
oxygen.    EPA   does   not   presently    have   enough   data    to
characterize this interaction.

3.3.6 Base Emission Levels

     While  a  percentage  reduction  model  has  a  theoretical
attraction  (since  higher  base emissions  imply that  there   are
more  modes  with  opportunity  for  enleanment),   it  may   not
strictly   hold   for  extreme   emission   levels.   Because   the
emission  levels  represented in the  data (as  shown  in Appendix
A) are so low  compared to in-use levels  (as  shown in Table  1),
this  effect,   if  present,  could  reduce  the  accuracy   of   the
extrapolations from the data to a fleet.

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                              -18-

     In EPA's  analysis,  the  results  of individual  studies  are
kept distinct up  to  a point,  so  it is  possible  to look  for  a
relationship  between  base  emission levels  and the  percentage
reductions.   EPA  could  find  no  such  relationship,   but  the
difference between the emission  levels  of  the different studies
is not  as great  as the  difference between  the levels  in that
data base and  in-use  emissions.   The  reader  is  encouraged  to
examine the results in Appendix A to confirm this  conclusion.

4.0  RESULTS

     The  following  table  shows the  technology-specific effects
on  emissions   that   would  be  caused  by   switching  from  a
non-oxygenated gasoline to  a  gasoline/oxygenate blend  with  the
same volatility and a  3.7%  oxygen content.

                            Table  7

                   Technology Specific Effects
                on Emissions of a Fuel  with 3.7%
           Oxygen and  Volatility Matched to Base Fuel

  Vehicle       Number of       Effect  of Blend on Emissions
   Group        Vehicles          HC          CO

No Catalyst        48            -5.5%      -24.5%

Oxidation
catalyst           160         -15.5%      -34.7%       +4.1%

Closed
Loop               138          -2.3%      -19.5%       +8.0%
     Note  that  these values  are  slightly different  from those
listed in  Table  3-1 of  the  Guidance Document.   The  difference
stems from  an  error which was  found in  the  original data base
after the  final version  of   the  document was  published.   The
correction of  this  error yielded values which are  in all cases
but one  within  0.3  percentage  points  of the values  originally
published.   The  estimate of  the effect  on  NOx  emissions from
closed loop vehicles  increased by  1.1  percentage  points.   EPA
does  not  consider  these  corrections  to be large  enough  to
require  re-issuing  the  Guidance Document.   A complete  listing
of  the   data  and sources  used  in developing  these values  is
presented in Appendix A.

     If  the fuel  has an oxygen content  other  than  3.7%,  then
these effects  must  be  adjusted  in  proportion   to  the  actual
oxygen content.   If  the blend is of a different  volatility than
the fuel it replaces,  then Table  5 should be used to adjust the
resulting effect.

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                              -19-

                           References
1.    "Guidance on Estimating  Motor  Vehicle Emission  Reductions
     From the Use  of  Alternative Fuels  and  Fuel  Blends,"  EPA
     Technical Report,  EPA-AA-TSS-PA-87-4,  January  1988.

2.    "Feasibility  of   Using   Alternative  Fuels   as  an   Air
     Pollution  Control  Strategy,"   Energy   and   Environmental
     Analysis,   October   1987,   prepared   for   The   Maricopa
     Association of  Governments.

3.    "Comments of  the  Ad  Hoc Ethanol Committee  Regarding  the
     July 1987 Draft Technical Report,   'Guidance  on  Estimating
     Motor  Vehicle  Emission  Reductions   From   the  Use   of
     Alternative  Fuels  and  Fuel  Blends',"  Rivkin,   Radler,
     Dunne,  & Bayh,  December 1987.

4.    "Ethanol-Blended  Fuel  as  a  CO Reduction Strategy at  High
     Altitude,"   Section  C,  Vol.  II,  Colorado  Department  of
     Health,  August  1985.

5.    "Fleet   Demonstration,"  Colorado  Department  of   Health,
     November 1987.

6.    "Effects of Ethanol-Blended Fuel on Motor Vehicles at  High
     Altitude,"  Colorado Department  of Health, September 1983.

7.    "Exhaust Emissions and Fuel  Economy from Automobiles  using
     Alcohol/Gasoline   Blends  Under High Altitude  Conditions,"
     David Richardson,  EPA,  October  1978.

8.    "The Effects of. Two  Different  Oxygenated Fuels  on  Exhaust
     Emissions   at  High   Altitude,"   Colorado  Department   of
     Health,  January 1987.

9.    EPA Ann  Arbor  1987-88  In-House  Gasohol  Test Data  as  of
     December 1987.

10.   "Exhaust  and  Evaporative   Emissions  from  a   Brazilian
     Chevrolet Fueled  with Ethanol-Gasoline  Blends," R.  Furey
     and  M.   Jackson,  GM  Research  Publication  GMR-2403,  June
     1977.

11.   "Analysis of Gasohol  Fleet Data to Characterize  the  Impact
     of  Gasohol  on  Tailpipe  and Evaporative  Emissions,"  EPA
     Mobile  Source  Enforcement Division Report, December 1978.

12.   "Characterization   and  Research  Investigation  of  Alcohol
     Fuels  in  Automobile  Engines,"  Santa   Clara  University,
     prepared for DOE as DOE/CS/51737-1,  February  1982.

