Summary and Analysis of Comments
                                   on the
                       Notice of Proposed Rulemaking
                  Emission  Standards and Test Procedures
                 for Methanol-Fueled Vehicles and Engines
                                January 1989
                 Standards Development and Support  Branch
                   Emission Control Technology  Division
                          Office of Mobile Sources
                        Office  of  Air  and Radiation
                   U.S.  Environmental Protection Agency
                                  HEADQUARTERS LIBRARY
                                  ENVIRONMENTAL PROTECTION AGENCY
                                  WASHINGTON, D.C. 20460


    Summary and Analysis of Comments
                 on the
     Notice of  Proposed Rulemaking
 Emission Standards and Test Procedures
for Methanol-Fueled Vehicles and Engines
              January 1989
Standards Development and Support Branch
  Emission Control Technology Division
        Office of Mobile Sources
       Office  of  Air  and Radiation
  U.S. Environmental Protection Agency


                Summary  and  Analysis  of  Comments
                             on the
                 Notice of Proposed Ruleraaking
             Emission Standards and Test Procedures
            for Methane1-Fueled Vehicles and Engines
                       Table of Contents
I.    Overview
       Introduction 	     4
       Goals of the Rulemaking 	     8
II.   Organic Emission Standards
       Basis of Organic Standards 	    12
       Separate Health Effects Based Standards
        for Methanol and Formaldehyde 	    37
       Optional Combined Exhaust and Evaporative
        Standards for Methanol Vehicle Organics 	    61
III. Other Emission Standards and Fuel
        Equivalency Factor
       Particulate and Smoke Standards 	    65
       CO and NOx Standards 	    72
       Crankcase Emissions 	    75
       Emissions Averaging Programs 	    78
       Determination of Fuel Equivalency 	    81
IV.   Emission Test Procedures
       Certification of Flexible Fuel Vehicles	    85
       Complexity of the Procedure for the Determination
         of Organic Emissions  	    89

Sampling and Analytical Procedures for the
  Measurement of Methanol Emissions,  Hydrocarbon
  Emissions and Formaldehyde Emissions	    96

Determination of Formaldehyde Background Levels...   104

Duct Connecting Vehicle Tailpipe (Engine
  Exhaust) to CVS (Dilution Tunnel)	   106

Vehicle Preconditioning  or Evaporative
  Emissions Testing	   110

Lean Flammability Limit in SHED	   Ill

Test Fuel Specification	   113

     On April  10,  1984  EPA published  an Advanced  Notice  of
Proposed  Rulemaking  (ANPRM),  which   announced   the  Agency's
intention to establish  emission standards  and test  procedures
for  methanol-fueled  engines and  vehicles of  every  currently
regulated class (51 FR  14244).   A  workshop was held  on  May 30,
1984  allowing  for  public  interaction  with the  Agency  on the
major  issues  of  the  rulemaking.   Written comments  were  also
solicited and  received.   These  comments were  fully  considered
by  the  Agency  during its  preparation  of  a  Notice of  Proposed
Rulemaking  (NPRM),  which  was  published August  29,  1986,  and
which  put  forward  EPA's  proposed  emission  standards and  test
procedures  (51  FR 30984).  Comments on  specific  topics  as  well
as general comments were solicited in the NPRM.
     A  public  hearing  was  held  on  October
oral comments  to the NPRM were  received  and
comments   were  also   received   from   24
publication of the rulemaking.
30,  1986 at  which
recorded.   Written
parties   following
     This  document  presents  a  staff  analysis  of  all  relevant
comments received in  response to  the  NPRM.   Where appropriate,
recommendations  are made  based  on this analysis  regarding the
format  of  the final  rules for methanol  engines  and vehicles.
While  the  analysis  serves to  facilitate  fulfillment  of EPA's
legal  requirement to  consider public comment in  the rulemaking
process,   it  also   serves   in  several  cases  to  update  the
technical  analysis   presented   originally  in   the  Regulatory
Support  Document (RSD)  to the NPRM.   The  RSD is  located in the
official rulemaking docket.

     A  list  of  commenters, showing date of  receipt of comments
by  the  Central  Docket  Section,   is   provided  below.   Common
abbreviations   for   the  organization  names  which  are  used
throughout  this document are  also listed.   It   is  noted that
many of  the  comments were received subsequent to  the deadline
(announced   in  the  Federal  Register   notice)  of November 28,
1986.   Legally,  EPA is  not required to consider  these comments
in  formulating  the  final  rules.   In  fact,  it  needs  to  be
cautious about considering them, because  late commenters may be
able  to unilaterally  rebut  arguments put   forward  by  earlier
ones.   All but  two  of the late comments were received prior to
December   17,  within  three  weeks  of the   official  deadline.
Given  the  significant  number  of  commenters  submitting  in this
time  period  and considering  the  minimal  period of  delay  in
submission,  staff  sees no overwhelming reason not  to consider
their  comments.  Two  of  the  commenters  (MECA   and  Crowell   &
Mooring  for  Brooklyn  Union   Gas   Company)   were,  however,
significantly  later  in their  submissions  and  would  have had
substantially  greater  opportunity  to   analyze  earlier comments
in  preparing their  own.   It  was,  however, the determination of


the authors  of  this document that  consideration of these  late
comments would  not unfairly  compromise the  opinions  of  those
whose  responses  were  more  timely,  nor  would  it materially
affect  the  formulation  of  the  final  rule.   On  this  basis,
therefore,  the  authors  have  chosen  to  include these comments in
the present  analysis  and  to  respond to  them.   In  considering
the recommendations  put  forward  in this  document,  the  Agency
need  not  be concerned  that  it  is acting   inappropriately  in
response to  late comments.*

     The comments  have  been  organized into  major  topic  areas
which are  addressed sequentially.   Concerns  about  EPA's  goals
in  the   present rulemaking  are  addressed  first.   Due to  the
number  of   comments  received  in  response  to  EPA's  proposed
organic  emission  standards,  and  the overall  importance of this
issue to the rulemaking,  this topic is handled  in  the next set
of  discussions.  These  are  followed by  sections on  the other
emission   standards  that   were   proposed   (carbon  monoxide,
nitroaen   oxides,    smoke/particulate,   crankcase   emissions),
emissions  averaging and  fuel  economy programs, test procedures,
certification fuel and treatment of flexible  fuel vehicles.
     California Air Resources  Board's  comments were received by
     EPA  in Ann Arbor  on or before December  17,  1986, but the
     copy  sent to  the docket  by the  Board was  not  received.
     The  Office of Mobile  Sources  sent another copy  in March;
     this  explains the  late date  of   receipt on  the  list of

List of Written Commenters
       to  the  NPRM*



at Docket







CNG Services of Pittsburgh, Inc.
Harry H. Hovey, Jr., P.E,
(N.Y. Div. of Air Resources)
American Gas Association
Caterpillar, Inc.
Chrysler Corporation
Jenner & Block
(Engine Manufacturing Asso.)
Volkswagen of America, Inc.
Nissan Research & Devel. , Inc.
California Energy Commission
Cummins Engine Co.
Nat'l Automobile Dealers Asso.
Chevron U.S.A., Inc.
Dept. of Energy
George S. Dominguez
(Oxygenated Fuels Asso.)
General Motors
MAN Nutzfahreuge Gmbh
Mercedes-Benz Truck Co.





IV-D-20   12-17-86     12-08-86   Toyota Tech.  Center,  USA,  Inc.    Toyota

IV-D-21   12-17-86     11-26-86   Chevron

IV-D-22   01-21-87     01-08-87   Manufacturers of Emission        MECA
                                  Controls Asso.

IV-D-23   03-20-87     03-18-87   Crowell & Moring
                                  (Brooklyn Union Gas Co.)

IV-D-24   04-14-87     11-26-86   California Air Resources        *  CARB
     Oral  comments were  received from  Ford,  Chrysler, General
     Motors,  and  the  Oxygenated  Fuels Association at the public
     hearing  on October 30,  1986.

Issue:  Goals of the Rulemaking

     EPA  decided  to provide  emission  standards for  methanol
vehicles in response to public and  private  interest  in methanol
as a  future motor  fuel.   The purpose of the  rulemaking was to
remove  a  potential impediment to  the introduction  of  methanol
as  a  motor  fuel  by  providing  auto  manufacturers  with  an
understanding of  the  regulatory requirements  to  which methanol
vehicles   would   ultimately  be    subjected.    The   Agency's
regulatory   approach  was   to   provide   standards   that   are
comparable  in  stringency  for  petroleum-fueled  and  methanol
vehicles.   This  section  of the  analysis addresses  any comments
received  which  are related generally  to the stated  purpose and
goals of the rulemaking.

Summary of  Comments

     Several of the commenters felt  that EPA should  be creating
standards  for  other alternative fuels in  addition to methanol,
or they felt that  methanol  vehicles  should  be  regulated  to  a
different degree  of stringency than  gasoline or diesel vehicles.

     The   state  of  New  York  commented   that   there  is  "a
substantial  research   effort   being  conducted  world-wide  to
produce  mixed  alcohols  from  synthesis gas."   Such  a mixture
might  contain   50  percent   methanol   and   50  percent  higher
alcohols  such  as ethanol,  isopropanol, and tert-butanol, and be
economical  to  produce,  while maintaining acceptable performance
in combustion  processes.   New York  argued that oxygenated fuels
will cause  emissions to  vary  from  those resulting from gasoline
fuel  in  a manner  related  to  total  oxygen  content.   This is
because of  two  factors.   Incremental  additions of  oxygen serve
1) to lean out  the  combustion  process incrementally,  and 2) to
increase  the quantity of  oxygenated species  in  the emissions.
New  York  therefore felt that the  current  regulations should be
broadened  to  include all oxygenated fuels  by setting standards
that  vary with oxygen content;   this  would  eliminate any future
need  to create  separate  regulations  for  each  new oxygenated
fuel that might  make its way to market.

     CNG  Services of Pittsburgh  felt  that  EPA should recognize
natural gas' potential  as  a clean  burning,  economically viable
alternative to  gasoline and  set  emission  standards for natural
gas-fueled  vehicles as well as methanol vehicles.

     General Motors  (GM) felt EPA's proposed  standards and  test
procedures  constituted  "rigid  and  complex   regulation."   GM
suggested  society might be  willing to accept higher emissions
from  methanol   vehicles   than  existing vehicles  in  order to
encourage   their  introduction  on  an  economically  competitive
basis  with existing  technology.    They  also  recommended   that
manufacturers   be   allowed   to   self-certify  their  methanol
vehicles  to  avoid  formal  and  costly EPA  certification.   Any

differences  in  the  stringency  of  requirements  for  methanol
vehicles and existing vehicles could  be reconsidered after  the
new technology had gained a foothold in the market.

     Volkswagen  and Chrysler expressed  the concern  that  there
is potential  for much optimization  in methanol technology  and
that the current  rulemaking  should not inhibit progress through
overly restrictive requirements.

     Despite generally agreeing  with  EPA's proposals,  both  the
Department of Energy  (DOE)  and  the Oxygenated Fuels Association
(OFA) wished  EPA to  set  standards on an  interim  basis,  to  be
revisited  after  several  years.    DOE noted  that  the  proposed
standards  will  reguire  essentially the same  technology  as  is
used on  current gasoline vehicles and  "do  not appear to impose
any  undue  economic   burden  on  potential   methane1   vehicle
manufacturers relative to  gasoline vehicle manufacturers."  DOE
felt,  however,   that  it  is  too early  to determine that  the
proposed  standards  represent the maximum control  stringency
applicable as identified by the  Clean  Air  Act  and as achievable
using  existing  or  anticipated  technology.   Interim standards
would  allow  a  phase  in  of   maximum  control  and  encourage
continued development of methanol engine technology.

     Other  commenters,  such  as  Chevron, NADA, and MECA,  agreed
with EPA's  position that final   rules,  comparable  in stringency
to  those currently  existent  should be  established.   MECA felt
that  standards  of  comparable  stringency  to   gasoline  vehicle
standards  should be  technologically  feasible  and  not  create a
disincentive  to  the development  of  methanol-fueled vehicles.
MSCA  argued  (similarly  to  DOE)  that   if   in  future   it  is
determined  that more stringent  standards  can  be  achieved with
methanol  vehicles  in  a cost effective manner,  they should be

Analysis of Comments

     With  regard to  the  inclusion of  other  alternative  fuels,
such  as  higher  alcohols   and  natural   gas,   in   the  present
rulemaking,   staff   notes   that  the   express   purpose   of  this
rulemaking,  as  first  stated in the  ANPRM, has  always been to
establish  standards specific to methanol.  The  rulemaking was
initiated  in response to  congressional,  executive,  and private
sector   interest  in  methanol   because  of   its   environmental
benefits,  its  engine performance  advantages,  and  its  relative
production economics  and   energy policy  implications.    Such
broad  based interest  in  other   fuels  has  not   been  demonstrated
to date.   If, however,  such  interest develops, the  Agency could
consider   setting  standards  for   these   fuels  as  well.   The
analyses  developed  in  connection  with the  present  rulemaking
are  specific  to  methanol,  and   it  is  appropriate  that  the
rulemaking go forward with its  focus  on that  fuel  alone.  It  is
noted  that if  the  Agency did wish to expand  the  scope of  this

rule,  specific  proposals  would  first  have  to  be issued  for
comment.  Thus it would not be possible for EPA to  finalize any
approach today that was  substantively different than that which
was  proposed.  Finalizing the rules  with their  present  scope,
however, does not prevent the Agency from  acting in the future
to address other  fuels with specific proposals.

     It  is  noted that the  standards  being finalized  with this
action  essentially  include  methanol  vehicles  under  the  same
framework   of   standards   that   already   exist   for   current
Otto-cycle  and diesel vehicles,  and  the  Agency could  adopt the
same  approach in regulating  other  alternative fuels  (taking
into  account  factors unique to them  as  appropriate).   Such
evenhanded   treatment  of   alternative   fuels   would  provide
equitable environmental  protection.   It  would also expedite the
process  of  including  other   alternative  fuels  under   the
regulatory  umbrella,  since  it  will not  necessarily  require
returning to  square  one  to derive  appropriate  standards.   Thus
while  the  present rulemaking does  not address  fuels other than
methanol, it  does lay the groundwork for an  expedited approach
to  addressing  them  as   it   becomes  apparent  that  a  lack  of
standards is hindering their  ability to enter the market.

     The  concerns of  various  commenters that  EPA should  not
establish  regulations which  might  be too  stringent and hinder
the  development  or   sale   of   methanol   vehicles  are  noted.
Methanol  offers  many  potential  benefits   to  society,  as  GM
points  out, and the Agency has  a strong  interest in recognizing
these  benefits  wherever  possible under  the law.   By the same
token,  the  Agency is  bound  to treat methanol vehicles equitably
with  existing technologies.   EPA's goal  in this rulemaking has
been   to   apply  standards   of   comparable   stringency   and
environmental benefit to  methanol  vehicles  as currently exist
for   other   technologies.    This   philosophy   is   especially
warranted  if,  as DOE  and,  by inference, MECA point out and as
other discussions in  this  document  will  show more  conclusively,
similar  control  technology  (in cost  and  complexity)   can  be
utilized  with  methanol   vehicles  as with  gasoline-fueled  or
diesel  vehicles.   Thus,  the feasibility and  relative  cost  of
the  standards are  not  at   issue,  and  there  is  no  basis  for
setting  relaxed  requirements   for  methanol   vehicles.   The
proposed  standards  do not  represent  disincentives to  produce
methanol  vehicles,   as   GM   suggests,   but  merely  equitable
application of   existing  environmental  protection   to  a  new
technology.   Furthermore,  by  providing  final,  as opposed  to
interim,  standards  of  comparable  stringency to  those   already
existent, EPA will  eliminate uncertainty over  further potential
restrictions.  Manufacturers can clearly  estimate,  under this
approach,   the   regulatory   burden  to  be  placed   on methanol
vehicles and  plan their  development programs accordingly.  This
argument  is not  intended to  suggest  that once a final  standard
is  established,  EPA may not  revisit  it  later.   The Agency may
revisit  any  standard   not   specifically  determined  by   law.

Setting   interim   standards   would,   however,    require    a
revisitation, and for EPA  to  leave the final standards open  in
this manner  would  result  in uncertainty  that could of  itself
affect manufacturers'  willingness  to  develop methanol vehicle


     With regard  to  the  question  of  including other  fuels  in
this rulemaking,  staff believes   that  EPA's  initial  focus  on
methanol was a proper  response  to the interests  of both  the
public and  private  sectors.  It  is therefore  recommended  that
this  rulemaking  continue  to  be  oriented  towards   methanol
exclusively.  Staff does suggest,  however,  that  EPA continue to
monitor  the  potential  of  other  fuel  alternatives  and  take
regulatory action in  their regard as may be  appropriate  in  the

     The  Agency's  initial goal  of  providing  final  standards
that   are    comparable   to   those  currently  applicable   to
gasoline-fueled  and diesel  technology has  several advantages.
First,  it   treats  methanol  vehicles  on  an  equal basis  with
alternative  technologies,  allowing  the market  to  operate more
efficiently.  Second,  it  removes  uncertainty  from  the  minds of
key  decision  makers  in   the automotive  industry.  Given  the
state  of development of  methanol  engine  technology  and  its
similarity  in terms  of emission  control  technology and cost to
gasoline-fueled  and  diesel   engine  technology, staff  sees  no
reason   to   either   promulgate   less  stringent  standards  for
methanol engines  or  to promulgate interim  standards  that need
to  be  revisited after  a  period  of  time.   Staff, therefore,
recommends  that  EPA  maintain its  previously stated philosophy
of  providing final emission  standards of comparable stringency
for petroleum-fueled  and methanol-fueled vehicles.

Issue:   Basis of Organic Standards

Summary of the Issue

     EPA  proposed  organic emission  standards that would  limit
the  amount  of   carbon  allowed  to  be  emitted  from  methanol
vehicles   (in   the   form  of   methanol,   formaldehyde   and
non-oxygenated  hydrocarbon*)  to  that   allowed   from  current
vehicles  under   their  applicable  HC standards.   Based on  the
results  of  computer  modeling  and  the  known  scientific  link
between the  photochemical  oxidation  of  carbon and ozone levels,
EPA  concluded  that  these  standards  would  be  sufficient  to
protect  against  increases  in   ambient  ozone.    The  NPRM  also
discussed  the  relative  merits  of  proposing  standards,  based
upon  photochemical  modeling,   that  would  ideally  result  in
equivalent ozone producing potential  from  methanol and gasoline
vehicles.   The  Agency  recognized  two major problems  with this
latter  approach.   First,  there  existed  significant uncertainty
regarding   how   best   to   translate  modeling   results   into
meaningful  standards.   Second,  EPA was  uncertain  as  to whether
photochemical modeling-based standards,  which  appeared to  be
less stringent based on a  single modeling  study of Los Angeles,
would  provide any  real cost advantage  to the  manufacturer  of
methanol vehicles.  EPA specifically requested  comments in both
of  these  areas  and stated  that  "should public  comment  ...  or
further  scientific  inquiry  establish  a  much  superior  cost
effectiveness and  demonstrate an acceptable environmental risk,
EPA would  consider  performing further photochemical modeling in
order  to  promulgate  such  standards in  the  final  rule."   The
major  issue  related  to  this  discussion  is  therefore whether
further  consideration of  photochemical  modeling-based  standards
is  necessary.   Another issue is whether  it  is  appropriate  to
regulate  the organics  under  one combined standard, as  proposed,
or whether there is a need for  a separate formaldehyde standard
to prevent  increases in ozone.

Summary of the Comments

     Most    commenters   found   EPA's   proposed   carbon-based
standards  acceptable.   Many  stated that there  is currently not
sufficient   modeling  data  to  support   standards   based  on
photochemical  modeling.   The   California  Air  Resources  Board
(CARS)  supported  the  carbon  standards  not  only because  it
believed  them to  be more  scientifically reasonable,  but also
*    Technically,  hydrocarbons  are  compounds  containing  only
hydrogen  and  carbon  and  by  definition  such  compounds  are
non-oxygenated.   The  term  non-oxygenated  hydrocarbon  is  used
here  to  distinguish  the traditional hydrocarbon  emissions  of
petroleum-fueled   vehicles   from   the  organic   emissions  of
methanol-fueled  vehicles.   Hereafter,  the  term  hydrocarbon
will be used.

because   it  believed   them  to   be   more   stringent   than
photochemical modeling  standards.   As  a  result such  standards
would  do  more  to  ensure  that  methanol  vehicles   would  be
environmentally favorable.

     Those  who  felt   that   there   is   currently  insufficient
photochemical  modeling  available   to   provide  a  basis   for
standards include  GARB,  Chevron, Chrysler, GM, Toyota,  and the
Department  of Energy.   Three main  concerns  were  raised by the
commenters  in this regard.  First,  it  was noted that modeling
to date  has been  simplified  box or trajectory modeling,  which
is  less   accurate  than  airshed  modeling.   Second, there  were
concerns  that  the  available   data  are  all  for  single-day
modeling, which  does  not  provide  information  on  the  effect of
methanol on multi-day episodes.   General Motors explained that:

     "Since  methanol  reacts  very  slowly,  its  total  effect on
     air  quality  cannot   be seen  accurately  in  single-day

Finally,  Chevron noted  that  the  photochemical modeling  based
standards   discussed  in   the NPRM  were  based  on  a  single
city-specific study.   Variations in local meteorology,  ambient
conditions,  and  HC  to  NOx  ratios  could  cause  substantial
variations  between any  two  given  cities.   In addition,  GARB
suggested  that  there could be   substantial variations from day
to day, even within a single city.   They stated:

     "Since   the   equivalence   of   methanol   and  formaldehyde
     reactivities   to   hydrocarbon   reactivity   depends    on
     atmospheric   and   meteorological   parameters   which   vary
     continuously,  any  factor that would convert  formaldehyde
     and  methanol  reactivities  into   equivalent   hydrocarbon
     reactivity would be unreliable."

     This  statement  indicates a lack of  confidence not only  in
the  currently available data base,  but  also in  the  concept  of
using  photochemical  modeling as the basis  of  setting emission

     In  addition  to  the issues   of  environmental  impacts,   there
are  also  economic  issues.   DOE stated:

     "The  proposed  [carbon-based]  methanol   vehicle emission
     standards  do not  appear  to  impose any undue,  economic
     burden  on   potential  methanol    vehicle    manufacturers
     relative to gasoline  vehicle manufacturers."

     Similarly, MECA stated that the proposed  standards "should
be   technologically    feasible   and   should  not   create   a
disincentive to the development  of  methanol-fueled  vehicles."

     Ford, GM,  and Caterpillar, who  felt  that EPA  should more
strongly  consider  the  possibility  of  photochemical  modeling
based  standards,   felt   that   such   standards  would  be  less
stringent  and therefore  less  expensive than  the  carbon-based
alternative.    Although,  GM  noted  that  they were  unable  to
estimate the economic benefits of this  approach.   The only real
data  provided  in  this   regard  came  from  Ford;   data for  17
methanol  vehicles  showed that  only 65  percent  of  prototype
vehicles  could meet  the  proposed exhaust  standards,  while  82
percent  could meet  the  photochemical  modeling-based standards
which  were discussed in  the  NPRM.   They did not  provide  any
data   on  evaporative  emissions   but   did   agree  that  the
carbon-based    evaporative    standards   would   be   feasible.
Caterpillar stated  that they expect  organic emissions  from the
heavy-duty methanol engine  that they  are  currently developing
will exceed the carbon-based standards  by at  least  a factor  of
two.   However,  no commenter  was  able to  provide  data  which
would enable a quantitative estimate of the  dollar  value of any
decreased stringency of photochemical modeling-based  standards.

     Ford  emphasized that  all  of  its data  was  from  vehicles
with  fairly   low  mileage, and  thus  did not  resolve  issues  of
durability.   They  did  qualify this  claim  by stating  in their
oral testimony that they  had  "not had  the  benefit  of  the full
development capability  of the Ford Motor  Company" in the design
of their methanol prototypes.

     With  respect  to  such  concerns   about   feasibility  and
durability, MECA  stated:

     "we   expect   fully   optimized   systems   with  excellent
     durability  will  be  available  and   that   the  standards
     proposed  by  EPA will  be  achievable  over  the applicable
     useful life  of the various vehicles covered."

     In  order  to compensate for the fact that there may not  be
enough  modeling  information  to promulgate  photochemistry-based
standards,  Chrysler suggested  that  the  carbon-based standards
could  be  adjusted to  make  them  equivalent  in  stringency  to
photochemistry-based  standards.   As   an  alternative.  General
Motors  suggested that multi-day airshed modeling of six  cities
(Los  Angeles,  Philadelphia,  St.  Louis,  Denver,   Washington  DC
and  Houston)  or  regional  modeling would  provide sufficient
basis to promulgate standards  based on  photochemistry.

     Ford,  who  presented the  results  of   their   own  modeling
study  of 20  cities, was  the  only  commenter  to state that there
is   already   enough   modeling   data   to   promulgate   final
photochemistry-based  standards.   Their  analysis  showed methanol
to be  38 percent as reactive  as hydrocarbons,  and  formaldehyde
to be 4.8 times  as  reactive.


     Several  commenters   (AGA,  Brooklyn  Union  Gas,   GARB  and
Chevron)   were   concerned   about   the   photoreactivity   of
formaldehyde.  They felt  that  a separate formaldehyde  standard
would  be  necessary to prevent  increased ozone  formation.   AGA
argued  that  formaldehyde  is  different   from   other   organic
emissions.   They stated  that  "formaldehyde  is  photosensitive
and,  in  sunlight,  reacts  in  such  a way that  it becomes  a  key
component of smog."

     Both GARB and  Chevron cited the study by the University of
California,  Riverside,  which  indicated that  the  formaldehyde
content of  emissions  from methanol-fueled vehicles must be less
than 10 percent of the organic emissions to prevent an increase
in  ozone.   CARB  suggested numerical  standards  that would limit
the amount  of  formaldehyde emitted to that of  current gasoline
and  diesel  vehicles.    CARB   also  listed  the  toxicity  and
carcinogenicity of  formaldehyde  (discussed  in a  later section)
as  reasons  for these standards.   These standards  are  shown in
Table  1.   They  stated,   "based on favorable  input  from (two)
manufacturers  and  CARB  data,  CARB  believes  that  a  15 fug/mi
formaldehyde emission standard for  certification is feasible by

Nissan warned, however, that:

      "If  a separate formaldehyde  standard  is established using
      formaldehyde emissions  data from gasoline fueled vehicles,
     Nissan   anticipates   difficulties   complying   with  the
      standard using currently available technology."

CEC felt  that while  these standards might not be feasible at
this  time,  they should be  imposed  as  soon as possible.

      EMA,  however,  felt  that,  in  the absence of adequate ozone
modeling,  it would  be  inappropriate  to promulgate  a  separate
formaldehyde   standard   based  upon  photochemical   reactivity

      Brooklyn  Union  Gas  felt  that  it  is  not  sufficient to
assess  the ozone   impacts  of  formaldehyde  using   data  from
prototype vehicles,  which,  they  stated,   "cannot  be  reliably
translated into  in-use performance."

Analysis  of Comments

      Based  on   an   analysis  performed for  the   NPRM  it   was
concluded that the  carbon-based standards  will be  sufficient to
prevent any increases  in urban  ozone levels.  This  analysis  was

                               Table  l
         CARB's Recommended Formaldehyde Emission Standards
Passenger Cars
LDT, MDV 0-3999 Ibs.*

LDT, MDV 4000-5999  Ibs

MDV 6000-8500 Ibs.
Heavy-Duty Engines
  & Vehicles
Cert.  Standard
(1990  and later)

15 mg/mi

18 mg/mi

22 mg/mi

0.05 g/BHP-hr
   In-Use Compliance
23 mg/mi (1990-1993)
15 mg/mi (1994 and later)

27 mg/mi (1990-1993)
18 mg/mi (1994 and later)

33 mg/mi (1990-1993)
22 mg/mi (1994 and later)

0.1 g/BHP-hr (1990-1993)
0.05 g/BHP-hr (1994 and
     Equivalent inertia weight.


repeated using more recent  emissions  data  (see [1]),  as well  as
newly available  photochemical  modeling data  (discussed below).
The results  (Table  2) indicate that  methanol  vehicle  emissions
under the  carbon-based  standards  will  have between  54  and  95
percent  of  the  ozone  forming potential   of  gasoline vehicle
emissions,  depending on the city and  study.  The fact  that  many
additional  cities have now  been modeled (which means  a range  of
conditions  were modeled)  offers some additional assurance  that
EPA's  earlier conclusion  was  fairly accurate  and that  these
standards can be expected to be sufficient  to  generally prevent
ozone  increases.    No commenter  disagreed with  EPA's earlier
finding in this regard.

     It should be  noted that  estimation of the emissions  from
gasoline  vehicles  represents  emissions   of   1990  and   later
vehicles at  50,000  miles and  is  based  on  the assumption  that
the problems  of  misfueling  (using  leaded gasoline in a catalyst
venicle) and excess volatility  are  corrected.   This approach is
reasonable for  two  reasons.  First,  it results in  a much more
conservative  estimate of  the  relative ozone  forming potential
of  methanol  vehicles  than  would  assuming that these problems
are  not corrected  for  gasoline  vehicles.   (Estimates  of  the
ozone  forming potential  of methanol  vehicles  would be about 20
percent  lower than those  in  Table  2 if  it  were  assumed that
these problems were not corrected.)