-------
                              -20-

13.   "Exhaust  Emissions,   Fuel  Economy,   and  Driveability  of
     Vehicles  Fueled  with  Alcohol-Gasoline Blends,"  Brinkman,
     Gallopoulos,  Jackson,  SAE Paper 750120 1975.

14.   "Evaporative   and  Exhaust  Emissions  of  Two  Automobiles
     Fueled with  Volatility Adjusted  Gasohol," David  Lawrence
     and Daniel Niemczak, EPA  Report  EPA-AA-TEB-81-12,  December
     1980.

15.   "Exhaust  and  Evaporative  Emissions from Alcohol  and Ether
     Fuel  Blends,"  T. M.  Naman  and  J.  R. Allsup,  SAE  Paper
     800858,  1980.

16.   "Gasohol;  Laboratory  and  Fleet  Test  Evaluation," M.  D.
     Gurney,  et al, SAE Paper 800892,  1980.

17.   "Gasohol, TBA, MTBE  Effects on  Light-Duty Emissions,"  B.
     Bykowski,  Southwest    Research    Institute,   EPA   Report
     460/3-79-012,  NTIS PB 80224082, October 1979.

18.   "Evaporative   and  Exhaust  Emissions  from  Cars Fueled  With
     Gasoline  Containing  Ethanol  or  MTBE,"  R.   Furey   and  J.
     King,  SAE Paper 800261.

19.   "Performance  Evaluation of Alcohol-Gasoline Blends  in 1980
     Model  Automobiles: Phase  1  - Gasoline-Ethanol Blends," CRC
     Report No. 527, July 1982.

20.   Clean  Air Act Waiver  Application  for Oxinol,  ARCO,  May
     1981.

21.   Clean  Air Act  Waiver   Application for  the   DuPont  blend,
     July 11 1984.

22.   "In-House 23  Car  In-House Oxinol  Blend Test  Program,"  EPA
     memo from Craig  Harvey to  Charles  Gray,  ECTD, November 19,
     1984.

23.   "Characterization  of   Emissions   from   Vehicles   Using
     Methanol  and  Methanol-Gasoline Blended  Fuels,"  P.  Gabele
     et al, JAPCA  Vol. 35,  no.  11, 1168-1175,  1985.

24.   "A  Generic  Report  of  Toxics  from Oxygenated   Fuels,"
     Colorado Department of Health, Spring 1987;   Note:  CDH has
     stated these  preliminary data  are  released for use  in  our
     report.

-------
   Appendix A
Data and Sources

-------
Dunary of Fuel Data, by Study
                                                             Page A-l
I.  No Catalyst

                     $ Alt
Altitude Ref # #Vehs Fuels Notes
high A
high 3
high D
high AB
high E
High Total
Low if
low ?
lOH T
Low Total
10
4
*?
4
4
24
l
i
22
24
i all HDU's
1 CDH fleet deao
i big cars
: CDH Toxics
: Trucks

3 very approx
'^
I sostly LDT's


'/are
9.0
10.7
10.8





Emissions on Base Fuel
	in (g/ii)	
SUP   'JOC    CO
      4.66  80.50
      2.72  72.97
      4.00  89.80
      5.29  51.94
             NOx
             3.23
             3.53
             2.59
             1.30
5.91 109.30  3.42
                                                      3.00  120.00  0.50
                                                      1.50   25.40  1.93
                                                      4.58   32.30  4.60
      Splash
	10%    Eton   	
 RVP   <;oc%    GO;   nox%
 N.D.   -14.61 -23.7'.   5.0%
                                   -15.0V -16.6V  60.0V
                                     -2.0'. -30.0-°.  -23.0'.
                                     2.8V -22.3V  -2.81
TOTAL Son-Cat
 II.  Ox cat. Open  loop
                      i Alt
 Eaissions on Base Fuel
      in  (g/ii).
Altitude Ref #
high B
high
high
high
high
high
High
low
low
low
low
low
low
low
low
low
low
low
low
low
low
low
low
Low
b
C
D
AB
E
Total
J
j
S
5
s
T
a
u
\!
H
U
K
X
Y
y
7
w
Total
JKUehs Fuels
4 1
7
33
8
q
q
70
24
19
i
b
c
C
u
31
2
">
L
1
7
7
(
8
3
3
i
7
90
1
1
1
2
V

1
^
3
i
I
1
X
1
i
3
2
1
2
1
1
1
1

Notes
CDH fleet deao
other vehs

large engines
CDH Toxics
CDH Oxinl/MTBE

tests not aatched
conn base fuel


other blend
fleet tests

other blend


other blend
ARCO waiver
other blend
DuPont
other blend
EPA 23 car

RUP
uars
vars
9
9
10
10

9
10
9
3
3

9
9
9
9
9
12
12
9
9
11

.0
.0
.7
.8

.0
.0
.3
.6
.6

.1
.1
.0
.6
.6
.5
.5
.2
.2
.6

VOC
2.45
1
1
2
1
3

0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0

..42
.42
.06
.91
.06

.80
.83
.86
.85
.85
.08
.63
.63
.65
.27
.27
.96
.96
.53
.16
.54

CO
63.
38.
24.
31.
27
55.

8.
n.
10.
3.
8.
14.
7.
7.
8.
4.
4.
38
80
73
76
.4
70

77
95
44
56
56
80
58
58
52
67
67
20.40
20.40
6.67
•5
u •
20
5.43


NOx
1.77
1.62
1.32
1.49
2.38
1.97

1.53
1.59
2.41
1.63
1.53
3.36
0.97
0.97
1.79
1.43
1.43
1.98
1.98
1.80
1.02
0.99

                            Splash
                     	10%    EtOH	
                       RVP   von    cm   NOX*
                      uars
                      uars
                        9.8  -15.4% -34.8%   8.3%
                             -23.4% -24.8%   2.4%
                                                                              9.6  -16.4% -39.0%  11.6%
                                                                             10.9  -20.9V -32.6V   7.4%
                                                                             10.2  -23.3V -39.5%  -2.5%
                                                                                   -13.0V -34.5V  -8.6%
                                                                              9.7  -13.5V -28.1V -22.3%
                                                                             10.5    0.0% -25.3%  16.8%

                                                                             13.0  -35.4% -47.3V  -4.5%
 TOTAL Open Loop  160

-------
Suiiary of Fuel Data, by Study
                                                             Page A-2
!!I. Closed loop (pre '84 model year or not preconditioned)
                     * Alt
Altitude Ref # #Uehs Fuels Notes
high     C        19     1
high     SB        7     I CDH Toxics
high     £        13     2 CDH Oxinl/MTBE
High Total        39
 TOTflL
Emissions on Base Fuel
	in (g/mi)	
RUP   UK    CO    NOx
 9.0  0.47   8.21  5.68
       Splash
	10%    EtOH	
  SUP   UOC%    C0%   NOX%
   9.S   -1.8% -13.61   7.9%
low
low
low
low
lew
low
iOH
low
low
low
low
low
low
low
low
low
Low
J
j
X
s
3
u
u
'J
»
H
;{
X
Y
Y
z
AA
Total
11
9
1
-\
0
3
1
1
•>
7
7
3
3
5
2
14
2
49
j.
.1
1
i
i
1
1
]_
J
O
1
i
1
1
1
1
1

Indol base
coaserc base
very approx

other blend

other blend
prototype vehs

other blend
ARCO waiver
other blend
DuPont
other blend
EPft 23 car
RTP

9.0
10.0

3.6
3.6
9.1
.1
.0
.6
.6
12.5
12.5
9.2
9.2
11.6
11.7

0.34
0.37
0.27
0.43
0.43
0.24
0.24
0.23
0.30
0.30
0.37
0.37
0.22
0.21
0.55
0.44

4.86
5.70
2.60
6.23
5.23
3.41
3.41
1.38
5.08
5.08
5.78
5.78
3.44
2.65
5.59
4.60

0.66
0.65
0.38
0.48
0.48
0.79
0.79
0.70
0.62
0.52
1.57
1.57
0.72
1.04
0.91
1.08

9.6 -6.2'.
10.9 11.61
-22.2'.




9.7 13.0%
10.5 16.7V

13.0 -28.8%






-19.4%
-7.5%
-23.1%




3.7%
-26.0%

-49.0%






3.7%
S.5%
13.0%




1.4%
11.3%

-3.8%






 IU. Closed loop (84+ lodel year,  preconditioned)
                      # Alt
 Altitude Ref # Wehs Fuels Notes
 high     3         7     i CDH fleet de»o
 high     b        10     1 different uehs
 low      G        33     1 EPA In-house
 TOTAL             50
 Eiissions on  Base  Fuel
     _in (g/ui).
RUP
uars
uars
11.7
roc
0.63
0.37
0.55
i:0
16.41
6.02
9.41
NOx
1.33
1.13
0.79
RUP
        Splash.
        10%     EtOH
         'JOC%    C0%
                                                  NOK*

-------
Suiiary of Fuel Data, by Study                                                                                Page A-3
	Emission Changes  caused by blend use
                       Other Fuel
                        '3.7'. Ox    	      	Other  Fuel,  -  21. Ox
         type       *0xy  RVP  VOC*    CO*.   NOx*           type       *0xy RVP    VOC*    CO'.'   tIOx%

     splash EtOH   3.2 uars    3,1'. -16.2°.  15.7V

        £10 adj      3.7 10.2  -14.6* -20.6'.-  -1.0-*,       11* MTBE        2 10.5   -1.1'. -11.6'.  -4.5%
      OxinolSO      3.5   11  -12.0* -21.4*  -0.9%       in MTBE        2   9.8  -14.4* -23.8*  15.4%


        S10  adj      3.7 adjus -25.0'. -20.8%  80.0'.     5*EtOH  splash  1.9         -7.5'.  -3.3'.  40.0%
 	Emission Changes caused by blend use
Other Fuel
•3.7'. Ox
type
splash EtOH

E10 adj
OxinolSO
E10 adj
E10 adj




E10 adj
E10 adj 2
E10 adj 3
TBA16
Oxinol
Fuel 82
Fuel93(E10)
Oxinol
'.Oxy
2.92

3.7
3.5
3.7
3.7




3.7
3.7
3.7
3.5
3.7
3.7
3.7
3.5
CTP
uars

10.2
11
10
9.4




9
9.4
9.4
12.4
14.9
9.1
9.1
11.2
VOC*
10.0*

-7
-2
-.
-3




-21
f
- 1
-7
-30
-33
-18
-12
7

.91
.6%
.2'.
.1'.