     Second,  it  would not  be  appropriate   to  base  the analysis
on  actual  current  gasoline   vehicle emissions  which  include
emissions  due to  misfueling  and  excess volatility  when  these
problems  may very   well   be   eliminated   in  the  future,  and
possibly  even before methanol vehicles achieve  a significant
market  penetration.   The  incidence of   misfueling  has  been
declining  in recent years,  and it  is not unreasonable to assume
that  this  trend  will continue  as the  availability  of  leaded
gasoline declines  in response  to  lower numbers of non-catalyst
vehicles   in the   fleet.   EPA's   more  stringent  controls  on
addition  of  lead   to fuel may also reduce  the  incidence and
severity  of  the  problem.    Therefore,  it  is  appropriate  to
assume   that  by  time  methanol    vehicles   represent  a   large
fraction of  the market, misfueling  will  be only a minor problem
at  worst.    It  is  also  reasonable  to  assume, conservatively,
that   the   problem  of  excess  gasoline   volatility  will  be
addressed  in  a  similar  time  frame.   On  August  19,  1987, the
Agency  proposed  limiting  the  volatility of in-use fuels to more
closely match  that  of  the   certification fuel.    This   action
would do much to eliminate  the  problem of  excess volatility.

     Assuming that  both  of  these  problems   that currently  affect
gasoline  vehicle  emissions  are  eliminated  is  consistent with
the approach taken  in  EPA's  earlier analysis as  presented  in
the Regulatory Support Document for the NPRM.

                   Table 2

Relative Ozone Potential of Methanol Vehicles
     Certified to Carbon Based Standards
        Relative to Gasoline Vehicles  	
              Los Angeles


              El Paso
              Fort Worth
              St. Louis
              Washington, D.C.
Relative Ozone




     It was  also concluded  in the  earlier analysis  that  the
proposed  carbon-based   standards   would  be  feasible,   using
technology similar to that used  for current gasoline  vehicles.
Ford and  Caterpillar  argued otherwise, but  their  arguments  are
not convincing.   They  did not demonstrate  that  there would  be
any  significant  hardware burden   associated  with  the  carbon
standards.  To  date there  has not  been extensive  development
work   done   on   emissions   from  methanol  vehicles.    Ford's
testimony makes  this clear.   In  Ford's case the only  emissions
goal was  to meet the  current gasoline standards.   Caterpillar's
development goals were  not  stated.  Prototype methanol  vehicle
emission  control  systems  are  not  generally  optimized  with
respect  to  a  set  of   design standards  specific  to  methanol
engine  technology.   Based   on   the  data  that  is  available
(including that  submitted by Ford,  as will be  discussed later
in  this  section),  it  is still  expected that the carbon-based
standards will be feasible,  and as  DOE stated, will  not "impose
any undue burden on potential methanol vehicle manufacturers."
This is further  supported by MECA's comments.

     Thus, the  available information  continues to  suggest that
carbon  based   standards  are  adequate  both to  protect  against
increases in ozone  and  to be technologically  feasible at costs
similar to today's standards.

     In  order  to  appropriately  decide,   however,  whether  to
recommend  promulgation  of   such   standards  or  to  recommend
continued   consideration    of   photochemical   modeling-based
standards, staff decided to  consider  the comments  in  the light
of these three relevant  questions:

     (1)   is    there    a   sufficient   modeling   basis    for
           promulgating  photochemical  standards?
     (2)   Would the  environmental  impacts of  these standards
           be acceptable?
     (3)   Would there  be   a  significant  cost  savings  with
           standards based on modeling?

     Before  assessing the  adequacy of  the  available  modeling
base,  it  would be  useful  to   briefly   review  photochemical
modeling  and  how EPA suggested it  would  use it as  a basis  for

     The  usual  approach to  modeling  assumes that  air  parcels
can be viewed  as completely  mixed  boxes (or cells) of air,  with
emissions  of  pollutants  from  ground  level,  dilution  by  the
aloft   layer,   and,  in  some  models,   exchange  between   the
different cells of air.   There  are  two  basic types  of  models:
airshed  and trajectory.  Airshed  models use  a  large number  of
cells  to cover  an entire  area,  and  usually  have two  or  three
vertical  layers  in  each cell.  These cells do not move,  but  air
is  moved from cell to  cell based  on meteorological data.   In
trajectory  modeling,  a  single  cell  (or  several  cells  stacked

vertically)  moves  across  the  modeled  area.   Often  the  path
followed is  determined from  a previous airshed run;  however, in
some  cases  it  is  simply  assumed.   Chemical  reactions  are
modeled  by  a  chemical  mechanism,  which  is  a system of  rate
equations.   By modeling the mass transfer  and chemical kinetics
simultaneously, the  model  is  able to  predict concentrations of
various pollutants inside  an  air  parcel as a  function  of  time.
The  inputs  to  these  models  include  meteorology,  emissions
(amount  and  speciation),  and  initial  and boundary  conditions.
The   outputs  can   be  concentration  profiles  for   various
compounds,    but   usually   just   the    maximum  hourly   ozone
concentration  is  reported.    Results   for  a  set  of  emission
scenarios,  defined  by the amount and chemical  composition of
the  emissions  used  as  input  to  the  model,  are  typically
included  in  a photochemistry study,   along  with  appropriate
sensitivity  runs to vary background and  initial conditions.
     EPA  has  found it useful,  when using  photochemical  models
to  evaluate the  impact  of methanol  fuel use  on  ambient ozone
levels,  to divide  mobile  source  organic emissions  into three
groups:   hydrocarbons, methanol,  and  formaldehyde.   By assuming
that peak hourly  ozone levels  for  the modeled  area  are linear
functions  of  each of  these   groups  of  emissions,   the  Agency
developed  a  simple model  which  can  predict   changes   in  the
maximum   ozone   levels   from   changes  in  emissions.    This
assumption  of  linearity  simply  means  that the  reduction  in
maximum  ozone  level  is  proportional  to the reductions  in the
emissions of each group, weighted by its  relative reactivity.

     In  EPA's  model,  the  relative  reactivity   for  a group  of
emissions  is  defined  as  the peak hourly  ozone produced by those
emissions divided by the peak  hourly  ozone  produced  by the same
amount  of mobile  source hydrocarbon  emissions.   For example, a
relative  reactivity  of  0.50  would  mean that  emissions  of  a
certain  type (e.g., methanol)  would  produce only 50 percent as
much  ozone as  the same  amount  (in  carbon)  of mobile  source

     In   order   to  calculate  the  relative   reactivities  for
methanol  and  formaldehyde  it  is  necessary to have  modeling
results  for at least four different  emissions  scenarios.   Of
these  one must be  a  base case (i.e.,   current  emissions),  one
must   be  a  blank  case   (i.e.,   mobile  source  hydrocarbons
removed),  and  the  other  two  must  include  some  combination of
methanol  and formaldehyde  emissions.    The  peak ozone produced
by  mobile source  hydrocarbons  can be  found  by subtracting the
maximum  ozone  concentration of the blank case  from  the  maximum
concentration  of  the  base  case.   The  blank  case concentration
is  also  subtracted from the  other cases,  and the  peak ozone
produced    by   the   methanol   and    formaldehyde   is   found
algebraically.   This  type of  model was developed in Appendix A
of  the  Regulatory Support  Document,  where  it was shown  to

accurately  predict   ozone   levels  for  various   substitution
scenarios for Los Angeles,  as modeled by SAI.

     Many of  the cormnenters agreed  that  the single study  used
to  develop  the  example   of   a   photochemical   modeling-based
standard  for   the   NPRM  was  not   a  sufficient  basis   for
promulgating final  standards.   To date there  have been only  a
limited  number  of  studies  involving photochemical modeling  of
methanoi  substitutions.   Of these,  EPA finds  that only  three
are appropriate for purposes of developing standards;  they are:

     (1)   SAI's study of Los Angeles for ARCO, February 1983[2]
     (2)   SAI's study of Philadelphia for EPA, March 1986[3]
     (3)   Ford's study of 20 non-Californian cities 1985[4]

     The  first  study was considered in the NPRM,  but  the other
two  have become  available  more  recently.    These studies  all
included  runs  for  the  base  case,  no mobile sources,  and at
least two combinations  of  methanoi  and  formaldehyde  emissions,
A  study of  Los Angeles by  Jet Propulsion Laboratory! 5] was not
used because it did not have a "no mobile sources" case.

     The  three  studies  that were  appropriate  for  EPA's current
purpose  have  some  similarities.   For  example,   the  two  SAI
studies  both  included  some  airshed  modeling,   and  all  three
studies  used some  form  of the  Ozone  Isopleth  Plotting  with
Optional Mechanisms  (OZIPM)  model which incorporated a modified
version  of  the  Carbon-Bond  Mechanism  for   kinetics.[6]   The
OZIPM is a single-cell  trajectory type  model.   As was mentioned
previously,  this  type  of  modeling  only   provides  the  ozone
values  for  one air  parcel,  while  airshed   modeling  predicts
values   for  the   entire   modeled   domain.    The  Carbon-Bond
Mechanism  simulates chemical  kinetics using  reactions between
types  of chemical  bonds,   and not  between  explicit  compounds.
This  is  done  to  limit the  number  of  rate  equations  in the

     The  SAI  study of  Los  Angeles  modeled  a 24-hour period of
June 26th and 27th, 1974,   The study included  a  base  case run
of  the  entire  airshed  that was validated against monitor  data.
This run was used to identify the  trajectory of the air parcel
which had the maximum one-hour ozone concentration.  Additional
scenarios were  run for this  trajectory only, since  it is  much
less  expensive  to  model a trajectory than  it  is  to  model an
entire  airshed.  Considerable effort was  put  into  developing
the  input  for  this  study,  including  the  base  case emissions,
which  were projected  to 1987.   Scenarios  with replacement of
emissions  from  gasoline vehicles  by various  amounts of methanoi
and  formaldehyde were  investigated by SAI.   Selected results of
this modeling are shown in  Table  3.

                            Table 3
          Selected Results of SAI Study of Los Angeles
Base Case
Mobile Sources Replaced with
100% Methanol**
Mobile Sources Replaced with
80% Methanol & 10% Formaldehyde
Mobile Sources Replaced with
80% Methanol & 20% Formaldehyde
Mobile Sources Replaced with
180% Methanol & 20% Formaldehyde
Mobile Sources Replaced with
135% Methanol & 15% Formaldehyde
No Mobile Sources
Maximum 1-hour





        0. 186
*    All scenarios use base case NOx emissions.
**   All percentages are with respect to moles of carbon,


     The SAI study of  Philadelphia was  similar  to its study  of
Los  Angeles.   In this  study SAI  modeled a  16-hour  period  of
July 13, 1979  with  emissions projected to  the  year  2000.   The
airshed modeling  was  used  in a  similar  fashion  as  in the  LA
study  to  identify  the  trajectory  of  the  peak  ozone  parcel.
Trajectory  modeling  was  then used  to  identify  the  effect  of
various   methanol   substitution   scenarios   on   peak   ozone
concentrations in this parcel.   EPA  later  performed  additional
trajectory  simulations,  extending  the  modeling  period  to  19
hours.[7]    Two of these  additional   runs were  duplications  of
the  "base case"  and  "zero  mobile  source hydrocarbon  case"  runs
performed by  SAI.   The  "base case"  duplication after  16  hours
showed  good agreement  with  SAI's  results  (0.202  ppm of  ozone
versus  SAI's   0.204  ppm),   but  the   "zero   mobile   source
hydrocarbons case" did not  (0.171  ppm versus SAI's 0.156  ppm).
Discussions  with SAI  have  failed  to resolve this  discrepancy.
Additionally,  in each  simulation  performed  by  EPA  the  ozone
concentration  in  the  parcel  was still   increasing after  16
hours,  and  reached  its maximum between 16   and 19 hours.   For
these  reasons,  only the results  of  EPA's  simulations  are used
here.  These results are shown in Table 4.

     Ford's    study   modeled   ozone    exceedances    in   20
non-attainment  cities  outside  of California  using the  City
Specific  EKMA Model.   This approach does  not  use  an  airshed
model  to  generate trajectories;  instead simplified trajectories
are  assumed.   This  assumption precludes the  use  of  information
about  the  actual trajectory, such as the  velocity,  whether it
passes  over  any distinct   sources  which  may   or  may  not  be
affected  by methanol  substitution,  and whether  the  air parcel
undergoes   significant  local  stagnation.    Emissions data   for
this study  were  obtained primarily from state  SIPs,  but default
values  were used to  speciate organic emissions.   Some cities,
however,  may  have  organic  emissions which  are  different  from
default emissions (perhaps  due  to  a  particular  industry's local
predominance).   The  model's assumptions do  not allow situations
such as this to be  addressed.   These  two  assumptions could have
a  significant  effect on the accuracy of the  study  and thus,  the
results must be  used with  some  caution.   That is, for any given
city in the study,  the results might  not  be  representative of
what would  typically or, for that  matter, ever  happen in use in
that city.

     In each of  the  cities  four scenarios were  modeled:

      (1)    Base  case.
      (2)    All LDV  hydrocarbons   replaced  with  methanol  on a
            one-to-one  carbon basis.
      (3)    All  LDV  hydrocarbons  replaced  with  a  90   percent
            methanol,   ten   percent formaldehyde  mixture   on a
            one-to-one  carbon basis.
      (4)    Blank case; where all LDV  hydrocarbons are removed.

                             Table  4
         Selected  Results  of  SAI's jStudy  of  Philadelphia
Base Case
Mobile Sources Replaced with 15% Methanol**
Mobile Sources Replaced with 25% Methanol
Mobile Sources Replaced with 50% Methanol
Mobile Sources Replaced with 75% Methanol
Mobile Sources Replaced with 1% Formaldehyde
Mobile Sources Replaced with 5% Formaldehyde
Mobile Sources Replaced with 10% Formaldehyde   0.2126
Maximum 1-hour O^Cppm)
*    All scenarios use base case NOx emissions.
**   All percentages are with respect to moles of carbon.

The results are show  in Table 5.

     As stated  before,  if one assumes that ozone production  is
a linear function of emissions,  then one can use these  modeling
results to  create  a  linear model  for  ozone  formation, as was
done  previously  with  the  results  of  SAI' s  study   of  Los
Angeles.  This  approach was  found  to accurately predict  ozone
levels for a  few  other  scenarios  in the Los Anaeles study.   It
is  now  shown  to  also  work  very  well with  the  Philadelphia
study.   Unfortunately,   it  was  not   possible  to  test  the
appropriateness of  the  linear approach using the data  from the
Ford study, since  results  were  presented for  only  enough  cases
to  allow  calculation  of  the  relative  reactivities.   EPA's
calculated reactivities, from these three studies,  are  shown  in
Table 6.

     Ford used  an alternate method to  translate  their  modeling
results  into  reactivities.   While  EPA  calculated  reactivities
for  each city,  Ford chose to combine  all 20  of the maximum
ozone concentrations  for  each of  the  four  scenarios, to obtain
an  average maximum ozone concentration  for  each scenario.   They
then  calculated a single  reactivity  for methanol  and  a single
reactivity  for   formaldehyde   based  on  these  average  ozone
results.  The Agency  felt that this  approach  was  not  the most
appropriate,  however,   since  ozone  values  for  different cities
are not necessarily similar,  and  thus average  ozone  values for
each  scenario  lack  practical  significance.    It  seems  more
reasonable    to   calculate   reactivities   for    each   city
individually,  and  to  compare  these  reactivities,  as  EPA has
done. Admittedly,  EPA's approach  does  not  produce dramatically
different  results, on  the average across  all 20  cities, than
Ford's  in this  case, but could do so  given  a  different modeling
base.   EPA's  approach  does allow the  relative reactivities  of
methanol and  formaldehyde  in  different  cities to  be compared to
one another, whereas Ford's approach does not.

     As   several   commenters   noted,   there   are  significant
limitations to  the  modeling described by  EPA  in the NPRM.   Even
given  the additional  modeling described  here, there  is   still
concern  about  the  sufficiency  of  the  available  data.   For
example,  while  Ford's  study  does  address   the  question  of
city-to-city  variations,  it  does not  do  so  conclusively.  In
order  to adequately  account for  such variations,  modeling  of
all   (or  many   more)   ozone  non-attainment   cities   would  be
necessary  before a standard  could  be set.   Additionally,  there
is  uncertainty  in  the  assumptions   regarding  emissions  and
trajectory  data,  as  discussed  previously.   Modeling using more
detailed   input  data  could   change   the   reactivity  factors
developed  for each modeled city.   Finally, Ford did not perform
its modeling with  EPA's linear ozone  model  in mind,  and thus
did not  run  enough  emission scenarios   to  allow  the  linear
assumption to be  tested in each city.

                                 Table  5

                   Peak Hourly Ozone Concentrations*
                   Reported  in Ford's  Modeling  Study
El Paso
Ft. Worth
St. Louis
Washington, D.C.
100% Methanol 90% Methanol
Base Case
0 .272
10% Formaldehyde
0 . 172
No Mobile

  0. 140
     All concentrations in ppm.

     The other concerns mentioned  by  the  commenters also remain
valid.   The  concern   about   the  reliability  of   trajectory
modeling is  justified,  since such modeling gives  only  the  peak
concentration in the  modeled  air parcel,  and  not  the  peak  for
an  entire   area  as  airshed  modeling  would.    Since  the  peak
parcel is identified  using only the  base  case airshed  run,  it
is  possible,  perhaps even likely, that  the modeled parcel  is
not  the  peak  parcel  for  all  of  the  emissions  scenarios,
especially  those that  are very different from  the base  case
(e.g.,  100  percent  methanol   substitution).   Also,   airshed
modeling is more sophisticated  than trajectory or  box modeling,
and thus if performed properly can be more accurate.

     The concern about  the effects  of  methanol  emissions  in
multi-day episodes  is  also justified.   As  GM  noted,  methanol
reacts  slowly  and  thus   could  possibly  accumulate   in  the
atmosphere or be transported  downwind.   If methanol accumulates
to  a  high   enough   concentration   its  effect  on  ozone  could
increase  in  significance.   Also,  transported  methanol  could
lead  to  increased  ozone  levels  downwind.   The  extent  of these
multi-day  effects  cannot  be   reasonably  predicted  from  the
single-day modeling that is currently available.

     CARB's  comment  that  day-to-day variations  in atmospheric
and  meteorological   parameters   could  make  it  difficult  to
reliably characterize the  relative reactivities  of methanol and
formaldehyde,  even   in  a  given  city,  is  also  relevant.  Staff
does  recognize  the  need  for  caution,  because of  concerns such
as  this,  when  considering the results  of  a  limited  set  of
modeling runs.

     Given  the  limitations  in  the   existing  data   base,  as
discussed above, staff  concludes that  an  insufficient  amount of
modeling has  been performed  to justify the  elaborate  analytic
manipulations  that  would  be  necessary to promulgate meaningful
standards    based    directly    on    empirical    photochemistry
relationships.   Standards  based on  the  existing  modeling data
would  have to be developed using a conservative methodology, as
will be discussed below.

      Some  of these  limitations  could be addressed by  further
modeling, as noted by General  Motors.  In fact, Carnegie Mellon
University  is currently performing  multi-day  airshed  modeling
of  Los Angeles,  under contract  for the California Air  Resources
Board;  however,  it is   doubtful that   the  results   will  be
applicable  to other  cities,  because of  the  unique  meteorology
of  the  South Coast Air  Basin.  The  basin  is bounded by  the
ocean to  the west  and  mountains to the  east,   and  thus  it
experiences  a great  number of  severe  stagnations, which  is  not
representative  of meteorology in  most non-attainment  areas.   A
sufficient  amount  of multi-day modeling studies, even  for  just
six cities  as  GM suggested, could take years  to  complete.

     Even if  EPA  were confident that enough  modeling  data were
available to  address all  of  these  concerns,  or  if  a  method
could be  developed  by  which  uncertainty  in the  modeling data
base could be accounted for (e.g.,  the use of  a  safety factor),
there  would  still  be  other  issues   related  to how  to  set
standards based on photochemical modeling.

     Since the NPRM  was  published  and additional  modeling data
made  available,   EPA  has  examined  several  examples  of  how
photochemical modeling could be used to  set  standards.   Each of
these  takes  a  different  approach  to  choosing  the  relative
reactivities  for  methanol  and formaldehyde  for  use  in  the
mathematical  expression   of  the  standard.    (In  the  NPRM,
reactivities  based  only on  Los Angeles modeling  were  used by
way  of  example.)   These  could  be  average  values  for  the
reactivities  of  methanol and  formaldehyde  for  several  cities,
reactivities  for  a  single  worst  case city,  or  worst  case
reactivities  for  each  pollutant  (regardless  of  city).   These
three   approaches   are  discussed  below.    In   addition,  the
question of whether  it would  be  necessary  to include  a margin
of  safety,  due  to  the  uncertainty  concerning  photochemical
modeling, is  considered.

     Average  values  for the  22  relative  reactivities  in Table  6
(which  includes   data for  each of  the three relevant  studies
discussed  previously)  are  0.41  for  methanol   and  4.76  for
formaldehyde.   These numbers   could  be used to  set  standards
simply by replacing  the numbers used to  weight emissions in the
photochemical  modeling-based  standards  discussed  in the NPRM
(0.02 and  2.95  for methanol and formaldehyde respectively).   A
major  problem with  this  approach,  however,  is  that  it would
probably  result  in  methanol  vehicles  in some cities  producing
more  ozone  than the  gasoline  vehicles which  they replace.   An
example of  this  can be seen by assuming that exhaust emissions
are  37  percent   hydrocarbons,  58  percent  methanol,   and  five
percent  formaldehyde  and  that evaporative   emissions  are  47
percent  hydrocarbons (all  percentages  are  on a carbon basis),
as  appears  to be likely based  on  EPA's emission  data  base for
prototype  methanol  vehicles  (see  [1]);  according  to Ford's
data, Houston, already  in non-compliance with the ozone NAAQS,
would have  a  17  percent increase in mobile source related ozone
for  complete  methanol  substitution,   and  other  cities  would
experience  smaller  increases   as  well.   This  approach cannot,
therefore, be recommended.

     The  second  approach would be to  use  the  reactivities of
the  worst  case city in  the modeling data base.    Unfortunately,
which city would be  considered  the worst case city is dependent
upon  the amount  of formaldehyde co-emitted  with the methanol,
since   the   ratio   of   formaldehyde   reactivity   to   methanol
reactivity  varies from city  to city.   While  the ratio between

                           Table 6

                  Calculated Reactivities of
                  Methanol and Formaldehyde
                  (Relative to Hydrocarbons)

Study       	City	       Reactivity        Reactivity

 SAI        Los Angeles             0.02*              2.95

 SAI        Philadelphia            0.413              5.873

 Ford       Allentown               0.350              4.600

Los Angeles
El Paso
Ft. Worth
St. Louis
Washington B.C.
Youngs town
    For   substitutions  less  than   100  percent  only.    For
    substitutions beyond 100 percent  the reactivity is  0.481.

methanol  and  formaldehyde emissions  differs  from vehicle  to
vehicle,   it   is   possible  to   estimate   a  fleet   average
formaldehyde  fraction  based   on   prototype  methanol  vehicle
performance;  however,  an  accurate  fleet average  formaldehyde
fraction would  require in-use  emissions  data for  all  types  of
vehicles,  as  well  as  data  on the  relative  market  fraction  of
each type  of  vehicle.   Furthermore, as the  relative numbers  of
each type  of  vehicle  change,  then the  city considered  to  be
worst case could change,  and as a  result  the standard may need
to be  changed.   The standard may also need to be  modified  as
vehicle  technology  changes   result   in   variations   in  the
formaldehyde  to  methanol  ratio.   For   these  reasons,  this
approach also seems inadequate.

     The final  approach would  be  to use  the highest value for
each of the  reactivities.   Based  on  the  existing  data,  this
would mean using  the  methanol  reactivity  for  Houston  (0.625)
and  the  formaldehyde  reactivity  for   Ft.   Worth  (5.972).
Assuming the  same  relative emissions  as  before,  this approach
would allow the amount  of carbon  emissions to  be essentially
equivalent  to  those under  the carbon-based  standards, and ozone
reductions  might still  be expected  to  occur   in  each  of  the
cities  modeled  to  date.   This  approach   seems  to be  the most
reasonable  of  the  three,  since  it  would   adequately   protect
against  ozone  increases,  assuming that the  the  current modeling
data base   is  sufficient.   It  should  also  be  noted  that this
approach  would  not result  in   true ozone  equivalence  between
methanol and  gasoline vehicles,  which was  the stated  goal  of
considering  photochemical  modeling-based   standards.    Rather,
this  approach  would  serve  to  limit  methanol  vehicle ozone
potential  to  that  of  gasoline  vehicles.   However,  there is  no
apparent  alternative  to  ensure  that  no  city would have  an
increase  in ozone  due to  methanol vehicles.   Thus,  as  is the
case for the carbon-based  standards,  there  is  no need  for  an
additional  margin  of  safety  since this  approach  is  already

     Thus,  with  regard  to  the  second question  posed  in the
introduction  to this  analysis,  staff  concludes that  it  may be
possible  to design  environmentally acceptable  standards based
on  photochemical   modeling  but  that   such  standards  are  not
likely  to  be  any  less  stringent   (in  terms  of   total   carbon
emissions)  than  carbon-based  standards.   Additionally,  it  is
noted that  the  standards may need to be revised as new modeling
studies    are   performed,    reflecting   changes   in  modeling
techniques  and/or real world parameters.

     The   final  and   perhaps   most  relevant  question  to  be
answered   is   whether   photochemical  modeling-based   standards
would provide a significant  benefit to  the manufacturers.  To
answer  this  question,  the  third  approach  described  above  is
compared to the proposed  carbon-based standards.  While it  is
true that  the two alternatives will allow roughly  equal  amounts

of  total  carbon to  be emitted,  it is  not true  that the  two
would  be  identical.   Due  to  differences  between  individual
vehicles, and the differences between  the  makeup of exhaust  and
evaporative emissions, there  could still  be economic  benefits
from standards based on photochemical  modeling.

     For  exhaust  emissions,  the  relative  stringency of  these
two   alternatives    depends  on   the   relative   amounts   of
hydrocarbons,  methanol  and formaldehyde  in the  emissions.   If
the formaldehyde to  methanol  ratio (as  carbon) in  the  exhaust
was greater  than 0.075,*  then exhaust  standards based  on  the
third  photochemical  modeling approach  (without  any additional
safety  factor)   would  be  more  stringent  than  the  proposed
carbon-based  standards.   That  is,  a  vehicle could  potentially
meet  the  carbon-based   standard  but   not  the  photochemical
modeling  based  standard.   Since  the  average  formaldehyde  to
methanol  ratio  has  been  determined  to  be  around  0.0943  for
current  methanol  vehicles  (based  on  [1]),  on  average  the
carbon-based  standards  are the least  stringent.   An additional
point to  note is  that carbon  based standards  would allow more
flexibility  for manufacturers   if formaldehyde   emissions  are
found  to be  difficult  to  reduce selectively,  since they  are
weighted  less  heavily  under  this  approach  than  under  the
photochemical modeling-based approach.

     Ford presented  exhaust data  for  light-duty  vehicles which
they  claimed  showed  a  significant benefit resulting  from  the
photochemical-based  exhaust standards  discussed  in  the NPRM;
however,  there  are  two  issues  which Ford  may not  have fully
considered and which  are  significant  enough to invalidate their
conclusions.  First, they  included in  their  analysis vehicles
which  did not meet  the proposed  CO standard.   Further analysis
of  Ford's  data shows  that  only eight  of  17  vehicles were
capable  of  meeting  the   CO  standard.   Each  of  these  eight
vehicles  could  also  meet  the  carbon-based  exhaust organics
standards  (see  Table  7).  This   indicates  that  lessening  the
stringency of the  exhaust organics standards may  not reduce the
control  costs  greatly,  since  the available  (albeit limited)
data  indicate that  the CO standard is  the limiting  factor for
catalyst-equipped vehicles.

     Second,  Ford  based  their  finding  on the   photochemical
modeling-based  standards  that were based  only on data for Los
Angeles.   The more  recent  data,   as discussed  in the  foregoing
     This  is the  critical  ratio,  above which the  photochemical
     modeling-based  standards  become  more  stringent  than  the
     carbon-based  standards.  It  can be  derived by setting  the
     equations   for    the    carbon-based   and   modeling-based
     standards  equal  to  one  another  and solving  for it.   See
     Table  7 for  equations.   The  ratio  equals one  minus  the
     reactivity of  methanol,  divided  by   the reactivity  of
     formaldehyde  minus one (0.375/4.972).