.5V
.4*
.4*
.2*
.9".
.9%
.5%
.4*
CO*.
-19.0*

-32.5*
-22.4%
-26.5*
-34.7*




-32.7*
-45.6*
-29.1*
-47.5*
-49.6*
-41.5*
-28.1*
-14.5*
N0x%
21.3*

5
1
7
-21




-26
23
22
-10
-13
-4
-1
13

.5*
.0%
.7*
.6*




.3*
.3*
.4*
.6*
.1*
.4%
.0*
.2*
Other
type *0xy RUP
MTBE 1 - 2* 1.54 vars
11% MTBE 2 10.5
11% HTBE 2 9.8

5* EtOH 1.9 10.4
7* MTBE 1.3 8.7
7* TEA 1.5 9.1
7* MTBE 1.3
7* TBA 1.5
15* MTBE 2.7 9.1







Fuel, "
uoc%
-13.2*
0.7*
-14.1*

2.2*
-20.0*
-3.2*
-7.7*
-10.3*
-20.0*







2* Ox
CO*
-12.0*
-11.9*
-21.5%

-4.2*
-32.5*
-7.9*
-39.7*
-44.8*
-25.9*








H0x%
-3.1%
4.0V
8.1%

2.5%
-0.6*
7.4%
10.0*
10.0%
-21.8%








-------
Suiiary of Fuel Data, by Study                                                                              Page A-4
	Saission Changes caused by blend use
Other Fuel
•3.71 UH
type
E10 adj
Gxinol 50
E10 adj




£10 adj
E10 adj 2
£10 adj 3
TBftl6
Oxinol
Fuel 82
Fuel93{E10)
Oxinol
",0xy
j .
3.
3,




•;
j
3
3
3
•^
3
3
.1
.5
'T
. /




.7
.7
.7
.5
.7
.7
.7
.5
RVP
10.2
11
10





9.4
9.4
12.4
14.9
9.1
9.1
11.2
vocv
•i.
s
13




15
-13
0
-29
-19
-4
9
7
.3'.
.2V
.9;




.0".
.3',
.0;
.7'.
.7%
.5'.
.5;
.3'.
CO'.
-11.5*
-16,
-0




33
-43
-19
-51
-29
-24
-35
-10
,4V
.34




.3".
.9V
.7'.
.01
.2%
.4V
.8V
.6V
NOxV
-2,
f\
11




Q
19
16
•^
- i
-10
-5
-1
0
L,
.4V
.7V
.0V




.0V
.4V
.IV
.0V
.8V
.6V
.9-V
.2V
Other Fuel. ~ 2V Ox

type VOxy RVP VOC% COV MOxV
11V HTBE 2 10.5 -2.8V -3.8V -0
11V HTBE 2 9.8 3.3V -9.6V 10

7', HTBE 1.3 8.7 -27.9V -27.5V 35
7V TEA 1.5 9.1 -25.5V -21.5V 20
7VTBB 1.5 -26.7V -39.6V 0
7V MTBE 1.3 -26.7V -34.4V 2
15V HTBE 2.7 9.1 -4.3V 2.7V 6







.6V
.7V

.0%
,8V
.0%
.01
.4V







    Oxinol(hiRVP)   3.5 12.9  -20.5V   1.1%   0.9%
 	Eaission Changes caused by blend use
                       Other Fuel
                        /3.7V Ox	      	other Fuel,
         type      ",Cxy  RVP  VOCV    COV    MOxV           type      VOxy RVP   UOCV
      splash EtOH  3.27 vars  -22.4V  -30.3V   -3.8%
                                                        MTBE 1 - 2V  1.34 vars    -3.1V  -13.1V    0.9%
        £10 adj      3.7 11.8    -6.3V  -21.5V   15.3V

-------
Siuiary of Fuel Data, by Study                                                                               Page A-5
                   .Calculations:  Account  for  Different Oxygen  Content  and  Volatility
         Forcing Matched RVP  Forcing Matched RVP & Guy          Forcing rlatched RVP          L7orcir.g 3.7*. Ox
         Splash 10% Ethanol   froa other  "3.7 Ox fuels       _ * 2*.  Ox froa "2'.Ox	     	frca 2% fuels	
Ref #    ID psi UOC%   CO:     D  psi  i/OC».    C0%   N0x%       D  psi 
-------
Suiiary of Fuel Data, by Study
                                                                                                   Page fl-6
                   .Calculations: Account for Different Oxygen Content and Volatility
Sef I

A3
 U
 a
 '••}
 'A
 w
 ii
 X
 Y
 y
 z
 AA
Forcing Matched RVP  Forcing Matched RVP & Oxy
Splash 101 Ethanoi   froa other "3.7 Ox fuels
3 psi von   coi     o psi  yon   coi   NOXI
0.80  -4.71 -23.21
         Q.60  -3.3*  -22.81
         0.90    7.9%  -13.«
         0.76  -24.4*  -27.2'.
0.70  10.11   -1.4°,
0.90  12.8'.  -30.7".