                                      Table 7

                Comparison of Standards Using Ford's Emissions Data
18/83/Escort( LAX/ 5030)
19/83/Escort< LAX/5531)
08/81/Escort/ 14600
Carbon Equivalent**
Photochemical Equivalent***
*    Vehicle designations are Ford's, last number is the odometer reading.
**   Carbon equivalent = HC(g/mi) + 13.876 MeOH(g/mi) + 13.876 Form (g/mi).
                                    32.042              30.026
***  Photochemical
     Equivalent = HC(g/mi) + (.625) 13.876  MeOH(g/mi)  + (5.972) 13.876  Form (g/mi)
                                    32.042                       30,076


analysis  would  result  in  more stringent  standards.   As  noted
before, the relative  stringency depends  on the formaldehyde  to
methanol  ratio.   Only seven of the eight vehicles met the most
stringent   photochemical   modeling-based   exhaust    standards
(without  a margin  of safety), while  all  eight met the  carbon
based  exhaust  standards.   (Admittedly,  the vehicle  which  did
not meet  the  photochemical modeling-based  standard  just  barely
met the carbon-based  standard.)   The four  vehicles for  which
the carbon-based  standard was  the less  stringent standard all
had formaldehyde  to methanol  ratios  greater  than the  critical
ratio  of  0.075.    The  cost  of  this increased  stringency  of
photochemical   modeling-based   standards   is   difficult   to
determine,  since  no commenters provided  any relevant  cost data
in this  regard.   GM's comment that it was unable to provide  an
estimate  in this regard  is particularly relevant.

     Since  evaporative  emissions  do  not  contain  formaldehyde,
the  evaporative   standard  based  on  photochemical   modeling
(without  a  margin  of  safety included)  will  always  be less
stringent  than  the carbon  based  standard.  This  is because a
mixture  of only  hydrocarbons  (reactivity of  one)  and methanol
(reactivity  less   than  one)   will   always   have   an  average
reactivity  that  is less  than one  (relative to an  equal  amount
of carbon as gasoline hydrocarbons).   Thus, standards  based on
photochemical  modeling  would allow  methanol  vehicles  to emit
more carbon than  gasoline vehicles in order to result  in  equal
ozone.   For example,  if one assumes that 47 percent (as carbon)
of  the   evaporative   emissions   from  a  methanol  vehicle  are
hydrocarbons  (as   was  calculated  in  [1]),   then  using  the
methanol  reactivity from the most  stringent standards  based on
photochemical  modeling, the  average   reactivity  of  the mixture
would  be 0.80.   The  amount  of carbon allowed  relative  to that
allowed  by the  carbon-based standards equals the inverse  of  the
reactivity (1.0  / 0.80 = 1.25).  Therefore,  this  approach  would
allow   25  percent  more  carbon   to  be  emitted  than   the
carbon-based standards would.   It  is  noted  that  methanol's  low
volatility tends,  depending  on  the nature   of any  additive
packages,  to reduce  evaporative  emissions,  making  it  unclear
whether   a  relaxed   limit   on  evaporative   carbon  emissions
represents reduced  stringency.

     A reduction  in  stringency for evaporative emissions  would
likely  result  in  some economic  benefit, but  no commenters
provided data which would  allow a quantitative estimate of this
benefit.   The only comment received  specifically  in regard to
evaporative emission  standards feasibility was  from  Ford,  who
agreed with EPA's conclusion  in  the  Regulatory Support Document
that   the  carbon-based  standards  were  feasible.    Whether  the
benefit  of photochemical  modeling-based  evaporative  emission
standards would  be  substantial,   or   even  whether   it  would be
sufficient to offset the  expected increase  in  stringency  of
modeling-based  exhaust  standards  cannot  be determined  due to
the  general  lack  of cost  data.   Nevertheless, it is  obvious

that  the  relative  stringency of  the carbon  and photochemical
modeling-based options  are  generally similar  and therefore,  in
response  to  the third  question,  compliance  costs ought also to
be similar.

     To   summarize  the   foregoing  analysis,   the  available
modeling   base   upon   which   standards   could  be  founded  is
insufficient to  allow  development of environmentally acceptable
standards with  other  than a  conservative approach.  Using such
an approach  results in standards that are generally similar to
carbon-based  standards, both  in terms  of  environmental impact
and  stringency.   Any difference  between the  two  approaches  in
this   latter  regard   which   might  weigh  in   favor   of   the
modeling-based  approach need to  be balanced  by a  concern for
the  weak  philosophical  foundation of  such  standards.   These
standards  rely  upon  elaborate manipulation  of  empirical  data
and  are  subject  to  change  as  further  modeling  is performed.
Carbon-based  standards, on the  other hand,  rely on  the known
scientific  link between  oxidation of organic  carbon  and ozone
formation, and  are equivalent to existing HC  standards  in this
regard.   For these reasons,  carbon  standards  are  superior to
modeling-based  standards.

      Some  commenters   were   also   concerned   that   formaldehyde
emissions  from  methanol  vehicles  could  lead  to  increases in
ozone levels, and  felt  that separate formaldehyde standards are
necessary.    They  raised   several  valid   points   about  the
reactivity  of   formaldehyde.    However,   as  mentioned   earlier,
based  on  the   results of  available  modeling  studies it  is
expected   that   fleet   average  emissions  from   methanol-fueled
vehicles  certified for carbon-based standards  will have 54 to
95 percent of the  ozone forming  potential of  those  of  gasoline
vehicles  (see Table 2).  These results  do not indicate  that the
arguments   (of  AGA,   GARB,   and   Chevron)   for   a    separate
formaldehyde  standard  are  incorrect;   formaldehyde  is  a  very
reactive  compound, and can  be a  key component of atmospheric
reactions.   However,  the  results do show  that these arguments
are   not   sufficient   to  require   a   separate  (ozone  based)
formaldehyde  standard,  since the  carbon-based  standards  will
limit average formaldehyde  emissions  to  acceptable levels.

      The  emissions  data upon  which  this  conclusion  and all
other ozone  projections made in this discussion are  from  [1].
Brooklyn  Union  Gas, however,  argued that these data  cannot be
reliably  translated into in-use  emissions.   As  is discussed in
that   reference,   it  is  true that  more  data   are  needed  to
precisely quantify the  impacts   of  different methanol   fuel
compositions,  vehicle  types,  and  mileage  accumulation  on the
ratios of organic  emissions  from methanol vehicles.   It is  also
true  that availability of  such  data,  as well  as  data on the
types of  fuels  and vehicles that will be  found in-use, would


allow  more  accurate  predictions  of   the   emission  factors.
However, in  the  absence of  such  data,  the data  base is  still
sufficiently  large*  and  adequately   qualified  to   give   EPA
confidence that,  at least as  far as  first generation  methanol
technology  is  concerned,  the  data  base  is  representative  of
real, expected emissions.  This finding  is  also based upon  EPA
staff's  past  experience  in  estimating  in-use emissions  from
gasoline and diesel vehicles.  Additionally,  it should  be  noted
that because substantial penetration of  methanol  vehicles  into
the  market  is  not  expected  to occur  in  the  very near  future,
there will  be sufficient  time to  verify the  estimated  in-use
emission  factors  before  methanol  vehicles   could  have  any
significant   impact  on   the   environment.    Thus,   staff   is
confident that the  estimated emission factors  are  sufficiently


     The   environmental   analysis   of   the   impact  of   the
carbon-based  standards  shows  that   they   are  sufficient  to
prevent  any  increase in ambient  ozone levels.  In fact,  as the
results  in  Table 2  show,  the standards  will  have  a margin of
safety  between 5  and 46  percent.   It  is  also  concluded that
these standards will  be  technologically  feasible  using controls
similar  to  current vehicles,  and thus will  have  similar costs.
For  these reasons,  the  carbon-based standards are determined to
be  an acceptable  alternative.   The question EPA considered in
this  analysis  was  whether   standards   based  on  photochemical
modeling would be more appropriate.

     There  are many  problems associated with  basing standards
on  photochemical modeling.   Most notable  are the  problems of
reliability  and  sufficiency  of the available modeling data base
and   the  possibility   that   future   studies  would  indicate
different reactivities  for methanol  and formaldehyde, requiring
the  standards  to  be  changed.   The  problems   of   reliability
include  concerns   about  trajectory   modeling,  the  multi-day
effects   of  methanol,   and  city-specific   analyses.    These
uncertainties  could be  addressed through further modeling,  use
of  a conservative  methodology to translate  available modeling
into standards,  or  by using  a margin of safety, though it  is
not  presently  known how much more modeling,  which  is expensive
and  time consuming,  would be necessary, or  how  large a  safety
margin  would be needed.   Also,  more  recent  studies,  including
Ford's,  greatly  reduced  the  expected  compliance  benefits  of
photochemistry-based  standards  from the levels suggested  in  the
     Exhaust   data   were   available  from  457  city  FTP  tests,
     including 64 distinct vehicle configurations.   Evaporative
     data were available  for  35  tests  including 18 vehicles.

NPRM.  In fact, based  on the amount of formaldehyde found to be
co-emitted   with   methanol   from   prototype   vehicles,   the
carbon-based  standards  and  conservatively  chosen photochemical
modeling-based   standards   are   essentially   equivalent   in

     As  discussed,  the  photochemical  modeling-based  standards
could provide economic  benefits for evaporative  emissions,  but
could  also  result  in  increased  costs for  controlling  exhaust
emissions.    Therefore,   without   much   more   detailed   cost
information,  it   is   not   obvious   that   standards  based  on
photochemical modeling  would provide  any  net  economic  benefit
at all.

     The   major   difference   between  conservatively   chosen
photochemical  modeling-based   standards  and  the  carbon-based
standards  may  be  philosophical  in  nature.   The  carbon-based
standards  rely philosophically on  the known  scientific  link
between  the  oxidation  of organic carbon and ozone production to
account  for  the  chemical  differences between  emissions  from
methanol  and gasoline  vehicles;  the  modeling-based standards,
on the  other  hand,  rely on  elaborate  analytic  manipulations of
limited  photochemical  modeling data.   Considering  the  absence
of a more complete understanding of  photochemical  reactivity,
it is  recommended  that  EPA maintain  its  previous position that
carbon-based  standards  are  the most  appropriate  alternative to
protect   against  increases  in ambient  ozone   levels  and  to
provide  a firm basis  for  emission standards  that  will  not be
subject  to change with each  new modeling study performed.

     As  mentioned  before,   the environmental  analysis   of  the
proposed standards demonstrated that  they  are  sufficient  to
prevent   increases  in  ambient  ozone  levels.   Thus,  it  is
concluded  that  there  is   no   need  for  separate   formaldehyde
standards   to  account   for   the   very   reactive   nature  of
formaldehyde  in the  atmosphere.   It  is   therefore  recommended
that  the  carbon-based  organics  standards  be  promulgated  as

Issue:   Separate  Health  Effects-Based Standards  for  Methanol
and Formaldehyde

Summary of the Issue

     In the NPRM, EPA  discussed  the possibility of promulgat ig
separate  standards  for  methanol  and  formaldehyde  based  upon
toxic a d  carcinogenic effects.   The  Agency  performed analyses
to    estimate    concentrations    of    these   pollutants    in
driving-related scenarios  where the  public might  be  routinely
exposed to  high levels  of  methanol and  formaldehyde.   It  was
concluded   that   the   proposed   carbon-based  total   organics
(hydrocarbons,  methanol,   formaldehyde)    standard  would   be
sufficient  to  protect  the  public  from toxic  concentrations of
methanol  and  formaldehyde  due  to  methanol  vehicles   in every
situation  considered  except  the personal  garage.   Here, toxic
levels   of   formaldehyde   could   only   be   reached   with  a
malfunctioning  methanol   vehicle   idling  inside   a   personal
garage,  but it was concluded  that it  was  not  the  Agency's
responsibility  to  set standards   to  protect  against  such an
obviously  unsafe  practice.   The   level  of  concern  was   also
predicted to be  reached in the severe tunnel scenario, but, for
several   reasons,   it   was  concluded   that  the   analytical
assumptions leading to the prediction  were extreme and unlikely
to  be realized;  thus  no  standards relating  to   this  scenario
were proposed.

     The  analysis  noted that  an  increase in  overall  ambient
formaldehyde  concentrations  could  potentially  occur   due to
methanol  vehicles,  with an  attendant  increase  in  any cancer
risk  associated with  formaldehyde.   It  was  unclear,  however,
whether  formaldehyde  should  actually  be considered  a human
carcinogen,   whether    the   level   of  cancer   risk   due  to
formaldehyde  from  existing mobile sources was acceptable, and
how  much,  if  any,   methanol   vehicles  would  exacerbate  the
situation.   Additionally,  it was  noted  that it  would  be at
least  several years  before  methanol  vehicles  could   penetrate
the  market sufficiently to affect ambient formaldehyde  levels.
It  was concluded,  therefore, that  cancer-related  formaldehyde
standards  targeted  at  methanol  vehicles  would be  inappropriate
at  present and that  the Agency should regulate  mobile  source
formaldehyde  only  after  a more detailed  consideration  of the
relative contributions of  all  potential emitters.

      The  major issue  of  this section is  whether  the  proposed
carbon-based   organics  standards   are   indeed  sufficient to
prevent  adverse health  effects  to  the  public due to  methanol
and  formaldehyde  from  methanol vehicles, or whether  separate
emission  standards  are necessary.

Summary of the Comments

     The  Agency did  not  receive  any comments  opposed  to  its
decision not to  propose  separate  standards based  on methanol's
health effects,  but  five  of  the commenters (AGA, Brooklyn Union
Gas Company,  CARB,  CEC and  Chevron)  did oppose  EPA's  position
that no  separate health  effects-based  formaldehyde standard is
necessary.* The  American Gas Association  felt that  this issue
was so  important that the rule should not  be promulgated until
formaldehyde emissions and  their  associated  health effects  are
better  characterized.   Other  commenters  (Chrysler,  Cummins,
DOE, GM,  Toyota,  and Volkswagen),  however, were  supportive   of
EPA's  position  that  a  separate  formaldehyde standard  is  not
necessary at this time.

     Several organizations felt that  EPA's  level  of concern for
formaldehyde   (0.50   mg/m3),  was   inadequate  to  protect  the
public  health.   CARB  cited   the   findings   of  the  National
Research  Council,  which  stated that  sensitive individuals will
encounter eye  irritation  at  formaldehyde levels as  low  as 0.05
ppm  (1 ppm =  1.16  mg/m3  at 70  F) ,  and in the  presence of
other pollutants, certain individuals will detect  and  react to
formaldehyde  as low  as   0.01 ppm.   AGA  cited the  same study,
stating  that  as much  as  10  to  20  percent  of   the  nation's
population  may  react  to low  levels (0.25 ppm -  0.50  ppm) of
formaldehyde  in the  atmosphere. Brooklyn  Union Gas  also cited
the study,  saying that  10  to  12 percent  of  the population has
no threshold at  all to the effects of formaldehyde.

     General Motors stated that the  levels  of concern chosen by
EPA are  reasonable  and should prevent unsafe levels  of methanol
and its  metabolites  from occurring in the  blood  of the  exposed
persons.   They  also  stated that  at the  level of  concern  for
formaldehyde,   most   health   effects   would   be   minor   and
reversible.   This position  was supported  by Chrysler  who also
stated  that it  is  not the  Agency's responsibility  to   protect
against   reversible   and  slight  irritant  effects.   Chrysler,
Volkswagen, General  Motors,  and the Department  of Energy (DOE)
all  agreed with EPA that  the  proposed  carbon-based standards
will  adequately protect  the public  from  risk  of  exposure to
toxic levels of  methanol  and formaldehyde.
     These  commenters  also  suggested that  the  ozone forming
     potential   of   formaldehyde  supported  the   need  for   a
     separate   standard.    This   aspect  of  the   comments  was
     addressed   in   the  "Basis  of   the  Organics  Standards"
     section.   The  present  section  addresses  only  the health
     effects issues.

                 Chrysler  agreed  with  EPA  that  vehicle  owners  should be
            expected  to  assume  primary  responsibility  to  ensure   that
            methanol vehicles are not operated  in  personal garages;  such an
            expectation would be analogous to  the case of  CO emissions  from
            current vehicles.   Cummins disagreed;  they stated:

                 "We do not believe  it  is good  public policy to  assume  that
                 the public would take  the  necessary precautions to  insure
                 his   or   her  own   personal   safety  where  exposure  to
                 formaldehyde  and  methanol  emissions are concerned.  The
                 analogy  that  EPA  draws   ....   with  exposure   to  CO  in
                 non-ventilated  areas  is   not  valid  when   dealing  with
                 substances whose health effects and  threshold limit values
                 are unknown."

            Cummins  felt  that  this  and other  personal  exposure  scenarios
            warrant  additional  study,  but  they  supported  EPA's  position
            that  separate  standards  are   not  necessary at  this  time.
            Related  to  the issue of  owner  responsibility, GM felt that  it
            would  be  appropriate  for  EPA  to  issue  a  warning  about  the
            severe risks of tampering with  the  emission systems  of methanol
            vehicles,   (A malfunctioning system  would  allow  much  higher
            emissions of formaldehyde.)

                 A concern  about  the emission data used for EPA's analyses
            was raised by Chevron, who  claimed  that  "formaldehyde emissions
            are  typically  underestimated   . . .   due   to  the  very  reactive
            nature  of  formaldehyde  and  the   difficulty  in  maintaining
            exhaust  sample integrity."  They  cited   a  study by Southwest
            Research  Institute that  showed  losses   of  40 percent  in  the
            exhaust    sampling   system.[8]    This   would    result    in
            underprediction of  concentrations,  and thus underestimation  of
            the risk.   AGA was also  concerned  about  the  limited amount  of
            emissions data available  at this time.   Further,  Brooklyn Union
            Gas  discussed the  validity of  the  emission  factors  used  in
            EPA's analyses.   They  cited "EPA's  disclaimer that  the limited
            prototype  vehicle  testing   emissions  data  now   available  for
            methanol  and  upon which  the proposed rule  is based  cannot  be
            reliably  translated into in-use  emissions."   They,   as well  as
            Chevron,  were particularly  concerned  about  the   durability  of
            catalytic  converters  on  methanol  vehicles.    Chevron  indicated
            the potential risk of an  ineffective  catalyst  system by stating
            that without  a catalyst  "formaldehyde levels  in  exhaust are in
            the order of several thousand PPM."

                 The  commenters  also addressed  the  carcinogenic   risk  of
            formaldehyde  exposure.   AGA  ci~ed  the  National  Academy  of
            Sciences  again,   stating  that  formaldehyde  has  been  shown  to
            create  mutagenic  activity  in  living organisms,  and  that the
            severity  of  the  response is dependent upon the severity of the
            dosage.   CARB stated that  according to  the  1986  EPA Guidelines
            for   Carcinogen   Risk   Assessirvant,   formaldehyde   would  be

considered a  probable human carcinogen because  of the  results
of animal  tests.   GARB,  AGA, and Brooklyn Union  Gas  all agreed
that the most  appropriate  approach  to deal with  formaldehyde's
cancer risk  would be to limit emissions of formaldehyde to the
minimum  level  possible.   CARB  suggested  specific  standards
which  were  discussed  in  the  "Basis  of  Organics  Standard"
section of this document.

     Both Chrysler and GM  were unconvinced of the  cancer risk.
They  cited  the  National  Cancer  Institute  Study  of  26,000
industrial workers exposed  to  formaldehyde,  which  they claimed
showed   no   excess   cancer   mortality   due  to  formaldehyde
exposure.   General  Motors  also  noted that  methanol  vehicles
would  not  be  expected  to significantly affect  the  ambient
formaldehyde  concentrations,  especially considering the  small
number  of vehicles  expected  to be  produced initially.   They
stated that  there is adequate  time to further  investigate the
cancer  risks  before  methanol  vehicles  enter  the  fleet  in
numbers  significant  enough  to  substantially  affect  ambient
formaldehyde   levels.   They  therefore  felt  that  a  separate
formaldehyde  standard is not necessary at  this time  to prevent
increased  cancer  risks.   DOE  noted that  there is  currently no
ambient  standard  for formaldehyde,  and  thus  felt  it  would be
inappropriate  to  have a  separate emission  standard based on the
effect on ambient  formaldehyde concentrations.

Analysis of Comments

     There  are two  aspects of  the commenters'   major  concern,
that  use of methanol vehicles  could  lead to  the occurrence of
toxic  concentrations of formaldehyde  in  situations  involving
routine  exposure  to  motor  vehicle  emissions,  that   require
analysis.  The first relates to the concentration,  or  level of
concern,  at  which formaldehyde should be considered a potential
health  risk.   The  second  is   whether expected  emissions  are
anticipated to  result in the level  of  concern being achieved.

     The  Agency decided in  the  NPRM that  the appropriate  level
of concern for  formaldehyde  is 0.50 mg/m3,  stating that:

      "The  studies  indicate that   at  0.50 mg/m3  the   odor  of
     formaldehyde  should be noticeable by most  people, and any
     health  effects  experienced (i.e.,  eye, nose,  or  throat
      irritation  or  discomfort)  should be minor  and reversible
     for the vast  majority  of the populace."

Among  the  studies used as  a basis  for this  conclusion was the
report by the National  Research Council which was cited  by AGA,
Brooklyn  Union Gas,  and CARB.   It  is noted  that the arguments
presented  by  the  commenters were  addressed  previously  by the
Agency in the  NPRM and the  Regulatory Support Document.  It was
concluded  that these  concerns  were  not   sufficient  to  justify
implementing  a lower level  of  concern, especially considering

the  fact  that exposures  to elevated  levels  of  mobile  source
formaldehyde  are  expected  to  be  brief  (usually  less  than  15
minutes).     Studies   of  non-sensitized   individuals   usually
involved  exposures  of  greater duration  and  it   is  not  known
whether the adverse effects would generally have  occurred given
a  shorter  control  period.   Further,  it  was  noted  that  the
severity  of  these individuals'  responses  at  levels  below  the
level  of  concern  was  minor.    For  example,   in  one  study,
respondents  characterized  the  effect  of  formaldehyde  at  0.25
mg/m3  as  barely  noticeable, similar  to  a light  windy  touch or
dry  feeling  which elicited conscious  blinking.   While  it  is
noted  that  there  is  a wide  variability in  human response  to
formaldehyde  such   that   some   individual   may  just   notice
irritation  at  levels  below  0.50  mg/m3,   the  conclusion  that
health  effects  below the  level   of  concern  are  expected  to
generally be minor  and reversible  continues  to be valid,  and
the  Agency  should not,  as Chrysler commented,   necessarily be
involved  in  protection against them.  With regard to  the data
which  indicate  a  portion  of  the  population  which  may  be
sensitive  to  concentrations  as  low  as  0.01  to  0.05  ppm,
emission  standards may be  of  little benefit,  since  typical
urban  concentrations  are presently  of this  order of magnitude.
Additionally, it  should be noted  that these data  from studies
of  occupational  exposures, and  not brief exposures  like those
discussed here.   Addressing exposures at  this level  is clearly
beyond  the  scope of  this  rulemaking.  EPA  is  in fact pursuing
an  Agencywide  approach  to  deal  with  ambient  exposures  to
formaldehyde.   An   intra-Agency   task  force  will  coordinate
activities  related to  formaldehyde, including  the development
and  implementation of a formaldehyde control strategy that will
account for  issues such as  sensitive populations.

     Since  the  commenters  presented no  new data  to  challenge
the  Agency's previous  logic in  determining a  level  of  concern
for  formaldehyde,  it  would be inappropriate to  alter  the  level
of  concern  in  response to the  comments.   It  should  be noted,
however,  that   the   Agency  did  consider,   in   its  previous
analysis,  what  effect  a  0.25   mg/m3  level  of  concern would
have had  on  the need  for standards and found none.

     The  Agency  chose  260 mg/m3  as  the  level  of  concern  for
methanol.    This   is   the   Threshold  Limit  Value  (TLV)   for
eight-hour   exposures  set  by   the  American   Conference  of
Governmental    Industrial   Hygienists    (ACGIH).    The    TLV
incorporates  a  fairly  large  margin  of  safety  against  toxic
effects.   No  comments  were  received opposing  this  level of
concern.   It is  worthwhile to note  that  an extensive review of
methanol  health   effects  and  the   implications  of   methanol
vehicles   was  recently   completed   by   the   Health   Effects
Institute.[9]   This  study's   conclusions  included  the  finding
that  the  mobile  source-related exposures  to methanol  predicted
by  EPA as a  result  of  methanol  vehicles,  would not cause  toxic
effects.  For example,  they stated:

     "A  70  kg  person breathing  at  a ventilation  rate of  20
     m3/day  (twice  resting)   who  is  exposed   to   200  mg/m3
     methanol vapor for  15 minutes  (as in a worst-case hot-soak
     garage  scenario),  accumulates  a  methanol  body burden  of
     0.0006 g/kg - at  least  500  times lower than doses of acute
     clinical significance."

HEI did, however, note that these conclusions  were  in regard to
ocular   toxicity  due   to   formate   (which   is  a  metabolic
intermediate of  methanol), and that there could be  other  toxic
mechanisms.  This  possibility needs  to  be investigated  in  the

     The availability  of  new  emissions data has enabled  EPA to
update  its  analysis of methanol  and formaldehyde concentrations
in  driving-related scenarios  in which  people  could  commonly
encounter  elevated concentrations of  mobile  source pollution.
It  would  be  appropriate  to  present this  analysis  prior  to
considering  comments  related to the earlier  analysis.   The
analysis   is  based   upon  mathematical  models   developed   by
Southwest  Research  Institute (SwRI).   The   scenarios  modeled
                            (urban  corridors  bounded  by  tall
     1)    Street  canyons
     2)    Tunnels
     3)    Expressways
     4)    Public parking garages
     5)    Personal garages

These  scenarios  are  discussed in more detail  in  the Regulatory
Support Document  for the  NPRM.   Both typical  and  more  severe
situations were  modeled;  however this  analysis focuses  on  the
severe situations, except as otherwise noted.

     It was concluded earlier  that  the only modeling  situation
in   which  unacceptable   formaldehyde  concentrations   (i.e.,
concentrations significantly above  the  level  of  concern)  might
occur  involves idling of  a severely malfunctioning vehicle in a
personal   garage.     Formaldehyde   concentrations   were   also
           to  be  near the level of concern  in  the severe tunnel
           Methanol  was  found  never to  exceed  its  level  of
          but   it  did  approach  the  level of  concern   in  the
           garage   -   hot  soak   (trip   end)    scenario   (235.6
          The   results of  the  updated  analysis  are  shown  in
           through  13.    These   new  results   do   not   differ
substantially  from   the  previous   ones,  except   for   those
scenarios  involving  hot  soak emissions,   and  those  involving
cold  idling   (idling immediately  after  starting the  engine).
The  scenarios  affected  are  the  public  parking  garage  and
personal garage trip start and trip end scenarios.
Tables   8

     In the previous analyses of  the  trip end scenarios it  was
estimated that  maximum certification  level  hot soak  emissions
of methanol would be 3.0  grams  per test.  Based on more  data,
it  now   appears   that   2.0  grams  per  test  is   a  better
estimate.[1]  Using this  newer  estimate,  the  models  predict
maximum  concentrations  of   100.9  mg/m3  and  152.8  mg/nP,  for
the public parking  and  personal garage  scenarios,  respectively
(Tables  12  and  13).  Both  of  these predictions are well  below
the level of  concern,  and  are  based  on worst  case  assumptions
so that  it does  not appear that hot soak  methanol  emissions
pose any significant threat to  the public.  It should be  noted
that the malfunction-based  offsets*  used in  Tables  12 and 13
were based on limited and somewhat  questionable data.   However,
because  the margins of  safety for these two  scenarios are so
great,  and  because, for  the  public  parking   garage  scenario,
other  offsets based on  fleetwide gasoline  vehicle  performance
can be adopted  as  surrogates,  this should not  be  a  significant
concern  in  that scenario.  For the personal  garage,  the margin
between the predicted concentration and  the  level  of  concern is
also large, even considering a 2.0 safety margin on emissions.**

     The  scenarios  using  cold  start  emission  factors  also
involve  exposure   in  public  and  personal  garages.    Several
changes  were  made  to  the  analyses that were  discussed in the
proposal.  The  first  is  related to the  exposure model used for
the public  parking garage.  The  previous  analysis focused on a
model that was based on an  actual underground garage,  which was
poorly ventilated.  However, this model is no  longer  considered
representative,  since   pollutant  concentrations   inside  the
actual   garage  were  so  high  that  it  had  to  be   completely
reventilated.   Additionally, there   is  some  concern  that  the
garage  model might be  inaccurate.   The model  of the  severe
scenario  was tested  (for  validation  purposes)   using  ambient
data from  a 1978 study which measured a CO concentration  of 374
mg/m3  during  a parking episode in the  actual garage on  which
the  physical  parameters  defining the  severe scenario  analysis
were based.   Using an  average CO emission factor  of  7.7  mg/min
based  on  an  EPA  study  (how   this estimate  was  obtained  from
EPA's  emission  factors  was not discussed  in detail  in the  SwRl
document),  the model  predicted  a  concentration  of  430  mg/m3.
SwRI claimed  that  this analysis validated the model,  but there
is  concern that  actual  in-use  emissions of  CO  in  1978  could
have been much  higher.  Using the same  EPA study as was used  by
SwRI,  and  making  reasonable  assumptions  about the  overall
mostly catalyst equipped  fleet's model  year distributions, the
 *    Offset   is   the   expected   ratio   of   in-use   emissions   to
     certification  level.
 **   Since the gasoline  vehicle offsets were developed based  on
     fleetwide  performance  and only one  vehicle  is present  in
     the  personal garage,  a 2.0 safety margin  on the predicted
     emission level is used  as  a surogate  for an in-use  offset.