0.50  -30.11  -50.8-1
 -0.5
 0.2
                             6.21
      ....  -5.41  -2.41
      n.S1 -13.61  -2.91
                       0.0  13.91  -6.31  11.01
0
0
.-%
L
•0
•0
•I]
1
.0
f\
.1
.1
.4
.1
.1
.4
.2
15.
-1 9
0.
-31.
-26.
-4.
0.
9.
-25.
01
•M
; o
71
11
91
11
91
41
41
33
-43
-13
-53
-41
-23
-35
-3
-7
.31
.11
.61
.51
.21
.91
.31
.51
.9%
')
19
16
-10
-5
-1
2
1
.01
.4-1
.11
.41
.81
.61
.91
.31
.01
Forcing Matched RVP
. & 2-1 Ox froa "ZIGx 	
psi
•0.2
•1.0
0.1
0.5
0.0
0.0
0.1
von
_2
7
-43
-35
-35
-41
-3
.11
i'
.31
.91
.61
.11
.41
C01 N0x%
-7
*
-43
-32
-52
-52
i
.51
7"
.21
.41
.81
.91
.51
-0.61
107"
C7 Qo
Jv* . 0 t
27.71
0.01
3.1".
4.71
Forcing 3.71 Ox
	 froa 21 fuels 	
VOX
-3.
13
-30.
-66.
-65.
-76.
-5.
CO* NOx*
81
•>•
21
31
91
01
41
-4
^
-80
-59
-97
-97
2
.5*
9°,
.01
.9%
.71
.9-1
.71
-1
19
99
51
0
5
8
.11
.81
.61
.31
.01
.71
.81
 Ref #
 6
 b
 G
                    .Calculations; Account for Different Oxygen Content and Volatility
 Forcing Matched RVP  Forcing Matched RVP & Oxy
 Splash 101 Ethanoi
 0 psi VOC1   C01
t'roa other
0 psi  von
          3.7 Ox fuels
            CGI   H0x%
0.8 -27.81 -33.51  -4.31
                        0.1  -6.61 -22.11  16.31
   Forcing Matched RVP
_ i 21 Ox froi "2 ".Ox	
D psi  VOn   C01   NOxl
  Forcing 3.71 Ox
	froa 21 fuels	
;;on    cov   HOX%
                                                       0.0  -3.81 -14.21   1.01    -16.31 -26.31   1.81

-------
Susiary of Fuel Data, by Study                                                                              Page A-7
          Average reductions by study
          aatched 3.71 Ox and RVP.
          weighted together by ueh   	Base g/ai.






Hi alt



Lo alt
•otal
u
rr
A
3
U
AB
E
tot
H
p
T
tot

VOC%
-15.81
2.01
-9.4%
-7.6%
-13.41
-11.4%
-19.31
-3.31
1.41
9.4%
-:.51
CO*
-25.51
-21.01
-21.71
-19.9%
-31.41
-24.51
-19.81
-51.21
-24.11
-25.01
-24.81
N0x%
5.01
13.21
20.11
-4.61
1-1.71
•a. 51
72.61
-23.01
-2.81
-0.51
4.0-1
!/OC CO HOx





4.60 81.73 3.10



4.59 35.67 4.32
4.59 58.70 3.71
           Average reductions by study
           latched 3.71 Ox and RVP,
           weighted together by veh       Base g/ii	
                                      VOC    CO    NOx







Hi alt
















io alt
total
#
B
b
C
0
AB
E
tot
.]
j
S
5
3
T
U
u
V
W
w
X
X
Y
y
T
tot

uoc-;
10.8%
-31.71
-17.6%
-24.4%
-2.5%
-13.21
-15.7%
-17.31
-12.2".
-10.71
-57.31
""7 *>«
-LL.t* d
-14.21
-21.91
-25.4%
-22.91
-4.3%
-7.1%
-33.9%
-36.71
-18.8%
-12.31
8.6%
-15.31
-15.4%
C0%
-26.4%
-23.8%
-36.4%
-26.5%
-26.2%
-29.8%
-31.8%
-40.11
-30.51
-30.11
-93.1%
-22.91
-36.01
-100.01
-100.0%
-32.71
-36.3%
-28.71
-49.1%
-53.31
-41.31
-27.91
-14.21
-37.51
-35.0%
NOX%
0.0%
-7.41
8.3%
2.4%
5.4%
3.0%
5. Si-
ll. 61
7.51
-6.4%
-1.71
'18.31
-3.6%
28.51
24.71
-25.21
20.31
22.41
-7.9-1
-13.11
-4.4%
-1.0%
19.2%
2.21
3.6%
                                      1.33  33.47  1.62
                                      1.18  11.34  2.13