30% Penet
100% Penet

30% Penet
100% Penet

30% Penet
100% Penet
                                 Table  8

                 In-Use Formaldehyde Concentrations for
                 Canyon, Tunnel, and Expressway (mg/m3)
            (Level of concern  for formaldehyde is  0.50  mg/tn3)
Likely Cert.
Level (g/mi)
Std. *
2.6 Malfunction**
* *
Offset =1.0.
Offset =1.0.
Offset =2.26 canyon, 2.26 tunnel, 11.75 expressway.

                            Table 9

               In-Use Methanol Concentrations for
             Canyon, Tunnel, and Expressway (mg/ra^)
          (Level of concern for methanol is 260 mq/m3)
30% Penet
30% Penet
30% Penet
Likely Cert.
et 0.
net 0 .
et 0.
net 0 .
.et 0.
met 0 .
Offset =1.0.
Offset =2.28 canyon, 2.28 tunnel, 39.40 expressway.







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                                   Table 12
                        In-Use Methanol Concentrations
                     for Hot Soak,  Parking Garage 
                            Table 13
               In-Use Methanol Concentrations for
               Hot Soak, Personal Garage  (mg/m3)
          (Level  of Concern for Methanol is 260 rag/m3,)
20 CFM
No Vent
Likely Cert .
Level (q/hr)


2.0 Safety

*    Offset =1.0.
**   Offset =4,8.
***  1.3  is  estimated  fuel  injected  emissions  and  2.0  is
     estimated carbureted emissions.


average CO  emission factor could  be  estimated to  be  more than
twice as high  as  the estimate used by  SwRI.   If this  is  true,
then  the  severe  model  is overestimating  concentrations.   This
concern is  supported  by  the  fact  that  the model of the  severe
scenario would have  predicted  very high  CO  concentrations,  on
the  order  of more  than  2000 mg/m^,  for  earlier,  pre-catalyst
gasoline vehicles  emitting  40  g/min  or  more  in-use at  cold
idle,  and   this   level   would   likely  have   been  considered
unacceptable.    Furthermore,    recent   gasoline  vehicle   data
indicate that  cold  idle formaldehyde  emissions  might be high
enough to  produce concentrations as high  as  twice  the level of
concern in this scenario.  However, the fact  that  complaints of
eye  irritation from frequent garage  users are not  received in
this  regard  lends  further   evidence   that  the  model  is  not
representative.   Therefore,  the current analysis  is focused on
a  model  of a  more  typical  garage.    The model  predicts  the
maximum concentrations that  would occur under congested traffic
conditions,  in which the garage is emptied in a short  period of
time,  such  as  that  after   a  concert.   Individuals   would  be
exposed to  the highest  predicted concentrations in the  garage
for  about  four  minutes,  and  to  concentrations  that are  28
percent as  high for another  four minutes.   For  comparison,  the
concentrations  predicted  for   the  severe   model,  which  was
previously  the focus  of EPA's  analysis,  would  be about four
times  the   maximum  predicted  concentrations  of  the  typical
model.   It  should  be  noted  that  validation  data  were  not
available for  the typical model,  thus  its accuracy must also be
considered  somewhat uncertain.

     The second problem  with the previous  analyses  of the trip
start  scenarios   relates  to  the  emission   factors   that  were
used.  First,  the analysis did  not  use actual  cold  start idle
data for  methanol vehicles;  the  emissions were estimated based
on  hot  idle data  (idling after the engine has been warmed up).
It   was  assumed   that   the   ratio  of   cold   idle  formaldehyde
emissions to hot  idle formaldehyde emissions  would  be the same
for  methanol  vehicles  as  it  is  for  gasoline  vehicles   (2.25,
based on limited  testing).  Using  this  ratio,  and hot  idle data
from four  methanol  vehicles,  the upper  limit  for  cold idle
emissions was  estimated  to be 2.03 mg/min.   There  are now four
studies  available which have  reported  cold  start idle emission
data  for   methanol  vehicles  (three   studies  involved  1983
Escorts, the other involved a 1986 Carina).[10,11,12,131  These
cold idle  data now indicate that  the previous approach was not
appropriate.   The  new  data  (Table  14) suggest  that  cold idle
formaldehyde emissions are 4-60 times the  previous estimation.

     Three  of  the  studies which had cold start idle data for
methanol  vehicles  also  investigated   the   effect  of  ambient
temperature on the  formaldehyde  emissions,   and  found similar
results.   Idle formaldehyde  emissions  at  20F were found to be
2.4-4.0   times   the   idle   emissions   at   FTP  temperatures.
Therefore,  analysis  of  health effects  based on emissions data
at   FTP  conditions   is   not  sufficient  to   ensure   that cold

                           Table  14
              Methanol Vehicle Emission Factors
                          (Cold Idle)
EPA [10]
Temperature Methanol
Vehicle (F) (g/min)
Used summer
d winter
70 0.847
40 2.619
40 2.166
20 4.850
arade fuel.
rade fuel .


    CO to

Ratio of levels of concern of CO and formaldehyde is 880,

temperature  emissions  will  not   be   unsafe,  and   the   20 F
emissions data are used in the analysis.*

     Second,  other  new  data  also  enabled  EPA to update  its
estimates  of  gasoline vehicle  contributions  to  formaldehyde
exposure  in  garages.   The  data  show  that   gasoline  vehicles
contribute  more than  was  previously   thought,  such  that  low
mileage, well  maintained  vehicles  gasoline vehicles alone could
result in fairly high levels of formaldehyde  (see  Tables  10 and

     A final  problem  relating  to  the emissions factors used in
the  previous   analysis   in   the   Regulatory   Support  Document
concerns  the  three  offsets  used  to  estimate in-use  parking
garage  (see  Tables  2-7   and  2-8  of  the  Regulatory  Support
Document)  idle  emissions of  methanol  and  formaldehyde.   The
malfunction  offset  was originally  based  on hot idle  data.   It
assumed   that   25   percent   of   the   methanol   fleet   is
malfunctioning, with  malfunction  emissions being represented by
non-catalyst    vehicle    emissions.    Hot    idle   formaldehyde
emissions from a non-catalyst vehicle were determined to  be 7.6
times those  from  catalyst vehicles; the ratio was determined to
be  34.0 for  methanol emissions.    However,  hot  idle emissions
would be  expected  to  be  affected by catalyst  function much more
than  cold  idle emissions  would  be,   since   catalysts  do  not
become   effective   until   they   are  warmed   up.    Thus,  the
malfunction  offset based  on hot idle data  is  probably too high,
resulting  in  an  overestimate  of  concentrations.   Malfunction
based offsets  were not used  in the  present analysis.   The other
offsets used as alternatives were based on performance over the
urban driving cycle of the  FTP  at FTP  temperatures  (i.e., 2.2
and  2.6).   There are  two potential problems  with this.   First,
since  cold  start  idle emissions  at low  temperatures are not
necessarily  affected  by  the  modifications that are relevant to
emissions  performance at  70F, it  is not  obvious that offsets
for   low   temperature  cold  start  idle  emissions   from well
maintained  vehicles will be similar  to  offsets  for  the same
engines operated  at FTP  temperatures.   Second,  the relevance of
performance  over  the  FTP driving cycle  to that at  idle   is not
clear.   It  is possible that small  changes  in engine or catalyst
parameters   may   significantly   affect   the  optimized  FTP
emissions,  but not  cold start idle  emissions.   However,  since
it  would not  be  appropriate to assume  that   the  fleet average
offset  for  idle  emissions would  be unity,  the parking  garage
cold  idle offset will  be  assumed
     As  was  noted  in  the  Regulatory  Support  Document,   this
     phenomenon  could  also  affect  the  results  of  analyses  of
     other  scenarios,  however  the  margin  of  safety  between
     calculated  concentrations based  on  70F  emissions  and the
     level  of concern  was  so great  that  the  effect  could  be

to range between 2.2  and  2.6  as was done for the  other  offsets
for  exhaust  emission scenarios,   It  is  recognized that  there
are  weaknesses  to  this  approach,  however,   it  is  the best  one
available;  thus it:  is appropriate,  especially considering  other
sources  of  uncertainty in  the analysis.   Similarly,  there  is
not  sufficient  information to  accurately  calculate  an  offset
for  the  personal garage  scenario.   Here a  2.0 margin  of safety
will be used in place of  an offset.

     Using   these   newer   data,    the   SwRl   models   predict
formaldehyde  concentrations  of  up  to  2.78   mg/m3  for  the
public parking  garage scenario and 16.3 mg/m3  for the severe
personal garage scenario  assuming  worst case methanol  vehicle
emissions;  these concentrations are both greater than the level
of concern  (0.50 mg/m3).   Thus,  the  concern about  exposure to
toxic concentrations  of  formaldehyde  is reasonable.   Tables 10
and  11  also show the impacts of other  types of vehicles.  The
impacts of mixed fleets  on exposures  in public garages can be
predicted by averaging the predicted values  for these vehicles.

     Similarly, recent cold  idle  data for methanol (from  one of
the  studies  shown  in Table  14)  indicate that actual  cold  idle
emissions   of   methanol   are   8  to   110   times   the   previous
estimate.  As before, the data  from the  tests at  20F are used,
as   a  worst  case.    Using  these  data,  the  models  predict
concentrations  of   up to  147  mg/m3  for  the  parking  garage
scenario   and   650   mg/m3   for  the   severe   personal   garage
scenario.  Here only the  concentration for  the  personal  garage
scenario is  above  the level  of concern.   It  is  useful to  note
that  in  these  scenarios,  based on  ratios  of  emission factors
and  levels  of  concern,  formaldehyde concentrations would  exceed
the  level   of  concern   by   a  greater  margin  than   methanol
concentrations.  Therefore,   formaldehyde concentrations  can be
considered  the  more  serious concern,  and as such  are the focus
of the following discussions.

     There   are several   possible  problems  with   the  public
parking  and personal garage analyses  which  could  make  them
invalid.   This discussion  will begin  with a  consideration  of
the  public  garage,  but  several  of the   concerns   with  that
analysis apply to  the personal garage  scenario as  well.  First,
the  maximum  concentrations  represent  a worst  case  analysis,
based  on  the   highest  emitting vehicle  tested at 20F  (three
1983 carbureted Ford Escorts were  tested  at this  temperature).
None of  these  vehicles was apparently  near the compliance level
for  the proposed  CO or  total organics  standards  for  the  FTP
(they   were  emitting  at   roughly  two  to  three   times   the
standard).   If they had,  it  can  be anticipated  that  their  idle
emissions  would be  somewhat  lower as  well.   It  is  not obvious
however, the degree  to which compliance with the  total  organics
standard would affect cold idle  emissions.   If the weighted FTP
emissions   were  reduced  by  any   adjustment  which  affected
emissions    from   a   warmed-up  engine,  then   the   cold  idle

emissions,  which   pass   through  a   cold,   hence  ineffective
catalyst  during  much   of   the   idle  period,  might   not  be
affected.  If on the  other  hand,  the FTP emissions were reduced
by  affecting  bag  1  (cold)   emissions,  then  it  is  likely that
cold idle emissions would be affected.

     Second,  the   emission  performance  of   1983  carbureted
Escorts  is  not likely  to  be  representative  of  the  future
methanol  fleet.   As  is  discussed elsewhere  in this  document,
the  development  effort  on  this  vehicle,   with  respect  to
emissions  performance,  was  limited.   The  Toyota Carina,  a more
advanced   technology   methanol   vehicle,  emitted  only  16-27
percent  as much formaldehyde at  FTP  temperatures  as  the early
Escorts,   and  was  in   the  range  of   emissions   of  gasoline
vehicles.   Cold  temperature data  for  this  vehicle were  not

     Finally, as was noted before, the  accuracy  of the modeling
is   uncertain.    It   is  used   here  to  give   a  reasonable
approximation  of  exposures  in  public  garages;   the  results
should  not  be  taken  as  the  final  word  on such  exposures.
Rather  work may need  to be  done  to   improve  the  reliability of
the model.

     Because  of concerns  such  as  these,  it  is   difficult  to
conclude  with  any certainty that  methanol vehicles  will cause
unsafe  levels  of  formaldehyde  or methanol   in  public garages,
especially at  the  expected  low initial  market  penetrations.
Additional  investigation of  emission  data for advanced methanol
engines  tested  at  low  temperatures  is warranted  as  is further
validation of the model  itself.

     Many  of  the previous  concerns  are also  applicable to the
analysis of the  personal garage  scenario (see Table 11).  Since
the  same cold  idle data that  were used for  the  analysis above
are   also  used   for   the  personal   garage  analysis,   the
data-related   uncertainties  discussed  above  (concerning  the
effects   of  non-compliance with  the  FTP   CO   and  organics
standards,  and  the  fact  that  low   temperature  data  are only
available  from  early  model carbureted  Ford  Escorts)  are also
applicable to  this  analysis.   Also,   as before, there  is concern
about  model  validity, since the  personal garage  model  was not
tested   using   data   from   an   actual  garage.    The   recently
published  gasoline vehicle cold idle  data  indicate that many of
us  would  even  today  experience discomfort   from starting our
vehicles  in  our garages on cold mornings  due to  concentrations
in  the  range  of 1.5  mg/m3 as  predicted by the  garage  model.
The  personal  garage analysis is similar to the  analysis of the
public  parking  garage scenarios  since in both analyses  there is
sufficient uncertainty  to  make the  accuracy of  the predicted
concentrations  somewhat  questionable.

     The two analyses differ greatly, however, in  two  important
respects.    While  the  driver   in  the   public   parking  garage
analysis  has  no  control  over  the  severity  of  the  exposure
(i.e., the  concentration to which the  driver is  exposed),  the
driver  in the  personal  garage  analysis  has  the  ability  to
control the  severity by limiting the  time that the vehicle is
operated  in  the garage;  the  difference  between  severe  and
typical personal garage  scenarios only  reflects  a  difference in
the  amount  of  time  the vehicle  spends  in  the  garage  (five
minutes for  severe  and  30 seconds  for typical),  and not  any
altered physical parameters.  For example, the  situation could
be avoided  altogether simply by  idling the vehicle outside of
the garage.    This  is widely acknowledged  to  be a  safe vehicle
handling  practice;   most owner's  manuals  warn  against  idling
vehicles  in garages,  and some  even  warn against idling next to
buildings.  Thus,  since  the  driver may voluntarily  avoid  the
severe scenario, it  is  appropriate  to  consider  both  the severe
and  typical  scenarios   in  this analysis.  In  addition  to  his
ability to  control  the  exposure concentration,  the  driver in
the personal  garage scenario also has  the ability to   limit the
duration  of  the exposure  and  thus prevent  any  irreversible
toxic  effects.   For example,  while  he  may allow his vehicle to
idle  in his garage for five minutes  to  warm up,  he need only be
present  in  the  garage  at  the beginning and  end of  the  idle
period.   Chrysler   agreed  that  drivers  should  assume primary
responsibility for avoiding such obviously unsafe situations.

      Additionally,  because the  formaldehyde  concentrations in
this  scenario would  lead  to  some irritation,  and owners would
be discouraged  from remaining  in the garage, they would  also be
warned  of poor  ventilation before CO levels  reach the level of
concern.    In  fact,  the   limited   data  that  are   currently
available (see  Table 14)  indicate  that the  CO  to  formaldehyde
ratio in  exhaust for methanol  vehicles  at cold  idle ranges  from
150 to 850.   The values in this  range  are less  than  the ratio
of  the levels of  concern which  is  880.   (The level  of  concern
used  here for carbon monoxide  is 440  mg/m^ which  is   the ACGIH
Short  Term   Exposure   Limit   (STEL),   designed   to  limit
concentrations  during exposures  of  15  minutes  length.)  Thus,
formaldehyde  would  be  expected  to  reach  its  level  of  concern
before CO  would,   and  when  the  vehicle  is  removed  from  the
garage immediately   after  formaldehyde  reaches  its  level of
concern,  the  STEL  for  CO  would not  be  reached.   Similarly,
since  (as  noted   earlier)  formaldehyde   concentrations would
reach  the    level   of   concern  before   methanol   would,   the
irritation  from the formaldehyde would provide  a warning  for
methanol  exposure  as well.

      Cummins  argued that  it   is  inappropriate  to  assume  the
public will  avoid  exposure in personal garage  scenarios.   They
claimed that the health effects  from  formaldehyde  exposure are
not    adequately  known,   making   EPA's   (and   by   extension,


Chrysler's)  parallel  of  formaldehyde  to  the carbon  monoxide
situation  inappropriate.    In  response,  it  is  true  that  the
current knowledge is  limited,  but it is nevertheless sufficient
to conclude that exposures to  formaldehyde  at  levels around the
level of  concern will cause only minor and reversible effects.
Further,  even  when  the  concentration  does briefly exceed the
level  of  concern   during   idling  on  cold  winter  days,  as
discussed  above, exposures  could produce brief  irritation, but
almost  certainly would not cause any irreversible or  otherwise
more severe health effects to  a  healthy driver.   The driver has
the  ability  to  prevent dangerous exposures to formaldehyde in a
personal  garage, and it  is   not unreasonable  to  expect  that
drivers  will avoid  such  scenarios if  1)  they are  known  to  be
unwise,   and  2)  concentrations  reach  the   irritant  level.
Regulations cannot substitute  for common sense.

     GM's  suggestion that  EPA  warn  the  public  about  the
possible   effects  of  tampering  with   a   methanol  vehicle's
emission  control system  is  well taken, and if such  tampering is
found,  after methanol vehicles  begin  to  be  sold,  to  affect
formaldehyde concentrations sufficiently in any common scenario
(not  just  the personal  garage),   such  a  warning  may  be
appropriate.  At this time,  however,  sufficient evidence is not
available  to justify the Agency taking such  action.   It is,
however,  reasonable  to expect  that  manufacturers will show the
same   sense   of  responsibility  with  formaldehyde   as  they
currently  do with  CO, such that  they may feel compelled include
a   discussion   of    formaldehyde  in   the  owner's  manual  if
necessary.   It  would be  difficult   to justify  more  stringent
treatment  of  formaldehyde  than CO   by EPA  in  this  situation
since   the worst  case   formaldehyde   concentrations  predicted
would  result in severe  irritation for the  general population,
while  the  cocentrations  of  CO  predicted  could  induce death,
which occurs after  exposure to  10,000 mg/m3  for  10 minutes or
so.   Further,   concentrations  of  5,000  mg/m3,   which   would
precede  these  higher levels,  would  result  in   headaches and
nausea  for most  individuals.

     To  summarize,  while  there  may  be  cause,   after further
investigation,   for  concern about  exposure  in   public  parking
garages,  the evidence given by  the present analysis is somewhat
weak.   The results  indicate that there  is  a  very low risk that
the  public  will be  involuntarily exposed  to toxic  levels of
methanol   or    formaldehyde   in  the   near   future   because
concentrations  will  be   low   at  very  low  market  penetrations.
Exposures  in personal garages can be  avoided altogether,  just
as  they are today  in regard  to CO  exposure,  and those that do
occur  will be  too  brief  to cause  serious health effects.  It
would be appropriate, however,  to investigate the issue of cold
idle emissions  further,  especially   with  regard  to the public
parking garage  scenario.

     Chevron    felt    that    formaldehyde    emissions     are
undermeasured.   EPA staff  agrees that  care  needs to  be taken to
avoid  sampling  losses   and  therefore  will  require  a  heated
transfer  tube   and sample lines.    Nevertheless,  it  has  been
shown  that  even  without  a  heated  transfer  tube   collection
efficiencies range  from  79 to  94 percent,[14] and that unheated
sample lines can have efficiencies  up  to 98 percent. [15]   Staff
does  not  consider the  data  cited  by Chevron  to  be  valid,
because  an  improper  procedure   was   used.   This   issue  is
discussed  in  more detail  in  the  test  procedures sections  in
this  document.   Thus,   the  formaldehyde   data  used  in  this
analysis are considered sufficiently accurate.

     In  regard  to  concerns   that   EPA's   estimated  emission
factors  are inaccurate,   staff  agrees  that the  emissions  data
base has  limitations; however,  because it  contains data from 13
different   studies   (screened   for   appropriate   measurement
techniques)  and  from many  different  types  of  vehicles,  it was
concluded  to  be   robust  enough  to  be  appropriate  for  the
purposes  of this   analysis.  Additionally,  staff is  confident
that   recent  additions    to  the   emissions  data  base  have
significantly  improved  the reliability  of  the projected in-use
emission  factors  beyond  those estimated   earlier.   Staff  is
convinced  that any errors  introduced  as a  result of the nature
of  the  data  base will   be small  and  thus  not  significantly
affect  the  validity of  this analysis.  An  exception here may be
necessary   for  cold   idle  emissions,  which  were  previously
discussed.   In this case,  the uncertainties  argue for continued
research  by  EPA   and   automobile  manufacturers  as  methanol
vehicles  are  developed.   It  is impossible  to determine actual
emission  factors  based  onthe  prototype vehicle developed to
date,  but  directionally,  data for   the  newer,  more advanced
Toyota  Carina  are  reassuring.

     Both   Chevron  and   AGA   were   concerned  about  catalyst
durability   affecting  formaldehyde  emissions.   To   the  extent
that  adverse  health  effects  are  avoided due to  the  action of
the   catalytic  converter,  the  issue  of   its   durability is
important  to  this  discussion.  As is  discussed in  more detail
in  the  "Basis  of  the  Organics  Standard"   section of   this
document,   however,  staff  believes  that   sufficiently  durable
catalysts will be  available.

     The second major concern  of  those commenters  supporting a
separate standard  for formaldehyde was  the potential  increased
cancer  risk due to increased formaldehyde  concentrations in the
atmosphere.     With   respect   to    the    carcinogenicity  of
formaldehyde,  CARB was correct; EPA has classified  formaldehyde
as   a   "Probable   Human  Carcinogen"   (Group  Bl)   under   its
Guidelines   for  Carcinogen Risk Assessment.   As  was  stated by

EPA's Office  of  Pesticides  and  Toxic  Substances
this classification is based on the following:
(OPTS)   [16]
     0     limited evidence  of  carcinogenicity in humans (i.e.,
           several    epidemiologic   studies    show   positive
           associations    between    respiratory   site-specific
           cancers and exposure to formaldehyde);
     0     sufficient  evidence  of  carcinogenicity  in  animals
           (i.e.,  formaldehyde  induced  an  increased  incidence
           of  rare,  malignant nasal  squamous-cell  carcinoma in
           mice and rats,  and in multiple experiments); and
     0     additional   supportive   evidence    (i.e.,    studies
           demonstrating   formaldehyde's  mutagenic  activity in
           numerous  test  systems  using bacteria,  fungi,  and
           insects,  and ability  to transform  cells in culture
           and  cause  DNA  damage  in other  in vitro assays for
           mutagenicity.    Also,   structure-activity   analysis
           indicates   that  formaldehyde  is   one   of  several
           carcinogenic aldehydes.)

 Included  among this  body of  evidence  was  the National Cancer
 Institute  study noted by Chrysler  and  GM.   This study showed an
 excess   of  cancer  among  workers  exposed  to  formaldehyde;
 however,  the study's authors  argued that this  provided little
 evidence  of  an association  with formaldehyde.  OPTS  disagreed,
 and  argued that these  results  are meaningful.  This position is
 supported  by  the  other  evidence  of  the   carcinogenicity of

     Since methanol  vehicles  have  the  potential   to  increase
 ambient  formaldehyde levels,  it  would be useful to approximate
 the  magnitude  of  any  increased  risk  they  might  represent.
 Unfortunately,   no  detailed   work  in  this   area  has   been
 performed.   One study,  admittedly limited in  scope, of the Los
 Angeles  airshed during an ozone episode predicted that  the peak
 hourly  formaldehyde  concentration  of   the  modeled air parcel
 would  rise from 26 ppb to 31  ppb  if 100 percent of  the  fleet in
 Los  Angeles  were  converted  to  methanol.[2]    Another  study,
 modeling   Philadelphia,   showed  similar results   (formaldehyde
 rose from 22.5  ppb  to  25.9  ppb). [3]   These  estimates  can be
 considered worst case  to  some extent since the models  assumed
 10  percent of  the  mobile source  organic  carbon emissions  were
 formaldehyde,  but data  indicate that the formaldehyde  fraction
 would  be  closer  to  four  percent.[1]   In  addition, preliminary
 results   of   another  modeling  study  indicate  that  the  lower
 reactivity of methanol may  even  result  in  a slight decrease  in
 formaldehyde levels.[17]  Thus,  at  low penetration  levels the
 increase  in ambient  formaldehyde concentrations  would be  very
 small,  and  in some areas negligible.   Accordingly,  the effect
 on  the  cancer risk  would  also  be  very  small  or negligible.
 However,   formaldehyde  concentrations   depend   on  a  number of
 variables  related  to  meteorology  and  emissions.   Thus,  given

the limited  work  available on  this  topic  to date,  it  is  not
possible at  this  time to determine the exact magnitude  of  this
increase, or whether there would even be an increase.

     It  should  be  noted  that  it  is  incorrect  to assume  that
ambient  formaldehyde  concentrations  will  increase proportionate
to any increase in formaldehyde emissions.  This  is at  least in
part  because  an  unknown  amount  of   ambient  formaldehyde  is
formed by  photooxidation  of  other  organic  emissions,   and  not
from direct  emission  of  formaldehyde.   The  fraction which is
photochemical ly produced has  been  estimated to  be 60 to  90
percent.[18]   This  issue  is  currently  being  investigated  by
EPA's Office of Research and Development.

     Furthermore,   the effect  of  methanol vehicle substitution
on  overall  formaldehyde  exposure will  be  even  less  dramatic
than on  outdoor ambient  formaldehyde concentrations.   This is
because  exposure  to  indoor   sources  of  formaldehyde   is  very
significant  compared to that  due  to outdoor sources.   Typical
outdoor  concentrations of  formaldehyde are  on  the order  of 10
ppb.[19]  Typical indoor levels vary  from 50  ppb  for  houses and
workplaces   to  over   1000  ppb  for  occupational  exposure  in
certain  industries.[20]   Given the  large amount  of  time  spent
in  indoor   environments,   any  potential  increase   in  ambient
formaldehyde levels  caused  by methanol vehicles would represent
a  much smaller increase in the  overall risk represented by all
sources.   Thus the  question of  equity  regarding the   relative
level  of  control  desirable  for  all  sources  of formaldehyde,
including   current   mobile   sources,   becomes   an   important
concern.   It  would  not  be  appropriate  to   address  the cancer
risk  of  formaldehyde from methanol  vehilces  without   allowing
the  Agencywide  task   force   on  fromaldehyde,   as  mentioned
previously,  to formulate  and  interpret  results  from a larger,
more comprehensive  point of view.  What  can  be concluded in the
light  of  the  low  expected  market  penetrating for   methanol
vehicles is  that,  as GM noted, there is  adequate time to assess
this  issue  before  there   is  any significant  increase  in the
cancer risk  due to  formaldehyde from methanol vehilces.

     As  a  final  note,  while  it  is  true,  as  DOE  noted,   that
there  is  currently no  NAAQS for formaldehyde,   this  does not
justify    a   decision  not   to   regulate   formaldehyde    (or
formaldehyde  precursor)   emissions.    EPA  has   the  authority,
under  Section 112  of the  Clean  Air Act, to regulate  compounds
on the basis of cancer risk without  an NAAQS.


     Based  on  the  available data,  it  appears  that   separate
standards  for  methanol  or  formaldehyde are  not necessary  at
this time  to prevent adverse environmental  impacts with respect
to either  methanol or  formaldehyde  exposure.   Nevertheless, the

Agency   should  continue   to   investigate   this   concern   to
accurately determine the  potential effects of  high penetration
levels of methanol vehicles into the fleet.

     There  does  appear  to  be  justification  for  some  concern
about  the  impact  of  methanol  vehicles   on  concentrations  of
formaldehyde  in  public parking  garages.   However,  because of a
very  limited  emission  data   base   and   questions  about  the
validity  of  the  analytical  model of  the garage,  there  is  a
significant  concern  that  the  analysis may  be  inaccurate,  and
that  no   action  would   ever  necessary.    Therefore,   it  is
recommended  that  no  additional  action  should be taken  in this
rule,  but  that  cold  idle  emissions  and  the  garage  modeling
itself be investigated further  to  ascertain the accuracy of the
current  analysis.   This approach  does  not endanger the public,
since the  risk of exposure  to toxic  levels  of  formaldehyde in
public  parking  garages  is  not  significant  until  there  is  a
substantial market penetration.

     With  regard to risk  in personal garages,  it  is currently
widely  acknowledged  that  idling  a vehicle  in  a garage  is an
unsafe  practice,  and  thus  formaldehyde and  methanol exposures
from  methanol  vehicles  would  represent  nothing  new  in this
regard.    In  addition,   the  odor  and   eye  irritation  from
formaldehyde  exposure  would discourage owners from  idling their
vehicles  in  a  personal   garage,  and  serve  as  a  warning  of
impending  excess CO  exposure.  Since  vehicle  owners  can,  and
should,  voluntarily  avoid  the risks  of  exposure,  additional
regulations  are  not  called  for.   There   are  numerous  emission
and modeling related uncertainties that call  for resolution in
regard  to  this  scenario,  and  EPA  and industry should  expend
effort  to resolve them.