                                      i.46  21.02  1.93

-------
Suasary of Fuel Data, by Study                                                                              Page A-8
          Average reductions by study
          matched 3.7"* Ox and RVP.
          weighted together by veh   	Base g/ai	
                                             CO    HOs
                                             8.30  3.80
if
\_,
A3
P
Hi ait tot
;
i
j
i\
.^
;3
u
u
•;
;<
W
FT
.1
X
Y
?
Z
M
lo alt tot
voc%
-4.7'i
1.2;
10.5'.
i.4".
-8.3'.
13.4V
-24. 41
-SO. 2".
-66.3*
-65. 9".
-76.0'.
6.2*.
3. It
0.7*.
-30.6'.
-26.9%
-4.1*
9.9*
9.4%
-25.4%
-5.1%
cot
-23.2%
-6.51.
-12.3%
-16.6%
-22.8V
-6.8V
-27.2V
-30. 0V
-59.9V
-97.7V
-U7.9-V
11.5V
-36.9V
-15.6V
-52.2V
-41.2V
-23.9%
-35.3%
-3.5%
-7.9%
-22.2%
H0x%
7.9V
-1.7%
3.5V
5.4V
3.7V
9.3V
13.0V
99.6V
51.3V
0.0V
» 7'
3.4V
15.4V
16.1V
-5.6%
-10.8V
-5.6%
-1.9%
2.3%
1.0%
9.3%
HOC



G.53
















0.3!
                                             4.95  0.80

 Total        -2.2%   -19.7%     3.0%   0.45   6.43  2.13

           Average reductions by study
           siatched 3.7V Ox and  RVP.
           weighted  together by veh   	Base g/ui	
                                      70C    CO    HOX
u
:T
3
b
G
Both alt
voc%
-27.8%
-16.3V
-6.6%
-11.5%
COV
-33.5V
-25.3V
-22.1V
-25.2V
N0x%
-4.3%
1.8%
16.3V
10.5V
                                       0.52   9.71  0.93

  all  CL       -5.6%  -21.7%    3.9%    0.5    7.6   1.7

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                                                       Page A-9

     Pages A-l through A-8 list all of the data which  were used
in this  report.   These pages also show  results at  intermediate
steps   in   the   calculations   which  lead   to   the   report's
conclusions.   The information  is presented  as  a  spreadsheet,  so
the easiest  way  to look  at  the entire  process  is  to  separate
the pages  from the report and tape them together  side  by side
in the following arrangement  (although it is possible  to follow
the process without doing so):


         Page A-l       Page  A-3       Page  A-5       Page A-7


         Page A-2       Page  A-4       Page  A- 6       Page A-8


     The  data  on vehicles  without  catalytic  converters  and
vehicles with oxidation  catalysts  and  open  loop  fuel  control
are on  odd numbered pages (top row),  while  the  even  numbered
pages have  the data  concerning all of the vehicles with closed
loop  fuel  control.   The  following  is  an  explanation  of  the
columns in the spreadsheet:

Altitude:  Indicates  the  altitude   at   which  each   study  is
conducted.   Most of the high altitude  studies  were  conducted in
the Denver area by the Colorado Department of  Health.

Ref tt:  The  letter shown in this column indicates  the  study frcvn
which the data  in each  row was taken.  The letter/study key is
listed  on  the last pages of  this Appendix.   Lower  case  letters
indicate that  the row  is  a  second entry for  the  study in the
previous  row.   Studies  are  listed  in more  than  one  entry
whenever they  include  more than one  fuel of  the  same  general
type, such as  two different  gasoline/methanol  blends.   Also, if
a study includes vehicles of different emission control  groups,
the study  is  indicated  (with  a capital letter) in each emission
control group  in  this  table.   Some letters  are skipped  because
the  studies  which would  have  been  indicated by those  letters
are  already  represented  in  a  summary study.    Though  some
vehicles are  represented  twice  in  this and  the next column, all
operations which  add the  results  of different studies  together
are designed to count the results from each  vehicle  only once.

KVehs:  This  column  indicates the  number of vehicles  which are
represented in the row.

tt Alt Fuels:  Indicates  the number  of  gasoline/oxygenate blends
which are represented in the  row.

Notes:   Notes were  included  to  help keep  track  of  important
points regarding each study.

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                                                       Page A-10

Emissions on  Base Fuel:   The  four columns  under this  heading
list  the RVP  of  the  base  fuel,  when known,  and the  average
exhaust VOC, CO,  and NOx emissions of  all  the vehicles  in the
group when tested on the non-oxygenated base fuel.

Splash  10%   EtOH:   The four  columns  under  this  heading  are
filled  only when  the  vehicles  represented  on  the  row  were
tested  on  a  splash  blend  of  gasoline with 10% ethanol.   The
columns list the RVP of the blend  and  the percent  reductions in
the  exhaust  emissions  of  VOC,  CO,   and  NOx  relative  to  the
levels in the previous columns (base fuel).

Other Fuel  -3.7% Ox:    The  six columns under  this heading are
filled  only when  the  vehicles were tested  on a blend  of fuel
with  an  oxygen content  of  more than  3.0%,  but which is  not a
splash  blend  of  ethanol.   Such  a blend  might be  a  volatility
adjusted blend  of  gasoline  with  10%  ethanol  or  a  blend  of
gasoline with  5%  methanol  and  a cosolvent.   The  columns name
the fuel, list its RVP and oxygen  content,  and show the  average
emissions  reductions  relative  to , the base   fuel  which  were
reported when the fuel was used.