     With regard to  cancer  risk due  to increased ambient  levels
of  formaldehyde,  not  enough  is  known  about  the impact  of
methanol  vehicles   on  ambient  concentrations  to  justify  a
standard.    Preliminary  modeling,  however,   does  suggest  a
negligible  impact, given  existing  outdoor  levels due to  current
mobile  and other sources  and overall  levels  of exposure due to
indoor  concentrations.

     The  Agency  should include methanol vehicle impacts in  its
continued  consideration of  formaldehyde's cancer  impacts,   and
any mobile  source-related studies in this  area should  consider
methanol  and petroleum vehicle technology at  the same time.  It
would  not,  however,  be  appropriate  to use  this rule,   intended
to  establish  a  level playing field  for  methanol  vehicles, to
regulate  formaldehyde  cancer  risk  from  methanol  vehicles  alone.

Issue:   Optional Combined Exhaust and Evaporative Standards

Summary of the Issue

     EPA  discussed  the  possibility of  creating  an  optional
combined exhaust  and evaporative emission  standard that would
allow  increases  in  evaporative  emissions  to  be  offset  by
decreases  in  exhaust   emissions.    Comments  were  specifically
requested concerning the expected size and  associated  value of
the  increase  in  evaporative  emissions  that  this  alternative
would permit,  the  environmental  risks  that  might accompany  this
alternative,   and  methods   for   establishing  a   basis    of
equivalency  between  exhaust  and  evaporative  emissions.    No
action was proposed.

Summary of Comments

     Comments  received  on  this   issue  fall  into three  areas:
those concerning  the heavy-duty  industry,  those concerning the
light-duty  industry,  and those  concerning  the  issue  without
regard for any particular class of manufacturers or vehicles.

     The  comments  from  the  heavy-duty  industry (Caterpillar,
Cummins, and EMA) were  in  agreement  that  a  combined  standard
would  not  be  appropriate   for  heavy-duty  vehicles since the
industry  is  non-integrated (i.e.,  engines,   from  which exhaust
emissions  emanate,  and vehicles,   from  which  much  of  the
evaporative  emissions   emanate,   are manufactured  separately).
They felt  that a  combined  standard  would,  therefore,  cause "an
unnecessary  administrative burden."

     Some of the  commenters  from the light-duty  industry  were
more  supportive  of the  concept.    Chrysler,  Ford,  and  GM all
expressed moderate interest,  though none of  them  were able to
provide   any  specific   information  concerning  the  expected
amounts  of  the offsets  which might  occur,  or  the  value  of the
option.    GM   stated    that   this   program   would   cause  no
environmental  risks; Ford agreed,  provided that photochemically
reactive  exhaust   emissions  are  not  allowed  to  increase by
lowering less  reactive  evaporative  emissions. GM also  commented
that assuming the  typical  vehicle  makes  3.05 trips and travels
31.1 miles   per  day (these  numbers  were presented  by  way of
example  in  the NPRM) would overestimate evaporative emissions.
Toyota was the only commenter  from the light-duty industry that
did not  support the option of a combined standard; they felt it
would not be  cost  effective  to  utilize  this option because it
would  require  an increase  in  the  number  of evaporative  tests
required per vehicle family.

     Chevron  opposed  the  concept   of  a  combined  standard in
general,  citing   environmental   concerns.    They  stated   "that
there   are   many   unresolved   questions   about   the  proper

characterization  of  vehicle  evaporative  emissions,"  and  felt
that  as  a  result,' establishment of  an  environmentally  benign
equivalence between evaporative  and  exhaust emissions would be
difficult.   For  this  reason,  they  suggested  that the  Agency
should deepen its  understanding  of evaporative  emissions  before
this type of regulation is undertaken.

Analysis of Comments

     The  Agency considered  this option  in the belief that it
might  provide   some  measure  of  regulatory  relief  by  enabling
manufacturers to  decide the  most  cost-effective combination of
exhaust and  evaporative  emission controls to limit  a  vehicle's
total  organic  emissions.   For  example,  this  option could allow
the  manufacturers to  use  smaller evaporative   control  systems
than   would  normally   be   required,    provided  that   exhaust
emissions are sufficiently  low.  The comments  received  from the
heavy-duty  engine industry,  though,  indicate  that  this  option
would  not be  desirable to  the industry.   It   is  not  obvious,
however,  that  implementation of such a  program would  cause any
significant  administrative   burden  for  non-integrated  engine
manufacturers,   since  they   are   currently   responsible   for
evaporative  certification,   and  since  the  program  would  be

     Most comments from the  light-duty  industry did support the
option, but manufacturers were  unable  to provide  any  specific
estimates for  the amount or  associated  value of the flexibility
this  program would provide,  making  it  difficult  to judge the
program's potential benefits.

     EPA  remains  concerned  that the benefits  of such a program
may  be inconsequential  since,   as discussed in  the NPRM,  the
evaporative  standards were  designed to be non-fuel standards,
that  is they were  "intended to  encourage manufacturers  to focus
their  efforts  on  eliminating  fuel  emissions."  The two grams
per  test  allowance  was implemented  to  account  for background
sources of  organics  (such as interior materials or lubricants),
to     accommodate     some     degree    of    test-to-test    and
vehicle-to-vehicle variability,  and  to  provide some compliance
cushion.   This  is supported by  the  fact  that  vehicles   that
exceed the  standard  often  exceed  the standard by a very large
amount,  because  the  canister  becomes  saturated and  ceases to
effectively   absorb   the   emissions.    Thus,   allowing  slight
exceedances   of  the   evaporative   standard  may   have  little
practical  value,  since slight  exceedances rarely  occur.   The
lack  of  comments in this area,  despite  EPA's   specific request,
suggests  a  lack of genuine  interest in  this type of program on
the  part  of the  manufacturers  and makes  it difficult  for the
Agency to proceed.

     Toyota's   concern   that   this    alternative    might    be
disadvantageous if  it  resulted in a  need  for more  evaporative
emission testing is noted; however the  alternative  need not  be
used by any manufacturer who  would be  harmed by its  application.

     A more  significant concern with this  alternative  is  that,
as  was  acknowledged in the   NPRM,  EPA is  not certain  how  to
reconcile  light-duty vehicle exhaust  and evaporative emissions
to a common basis for comparison,  to ensure that there  would  be
no  increase   in  total  emissions.    Since  total   evaporative
emissions  are  a   function   of  driving  patterns   (hot   soak
emissions  occur  after  engine shutdown, thus  the more trips per
day,  the  greater  the  expected evaporative  emissions),  these
patterns  must be  carefully  accounted  for  in establishing  an
equivalence  between exhaust  and  evaporative  emissions.   The
method presented  as an example in the NPRM  was to combine the
emissions  from the  hot soak  test  (HS)  with  the emissions  from
the diurnal test (DI) using the following formula:

           emissions  _  (trips per dayXHS) + (DI)
           per mile           (miles per day)

     This  approach,  however, may  not be  appropriate because it
assumes  that average  emissions can  be estimated  with average
values for the number  of trips per day and miles per day which
occur  in use.  Driving  patterns  can  vary  greatly  from vehicle
to  vehicle  however.    For  example,   some  vehicles  may  not  be
driven  every day  and   would  undergo  repeated  diurnals without
the canister  being  purged.   Other vehicles operate continuously
during the diurnal period and thus the canister would generally
be  well  purged.   While average  values can be derived for  the
relevant driving  related parameters,  it is not clear that they
would correctly  weight the  different  emission levels associated
with different driving  habits.   Thus,  an accurate assessment of
all  typical  driving  patterns and  their  associated emissions
effects  would  be necessary in  order  to   convert   evaporative
emissions  test data to in-use emission factors,   EPA discussed
this  issue in the NPRM and asked  for  input  from the  public,  but
no  commenter  was  able to provide  data which could  be used to
overcome the  deficiencies in the current analysis.

     Another  concern in  this regard  relates  to the fact that
the hot  soak  and diurnal tests might not be  generally  accurate
representations  of  actual   in-use evaporative emissions.   As
mentioned  previously,   the  evaporative emission  standards were
designed such that the majority of the emissions  from  vehicles
meeting  their standards should be from non-fuel sources.   These
emissions  will typically change with  age  as  background  vehicle
organics  "boil  off"  and lubricants  and  road sludge accumulate
on  the  vehicle  surfaces.   Additionally,  hot  soak  and  diurnal
emissions  are affected by  local climate  and time of  year;  the
same  is  true  for  exhaust   emissions,  though  to   a  differing

degree.   An  equivalence  established  between  evaporative  and
exhaust  emissions  at  FTP  conditions,  therefore,  may  not  be
realist    at  other  conditions.   Given  the  limited  amount  of
methane   vehicle  emissions  data  available  at  FTP  conditions
(much    js at  other conditions) and  given  that  the  gasoline
content  which  greatly  affects  evaporative emissions) of future
methane   fuels  is  unknown,  it  is   impossible  to  assess  the
potenti    for such errors  at this time.

     G^    comment  that  the example  approach to establishing
equival  cy   that  EPA   gave   in   the  NPRM   would  overstate
evapor*  ve  emissions  seems  to illustrate  the  uncertainties
discuss    here  but  does  not  help  to establish a more workable
exhaust  vaporative  comparison.   Given  the  lack  of  data made
availal    to   the  Agency,  staff  must  agree   with  Chevron's
statenw    that  the   issue of  equivalency  between exhaust and
evapor<  ve   emissions   is  still   unresolved.     This   makes
applic<  on  of  a  combined  standard  in  a  manner  that would
providt   flexibility   without   the   possibility   of    adverse
conseqi  .ces  to the  environment very difficult.

     F:  .lly,  the Agency  has  noted  elsewhere  that the goal of
this  r  emaking  is   to   provide  a   "level playing  field"  for
metham    vehicles.     Promulgating   a  combined  exhaust  and
evapor;  ve standard  could have far  reaching implications which
relate   D other  types  of  vehicles  as  well,  and would be more
appropi  .tely  addressed   separately  at  a  point when  better
inform;  on on  emissions  tradeoffs is available.

Conclu!  in

     Tl   concept of  a combined exhaust and evaporative standard
did no   receive strong support from the  commenters  in general.
While    e comments  from  the  light-duty  industry  were somewhat
suppor-  'e, the comments from the heavy-duty  industry were all
oppose*   to   it.    None   of  the  manufacturers   provided  any
inform;  .on   which   indicated   that   the  benefits   would  be
signif   int.  In fact,  some of them suggested  there would be  a
net co    associated  with  them.  Given the  fact  the  evaporative
standa:  ;  were  designed  as  non-fuel  standards,  it   is  not
obviou:  that  significant benefits  from  the  program  are even
possib       Therefore   since:   1)   designing    an   appropriate
combim   program would be  very  complicated,   2)  the  state of
knowlei  >  with respect  to emissions modeling  is  not  sufficient
to  gi^   EPA  confidence  that  negative  environmental   impacts
would    i  avoided  with  such  a program,  and   3)  the  present
rulema!  ig was  intended to establish a level  playing field for
methan'   vehicles,  not  to explore  new regulatory concepts that
might    >ly to  all vehicle types,  it is recommended  that action
on thi   :oncept be deferred at  this  time.


Issue:  Application of Particulate and Smoke Standards

Summary of the Issue

     EPA  proposed  applying the  current diesel particulate  and
smoke  standards  to  all  non-throttled  methanol  engines.    EPA
also  asked  for   comments  on   the  likelihood  of heavy-duty
methanol  engines   automatically  complying  without  the  use  of
trap  oxidizers  with  the  0.60  g/BHP-hr  particulate   standard
which takes  effect in  1988  and  the  0.25  g/BHP-hr  particulate
standard effective in 1991.

Summary of Comments

     Mercedes  Benz Truck Company  (MBTC)  disagreed with  EPA's
engine  classification  scheme  for  applying  smoke/particulate
standards   to   methanol   engines.   MBTC   claimed   that   the
throttled/non-throttled   differentiation  is   irrelevant   to  a
methanol   engine's   soot  forming   potential.    Rather,   the
important  factor  is the  kind  of lubrication  used.  MBTC  notes
that  so  far  particulates  have been found in  the  emissions of a
two stroke,  non-throttled methanol engine,  and points out that
a  two stroke throttled methanol  engine might  also  emit higher
levels  of particulate but  under  the  proposed  classification
scheme would not  be  subject to  the particulate standard.   MBTC
strongly  supported EPA's  proposal to allow for waivers  of test
requirements wherever  applicable.

      Citing   preliminary   data,   DOE    commented   that    "the
by-products  of  lubricating  oil  combustion   in  a  compression
ignition  engine included a significant quantity of  engine out
particulate   matter,"    regardless   of    fuel   type.    Since
non-throttled  methanol  engines  are derived  from  compression
ignition   technology,   DOE   found  the  proposed   standards

      The     state     of    New    York     stated    that    the
throttled/non-throttled distinction may be  ambiguous.   It noted
the   Daimler-Benz   OM  407  hGO  methanol  engine which uses   a
throttle   at  low  and   medium   load   ranges  but   operates
non-throttled  in the  upper  load  range.

      General Motors  stated  that,  based  on a  few  tests of  its
light-duty  methanol vehicles,  particulate emissions  should  be
well  below  the proposed  (for  non-throttled vehicles)  0.20  g/mi
standard  and that  this standard  is  unnecessary.

      With regard to heavy-duty  engines,  GM felt that  their  M100
methanol  engines  should have no  problem  complying  with  the  1988
and  1991  heavy-duty engine standards without  any aftertreatment
(although they  note  that  driveability testing  has  not  been

performed).    They  were  less  confident,  however,  about  the
prospects  for  automatic  compliance  with  the  0.10  g/BHP-hr
standard, proposed to  apply  to  bus  engines  in  1991  and all
HDME's in 1994.   GM's  data on HDME' s fueled with M100 suggests
a  possible   range  of  uncontrolled  particulate  emissions  from
0.12 to 0.22 g/BHP-hr.  With  catalytic  aftertreatment, GM noted
that this  level has been  limited  to  0.05 g/BHP-hr  in one test.
Smoke  levels  were  reported below  0.1 on  the  Bosch  scale over
the 13-mode test.

     GM  noted  that if  M85  fuel becomes  the  fuel of choice for
heavy-duty  methanol engines,  they may  not be  able  to  comply
with 1988 and 1991  particulate standards  as easily.

     Caterpillar  and EMA  both argued that  smoke  levels ought to
be  very  low for  methanol  engines  and  that EPA  ought  to allow
for  waivers  of  this   standard  in  a  fashion  similar  to that
allowed  for current  CO  standards for  HDDE's.   Neither party
commented on the  need for a particulate  standard.

Analysis of Comments

     In  order  to  appropriately  analyze  the   comments  on this
issue  it would  be useful to review the  logical context of EPA'"
proposed  rules  for   particulate   and  smoke   emissions  fr
proposed  rules   for  particulate  and   smoke  emissions  from
methanol engines.   It  has  long been  acknowledged  that methanol
combustion  produces  lower particulate  and  smoke  levels  than
petroleum combustion in  diesel engines.   Recently promulgated
particulate  and  smoke standards, however,  will lower emissions
combustion  produces  lower  particulate  and  smoke
petroleum  combustion in   diesel  engines.  Recently  ptwiuuxyai-eu
particulate  and smoke  standards,  however,  will  lower  emissions
from  heavy-duty diesel  engines  to  levels  which  are below  the
measured   emissions  from   at   least  one  prototype   methanol
engine.  As  long as  the possibility exists for methanol  engines
to  emit  particulate or  smoke  above  the  diesel  standard,  it
would  be  inappropriate  to  avoid  limiting particulate  emissions
on  methanol  engines.    On the  other  hand,  in  developing  its
proposed  standards, the Agency  wished  to  avoid  unnecessarily
burdening  manufacturers  with  *=-"'i *+-i~r,~  f*~   ,-,,~-;    ^v.^<-
	   _,    	   	   regulations  for  engines  that
clearly  would  not  emit  at  levels  in  excess  of  the  diesel
standards.   EPA's goal  was  to apply  the diesel  standards  to
methanol-fueled vehicles  with  characteristics  similar  to those
nf  ("Ml KfOnf  Al ocol  *raln I /i 1 do    C/MTIQ  i-> v -i - o*- i ;
 of   current
 or   current   aiesei   venicies.    some   criteria
 needed  by  which  engine  type  could be evaluated.*
                                                 were  therefore
      The   discussion   focuses   on  particulate  emissions.    The
      potential   for   emission   of  smoke,   which  is  not  often
      reported  in  the  literature  for  methanol   engines,   is
      assumed  to   be   related  to   that   for  emissions   of
      particulate.   The  discussion  recognizes  that  the  absence
      of  smoke in  engine exhaust does not  necessarily imply the
      absence of  particulate matter.

     Particulate  formation,   in  a  practical  sense,  has  been
considered a fuel related phenomenon.   As general rule  fuel  oil
has  been  used   in  diesel  (compression  ignited,  heterogeneous
fuel  air  mixtures)  engines  and  gasoline  has   been  used  in
Otto-cycle   (spark   ignited,   homogeneous   charge)   engines.
However,  with  the  emergence  of  methanol  as  a   fuel  this
categorization  breaks  down.    Methanol   can  be  combusted  in
engines  derived from  diesel  engines,  gasoline-fueled  engines,
and  engines which  are  hybrids of the  two.  Certain  methanol
engines  have demonstrated  the potential  to  emit  significant
levels  of  particulate;  thus  it  became  necessary  to  consider
engine  parameters  other  than  fuel  type  to apply  particulate

     One   criterion   considered   as  a   possible   basis   for
predicting  particulate  formation  potential  for  methanol engines
was  method of  ignition.   Current  diesel  engines,  with higher
particulate,  are  compression  ignited,  while gasoline engines
are  spark  ignited.  With regard  to neat  methanol,  compression
ignition  has been  difficult  to   achieve  under the  range  of
possible    operating    conditions,    and   therefore    ignition
assistance,  such as use  of  spark or  glow plugs  has  generally
been  found necessary.    (Cetane improvers  can allow compression
ignition  to occur  but have  been found  less practical  due to
their  high cost.)   For  example,  WAN's  heavy-duty   methanol
engine  uses spark plugs  as  do the  majority of  all light-duty
methanol  engines developed  to date, while the GM Detroit Diesel
Allison  (DDA)  heavy-duty methanol  engine  uses  glow plugs over
part  of  its  operating cycle.  The particulate  emissions from
the   MAN  have   been  generally  lower  than   the   new  diesel
standards,  but  those  from  the  DDA  have  been  higher,  as  is
confirmed  by   GM's   comments.   Particulate   emissions  from
light-duty engines have  not been  generally reported,  although
GM states that  its  light-duty engines  are very low emitters.

      While the  evidence summarized  here  suggests   that  spark
ignited  methanol   engines  are  low   particulate  emitters   and
engines   utilizing  glow  plugs  over  a  portion  of   the normal
operating  cycle  are  potentially higher  particulate  emitters,
the  data are simply too  empirical  and far too  limited  to  serve
as  the   basis  for  any  sort  of   regulatory decision.   A more
fundamental understanding  of  particulate  formation  potential
was   therefore   sought  in  order  to   develop  criteria   for
regulating methanol  engines.

      Particulate nucleation  is thought  to occur   in  localized
fuel   rich  areas   of   the   combustion  chamber.   A  series  of
pyrolytic reactions rearranges the hydrocarbons into  molecules
of  lower molecular weight   and  level  of hydrogen saturation.
Acetylene is apparently  the  last  stable  species present  as  a
result    of    this   process.     Acetylene    reacts    through
polymerization   and  continued  branching   to   form  polycyclic
hydrocarbon structures  of  high  carbon/hydrogen  ratio.   These

structures  are  thought to  account for the  crystalline nucleus
of  the  particulate  matter.*   Diesel  combustion  is  generally
characterized  by   a  fuel  droplet   distribution  within  the
chamber,  enabling  combustion  to  occur   at  numerous  localized
sites more  or  less  simultaneously as a result of the heat built
up through compression of the mixture.  The  outer  layers  of the
droplets  combust properly,  but  the  insides  are carbon  rich,
resulting  in  incomplete  combustion  (carbon combusts  only  at
temperatures   above   those   achieved   in   the   cylinder)   and
facilitating  the  nucleation  process  discussed  above.    This
process is  followed by agglomeration  of  carbonaceous and other
organic materials,  resulting in particulate matter.

     In  contrast,   Otto-cycle  engines rely on  a  homogeneous
charge  through  which a flame front,  initiated by  a  high energy
ignition source  (spark plug), propagates.   Since  fuel air ratio
is  fairly  uniform   and  within  the  flammability  limits  almost
everywhere  in the cylinder, particles do not form as readily.

     The  theory  of   nucleation  suggests  that  the  effectiveness
of   the  mechanisms  which   result   in  particulate  formation
depends,  at  least   in  part,  on  the presence  of  hydrocarbon
chains  in  the  fuel; methanol's  simple chemical  structure thus
deters  particulate  formation to  some  degree,  although probably
not  entirely,  since  the products of methanol combustion include
some  hydrocarbons   of  higher  molecular  weight.   Additionally,
the  presence of lubricating oil,  as MBTC  and  DOE  point out, in
the  combustion chamber, and  the as yet  unresolved  question of
whether  there will  be any  gasoline  additive,  as  mentioned by
GM,  all add to the   engine's particulate  formation potential by
providing  hydrocarbon  chains   for  the nucleation  process.   In
fact,  the  excess particulate  emissions  of the  Detroit  Diesel
Allison engine were ultimately attributed to  the combustion of
oil  which  had  been leaking  past the  seal between  the  piston
crown   and   skirt.    A  seal   design  change  appears, to  have
corrected   this  problem   and  reduced  engine-out  particulate
levels  significantly,   to  the  level  of  approximately  0.06

     Thus  while combustion of  pure  methanol  would probably,
according   to  nucleation   theory,   not   result  in  particulate
levels   of   regulatory    concern,    combustion   of   methanol
     Other  theories  exist to explain the nucleation phenomenon,
     which,  though  less  popular  than  the  one  discussed here,
     also  depend  on the  presence of hydrocarbon  molecules of
     higher molecular weight  than  methanol.
     This  information  has become  available  in the time  since GM
     submitted  its comments and thus is not discussed in those
     comments.   These  data  are  available  for  review  in  the
     rulemaking docket  (number  A-84-05).

containing hydrocarbon chains (due to the presence of  lube  oil,
gasoline,   or  other  fuel  additives)  might.  This is  especially
true when  one considers  such combustion  in a  heterogeneously
charged cylinder,  which  would contain numerous  fuel  rich  sites
to facilitate  nucleation,  as occurs  in  the diesel engine.   It
was for this  reason  that  EPA selected the throttle criterion as
a  basis  for  regulating  methanol engine  particulate  and  smoke
emissions, since the  lack  of a  throttle implies that power will
be controlled  by varying the fuel  rate through  injection,  and
this is likely to  result  in fuel droplets or mist dispersion in
the  cylinder,  with  the  attendant  possibility  of  particulate

     DOE,   which   like MBTC,  whose  comment  will be  addressed
below,   implicated  lube   oil   combustion   as   a   particulate
precursor, went  further  in its  analysis  to focus on lube oil
combustion  in,  specifically,   a  compression  ignited  (i.e.,
diesel  type)   engine.   While,   as  will  be discussed,  it  is
apparent  that excess  lube  oil  combustion   in  a throttled,  or
Otto-cycle, engine may also  cause  elevated particulate levels,
DOE's  comment  seems to recognize EPA's logic  and  supports the
proposed action.

     MBTC  argued that  since two stroke engines utilize more oil
than  four stroke  engines,   they  should be  the  focus  of  EPA's
regulations.   Such a focus  was  seen to have two  advantages;  it
would  prevent   throttled   two   stroke  methanol  engines   from
emitting  excessive  particulates,  and  would  eliminate burdens
for  non-throttled  four stroke  methanol  engines.  In  regard to
the  first point,  higher  oil  consumption would  indeed suggest
the possibility of  increased particulate  emissions,  even in the
case of  throttled  (homogeneous  charge)  engines.  This is  aptly
demonstrated  by the performance  of  older  motorcycle engines
which  were often  of  two-stroke  cycle design  and  which  were
noted  for  the  smoky  nature   of  their   exhaust.    Incomplete
combustion of  lube oil,  containing long chains  of hydrocarbons,
in the oil mist  that was inducted  into  the chamber resulted in
particulate   formation,  most   likely   according  to   a similar
mechanism  to  that   in   diesel  engines  from   fuel   droplets.
Additionally,  it  is  anticipated that  oil washed from  the  walls
by the high  energy  air  induction stream  characteristic of two
stroke engines may  result  in particulate formation in the  fuel
rich  quench  zones near walls  and  in crevices.  This sort of
gasoline  engine  is  too  rare  now  within  regulated  classes of
vehicles   to   warrant   present  consideration   of   particulate
standards.  Nevertheless,  methanol engine  regulations developed
on the basis  of  particulate formation potential,  as  discussed
previously,   ought  probably in  the  broadest  sense  take  into
consideration the  particulate formation potential of  two  stroke
methanol  engines  as  well.   It  is however,  noted that  there  is
no apparent effort  underway to develop  or commercialize  a two
stroke  throttled   methanol  engine.    Thus  promulgation   of
standards  applicable  to  these  engines  would be  premature  at

present.    Additionally,  the  premise  of  this  rulemaking  is  to
create a  level playing  field for methanol  engines.   Therefore
it  is  noted that consideration  of standards  applicable  to all
two-stroke  methanol  engines  ought only occur  concurrent  with
consideration of such  standards  for  two-stroke gasoline engines
in a separate rule.

     Regarding  the   second  point,  there  is  simply  not  enough
data  to  show  conclusively  that  all  non-throttled  four  stroke
methanol  engines will  not  have lube  oil combustion,  and/or
combustion   of   other   fuel   additives  sufficient   to   cause
significant  particulate  emissions.   (These factors are known to
contribute to particulate formation even in today's four stroke
diesels.)   The  proposal recognized that the possibility exists
that  some non-throttled  engines  may not  emit  particulate  at
levels  exceeding the  standard  without  any  aftertreatment and
that,  as  Caterpillar and EMA pointed out,  smoke  levels  may not
be   significant  for   any    methanol   engine.   Unfortunately,
however, at  least until  it  becomes  clear which type of methanol
engines  are practical  in  the  marketplace, and  whether  actual
particulate  emissions  are  in  line   with   what  the  theory
discussed  here  suggests  they should be,  it is  important  for EPA
to  regulate on  the basis  of emission  potential,  including   a
consideration  of what types  of  engines appear practical market
contenders.  Any engine which  falls  into  a  regulated category
but  which  proves to be a  low emitter  of  particulate or  smoke
would  be  able  to use the  waiver  process to  avoid  a  testing
requirement.   This  process, supported by several  commenters and
opposed  by none,  is a very simple one  as  it  applies currently
to  diesel  engine  CO  emission  testing.   It  should  be  just as
simple and nonburdensome in  the  case  of methanol engine  smoke
and particulate  testing.

      In  response to the State of New  York's  comment about the
Daimler-Benz engine, an engine which  is non-throttled during  a
significant portion of  its duty cycle, such that  potenital for
significant particulate  emissions  exists,  would  have   to  be
considered  a   non-throttled  engine   for  purposes  of   this

      The comments by  DOE,  MBTC, and  New York  point out  that
while  the  throttle  criterion  is appropriate  at this time,  it
may not  be complete.    To  guard  against  the  possibility  that
developments  in  emerging   methanol  technology  that   may be
unforeseen today result  in  engine characteristics  for which the
throttle criterion  is insufficient,  the Administrator  should be
provided  with  the  flexibility  to   consider   other   engine
parameters  to   determine   the   applicability   of  the  existing
gasoline (Otto-cycle)  or diesel  standards:  While the  throttle
criterion   is   expected    to    be    important   one,    other
characteristics   such  as   intended  in-use  duty  cycle,   engine
thermodynamics,  and compression  ratio may  also be important and
the Administrator  should   be  able to   use  them  in  making the


     GM was  the  only commenter  to address  the feasibility  of
the  proposed  standards,  and  they  found  that,  at  worst,   a
catalytic  converter  might  be  necessary  to  ensure  compliance
with  the  most  stringent  standard,  that  applicable  to  1994
heavy-duty  engines  and  1991  bus  engines.    Since  catalytic
converters  are  an established  technology and  are  acknowledged
to  be  a  less  expensive  technology  than   particulate  trap
oxidizers  (which  diesel  engines may  need in order  to  comply),
the standards are economically reasonable.


     The  limited  data  on particulate  and smoke emissions  from
methanol  engines,   taken together  with  particulate  formation
theory,   indicate   that   the   conditions  necessary   to  form
particulate   are   extant   in    the   combustion   process   of
non-throttled engines.   Thus,  at this  time,  it is  appropriate
to  focus  on the  non-use of a throttle to  apply  the current
diesel standards to methanol-fueled engines.   It  is  noted that,
for any  regulated engine which proves to be  a  low emitter, the
process EPA  proposed for obtaining a waiver  from  testing would
be  a  simple  one.   The proposed  standards  are  feasible and
control costs should be no more than those of current diesels.