Other  Fuel  -2%  Ox:    The  columns   under   this   heading  are
analogous to  those listed under  the  previous  heading,  but art
included only when vehicles were tested with a  fuel of  about 2%
oxygen content, such as a blend of 11% MTBE or 5% ethanol.

     The  next   four   headings   show   the   calculations  which
normalize the  listed  reductions  in  emissions  to  reflect  the
reductions  that  the  vehicles would have achieved  using  a blend
with 3.7% oxygen and matched volatility to  the base fuel.   Each
of the headings  indicates  which group of fuels data (from among
the  previous   three  headings)  is  being  normalized.   "D  psi"
indicates the  difference between the RVP of the  blend  and that
of  the  base   fuel.   The  effect  of   fuel   oxygen  content  was
calculated  assuming  a  linear  relationship  between fuel  oxygen
level and  exhaust emission  changes  from  the  base fuel.   The
effect  of   RVP  on exhaust  emissions  was  calculated using the
assumptions in MOBILES.9.

Forcing  Matched  RVP,   Splash 10%  Ethanol:   These  columns show
the  results of  the  adjustments  for  RVP  that  are  presented in.
section 3.3.4.   Entries to  these columns  only occur when the
vehicles represented  in a  given  row  were  tested  on a  splash
blend of 10% Ethanol.   Since there  is  no adjustment for  NOx due
to   RVP,   and   a   10%  ethanol   blend  should   already  have
approximately  3.7% oxygen  content, there  is no column  listing
for NOx under this heading.

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                                                       Page A-11

Forcing Matched  RVP  and  Oxy for  Other  -3.7 Oxy  Fuels:   Since
the blends  represented in this  column  do not  necessarily have
matched RVP to  the  base  fuel,  the VOC  and CO  reductions are
adjusted to  reflect  the  results  of matched  RVP  fuels.   Since
the blends  may  have  oxygen  contents  of other  than  3.7%,  the
VOC, CO, and NOx results  are further adjusted  in  proportion to
the oxygen content to reflect a 3.7% oxygen content.

Forcing Matched  RVP  &  2%  Oxygen  from  -2%  Ox:  This  heading
contains entries when  the group of vehicles represented  in the
row was  tested  using  a fuel of  about  2% oxygen  content.   The
exhaust emissions  are adjusted  to  reflect matched  RVP  and 2%
oxygen content.

Forcing 3.7%  Oxygen  from  ~2% Oxygen:   Under this heading, the
results of  the previous  heading are scaled to  reflect  a  larger
oxygen content.

Average Reductions by Study:   In each entry under this heading
is  the average   of  the   percentage  changes  in  emissions  as
adjusted to  reflect  a matched RVP  and 3.7%  oxygen content over
all of  the  fuels  tested  in the vehicles  represented by this
line of the table.  At  the  bottom of each  technology group is
the average of these percentage  figures,  weighted  by the  number
of  vehicles  in  each  study.   Each  gasoline/oxygenate  blend
within a given  study  receives  weight  equal to other  fuels in
the same study,  even  when they are represented on more than one
line in the table.

Base  g/i> i:    Under this   heading   are  the  average  base  fuel
emission  levels   of   the   studies,  weighted  by  the  number  of.
vehicles  in each  study.  Averages are  listed  for  different
altitudes  within each  technology  group, and  for the combined
high and low  altitude  results of each group.   This  information
is  useful  for  comparing the emission levels of  vehicles  in the
studies to  those which would be predicted of  in-use vehicles.
Based on this  comparison, a qualitative judgement  can be made
regarding  how well the data set represents an in-use fleet.

     The following is  a  detailed  example  of  the calculations
involved  in  one  of  these  rows for  one  pollutant.   Study  V
included 2  closed loop vehicles  tested  at  low  altitude.   The
base (non-oxygenated)  fuel used in this  study had an RVP of 9.0
psi, and the average exhaust CO emissions of these vehicles was
1.88 g/mi.   These  vehicles were also tested with a splash blend
of  gasoline with  10%  ethanol,   which  had  an  RVP  of 9.7  psi.
When using  this  fuel, their  average  CO  emissions  increased by
3.7%.    When  the  vehicles  were   tested  using  a  volatility
adjusted blend   of  10%  ethanol in gasoline  (RVP =  9.0 psi),
their average CO emissions  changed by  33.3% from  the baseline
levels.   When they were tested on  a blend with 15%  MTBE, their
CO emissions changed by 2.7%.

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                                                       Page A-12

     Before the results can  be  averaged,  they must be  adjusted
to  offset  the  effects  of  different volatilities  and  oxygen
levels.    The  percentage  reductions  are  changed  to  represent
those  that would  be  achieved  by  a blend with  3.7%  oxygen
content and matched volatility to the base fuel.  When  a splash
blend of  10% ethanol  in  gasoline is used, the oxygen content is
already approximately 3.7%,  so the only adjustment that  is made
is  for  volatility.  This  RVP  adjustment  is made according to
the equations  presented in section 3.3.4  of this report.