     The   analysis   also  suggests,  however,that   EPA  should
broaden  its  approach  to  application  of current  standards   to
allow  for the future consideration of engine  parameters  other
than  the use  of  a  throttle.   The Administrator  should retain
the  flexibility  to  consider  other  engine   characteristics   to
determine  if a  methanol-fueled  engine would  have emissions more
similar  to  current  diesels or  to current  Otto-cycle engines.
Further,  all references  in the proposed rule  to  throttled and
non-throttled  methanol   engines  should be  altered  to  use the
more general Otto-cycle  and diesel nomenclature.

Issue:  CO and NOx Standards

Summary of the Issue

     The  Agency   proposed  applying   current   gasoline-fueled
standards for  CO  and  NOx  to  throttled methanol  vehicles,  and
current diesel  standards  to non-throttled  vehicles.   EPA  also
proposed  idle  CO  standards for all  methanol-fueled light-duty
trucks  and   heavy-duty engines,  though  the  current  idle  CO
standard  applies   to   gasoline-fueled   light-duty  trucks   and
heavy-duty engines only.  This was done to  account for methanol
vehicles  that  are  non-throttled  over much  of  their  normal
operating range,  but  throttled at  idle.    EPA  mentioned  that
manufacturers  of  engines   that  are expected  to  always  remain
below the level  of the idle CO standard would be  able to apply
for  a  waiver to avoid testing  (this  is currently  done with the
CO standard  for  heavy-duty diesel  engines).   For clarification,
such  a waiver  only relieves  the  manufacturer  from undergoing
certification  tests,   it  does  remove  liability  for  complying
with  the  standard.  The issue  is  whether  the  Agency's approach
in setting CO and NOx standards is appropriate.

Summary of the Comments

     The Agency  received comments  from  Caterpillar and Chevron,
which  were   generally   supportive  of the  CO and  NOx standards
proposed  for methanol  vehicles.   With  regard  to  the proposed
standards  for   throttled   methanol   engines  DOE  specifically
stated that  available data  indicate:

     "that   methanol  vehicles  have  little  or   no  difficulty
     complying with current exhaust standards  for CO and NOx if
     they are  equipped with  the  same  emission  control systems
     as certified  gasoline-engine vehicles."

     No   commenter  beside  MAN  specifically   discussed   the
feasibility   or    appropriateness    of   the   standards   for
non-throttled engines.  MAN suggested standards of  7.5 g/BHP-hr
be  adopted   for heavy-duty  methanol  engines for  the transition
period between  1988 and 1991.   They stated  that it  appears that
spark-ignition   methanol   engines   with   turbochargers   and
intercoolers will  be  capable  of  meeting  the  proposed  NOx
limits.   They  argued   that fuel  economy  would suffer  if  NOx
emissions  are reduced  to  6.0  or  5.0  g/BHP-hr  as was proposed
for  1988  and 1991, respectively, and that  this  would delay the
acceptance of methanol  engines.

     EPA  received only one comment opposing the  approach taken
to   setting  idle   standards.   Ford  stated  that  it  was  not
necessary  to  have an  idle  CO  standard  for  methanol-fueled
vehicles that are  non-throttled at  idle.   They felt it would be
more appropriate to have  a standard only  for vehicles that are

throttled  at  idle,  than  to  "arbitrarily  set standards  which
then put a burden on the manufacturer to either comply  or  apply
for a waiver."

Analysis of Comments

     As was discussed  in  the  previous  section, the two types of
methanol  engines  may   be  more  appropriately  referred  to  as
Otto-cycle and diesel,  instead of throttled and non-throttled.

     That  so  few  comments were received  in  regard  to  EPA's
proposed CO  and NOx standards  is  interpreted  as  an indication
that the proposals  were generally  reasonable and that EPA's use
of  the throttle  criterion  as   the  basis   for  application  of
diesel  and gasoline standards  is  appropriate.  The  support of
Caterpillar,  Chevron,   and   DOE  for   the   proposed  emission
standards  is noted.

     Since  it  is EPA's goal to  create  a  "level playing field",
there  is   no  reason  to  create  special  benefits   for  methanol
engines by decreasing the stringency  of  their NOx standard as
MAN  suggested.   Since  methanol's  flame  temperature,   which is
less than  that  of  gasoline or diesel oil, inherently limits  NOx
formation  to  lower  concentrations,  staff   is  confident   that
methanol engines  will be  able  to  comply with the 6.0 g/BHP-hr
(1990 model year) and  5.0  g/BHP-hr (1991  and later model years)
standards  at least as  easily  as  current  gasoline-fueled  and
diesel engines will.   Thus, the  acceptance  of methanol vehicles
will   not   be  affected   by   promulgation  of  equivalent   NOx

     The  Agency  chose to  propose  idle  CO standards  for  all
(both  Otto-cycle and  diesel) methanol-fueled light-duty  trucks
and  heavy-duty  engines to  ensure  that  none  of  these methanol
engines emit  high levels of CO  at idle.   It was concluded  that
this  would not  place  any  significant  burden on  manufacturers
since  they would be allowed to  apply  for a waiver from testing
if  an  engine type was  expected  to  not  have significant CO
emissions  at idle.   Ford's  argument,   that  since  EPA's primary
concern is to ensure that  engines  throttled at idle are subject
to  CO  testing  then   standards should  apply only   to   those
engines,  is  noted.   The proposed approach  will accomplish  this
and  will   additionally  ensure  that  no   other   engine   emits
potentially   harmful   levels  of CO  at   idle.    This   approach
recognizes  the   fact  that  methanol   vehicles   are  a   new
technology,   and  EPA   has   an   incomplete  understanding  of
emissions  performance  of all  methanol  engine designs.   Given
this,  it seems  prudent to apply the  standards  as  proposed where
testing is not  necessary because  levels  are anticipated to be
low,  a waiver  would  be available.  Ford,  however, argued  that
application  for  a  waiver to  the idle CO  standard would  be  a
burden to  the manufacturer.   Staff  does  not   consider  the

application  process   to  be   a   significant  burden   to   the
manufacturer;  waiver  applications  are  easily  and  routinely
processed with  regard to  the  diesel engine  CO  standard today.
Thus there is no reason to change the proposed standards.


     The  CO  and  NOx  standards  proposed  to   apply  over  the
transient engine dynamometer test  cycles  for heavy-duty engines
and the  chassis  dynamometer  test cycles for  light-duty vehicles
and trucks  are equivalent in  stringency  to  those  for gasoline
and diesel  engines,  vehicles,  and  trucks and should  not cause
any unnecessary burden for manufacturers.

     With  respect  to  the idle  CO  standards,  it  is  concluded
that  the proposed standards  will  not create  any significant
burden to manufacturers  of methanol-fueled  diesel  engines,  and
that  in  the  general  absence  of   data  showing negligible CO
emissions  from these engines,  the  most prudent  approach is to
promulgate idle standards  for  all methanol engines.

     Therefore,  it is recommended that all  CO and NOx standards
be  promulgated   as   proposed,  with   slight  language  change
regarding engine type  (i.e., Otto-cycle ands  diesel).

Issue: Control of Crankcase Emissions  From Heavy-Duty  Engines

     Crankcase  emissions   are  currently  not  allowed  from  any
heavy-duty  engine  or vehicle,  except  for diesel engines  using
turbochargers,   pumps,   blowers,   or   superchargers   for   air
induction   (i.e.,   non-naturally  aspirated  diesel   engines).
Under the proposed  methanol  regulations no crankcase emissions
would  be allowed  for  any methanol-fueled  vehicle  or  engine,
including   non-naturally   aspirated  non-throttled   heavy-duty
engines.    EPA   proposed   classifying  methanol  engines   into
throttled   (gasoline-like)  and   non-throttled   (diesel-like)
categories  in order to apply particulate  and heavy-duty HC and
CO   standards.    Some  manufacturers   of  heavy-duty   engines
therefore   felt  that   a   universal   prohibition  of  crankcase
emissions  from  non-throttled  methanol  engines  represented  an
extension  of control  beyond  current  requirements.  At issue,
therefore,  is whether it  is  appropriate to restrict crankcase
emissions    from   non-naturally   aspirated,    non-throttled,
heavy-duty methanol engines.

Summary of Comments

     EPA received comments from Caterpillar, EMA, and GM all of
whom  opposed control of  crankcase  emissions  from non-naturally
aspirated,   non-throttled,  heavy-duty  methanol  engines.  They
argued  that  crankcase  controls are not  currently  required for
non-naturally  aspirated   heavy-duty   diesel   engines   because
crankcase   emissions   from  these  diesels   are  insignificant
compared to  the  associated cost of control.   In support of this
position  Caterpillar  discussed the  combustion and  scavenging
process   in  non-throttled  engines   to  show  why  crankcase
emissions   can   be   expected  to  be  low.   The  manufacturers
referred to  a 1979  analysis  and a  1983 analysis (which  referred
to  the 1979  analysis) by EPA  staff[21,22]  which showed that it
was not cost effective to control these  emissions.

      The   commenters   argued   implicitly   that  the  cost  of
controlling non-throttled methanol  engines would be  the same as
for  diesels  because  of  similar  emissions  characteristics and
required  control technology.   Control  on a turbocharged  engine
for  example  would  require  a  pump to  route the  crankcase gas
either  into  the exhaust  in  front of  a  catalyst,  or   into the
intake  manifold after  a  turbocharger.   The  manufacturers  felt
that  these  pumps would be prohibitively  expensive.   Routing the
gases into  the turbocharger would result  in fouling  due to oil
mist,  which would  cause maintenance  problems  and associated
high  costs,  and therefore should not  be  a  regulatory option.
The  commenters  presented no  emissions  or cost  data on  either
diesel  or  methanol  engines  with  which the  1979  study  could be
updated or  extended to methanol engines.

Analysis of Comments

     The   commenters   based  their   argument,   that  crankcase
emissions  should  not  be controlled for non-naturally aspirated,
non-throttled  (diesel),  heavy-duty methanol engines  because it
would  be   unnecessarily  expensive,   on  EPA's  1979  analysis
relating to diesel engines.  The  commenters claimed  that  this
analysis is also valid  for non-throttled methanol  engines, but
did  not  provide  any new  emissions  data  or cost  estimates to
justify this.
     The  previous f analysis,  however,  is  not  applicable  to
methanol  engines.    It  is  expected  that  control  costs  for
methanol-fueled  diesel  engines  will  be  much  lower  than  the
estimated cost  used in the original analysis  of  diesel control
cost,  for  several  reasons.   First,  methanol-fueled diesels are
expected    to   have    lower   particulate    emissions   than
petroleum-fueled  diesels,  and  thus  blow-by  gases  should  be
cleaner, easier  to  filter, and  less of a  concern  with respect
to   turbocharger  fouling.   Because  of  these   low  levels  of
particulates,  it may  be more appropriate to  compare  crankcase
                           engines  to  crankcase  emissions  from
                           have  been  routinely   routed through
                           A similar control technology could be
                          engine configuration,  including those
                         or   superchargers.    Therefore,  it  is
                 control    costs   of   non-naturally    aspirated
methanol-fueled  diesel  engines would  be  similar  to  those of
turbocharged  gasoline  engines,  whose  control  costs  are  much
lower  than  those of petroleum-fueled diesels.
emissions  from  methanol
gasoline  engines  which
turbochargers for years.
applied to  any methanol
using  pumps,  blowers,
likely   that
      Second,  the earlier  analysis  is outdated and represents  a
 worst-case   cost  effectiveness   for   petroleum-fueled  diesels.
 Since  the   time  the  analysis  was   done,   two  manufacturers
 (Daimler-Benz   and   Isuzu)  have  begun  voluntarily   controlling
 crankcase  emissions from turbocharged diesel  engines by  routing
 the  emissions   through   an  oil   separator,  and   into   the
 turbocharger.   Actual control costs for the  Daimler-Benz engine
 are  much   lower  than  EPA's   1979   estimate  of  $100   (1979
 dollars).[23]   Admittedly the estimate EPA received  was  for  the
 cost  of  controls  for  one  engine   model   and   may   not   be
 representative  of   costs  for  heavy  duty engines  in general.
 However,  if even only  a  moderate rate  of inflation is  applied
 to the  1979 estimate,  it  seems  likely that  current  costs  would
 on average  be  lower  than those  EPA estimated in  the  earlier
 analysis.       Thus,     even     if     the     petroleum-fueled
 diesel/methanol-fueled diesel comparison  were  valid,  the  1979
 analysis would still not  be  applicable.

      Finally,  the validity of the  1979  analysis with respect to
 this rulemaking is  questionable  because  since  that  time  the
 Agency has  found  it  necessary  to  consider   progressively  more
 costly  VOC   control   programs   to   bring   U.S.   cities   into
 attainment  with the  ambient  ozone  standard.   Thus,  what  was not

considered to be cost  effective  in L979  could be cost  effective
today.   In  fact,  given  current  air quality  priorities   the
Agency  could  eventually  decide  to  reconsider   its  earlier
decision  to  allow  non-naturally   aspirated  petroleum-fueled
diesel engines to emit crankcase gases.

     An  additional  point,   which  was   not  mentioned  in   the
comments,  is EPA's  concern  about  emissions  of  nitrosamines,
which  are  known carcinogens,  formed by  reaction of  amines  in
the lubrication oil with oxides  of nitrogen.   Nitrosamines  were
noted  as a  health  concern in the  1979 analysis.   Since  then it
has been shown  that   significant  amounts  of nitrosamines  are
found  in  the crankcase  emissions  of  petroleum-fueled  diesel
engines. [24]  It is highly likely that they  are  also  present in
methanol crankcase  emissions (because the  same basic formation
circumstances  exist   regardless   of the  fuel   type),   though
possibly at  lower  concentrations due to  the  lower NOx emissions
expected  with methanol-fueled  engines.    Control of  crankcase
emissions would essentially eliminate emissions of nitrosamines.


     Crankcase  emissions  from  methanol-fueled  diesel  engines
can  potentially represent  a  significant  source of  organics,
carbon  monoxide,  oxides  of  nitrogen,  and  nitrosamines;  thus,
closing  the crankcase  would provide significant environmental
benefits.   The  argument  that  controlling  crankcase  emissions
from  non-naturally  aspirated methanol-fueled heavy-duty engines
will  be as  expensive  as  controlling crankcase  emissions  from
petroleum-fueled diesels  is  not valid.    The control   technology
for   methanol-fueled   diesels   should    be   simpler   than  for
petroleum-fueled diesels  because of  lower particulate emissions
and costs  will likely  be more  like  those for gasoline engines.
Therefore,  it is  recommended those no   crankcase  emissions be
allowed  from any methanol engine,  as was  proposed.

Issue: Emissions Averaging Programs

     As noted  in the ANPRM,  EPA  originally considered allowing
manufacturers  the option  of  including methane1-fueled  diesel
vehicles  and petroleum-fueled  diesel  vehicles within  a  single
combined  particulate  averaging program.   Several  comraenters to
the ANPRM noted, however, that methanol-fueled diesel vehicles
might   not  compete  directly  with   petroleum-fueled  diesel
vehicles,  and   that  including  methanol  vehicles  within  the
averaging  programs   could   therefore   result  in   an  overall
increase  in  particulate emissions.  EPA decided  not to propose
this   option  in  the  NPRM  but   requested   comments   on  the
likelihood of  direct  market  competition between methanol-fueled
diesels  and  petroleum-fueled diesels,   and the desirability of
including  methanol-fueled  diesels with petroleum-fueled diesels
in a  combined particulate averaging program.

Summary of Comments

      The  Agency  received  three  comments   on  this   issue.   GM
supported   inter-fuel  averaging,  but  both  Caterpillar  and
Cummins felt that such  averaging  should not be  allowed.

      GM felt that  averaging  should be  allowed between  different
fuel   types   as  an  incentive  to  produce  methanol  engines.
However,  they  did maintain  that  if  fuel  prices  remain as  they
are  now,  it would be unlikely that  methanol HDEs would compete
directly  with  diesels,  except  for urban bus engines.   GM stated
that  they did  not believe that an adequate trap system would be
developed in time to meet the  0.10 g/BHP-hr  standard  for buses
in  1991,  and  that  use  of methanol  engines will  be required to
meet  the  standard.   They argued that providing  for  averaging
across  fuels    for   bus   engines  would  allow  areas  without
particulate  problems to  purchase less  expensive  diesel  buses
(which would be unable to meet the  standard), while areas  with
particulate    problems    could    be    required   to   purchase
methanol-fueled buses  or  diesel   buses  with  traps  in order to
receive  operating subsidies  from  the  Federal government.   They
also   stated  that  because  of   the   stringency  of   the   1991
standard,  a  substantial number of methanol buses  would have to
be  produced to provide  averaging credits  sufficient  to allow
production of  a single  diesel  bus without  a particulate trap.

      Caterpillar  and  Cummins  argued that   it  would not be
possible  to  predict direct  competition between methanol engines
and   diesels.    Cummins  agreed with  EPA   that without   direct
competition,   inter-fuel  averaging  could  result  in  increased
particulate  levels.    Additionally,   Caterpillar   argued  that
averaging between  different  fuel types  would give  an  unfair
advantage to manufacturers  of smaller  urban  type engines, since
methanol   will  be  more  available  in  urban  areas  initially.
Therefore,   they felt  that  averaging  should  be  allowed  only

after methanol is readily available in both urban  and  non-urban
areas.   Similarly,   Cummins  argued  that  inter-fuel  averaging
would  create  inequities for  manufacturers who  do not  produce
many methanol-fueled vehicles.

Analysis of Comments

     The position of both  Caterpillar  and Cummins that allowing
averaging  between   the  fuel   types   could  give   an  initial
advantage  to  manufacturers  that  produce  methanol  engines  or
small   urban  engines  may  be  valid.    However,   it  is  not
necessarily  true that  providing  regulatory flexibility,  which
might be more  advantageous  for  some manufacturers  than others,
would be anti-competitive.  The Agency's main  concern regarding
such  averaging  is  the possible  air  quality  degradation  that
could  result  if  methanol engines did  not compete directly with
diesel engines.

     This  problem  was  discussed  in  the  Regulatory  Support
Document to  the  NPRM,  where  a  detailed  analysis  was  presented
for  light-duty  vehicles.   This  analysis showed  that  unless
methanol  and  diesel  vehicles  compete   directly,  particulate
emissions  could   be  greatly  increased.    For  example,  in  one
scenario  it  assumed  that  200,000  light-duty  methanol vehicles
are  produced  and included  in   the  averaging  program,  but that
only  30,000  replace  petroleum-fueled diesels  (out  of  60,000
light-duty  petroleum-fueled diesel  vehicles),  while  the rest
replace gasoline vehicles.  The analysis  showed that  light-duty
particulate  emissions  would double  if averaging  were allowed.
The  analysis  simplistically  assumed  methanol engines  emit no
particulate; however the  conclusions  remain directionally valid
even  if,  as is  now  known to be  possible, methanol vehicles do
emit  a small  amount  of  particulate.    On the  other  hand,  if
methanol-fueled   diesels   and   petroleum-fueled   diesels  did
compete  well,   then  total   particulate  emissions   would  not
increase  because  each  methanol-fueled  diesel   produced  would
replace  a  petroleum-fueled  diesel,  and  the  total  number  of
vehicles  averaged  would  not   increase.   This analysis  can be
easily  extended to  heavy-duty  engines  to   show   that   unless
heavy-duty methanol-fueled  diesel  engines compete directly with
petroleum-fueled diesel engines,  allowing cross-fuel  averaging
could lead  to  increased  particulate  levels.    In  summary, if
methanol engines or  vehicles  which replaced gasoline  engines or
vehicles  were  allowed  to  be  averaged  with petroleum-fueled
diesels, then  particulate emissions would increase.

      It  was  stated  in the  NPRM  that   it  is   "impossible to
predict  with  any certainty the degree to which the two vehicle
types will be competitors."   However, this early analysis was
somewhat  limited in  scope.   Since  publication of the NPRM, the
Agency has  to  reconsidered  its  approach to   regulating  all
heavy-duty  engines,  including  methanol  engines.   There  is now
reason to  believe  that  it  may  be   possible   to  develop an

integrated program allowing  cross-fuel  averaging in  some cases
as well as some  form  of  banking and trading of emission credits
among manufacturers.   Because  the  scope  of  such  a  program  is
clearly beyond that  of this action, it is  more appropriate for
this issue to  be addressed  in a separate  action.   EPA  is,  in
fact, already doing so,  and therefore,  complete analysis of the
comments received will be deferred to that action.


     Since the issue of cross-fuel  averaging  is  much  broader  in
scope  than  this  rulemaking,   it  would  be  inappropriate  to
address it here.   Analysis  of  the  comments  should be deferred
to  a separate action.   There  is  no apparent  reason, however,
not  to  allow averaging within  classes  of methanol engines,  as
is  currently allowed  for  diesels,   and  as  was  proposed  in the
NPRM for this regulatory action.

Issue:   Determination of Fuel Equivalency

     EPA  originally   discussed,   in  the  ANPRM,   alternative
approaches to  determining  a fuel equivalency  factor (FEF)  for
methanol, to  be used  in connection  with the  Gas Guzzler  and
Corporate Average  Fuel  Economy  (CAFE)   programs.   However,  it
was  determined  in  the NPRM that   establishment  of  such  an
equivalency factor would be  premature prior  to  a  discretionary
decision by  the Secretary  of  the  Treasury,  in  the  case  of Gas
Guzzler, or the Secretary of Transportation,  with reference to
CAFE, to  include  methanol  in  their  respective  programs.   Since
neither Secretary had taken this action,  EPA proposed no  action
in this regard in the NPRM.

Summary of Comments

     Several  commenters {Ford,  GM,  Chrysler,  CARB,  Nissan and
NADA) felt that EPA  should  pursue the issue of  an FEF  further.
In  general,   the  reasons given  were that  establishment  of an
FEF, and inclusion  of methanol  in   the  CAFE  and  Gas  Guzzler
programs, could provide an  incentive for production of methanol
vehicles  through  CAFE and  Gas  Guzzler  credits.   Conversely,
failure  to  establish  an equivalency would be  an  impediment to
production  of  methanol  vehicles,  due  to  uncertainty   among
manufacturers  as  to   how  or  if  methanol will  be  included in
these programs.

     Ford  noted that   the  type  of   methanol  vehicle  produced
would  depend on how  methanol  is  handled with  respect  to  CAFE
and  Gas  Guzzler.   If  methanol were  excluded from CAFE  and Gas
Guzzler,  it  would  be  beneficial  to   produce large  methanol
vehicles  instead  of  smaller,  more fuel  efficient  vehicles.
This  is because  removing  fuel  efficient vehicles  from  a  CAFE
calculation (by substitution  of  a  methanol vehicle)  would  lower
a  manufacturer's  CAFE, while  excluding  less efficient vehicles
would  raise  it.   If   a  petroleum-based  FEF   were   used,   then
production  of  all  methanol  vehicle  types would  be encouraged
since   methanol  vehicles   use  very   little   gasoline,   and
production  of  any model,  regardless  of its  fuel   efficiency,
would  boost   a manufacturers  CAFE.   If,   however,  methanol
vehicles  were  included in  CAFE  and Gas  Guzzler based  on the
measured   methanol   fuel  economy,   then  there  would   be   a
disincentive  to produce any methanol vehicles, since the  lower
energy  content of  methanol  results  in  lower  per  gallon  fuel
economy  for  a  methanol  vehicle than  an  equivalent  gasoline

     Ford  suggested  that EPA establish  fuel  equivalency on the
basis  of the petroleum content  of  the  fuel  only,  because the
CAFE  and  Gas  Guzzler programs  "were  established with the
intention  of  reducing petroleum   usage,"   Ford  referred  to

Congress'  handling  of  electric vehicles,  noting especially the
1980 Chrysler Corporation Loan Guarantee Bill  which stated that
the  fuel  economy  of   electric  vehicles,  for  CAFE  purposes,
should  be  based  only  on  the  estimated  petroleum  used  in
generating  the electrical  energy  used by  the vehicle.   Ford
also  stated that  manufacturers  will  need  cost  incentives  to
offset the  higher  costs  of  production of methanol vehicles, and
also to offset the potential higher  operating  costs and limited
resale value  for  methanol  vehicles.   Such an incentive could be
provided  by  establishing  a   petroleum-based  fuel  equivalency
                               in  CAFE  credits.   Under  Ford's
                               example,  a  vehicle which achieved
                               on  an  85  percent   methanol,  15
                              would  have  a  fuel economy  of  67
                               equivalent  to ten miles  per  .15
factor,  which   would  result
petroleum based approach, for
ten  miles  per  gallon   (mpg)
percent  gasoline fuel  (M85)
miles  per  gallon.   This  is
gallon of gasoline.
     GM  also approved  of a  petroleum-based  fuel  equivalency,
but  felt  that  use  of  an  interim  zero  gallon/mile  basis  of
inclusion  would  provide a  useful  production  incentive.   The
zero  gallon/mile basis  implies that  methanol vehicles  use  an
equivalent  of  zero gallons  of  gasoline per  mile regardless  of
whether  any  gasoline  is  actually  present   in  the  fuel.   GM
estimates  that  if a  manufacturer  initially  produces  4,500,000
gasoline-fueled  vehicles with  a CAFE  of 26.5  mpg  and replaces
20,000  average  vehicles with methanol-fueled vehicles (getting
20  miles  per gallon on M85), then a petroleum-based  equivalency
would  effectively  increase  CAFE  by   0.095  mpg,  and  a  zero
gallon/mile  basis would  increase it by  0.112  mpg.

     Chrysler  noted  that since  a  vehicle's  fuel  economy and
emissions  are  related,  it  is  necessary to  know the  regulatory
requirements  for fuel  economy in  order to  optimize both fuel
economy   and emissions  performance.    They   stated   that  this
uncertainty  regarding  the regulatory treatment of methanol fuel
economy has  already  hindered their methanol  vehicle  development
program.   Chrysler  favored  a  fuel  equivalency based  on energy
content  of the  fuel  "to assure the most  economical  allocation
of  resources."

     CARS  and  Nissan  both  recommended establishing  an FEF, but
did not support  a  particular approach.   CARB stated  that action
by  EPA  would  not  create  an   incentive without action  by the
Department  of  Transportation   (DOT)  and/or  the Treasury,  but
that  without  EPA action  a  potential  impediment  would exist.
Nissan  felt that  establishment  of  a   fuel  equivalency factor
would   promote   research  and  development   of  methanol-fueled

     Finally,  NADA encouraged  EPA  to  pursue dialogue with the
Treasury  and DOT concerning  fuel equivalency.

Analysis of Comments

     Staff  believes  that  inclusion  of methanol  vehicles  into
these   programs   could  provide   an  economic   incentive   for
manufacturers to produce methanol vehicles if  a  petroleum based
fuel  equivalency were  used,  as was  suggested by Ford  and  GM.
The  incentive  would be  slightly  greater  if  a  zero  gallon/mile
basis was  used,  as  GM suggested,  on an interim basis.   However,
if  the  fuel equivalency were  based  on  energy  content  of  the
fuel,  as   was  suggested by Chrysler,  then it  is  likely  that
there   would   be   no  significant   economic   incentive   or
disincentive since producing  a  given vehicle to run on methanol
or on gasoline  would have  a roughly equivalent  impact  on CAFE.
(Admittedly,  methanol  engines  will  likely be more  efficient
than gasoline engines,  and thus  there  may still be  some small
CAFE  advantage,  under  this approach,  to producing  a  methanol
vehicle over a similar  gasoline vehicle.) Finally,  staff agrees
with  Ford that  exclusion  of methanol  vehicles  from  CAFE will
favor  production of  larger methanol  engines,  since  it would
remove   less  fuel   efficient   gasoline  vehicles   from  CAFE
calculations.   It is  further   recognized  that  inclusion under
any  of  these approaches has  implications for  energy  policy in
that  the  petroleum-based  equivalency favors  conservation  of
petroleum   resources,   where   as   an  energy-based  equivalency
values methanol  and  petroleum equally as  conservable resources.

     The  issue  of whether  a  fuel equivalency factor  should be
based  on  the  petroleum content  to  conserve  petroleum,  or on
energy  content  to conserve energy resources in  general  is very
important.   From  reviewing the  comments,  it  is  obvious that
there  is  no public  consensus on  which approach is  superior at
present.   This  issue  clearly  must be  resolved,  taking  into
consideration  all  relevant  statutory  language,  before  an FEF
can  be  developed.

     More   importantly  though,  staff  believes  that   present
action  by  EPA,   irrespective   of  the  approach  used,  will not
provide  any  incentive or disincentive to   produce   methanol
vehicles   unless  the   Department   of   Transportation   or  the
Treasury   acts   to   include   methanol   in  their   respective
programs.   Nor  will  it  allow  manufacturers,   as  Chrysler has
suggested,   to  optimize their  design  strategies to  a  greater
degree  than they can at present.   Admittedly,  the absence  of  an
established position   on  inclusion  of   methanol  vehicles  into
such  programs   creates uncertainty  for manufacturers.   This
uncertainty  could  affect  how  methanol   vehicle   development
programs   will   be   operated  and  what types   of vehicles  are
developed.   However, it is not obvious that action  by EPA alone
would eliminate  this   uncertainty,  since DOT  and the  Treasury
have not  yet  acted (and may never  act)  to include methanol  in
their respective programs.  (In  fact,  EPA's choice  of  one  fuel

equivalency  factor  over  another  might  influence the  decision
whether  or  not  to  include methanol.)   As  a  result,  present
action  will not  remove  any  regulatory uncertainty  from  the
minds  of key  decision makers  in the automotive  industry.   If
and  when methanol  were included  in  the  various fuel  economy
programs,   it  would  become  appropriate  for EPA  to  initiate
action to establish a fuel equivalency factor.

     NADA's  suggestion that  EPA  pursue  dialogue with  DOT  and
the  treasury on  this   issue  is appreciated  and staff believes
that EPA should remain  open to  such dialogue.


     The points  raised by  the commenters are generally valid.
However, staff believes that  EPA's  statement in the  NPRM also
remains  valid:

     "To   date,   neither   DOT  nor   the   Treasury   have
     determined that methanol  should  be included under the
     respective  programs.   EPA  therefore   believes  that
     determining  a fuel  equivalency  between methanol and
     gasoline  would be premature  at present.  If and when
     methanol  were included  in either  program,  EPA would
     initiate  action to establish such an equivalency."

     It  would  be  premature to  act  at this  time because action
by   EPA  alone  would   not  create  an   incentive  or  eliminate
uncertainty for  manufacturers.  Therefore,  it   is  recommended
that EPA take  no further action  in this regard  with the present

     EPA should  remain  open   to  dialogue  with other  federal
agencies on the question of  including  methanol  in the CAFE and
Gas  Guzzler programs,  and  should  be prepared to   initiate action
to  establish an FEF following  a  decision  on the part of either
the  Secretary of   Transportation  or   the  Secretary  of  the
Treasury to include methanol  in either program.


Issue:   Certification of Flexible Fuel  Vehicles*

Summary of the Issue

     Since  flexible  fuel  vehicles   (FFVs)   are   designed  to
operate on  any  mixture of  gasoline  and. methanol,   EPA  proposed
requiring   manufacturers    to    "demonstrate   compliance   with
applicable  standards  when  tested  on  any  of  those  fuels."
Comments  were   requested  on   the  appropriateness   of   this
approach.   Comments were  also  requested on any other aspect  of
this rulemaking which may be affected by the sale of FFVs.

Summary of the Comments

     No  cotnmenter  argued  against  EPA's  philosophy that  FFVs
need to be capable of meeting standards  on fuels  they encounter
in-use.   Most  of  the  commenters  were  concerned  that  EPA's
proposed  approach  to certifying  FFVs  would require tests  on a
range  of  certification fuel mixtures  and  felt that  this  would
be burdensome and unnecessarily complicated.

     A variety of  possible  alternative  approaches  were  provided
in  the  comments.   Ford  suggested  that  EPA  should  require
certification testing and mileage accumulation on  only  one fuel
determined  by EPA for  each  vehicle  at  the  time  of  testing.
Ford also argued that it is not  necessary  to  test  vehicles with
intermediate  mixtures  between  methanol  and  gasoline,  because
owners would habitually use one fuel.

     DOE  also felt that FFVs  should only  be tested on  one fuel
but  did not  believe testing  should  be limited to gasoline or
methanol  only.   They felt  EPA  should specify the fuel mixture
following a manufacturer's  request for certification.

     Chrysler felt that FFVs should be tested on both methanol
and  gasoline  to  ensure that the vehicles  are  not  optimized  for
only  one  of the  extremes of  possible  fuels.    GM,  however,
suggested that initially  testing  should be required on gasoline
only,  since it  will be the predominant  fuel  choice in  the near
future,   then  on  both  methanol  and   gasoline   once  methanol
becomes readily available to the  public.

     Chevron  felt  that,  in addition to  testing on both methanol
and  gasoline,  it  is  necessary  to  test  FFVs  on  intermediate
mixtures.   They  were   especially concerned   about  evaporative
emissions  in this  regard  since  methanol-gasoline mixtures  can
have   higher  vapor  pressures   (and   hence  higher   resultant
emissions)  than either  methanol  or gasoline separately.
     Flexible  fuel vehicles  are  also referred to as multi-fuel
     vehicles, dual-fuel vehicles, variable-fuel vehicles,  etc.

     There  were  three  other  concerns  that  were not  directly
related to  certification  fuel  specification.   First,  the state
of  New York  felt  that  the NPRM  did not  clearly  state which
standards   (methanol  vehicle  or  gasoline  vehicle)  would  be
applicable  when  a  vehicle  is  operating  on a  fuel  mixture that
contains  less  than  50  percent  methanol,  which  could  commonly
occur  in  use.  Next,  Toyota expressed concern that the proposed
regulations might be  interpreted to  mean  that  vehicles designed
to   accept   low-level  methanol  blends   would   be  considered
multi-fueled  vehicles  and  thus would  be  more  difficult  to
certify.  Finally,  Ford was concerned  about  how FFVs  would be
treated  with  respect  to  fuel  economy  and  labeling.   They
suggested  that  a  single  petroleum  equivalency factor  (PEF),
based  on  the  actual amount of petroleum expected to  be used by
the  vehicles  should be established for use in the  CAFE and Gas
Guzzler programs.   They  also felt  that while both  methanol and
gasoline  fuel  economy  estimates  should  be  available  to  the
consumer via the labeling  program, the two  estimates should not
be  compared to one  another,  but instead to  typical ranges for
vehicles  in the same  class.

Analysis  of the Comments

     The  Agency  stated  in the NPRM  that  it expects  FFVs to be
able  to demonstrate  compliance  on  any mixture  of  methanol and
gasoline  that could  be used  in the field  and no commenters
explicitly  argued  against  this concept.   To  ensure  that this
occurs  for  each  vehicle,  it is  necessary that at a minimum the
certification  test be  performed on  the worst  case fuels (for
both exhaust and evaporative tests,  which could necessitate use
of   different   fuels   for  exhaust   and  evaporative   testing,)
because   as  Chrysler  implied,   vehicles   will   probably  be
optimized  for  the  fuel(s)  they  are  to  be  tested  on.   For
similar  reasons,  it is also necessary to use  a  worst case fuel
for mileage accumulation.

     The  alternatives  suggested  by  Ford, GM,  and  Chrysler,
which  require use  of only  methanol  and/or gasoline,  will not
necessarily ensure use of the worst  case fuel for certification
purposes.   This is  especially  true  for  evaporative  emissions
because  of the  effects of  gasoline/methanol  mixtures on fuel
volatility, as noted by Chevron.  Chevron  was  referring to the
fact  that  a  few  percent  methanol added  to gasoline raises the
fuel's  volatility  dramatically.    This  volatility   tends  to
remain above  that  for  pure gasoline until a substantial  amount
of   methanol   (50   to  70   percent)  has   been   added.    Since
evaporative emissions  are  correlated with  volatility,  it is
likely  that   the   worst   case  fuel,  for  evaporative  testing
purposes,   is  an  intermediate  blend.   Ford stated  that  owners
will  generally use one  fuel  extreme  or  the  other,  and  that
testing on intermediate  mixtures  is not  necessary; however it


would  be difficult  to prove  the premise  of Ford's  argument,
especially given  the vagarious nature  of  the fuel market  over
the last  15  years.   EPA must continue to assert that  as long as
operation on intermediate blends  is  a  reasonable  possibility,
FFVs should  be  capable of meeting standards when fueled by such
blends.   Chevron's  suggestion,  testing on  gasoline,  methanol,
and  intermediate  blends,  would  be  environmentally  prudent,
though it would require several  certification tests per vehicle
and  this increased  testing burden might  be  a  disincentive to
produce FFVs.  Since it is  the Agency's  goal in this  rulemaking
to  remove impediments  to  the  development  of methanol vehicles,
this alternative is inappropriate.

     The  alternative mentioned by DOE,  using only one  fuel mix
specified by EPA at the  time of  the  certification test, would
allow  vehicles to  demonstrate  compliance  over the  range  of
fuels,  without  increasing  the  number  of  certification tests
from  that necessary  for   gasoline  vehicles.  This approach is
appropriate,  though   a  slight  modification  would   be useful.
Under this modified  approach the manufacturer would recommend a
specification,  for  Adminisrator  approval,  of whichever mixture
of  fuels  (of those which  could occur  in use) would produce the
highest  emissions.   This  modification is  useful because the
manufacturers will likely be more  familiar than the Agency with
the  specific emissions  characteristics of  each vehicle.  This
approach  would  not relieve the manufacturer of his liability to
meet  the standards  on any potential  in-use mixture.    EPA would
retain  the   right to  use   any  representative in-use mixture for
its own  certification  and recall testing.

     The  state of New York felt  that  the NPRM did  not  clearly
indicate  which  standards  would  be   applicable  to  an  FFV
operating on   a   fuel with  less  than  50  percent  methanol.
However,  it  is  stated  in  the NPRM  that:

      "EPA considers  it reasonable to subject vehicles  tested on
      a  mixed fuel containing methanol  ~o  the emission  standards
      for  methanol-fueled  vehicles."

This  is  appropriate because the  standards  for  methanol-fueled
vehicles  are  designed   such  that   they   become   essentially
equivalent  to  those  for  gasoline vehicles  when the vehicle  is
operated on  gasoline;   the  methanol   and  formaldehyde  terms
become negligible.

      In response to Toyota's  concern  about the definition  of a
flexible-fueled vehicle,   the  approach taken in the  NPRM was  to
consider a  vehicle  designed to  operate on  gasoline,  methanol,
and  intermediate mixtures to  be  an  FFV.   Thus,  a  gasoline
vehicle would  not be considered an  FFV  solely  because  it  is
capable of   accepting  low level  methanol blends.  Also, the NPRM


clearly distinguished  between mixed fuels (such  as  those  to be
used  in an  FFV)  and  blended  fuels   (with  small  amounts  of
alcohol) which  have  received EPA  waivers  under  section 211 of
the Clean Air  Act  and which  are treated like  gasoline.   Thus,
again,  a  vehicle  specifically  designed to  accept  a  low  level
methanol blend fuel would be  considered  a  gasoline vehicle,  not
an FFV.

     The issue" of  inclusion  of  methanol into  the  CAFE and Gas
Guzzler programs is  discussed in detail in a  separate section.
As  is  noted  there, methanol is currently not included in either
program.   Thus  it  is  appropriate to  treat  FFVs  strictly as
gasoline vehicles  with respect  to  CAFE and Gas  Guzzler.   With
respect to  labeling,  since  EPA  did not specify  a  methodology
for calculating the  fuel economy  of  methanol  vehicles  in this
rulemaking,  inclusion  of  a  methanol fuel economy  number on the
label would be  inappropriate.


      It  is  the Agency's  goal  to  remove  impediments to  the
development  of  methanol-fueled  vehicles.   Therefore,  it  is
recommended  that,  with  regard to  FFVs, EPA not require  tests
over  the  range  of possible  in-use gasoline/methanol mixtures
for   each  vehicle,  but  instead  allow  the   manufacturers  to
recommend,  for  Administrator approval,  the worst  case  fuels
(one  each  for  the  exhaust emissions,  evaporative emissions, and
mileage accumulation) .   In this way  compliance  over  the  range
of  possible  in-use fuels can be assured,  consistent with EPA's
consideration  of FFVs  in  the  NPRM.   The  act  of  specifying  a
fuel  would  not relieve  the manufacturer  of  his  liability to
meet  the  standard  on any other  reasonable  in-use fuel mixture;
it  would  simply  allow  him  to  avoid   an  increased  number of
compliance  tests  relative  to  dedicated  gasoline  or methanol
vehicles.   The methanol  standards would be  applicable for all
possible mixtures of gasoline and  methanol used by FFVs.

      With respect to the  CAFE and  Gas  Guzzler programs, EPA has
no  authority to establish  any  fuel equivalency factor for  FFVs
or  to  account  for methanol  fuel   economy  in  its  treatment of
FFVs.   It  therefore  follows  that EPA should  treat  FFVs as
gasoline  vehicles.   Since  EPA  is  not defining a methanol  fuel
economy test procedure,  it  is  logical  that  the labels of  FFVs
should include  the fuel economy  for gasoline only.

Issue:     Complexity of the Procedure for  the  Determination of
           Organic Emissions

Summary o the Issue:

     Pollutant gases  from  methanol-fueled engines  and  vehicles
consist of a  mixture of  hydrocarbons,  methanol  and formaldehyde
together  with other  exhaust  species  such  as  carbon  monoxide,
carbon dioxide etc.   As  was discussed  in the NPRM and in detail
previously in this document, EPA determined  that  measurement of
each  of  the  primary organic materials  (hydrocarbons,  methanol
and  formaldehyde)  would be required  to  secure  the  necessary
level of  emission  control.   To  avoid what EPA believed would be
an unnecessary  level of complexity  in the  emission  standards,
EPA  proposed  a  single,  carbon-based  standard  for the organic
compounds, comprising the three measured pollutants.

     In the development  of the NPRM,  EPA made every  effort to
limit  the  complexity  of  the  procedures  necessary  for  the
measurement of  these  materials.   In  the  proposal,  EPA  noted
that   a   flame   ionization  detector   (FID)*  (the  instrument
presently used for measurement of hydrocarbons),  can  be used to
directly  and  correctly measure either  hydrocarbon emissions or
methanol  emissions  separately but  not  both  of  these  pollutants
simultaneously.   EPA also  noted in  the proposal  that  a FID is
unsuitable for  the measurement of  formaldehyde because  of  its
very  low  (approaching  zero)  response to  formaldehyde.   While
the   FID   could,   with   appropriate   adjustments   of   its
measurements,   continue   to  be   used   in   measurements   of
hydrocarbon emissions from methanol  fueled vehicles and engines
it  was  necessary  to  include  additional   procedures   for  the
measurement of methanol and formaldehyde.

     Very briefly, the procedures  proposed  were as follows  (see
figure  1).   For methanol,  the  procedure  was  to  dissolve the
methanol  in water  and to  separate  the methanol  from the water
using  a  gas  chromatograph (GC).   The  methanol  is then measured
by a- heated  FID.  For hydrocarbons, the  procedure consisted of
the   collection  of   dilute bag  samples,   measurement  of  the
hydrocarbons  plus  methanol with  a  heated  FID   calibrated on
propane   followed   by  subtraction  of  the  methanol   fraction
(previously determined in  the methanol analysis)  from  the total
FID  measurement.  This  analysis would need  to account for the
FID's  response  factor  to methanol.   For formaldehyde,  the
procedure employed   the  collection  of  formaldehyde  from  the
exhaust   sample   by  reaction  with   2,4-dinitrophenylhydrazine
(DNPH),   followed  by analysis  with   a  high  pressure   liquid
chromotograph using  an ultraviolet detector.
 *    EPA  proposed   the   use   of   a  FID   that   is   heated.    As
 presented in  this discussion the  term  FID refers equally to  the
 heated FID.


                       Figure 1.

        Schematic of Measurement Procedures for
            Methanol Vehicle Exhaust Orgenics
Cartridges or


     EPA   recognized.  in   the  proposal   that   less   costly
measurement  procedures  would  be  desirable.    One   procedure
considered by EPA was  the  use of a  FID calibrated on  methanol
to  develop a  single  measurement  for HC  and methanol.   While
this approach would  be simpler  than  the proposed procedure  and
would   accurately   measure  methanol,   it  would   overmeasure
hydrocarbons.     While   this    approach   would   have    been
environmentally  conservative  as  well  as  simpler EPA  believed
that the  overmeasurement would  cause  manufacturers  to  oppose
its use.

Summary of the Comments:

     Seven  commenters provided comments  on  this  issue.   The
commenters  were  the   Department   of  Energy,   the   Engine
Manufacturers Association,  General  Motors, Mercedes  Benz Truck
Company, Nissan, Toyota and Volkswagen.

     DOE  stated that the proposed procedure would  require  the
use  of  expensive equipment  and that  the  measurement procedure
is   cumbersome.   DOE  felt   that    the   HC   overmeasurement
characteristic  of  the single  measurement  procedure  which  was
not  proposed by EPA  supported its use because  it  would provide
a larger safety margin with respect to ozone control.

     EMA  believed   that  the  techniques  proposed by EPA  for
measuring   the  non-oxygenated  hydrocarbons,   methanol   and
formaldehyde,  would  require  instrumentation  which   is  overly
complex  and costly  for  the  developing methanol-fueled  engine
and  vehicle industry.  Due to  the presently  small  size of the
methanol-fueled  engine  industry,  EMA  felt  that   it   is  not
necessary   at   this   time   to  separate  the  organic  compound
emissions  from  methanol-fueled  engines  and  vehicles  into their
three  components.    If,   in  the  future,  there  are  many more
methanol-fueled  engines   and   vehicles   in   operation,   EMA
suggested  that  EPA  might  again  consider  a  requirement that
manufacturers   provide  the  individual  component  information.
For  the  initial certification  of methanol-fueled  engines and
vehicles  however,  EMA recommended the use  of  a FID  calibrated
with methanol  to determine the organic  emissions.   In  addition,
EMA   recommended  that  factors   should  be   applied   to  the
FID-indicated  values  so  as to  account for  the differences  in
FID  response  to the carbon in  the   hydrocarbon (high response
when calibrated on methanol)  and to  the carbon in the  aldehydes
(very  low) .   EMA stated  that  such a method would be  the most
cost-effective  option, and would require no  new instrumentation
for  certification.   However,   if  a  manufacturer believed  the
standardized  factors  to be  inappropriate  for  its  technology,
EMA  suggested  that  manufacturer-specific  factors   could   be
determined and  employed.

     Nissan  felt   that   the  proposed   procedure   is   overly
complicated, the  costs  for new test equipment  are  high  and the
experimental  burden  would  be  increased.    Nissan  felt  that
indirect  measurement of  methanol  using the  current FID  (FID
calibrated  on  propane)  is  acceptable.   Nissan stated that  the
sensitivity of  the FID to  methanol when calibrated  on  propane
is roughly  85  percent of  its  sensitivity to  hydrocarbon  ,  and
the overall sensitivity of  the FID to exhaust emissions from an
M85  methanol-fueled  vehicle  is   about   94   percent.    This
information  led Nissan to  conclude that the  exhaust emissions
results  obtained  with a  FID  (calibrated on  propane) are  only
about  6  percent lower than  actual  exhaust  emissions  from a M85
methanol-fueled  vehicle.    Nissan   believed,   therefore,   that
organic  emissions  from methanol-fueled  vehicles can be measured
with   sufficient   accuracy  using   the   current  FID,   if   an
appropriate sensitivity correction  factor is employed.

     Toyota  stated  that  while   catalyst   equipped  vehicles
exhibit  very low  levels  of formaldehyde emissions (formaldehyde
is readily  oxidized in the catalyst),  non-catalyst vehicles can
have  higher formaldehyde  emissions.   Toyota  felt,  therefore,
that   formaldehyde   should  be  included  in  the oxygenated  HC
standard.   Toyota  requested,  however,  that  actual  measurement
of  unburned  methanol  and formaldehyde  be  exempt  from  the
requirement.     Toyota    recommended     using   an    optional
calculational  method  for  methanol and  formaldehyde using  an
assigned correction  coefficient.   Toyota  also  requested  that
manufacturers   be   allowed  the   option   to  use   their   own
coefficient instead of an assigned  one.

     GM  recommended  calibrating  the   FIDs   with methanol  and
applying a  factor to correct  for the  fact  that total carbon in
the hydrocarbon/methanol  mixture  of emissions would be reported
high  while  the carbon  in the aldehydes  would be reported very
low.   The factor  would  account for  the photochemical reactivity
differences between hydrocarbon, methanol and  aldehydes.

     While  there   is  no  apparent  technical  obstacle   to  the
proposed procedure  for  formaldehyde,   Ford  felt  that  its  use
will  significantly impact conventional certification testing as
well  as  end of line and  in-use  testing  because of  the need for
a  wet  chemistry  laboratory,  trained  laboratory personnel and
the  time  required  to  analyze  samples  (3  hours  minimum  was

     Nissan  stated  that   the  proposed   procedure  for  the
measurement  of  formaldehyde  can  not  provide  continuous  test
result  outputs  whereas  a  FID  or  NDIR can.   Also,  the  DNPH
procedure   requires  extra   equipment,   is  time  consuming  and
necessitates great care  in its  performance in order to  achieve
accurate results.   Nissan hoped   that the  use  of  a  less
demanding test  procedure  will  be  allowed  in the  future.

     Mercedes Benz stated that despite the  inherent problems,  a
FID  calibrated  with methanol  is the  simplest  and lowest  cost
method of measuring the  organic  compounds,  and  should be  given
further consideration.   If  this  approach is not adopted as  the
official measurement  procedure,  Mercedes Benz  recommended  that
it be  allowed as an option to the  gas-chromotograph  method  for
methanol   measurement,   because   of    its    simplicity    and
practicability for  in-line  continuous measurements which  are  a
necessary tool for further  developing  available methanol  engine

Analysis of Comments:

     In  developing   the   proposal,   EPA  sought   measurement
procedures   which  would   provide   accurate   measurements   of
hydrocarbons,   methanol   and   formaldehyde   without   unduly
increasing  test  procedure  complexity  and  cost.    Since  the
ratios  between  pollutants  in pollutant streams,   i.e.  exhaust
emissions and evaporative  emissions,  can  vary widely  between
vehicles and between  fuels,  procedures  which  either  failed to
measure one  or more  of the constituents  or  provided inaccurate
results could lead to deleterious  environmental effects.   This
ruled  out  the possibility  of  developing correction  factors to
allow  the FID to be used as a procedure which  could be presumed
to be  accurate for characterizing  total  organics.   EPA selected
the  procedures which  were  proposed  because  they  provided the
information  necessary for  the  control   of  the pollutants  of
concern  without  unreasonable   increase  in   test  procedure

     While   the   need  to   accurately  control   the  effects  of
exhaust emissions on  the environment has  in no way diminished
since  publication of  the NPRM,  it  is  apparent  that,  because of
their  limited numbers,  methanol-fueled vehicles  will  be  only
minor   contributors   to  atmospheric  pollution  during  their
introduction into the marketplace.   In  light  of  the preceding
and  the commenters'  concerns with  respect to the potentially
negative  impact   of  the proposed  measurement  procedure  on the
development   of   methanol-fueled   vehicles,    a  less  complex
procedure  may be warranted  on  an  interim  basis.   Since the
control  of   the pollutants   entering   the   environment   is  of
paramount  importance,  any  simplified interim  procedure should,
if  it  contains a measurement weakness,  tend  to err on the  side
of   overmeasurement.     One  such  procedure   which  has   been
supported  by a  number of  the commenters is the  use of  a FID
calibrated   on methanol.   Since calibration on methanol  would
result in an  overmeasurement  of  the hydrocarbons  by the  FID,
this  would  be  an  environmentally acceptable   interim  approach
because  the  error  would tend to  be on  the  conservative  side
(for  the  pollutants  measured  by the   FID).   Some  commenters
suggested  the  use of  correction  factors  to   account  for  the

overmeasurement  of  hydrocarbons  if  the  simplified  measurement
procedure were  to be allowed.   This  approach  is  not  warranted
for   several   reasons.     First,   the   highly   photochemically
reactive  formaldehyde,  which  is  produced  in  relatively  large
amounts by methanol  engines,  is not measured by the FID.   Even
on  an  interim  basis when there  are  very  few methanol-fueled
vehicles  in   service  it   would  be   prudent  to   view   the
overmeasurement  of   hydrocarbons   as  a  compensating factor  for
the failure of  the  FID  to detect  the  formaldehyde constituents
of  the exhaust  gases.   DOE's  comment  is consistent  with  this
logic.    Second,   while   the   manufacturers   noted   that   FID
correction factors  can  be developed,  they did not  discuss  the
fact  that  in  order  to  accurately  utilize  them,  different
factors    would    need    to     be    developed    for    each
vehicle/fuel/instrument  (response factors do vary even between
similar   instruments  by   the  same  manufacturer)  combination.
Thus  the  application of correction factors would  of  itself  be a
very  complex procedure.

      Nevertheless,  it appears reasonable  to  view the  use  of a
heated  FID,  calibrated  on methanol,  as an  acceptable interim
procedure for  the  measurement  of the   subject  emissions  from
methanol  fueled vehicles.   Because the purpose of allowing the
use  of  this  simplified  procedure is  to reduce  testing  costs
during  the development of  a  methanol   fueled vehicle  fleet,
without   incurring   any  significant   negative  impact  on  the
environment,  there  is   a  need   to  limit  the period of  time
wherein  the  simplified  procedure  can be  used.  Presently a five
year  period  would   appear to  be  sufficiently  long   to  allow
initial   development  of  a  methanol  fleet  without posing  the
potential of  any significant  environmental harm.

      Should   such  a period   for  the   use   of the   simplified
measurement procedure be allowed, EPA would  need  to monitor the
organic   material  composition  of  the  pollutant  gases  from
methanol-fueled engines and vehicles.   This  monitoring would be
performed to  enhance  the Agency's  knowledge  of  the organic
material  composition  (and  its  potential  health  effects)  of
methanol-fueled  vehicle  exhaust  gases.   The  Agency   would  be
able  to  expect  that manufacturers  would collect similar data
under the provisions of section  202(a)<4) of the Clean Air Act
and  make it  available  to  EPA.   The  manufacturers   currently
provide much useful  information  on unregulated  pollutants  and
on emissions  research under this  section, and  provision of test
results   for  methanol   and   formaldehyde would   be   a logical
application of  the  requirements  of that  section.

      As  correctly  pointed  out  by  Ford,   the   sampling   and
analytical   procedures   for  the  measurement  of  formaldehyde
emissions do  introduce new  laboratory  requirements  to vehicle
emissions measurements.   Elimination  of the  requirement for  the

measurement  of   formaldehyde  emissions   on   the   basis   of
laboratory  costs  or  complexity  is,   however,   not  warranted
because of  the relatively  high  concentrations  of  formaldehyde
in methane1-fueled  vehicle  exhaust  and the  high photochemical
reactivity of formaldehyde and its toxic potential.

     Nissan's  comment  that  the  proposed  DNPH  procedure  for
characterizing   formaldehyde  emissions  does   not   allow  for
continuous measurement whereas other procedures  might do  so  is
well  taken.   It  is  EPA's  understanding  that the FID  and NDIR
techniques referred  to  by Nissan  have  key drawbacks  related  to
sensitivity  and,  in the  case  of  NDIR,  cost.   Nevertheless,
manufacturers  are   always  allowed  to  substitute  technically
equivalent   test   procedures  for   those   required  by  the
regulations.   Through  such  an  allowance  it  is  hoped  that
superior measurement  techniques  will  eventually emerge.   Thus
Nissan  is  free  to  use  the  suggested  alternatives  if it  can
demonstrate  their  equivalence to the  procedures promulgated in
today's rule.

     The recommendation  by Mercedes  Benz that a  FID be allowed
as  an  optional   measurement  procedure  in   engine  development
work,  suggests  a misunderstanding with respect to  the overall
applicability  of   a  regulation.    For  testing  performed  to
determine compliance with an emission  standard,  compliance with
the  procedures  specified  in the regulation  is  necessary.  For
all  other  test  purposes,  a manufacturer  may freely  choose to
use  the test procedure that  it finds  most  appropriate.  Use by
a  manufacturer  of  test  procedures  and  test  equipment   during
engine  development   which  did not  conform to  the  requirements
for   emission   testing   would    not,    however,    excuse  the
manufacturer   from   the  requirement  of  compliance  with  the
emission standards when  using the specified test procedures end


     The   arguments   favoring   use   of  the   less   demanding
measurement  procedure  which  employs  a  heated  FID  calibrated
with  methanol  to measure total  organics during the very early
stages  of   the  development  of  a methanol-fueled vehicle fleet
are   compelling.    Such  an  option   should   allow   continued
development  of  these  vehicles without  posing  any  significant
environmental  threat.    It is recommended,  therefore, that the
simplified  measurement  procedure be  allowed for certification
and  recall testing  of  methanol-fueled vehicles  and  engines for
five  model  years  starting  with  the  effective date of  the
methanol-fueled  vehicle  standards.

Issue:      Sampling   and   Analytical   Procedures    for    the
           Measurement   of   Methanol   Emissions,   Hydrocarbon
           Emissions and Formaldehyde Emissions

Summary ofthe Issue:

     Comments were provided on only a few of  the  details  of the
sampling  and analytical  procedures which  were  proposed.   For
the  sake of  brevity  and  to  avoid  confusion,  those  details
addressed by the  commenters  will be identified  and underlined
in this issue summary.

     EPA  proposed that  the sampling  system  for  non-throttled
methanol  vehicles  include a  dilution  tunnel configured  like
that presently  used for  testing  diesel vehicles.   Though  this
is more  complex than the  system  used for  gasoline  vehicles and
throttled methanol vehicles,  it  was  judged necessary to  allow
for the sampling of particulate emissions.