     These  vehicles  had closed loop fuel  control  systems,  so
their emissions are  adjusted using  the  relationship of  RVP to
emissions  listed   for  vehicles  of  the   1981  and  later  model
years.   For  this   calculation,  the  following  values are  used.
The  CO  emissions   of  the vehicles  when   fueled  with the  blend
were  1.037  times the  emissions when the base fuel was  used (or
1 +  3.7%).  The  base fuel RVP  was  0.7 psi  lower than  that of
the  blend.  To simplify  the  calculations  at the  cost of only a
small error, the  effect of RVP  is calculated using a  base value
of  11.5  psi,  so  the  difference between   a  11.5  psi  fuel  and a
10.8  psi fuel is  calculated  first,  and  then  applied to  the
blend emission level.

CO @ -0.7 psi

     = CO (blend)  * (0.18753  + 0.07065 *  (ll.Spsi - 0.7))

     = CO (blend)  * 0.95055

     = CO (base)  *  1.037 * 0.95055

     = CO (base)  *  0.98572  (a reduction  of 1.4%)

     This  operation  separates   the effect  of  the  0.7  psi
difference  in  RVP  from  that   of   the   oxygen  content,  now
calculated  to be  a 1.4%  decrease.   For   the  matched  volatility
ethanol blend the  RVP  was already  matched,  so the matched RVP
column hc.s the same reductions as the actual test data.

     In  the next   column  test  data  from  blends  of  roughly 2%
oxygen are  adjusted to match the RVP of  the base gasoline and
to  have   exactly  2.0% oxygen.   In  the  case of  this  15% MTBE
blend,  the 0.1  psi  RVP  adjustment  and  the  oxygen  content
adjustment  from  2.7 to  2.0% result  in  smaller  effects  on all
three emissions.   This  is  followed  by  a column in which the
2.0%  oxygen numbers  are  proportionally  adjusted up   to 3.7%
oxygen to make  chem  directly  comparable  to  the  other  3.7%
oxygen data.   This  increases  the  effects on VOC, CO,  and NOx
to -6.4%, +2.7%,  and +8.8%.

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                                                       Page A-13

     The final combination of data is accomplished  in  the  three
columns labelled, "Average Reductions by  Study,  matched 3.7% Ox
and RVP, weighted together by  veh."   In the row for the  closed
loop vehicles  in Study V the  adjusted effects  of  each of  the
three  oxygenated  fuels are  combined by  weighting  the  effects
for each fuel by  the  number  of vehicles tested on  that  fuel in
that study, yielding  a CO increase  of  11.5%.   The totals  for
each column  are  similarly  combined by  weighting  the  results
from each study by  the number  of vehicles  in that study.   The
totals   for   all   closed-loop,  pre-'84  vehicles  show   a  CO
reduction of  19.7%.   The   last  three columns  provide  the  base
gasoline gram/mile emissions,  averaged  in  the same  way for each
column.  These values  may be compared between different  groups
of vehicles within  this summary  as  well as with  in-use emission
levels.

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                                                       Page A-14

                         Sources of Data
     The reports  from viich data  were  ta:
-------
                                                       Page A-15

R.   "Evaporative  and  Exhaust  Emissions  of  Two  Automobiles
     Fueled with  Volatility Adjusted  Gasohol," David  Lawrence
     and Daniel Niemczak, EPA  Report  EPA-AA-TEB-81-12,  December
     1. 80.

S.   "Exhaust and  Evaporative  Emissions  from  Alcohol  and Ether
     Fuel  Blends,"  T.~ M.  Naman  and  J.  R.  Allsup,  SAE  Paper
     800858, 1980.

T.   "Gasohol;    Laboratory  and  Fleet  Test  Evaluation,"  M.  D.
     Gurney, et al, SAE Paper 800892,  1980.

U.   "Gasohol,  TEA,  MTBE Effects  on  Light-Duty Emissions",  B.
     Bykowski,    Southwest   Research    Institute,   EPA   Rerort
     460/3-79-012,  NTIS PB 80224082, October 1S79.

V.   "Evaporative  and  Exhaust  Emissions  from Cars Fueled With
     Gasoline  Containing Ethanol  or  MTBE,"  R.   Furey  and  J.
     King, SAE Paper 800261.

W.   "Performance Evaluation of  Alcohol-Gasoline  Blends in 1980
     Model Automobiles:  Phase  1  - Gasoline-Ethanol Blends," CRC
     Report No.  527, July 1982.

X.   Clean  Air  Act  Waiver  Application  for  Oxinol,  ARCO,  May
     1981.

Y.   Clean  Air  Act  Waiver  Application  for  the  DuPont blend,
     July 11, 1984.

Z.   "In-House 23  Car  In-House Oxinol  Blend  Test  Program," EPA
     memo from Craig Harvey to Charles Gray, ECTD, November 19,
     1984.

AA.  "Characterization   of   Emissions    from  Vehicles   Using
     Methanol and  Methanol-Gasoline Blended Fuels,"  P.  Gabele
     et al, JAPCA Vol.  35, no.  11, 1168-1175, 1985.

AB.  "A  Generic  Report  of   Toxics   from   Oxygenated  Fuels,"
     Colorado Department  of Health, Spring  1987;   Note: CDH has
     stated these  preliminary  data are released for use in our
     report.

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