     For  the determination of  methanol  emissions,  EPA proposed
that the methanol sample  be  collected  from  the  dilute  exhaust
stream   or   from   the  SHED  by  bubbling  the  sample  through
impingers  containing  chilled  deionized  water.    The  use  of
heated   (235015F)   sample   collection   probes   and   sample
collection lines  leading to the impingers was  proposed  for the
dilute   exhaust   samples.   The   samples   collected  would  be
analyzed  using   a gas   chromotagraph   with  flame  ionization

     For  the  determination  of  exhaust  hydrocarbon  emissions
from  methanol-fueled  vehicles,  EPA  proposed  that  the  dilute
exhaust  sample  be collected using the bag sampling procedure as
presently employed with  gasoline fueled vehicles.   Analysis of
bag  samples  was  proposed  to  be performed  using a  heated FID
(250010F).    For  hydrocarbon  measurements  of   evaporative
emissions  in the  SHED,  the sampling  procedure proposed  was the
same as  that presently used with gasoline  fueled vehicles   (the
sample goes  directly  to  the FID) except that  a heated FID would
be employed.   Calibration  of  the FID would  be performed using
propane  as  is  present  practice.  A  FID  so  calibrated  fully
measures  the  hydrocarbons  present  in  the   sample  but   only
partially  measures  the   methanol  present.   The  hydrocarbons
present  in the  samples would be  calculated  by subtracting  from
the  FID  measurement the  product of the FID response factor to
methanol and the  concentration  of  methanol  as determined by the
methanol measurement procedure.

     For  formaldehyde  emissions  determinations,  the proposed
procedure  consisted of  the collection  through a  heated sample
probe  and  line  of a proportional exhaust formaldehyde sample by
bubbling  a  sample of  the dilute exhaust  gas  stream  through

glass      impingers      containing      a      solution      of
2,4-dinitrophenylhydrazine  (DNPH)  in  acetonitrile  (ACN).   The
resultant  solution  is  then analyzed  in  a high pressure  liquid
chromotograph  (HPLC) with  an ultraviolet  (UV) detector.   As an
alternative to  the  preceding vet  method  of sample  collection,
EPA proposed the  use of  cartridges containing silica gel  coated
with DNPH.  The remainder of the sample separation and analysis
procedure  would be  similar  to that used with the  wet  method of
sample collection,

     The proposal also required determinations of  the accuracy,
with  corrections  if  required,   of  the  sample  dilution  and
collection systems.  The  procedures  proposed for  this function
consisted  of  the  injection  of  a  known  amount  of  propane
(present  practice)  into  the  system,  sample  collection  and
analysis,  followed by  a  determination of  the amount of injected
propane  which   is  recovered,  i.e.,   losses  in  the  system  are
detected.  For  systems which  would be used with methanol fueled
vehicles,  the  system  would  also  be  tested  for   losses  of
methanol  which  would be  injected  as a gas  (the methanol would
be vaporized by heating).

Summary of the Comments:

     Comments  on  sampling  and  analytical  procedural  details
were provided by VW, Chevron, Ford, General Motors,  and Toyota.

     VW  stated  that  the  proposed procedures for the measurement
of  HC,   methanol  and  formaldehyde  are  overly  complex.   VW
suggested that   the   single  dilution-tunnel  sampling   system
proposed   for   the   testing  of   non-throttled  methanol-fueled
engines  and vehicles  (necessary  for particulate measurement) be
allowed  to be  used with   all  methanol-fueled  vehicles.    This
approach  would allow a manufacturer  to  test both throttled  and
non-throttled vehicles (engines) using a single test site.

     Chevron   felt   that   the   wet  chemistry   procedure   for
measuring methanol  is  relatively   accurate.   Chevron   stated
however,  that  methanol  losses may occur due  to  condensation  in
unheated  sample lines used in FID measurements  of  organics  (HC
plus   methanol)   from   throttled   methanol-fueled  vehicles.
Chevron   also  stated that  a sample  line temperature of 375F
will   cause   inaccuracies   in  measurements   for   unthrottled
methanol-fueled   vehicles  and  engines   because   of  methanol
decomposition.    As  a   consequence   of  methanol   lost   in   the
hydrocarbon   plus   methanol   analysis.    Chevron   felt   that
non-oxygenated  hydrocarbon  (hydrocarbon)   results  will  be  low
because  this value is determined  by  subtraction  of  the methanol
result  (accounting  for  the  FID  response factor  to methanol)
from the  FID result.

     General  Motors  felt  that  some  methanol   loss   may  be
associated  with  condensation  on  the walls  of unheated sample
bags employed in the HC plus methanol analysis.   GM stated that
the  use  of  continuous  heated  FID analysis  would  give  the
correct results.   GM did not believe that  the  use of continuous
FID  analysis  would pose  any  problems  because the  procedure is
already in use in many emission facilities of  the motor vehicle
industry  (i.e.,  is employed with diesels).  GM  stated  that the
FID  should be  heated  to  about  200F  rather  than  the  375F
presently  used  with diesels.   GM did not  believe that  a heated
FID  would be  required for  evaporative emissions  measurements
because of  the  absence of condensation.  GM recommends allowing
the  use  of  a  heated  FID   for  evaporative  emissions  if  a
manufacturer so desires.

     Toyota felt  that  a heated FID control temperature of 121C
(250F>  is too   low  for  use  with  diesel engine  testing  and
recommended   a  heated  FID  control  temperature  of   191+6C
(375+10F)  for  use  with both  methanol-fueled  and   "diesel"
engine  testing.   Toyota  felt  that  there  is  a minimal  loss in
measured   methanol   emissions  between   heated   FID   control
temperatures of 121C  and  191C.

     Chevron  also  felt   that the  proposed  procedures  would
underestimate  formaldehyde  emissions.    In   support  of   this
position,  Chevron  referenced  a  study  conducted  by Southwest
Research  Institute  (SwRI)  for  the Coordinating Research Council
(CRC).[8]   The   report   showed   that   significant  losses  of
formaldehyde  (approximately  40  percent)  occurred  in   dilution
tunnels  upstream  of the  sampling point.   Chevron believes  that
similar   losses  may  occur  in the  proposed  sampling  system.
Chevron  recommended additional investigation  of the problem and
study of  possible  solutions.

     While  Ford  does  not  use the impinger -  gas  chromotograph
(GC)  procedure for methanol  collection and analysis, Ford  felt
that  the  procedure should not  pose  any technical  problems.
Ford  suggested   that  heated  collection  lines   (methanol  and
formaldehyde  samples)  need  not   be used since   the   transfer
efficiency of  formaldehyde in unheated lines is  on the  order of
95  percent (test  results provided showed  a range of from 94 to
97  percent) and  pointed  out  that formaldehyde is more  reactive
than  methanol.   Ford  suggested  two alternative  procedures for
measuring methanol.   These alternative approaches are:   (1) the
use of  adsorbent  traps,  and  (2)  the  use of  Fourier Transform
Infrared  (FTIR) spectroscopy.

     For  formaldehyde measurements, Ford  stated that they  have
used both the   impinger  and  cartridge  methods   for   sample
collection.   Under ideal conditions, the  two procedures produce
equivalent   results.     However,    the   cartridges    are  not

commercially available  and  reproducability of  the coating  may
vary  from  laboratory to  laboratory with  resulting  variability
in  collection  efficiency.    If  cartridges  are  not  uniformly
coated and properly  dried,  erroneous  emission  measurements will
result.   Ford  expressed   the  opinion   that   the  alternative
cartridge  approach  for sample  collection, while  being  simpler
in the sample collection phase is actually more labor  intensive
when  all  phases, from  cartridge preparation  through  analysis,
are considered.

Analysis of Comments:

     The  commenters did  not  significantly  disagree  with  the
overall sampling  and analytical  procedures as  proposed.   Rather
the comments on this issue  addressed procedural details.

     The recommendation made by VW  was  to allow  the  use  of  a
single  type of  sample dilution and  collection  equipment for
methanol fueled  vehicles  whether Otto-cycle  or  diesel.   While
the  type  of  equipment  recommended  by VW (dilution tunnel) is
the  more  complex of  the  two  types  proposed  by  EPA  it  was
selected   by  VW   because   it  provides  the  capability  for
particulate  sample   collection  from diesel engines  as  well as
the  capability  to  omit   particulate  sample  collection  when
Otto-cycle engines  are  undergoing testing.  Since the emission
results obtained by either  procedure,  exclusive of particulate
emissions, should be equal, there is no  fundamental reason for
precluding  the  use  of  the  single  dilution  tunnel type of
equipment recommended by VW.

     On  the basis  of  the  wording  used  in  both  Chevron's and
GM's  comments,  it  appears   probable  that these  commenters did
not note the 250F  temperature  specification  for the heated FID
for    use   with    methanol-fueled   vehicle/engine   emission
measurements.  Chevron  also appears  not  to have noted the  235F
temperature  which was  proposed  for all  sample lines.   Both of
these  commenters pointed  out,  however,  that  decomposition of
methanol  can  be expected  to  occur  if  the  375F  temperature
specification  used  with  petroleum-fueled diesels were applied
to  methanol   sampling.   EPA agrees  with  this  position and
therefore  selected  the lower (235 and  250F) temperatures so
as to  avoid  this  problem.

      The   use   of  a common  temperature  for  both  diesel and
methanol fuel  testing (Toyota recommended 375F)  would  simplify
laboratory procedure.  Losses  in  measurement accuracy,  either
through  the use  of  the lower temperature with  diesels  or the
higher temperature  with methanol is not  an acceptable trade-off
for   the  small  simplification  in  laboratory  procedures  that
would  result.    Since  the  temperature   at   which   the  sample
collection lines operate   is  adjustable, and  since  the  FID's

operating temperature is either presently  adjustable  or  the FID
can  be   retrofitted   to   provide   adjustability,   laboratory
problems  would  center   on the  time  required  to  change  and
stabilize  the  FID  and  line  temperatures  between  tests  on
different   fuel   types   (assuming   the    use   of   a   single
sampling/analytical  system).    This  problem   can  be  readily
addressed  by  scheduling  groups  of  tests  on  one  fuel  type
followed  by  a  single  temperature  adjustment  before going  to
another group of tests on another fuel type.

     Prior  to publication  of  the  proposal,  EPA  evaluated the
response  of  a  heated  FID  and  an  unheated  FID  to  samples
containing  both  methanol   and hydrocarbons.   This  evaluation
showed  that  an  unheated  FID  responded  slowly  to  a  sample
containing  both  methanol and  hydrocarbons while the  heated FID
responded  at  a  much  higher   rate.   The  response rate  of the
heated  FID  was  comparable  to that  of  an unheated  FID  when
analyzing  only hydrocarbons.   EPA  proposed the use  of a heated
FID for analyses of  samples containing  methanol and hydrocarbon
to avoid  1)  errors  due to premature data collection, or 2) test
voiding  due  to  sample   bag   depletion   prior  to  instrument
stabilization.   While  there is agreement  with  GM that methanol
sample  loss  due  to condensation would not be a problem with
evaporative  emission  samples,  there  is  disagreement,  for the
reasons  given above,  that an  unheaced  FID  can  be  used with
evaporative  emissions samples as suggested by GM.

     Both  GM and Chevron  expressed concern with  respect to the
loss  of  methanol  sample  due  to   condensation.   GM's  concern
focused  on  losses   in  an  unheated sample bag while Chevron's
focused  on  unheated  sample lines  leading to  the  sample bag.
Since  the use of heated sample  lines was proposed,  the concern
expressed  by Chevron was addressed in  the proposal.  Chevron's
comment  therefore,  must have  been  the result  of  an oversight.
As a  first step in addressing the  concern  expressed by  GM, EPA
has  analyzed one  sample bag  (unheated sample  collection  lines
were  used)  with  the  bag  at  both room  temperature  and  at  a
temperature of  between 95 and 100F.  A higher FID reading was
obtained when the bag was  warmed.   However, the FID measurement
made  when the bag  was  warmed also occurred when the volume of
sample  contained  in  the   bag was  almost  depleted.    It  is,
therefore,  not possible  to determine  what significance  should
be  attached  to the  observed  difference.   Lacking  data with
which  to  quantify  the  significance  of the GM comment,  it is
recommended that the  sample collection  procedure  be retained as
proposed.    The   concern  raised  by  GM   should,  however,  be
investigated in detail  and,  if warranted, the  sample  collection
procedure  should be  modified at a future date.

     While there were  no  comments  on the proposed heating of
sample  probes  on   constant   flow  venturi  -  constant   volume


sampling   systems   (CFV-CVS),   evaluation   of   the   proposed
procedure  as   part   of  ongoing  testing  of   methanol-fueled
vehicles by EPA has shown that heating of the sample probes  for
the methanol  and  formaldehyde  samples  results  in some  heating
of the sample as it passes through the probe.[25]  This  heating
of  the  sample  causes  a loss  in proportionality  between  the
sample  volume  and the  total diluted  volume.   As  a result  an
error  is introduced  in the test  results.   Since the probe  is
very short, and  its temperature will  be that of the dilute  gas
stream,  condensation  in an  unheated probe would not  be expected
to pose  a  problem.  Heating of  the  probe will,  therefore,  not
be required in  the final rule.   Heating of  the  sample line from
the probe  to the  impingers  will,  however,  continue  to  be  a
requirement to  avoid  any losses in the lines  (the Ford comment
indicated  that  for its  particular system,  the   losses  could be
on  the  order of  three  to  six  percent).   Care must  be taken,
however, in  the construction of  sampling systems to  thermally
insulate the  heated sample  lines  from the  unheated  probes.  As
an option, heating of  the  sample  line may be  avoided provided
the  methanol  and formaldehyde  sample  collectors  are  close
coupled  to the  probe;  i.e., the  sample line is  either omitted
or  its  length  is so short as to preclude significant cooling of
the sample and any associated condensation.

     As  noted   by Ford,   formaldehyde  emission  measurements
results  obtained  with   properly  prepared DNPH  cartridges  (dry
collection procedure) are  equal to those obtained with the wet
collection  procedure,  while  the use  of  improperly  prepared
cartridges will cause  incorrect  measurement  results.   Also as
noted  by Ford,  there  is presently no commercial  source for DNPH
cartridges.    This   lack   of    commercially    available   DNPH
cartridges  is  not surprising because there is  presently  little
demand  for this product (given the  limited amount  of methanol
vehicle  emission  testing  being performed  at  present).   It is
reasonable  to  expect,  however,  that  one or  more manufacturers
of  DNPH cartridges could  enter the market  as  demand grows  for
this  product.   In the meantime, manufacturers  will  either  have
to  prepare their  own cartridges  or  use the impinger collection
technique.    There   is  no   disagreement,   however,   that  if
cartridges  are used,   they  need  to  be  accurately  prepared.
Procedures  for  the preparation and  checking of  the cartridges
have  been  developed by  EPA.[26]

      With  respect to the  comment  by Chevron pertaining to  loss
of  formaldehyde in the  dilution  and  sample collection  systems,
the referenced  report has been carefully reviewed.   In the  work
referenced by Chevron,  the formaldehyde was injected  into  the
exhaust gases   as an   aqueous  solution.   Since  the  dilution
tunnel  used  in exhaust  emissions measurements  is  designed to
dilute  and  mix   gases,  injection of   formaldehyde  in  aqueous
solution into  the tunnel  can  reasonably  be  expected  to  pose
significant   vaporization   and   mixing  problems   and  as  a

consequence sample  loss.   This  is  apparently what was exhibited
by the  low formaldehyde  recovery  (high loss) rate  reported in
the Chevron reference.   As part of EPA's evaluation of sampling
procedures for  methanol fueled  vehicles,  EPA investigated  the
potential  for  the  loss  of  formaldehyde  in  the  sampling system.
In this  work,  the  formaldehyde was  injected into  the  exhaust
duct  in  gaseous  form.   Loss  of  formaldehyde  sample was  not
detected  in this  evaluation of  the sampling  system.   It  can be
concluded, therefore,  that the  concern  expressed by Chevron is
not attributable  to the  sampling  system but to  the procedure
used  in the referenced testing to quantifying  the performance
of the sampling system.

     With  respect  to  the  suggestion  by Ford that  alternative
procedures be  allowed,  EPA's  position on alternative procedures
has in  the past and continues to  be  that they will  be allowed
provided  equivalent  results  are  obtained.   This  position is
stated  in  existing  regulations.    In  the  case  of  the  two
procedures suggested  by Ford, (the FTIR procedure and adsorbent
traps), they are presently  in the  development stage  and are not
generally  available to  all potential  users.  Specific inclusion
of  these procedures  in the  regulations for  use at  this   time
would,  therefore,  be  inappropriate.   Exclusion of the suggested
procedures does not, however, preclude  their  use  once they  have
been shown to provide equivalent results.


     While  the  dilution  tunnel  procedure  must  be  used   with
diesel  engines,  there is no  technical basis  for  precluding its
use  with  Otto-cycle  engines.   It  is  recommended,  therefore,
that  language  be included  in the  regulations  signifying  that  a
manufacturer  may   use   a   dilution  tunnel   in the   testing of
Otto-cycle methanol fueled vehicles/engines if the manufacturer
so desires.

     Since  there  is  very  little  data  which would  support the
concerns  pertaining to  methanol loss  in sample  bags and there
is  no data to  indicate an appropriate  sample  bag  temperature,
if  heating were  required,  the  regulations  should  be finalized
as  proposed.    EPA should,  however,   collect data  which would
resolve  the  concerns  raised by  GM with respect  to  the loss of
methanol  sample in sample  bags.   If  warranted by the data, the
regulations should be amended at the earliest possible date.

     The  use  of  heated  probes  which  rely  on   constant   flow
venturi  for  maintaining sample flow proportional to  main tunnel
flow   will   cause  measurement   inaccuracy.    This  proposed
requirement  should be removed.   The heated sample lines must be
thermally isolated from  the  probes to  prevent   heating  of the

probes.   Close  coupling  of  sample  collection systems  to  the
probes  should  be   allowed,  if  desired,   so  as  to  avoid  the
requirement for the use heated methanol and  formaldehyde  sample

     The  regulations  need  to be  carefully  reviewed prior  to
final publication to remove any ambiguities with  respect  to  the
use of heated FID and heated sample lines.

     Careful  preparation  of DNPH  cartridges  is  a  prerequisite
to obtaining  accurate formaldehyde  test  results if  cartridges
are   employed.    Laboratories   using  this   method  of   sample
collection should be  encouraged  to use the  procedures  detailed
in the EPA report.

      It  should  be clearly  stated  in the preamble  to the Final
Rule  that manufacturers  may  use  procedures which  have  been
demonstrated  to  produce  results  equal  to  those  specified.
Procedures  which   are  presently  not   readily  available  for
widespread  use  in  emissions  testing should,  however,   not be
specified by  EPA as required procedures.

      No  change  in  the   previously  specified  line   or  FID
temperatures   is   recommended.    Those   proposed   should   be
appropriate   to  ensure  adequate  collection  and  detection  of
organic  materials.   Use  of the  heated FID is still  recommended
over   use   of   the   unheated  FID  due   to   response   time

      Some  test  facilities  find  that  use  of  DNPH  cartridges
provides  time  and  space  flexibility in  the  testing  process.
The  present  lack  of  suppliers  of  DNPH cartridges  and Ford's
preference    for    the   impinger    technique    in  collecting
formaldehyde  should not  affect  EPA's decision to  allow use of
cartridges as an  alternative technique.

      Finally, accurate qualification of  the measurement  system
for   formaldehyde  recovery   efficiency   is  good  laboratory
practice.   EPA would expect that  test  facilities  would  conduct
experiments   in  this  regard  as  appropriate  to  demonstrate  the
validity of  their measurement  techniques.

Determination of Formaldehyde Background Levels
Summary of the Issue:

     As with  the background  level determination  of  all  other
measured  emissions,  EPA  proposed  that  background  samples  for
formaldehyde be collected  for  each phase (cold start/hot start)
in the case of  heavy-duty engine  testing,  or  for each  bag,  in
the  case  of  light-duty  testing,   of   the   test  procedure.
Analysis  of  these  background  samples  would  employ  the  same
procedures  as   were   described  for   the  analyses   of   the
formaldehyde in exhaust emissions samples.

Summary of the Comments:

     Toyota was the only  commenter  on  this  issue.  Toyota stated
that while  it is using the  recommended procedure, it requested
that the  measurement  of background formaldehyde  levels  be  made
optional  because  of  inherent  low background  levels  and  the
complexity  of  the  analytical  procedures.   Toyota  viewed  its
request   as   a   conservative   one,   simulating   worst-case
conditions, since  background would be assumed  to be  zero  and
there  would,  as  a  result, be  a higher  then actual indication of
emissions from the test vehicle.

Analysis  of Comments:

     Toyota's  request  to make  the measurement  of  background
formaldehyde  levels  optional  appears   at  first  glance  to  be  a
desirable  test  procedure    simplification   because   of   its
conservative    nature.     On    closer   inspection,   however,
implementation of this  option  would pose problems in areas such
as  emission standards  compliance  determinations and lab to lab
correlation   testing.     Problems   could   arise   in   these
determinations  when  the  formaldehyde  background  level  in   a
laboratory   was  high   but   was   not  recognized   as  such.
Measurement   of   formaldehyde    background   levels    appears,
therefore,  to be  necessary.    Reducing  the  number  of  samples
collected and consequently the number  of analyses which have to
be   performed  was  considered,   however,   to   be  desirable.
Background  sample collection  periods  which were considered as
methods whereby the  test procedure could be simplified were l)
a single  sample for  the  total  test, 2) a daily  sample,  and 3)  a
weekly sample.  Because of potential  -short term fluctuations in
formaldehyde  levels  in the background air which could impact
test  results  and which would not  be  detected by  the  daily or
weekly samples,  these  sampling periods appear to be  excessive.
To  avoid possible  problems  in lab to lab correlation and to
facilitate  correct  determinations of vehicle  compliance  with
emission  standards,  while allowing a  degree  of test procedure
simplification,   the   collection   of   a  single   formaldehyde
background  sample  covering the total  test  period  should  be


     Replacing bag  by bag background sampling  and  analysis  for
formaldehyde with  a  single  sample  and  analysis  covering  the
total  test   period  will  simplify  testing  without  significant
loss of  testing  accuracy.  The  regulations should  incorporate
this  provision.    Bag  by  bag  or  phase  by  phase  background
sampling should  be  allowed as  an alternative  since  this would
lead to increased accuracy.

Issue:      Duct Connecting Vehicle Tailpipe  (Engine Exhaust)  to
           CVS (Dilution Tunnel)

Summary of the Issue:

     For  methanol-fueled vehicles,  it  was  proposed  that  the
duct connecting  the vehicle  tailpipe to  the  CVS,  and  in  the
case of heavy-duty methanol-fueled engines,  the duct connecting
the  engine  to  the  dilution  tunnel,  be heated  to  235+15F
(1130+8C)  to  prevent  adsorption   or   condensation  and  the
associated  loss  of  exhaust  gas  constituents  (methanol  and
formaldehyde) in the duct.

Summary of the Comments:

     Caterpillar  and  Toyota provided comments  on  this  issue.
Caterpillar   believed   that   heating  of   the  duct   is   not
necessary.     Caterpillar    stated    that   while   momentary
condensation  following  a  cold  start  will modify real  time
indications  of emissions,   overall test  results  would  not  be

     Toyota  stated  that  the  heating  requirement  will  make
testing   equipment   complicated,   decrease   duct   flexibility
thereby  causing handling  difficulties.   Toyota  felt  that both
heating and cooling capability of  the  duct will be necessary to
maintain  duct temperature  at  235+15F  because of  changes  in
exhaust gas temperature during testing.

     Toyota  suggested  either  the  elimination  of   the   heating
requirement  for short  ducts  (identified  3.65  meters  (12 feet)
maximum  length  based  on diesel engine practice)  or turning the
heater off once the duct is preheated  to 121C  (250F).

Analysis  of Comments:

     Caterpillar's   comment   that   emission   losses   will   be
corrected for  as the exhaust system  heats up  during the course
of  the test,  causing  vaporization of any condensate, is noted.
Unfortunately  it rests  on  the  assumption that  losses during one
phase  of the test are  recovered  during  that phase.  If  this is
not  the  case,  potential   for  significant  test  result error
exists.   There is presently no data  at EPA's disposal which can
be  used to resolve  this question.   It  seems   prudent therefore
to  take  steps  which  would  eliminate or  at the least minimize
any  losses.

     Prior  to  and  since  publication  of  the  NPRM,  EPA  has
conducted test  projects  to  investigate the  effects  of duct
heating  on the  loss  of methanol  and formaldehyde  emissions in
the  duct.  The  first  of these  projects  was conducted at EPA's
Research  Triangle Park laboratory.[14]

     The exhaust duct used  in that  evaluation  was  approximately
20 feet long and constructed of  corrugated tubing.  Tests were
conducted both  with  the duct heated and unheated.  The  results
of the investigation  are summarized  below:

                              Formaldehyde Recovery
                   Unheated Exhaust  Duct      Heated Exhaust Duct
Cold Start              79%                         94%
Hot Start               94%                         96%

     The  conclusion   drawn from  the experimental  results  was
that the high formaldehyde  losses on the cold start tests with
the  unheated  duct  were  the  result  of  water  of  combustion
condensing  in   the  duct which   resulted   in  some  formaldehyde
being dissolved in the condensate.   The  dissolved formaldehyde
would  as  a  result  not be  measured as   part  of  the  gaseous
sample.  These  results  supported the requirement  for heating of
the  duct,  especially  a  long  duct  constructed  of  corrugated
tubing, prior to the initiation  of testing.

     Subsequent  to publication   of  the  NPRM, EPA  has  performed
tests  which  validate  Toyota's   concerns  that  follow  from  the
requirement   of   the   heated   duct.    These  tests   involved
methanol-fueled  vehicles  and  were  designed  to  monitor  the
temperature  of  the duct during   emissions  tests (data  is as  yet
unpublished).   The duct used in   this testing was  heated  and, to
minimize the energy  demand of the  heating elements,  insulated.
During the tests,  duct  wall temperatures as high  as  300F were
recorded.  Some decomposition  of the methanol  and possibly the
formaldehyde in the exhaust gases can reasonably  be expected to
occur  at  this   elevated  temperature.    It  appears,  therefore,
that  Toyota's  concern pertaining to the need  for  both  heating
and  cooling  of  the  duct may be warranted.   Since the  need to
cool  the  duct   (when  insulation   is  employed)  would  greatly
complicate   testing,   the  use  of  insulation   on   heated  ducts
should either be avoided or provisions  made for  the  removal of
the  insulation  whenever the engine  is in operation.

     Another  test  project  was   conducted  at the  Motor  Vehicle
Emission Laboratory,  (MVEL).  The duct used  in this testing was
constructed  mainly  of  smooth   wall pipe  and  was  5  feet in
overall length  including two 8 inch sections of corrugated  tube
and  one  45  bend;  i.e., this duct was short and smooth  relative
to the  previously  used 20 foot   long duct  which was constructed
entirely  of  corrugated tubing.   A  350 cfm Philco CVS was used.
The  test  vehicle  used  in  the MVEL  evaluation was a  full  size
automobile   (Ford  Crown  Victoria,   5.0   liter  engine,  4500 Ib
inertia   weight,  actual  dynamometer   hp  at   50   mph=11.9).
Statistical  analysis of the test data  collected at MVEL showed
that there  was   no  statistical   difference  between  emission

results  obtained  with  a  heated  or  unheated   duct   of  the
configuration employed.[27]

     Since  the  vehicle used  in  this evaluation  was  relatively
heavy, the  rate  at which the  temperature  of the  unheated duct
increased following  the  start of a test would  have been faster
than  would  have  occurred with  a lighter vehicle.   Therefore,
the test data from this  evaluation may not precisely define the
emissions effects  with  a small  vehicle.   The main  conclusion
that  EPA has drawn from  this test, however,  is that short ducts
constructed primarily  from  smooth wall  pipe, with  a  minimum of
flexible  (corrugated)   piping  should  minimize   any   losses.
Toyota's suggestion of heating the transfer  tube  until  the test
begins has  some merit, especially when coupled with  the use of
such  optimized duct configurations.

      Some test  facility  configurations may  preclude relocation
of the CVS  close enough  to the test vehicle, or test engine, to
allow use of  a  short duct.   In  these cases, relocation of the
point  at  which  the exhaust gases and dilution  air are  mixed is
considered  to be a viable alternative.   This  alternative could
be achieved by  routing the dilution air from the  filter housing
of the CVS  to  a mixing point  either  at,  or  very  close to, the
vehicle  tailpipe  or  engine exhaust  and  returning  the diluted
exhaust  to  the  CVS  unit.    Alternatively,  the  dilution  air
filter assembly could be moved  from the  CVS  and located close
to the vehicle  tailpipe  or engine exhaust.  Since the   proposal
called  for   heating of  the  tube between the  exhaust  and the
dilution  point,  eliminating  this  would  obviate  the   need to
provide heating.


      As  a result of the preceding, it is reasonable to  conclude
that  the duct connecting  the  vehicle  tailpipe  or  engine exhaust
to  the CVS or  dilution  tunnel should be  as short as  practical
within the  constraints of the test  cell and be  constructed of
smooth wall tubing  with a  minimum  of both bends and  flexible
tubing.   While   the  only data available at this  time showing
statistically  equivalent  results between  heated  and   unheated
ducts was  collected  on  a  five  foot  long  duct,  such  a  short
length  of  tubing  may be  difficult  to  work with  logistically.
Therefore,  the   following   recommendations  are   made.    First,
ducts conforming  to  the above design  specifications should be
allowed.  Second,  where  these are not  practical,  smooth  walled
ducts of up  to  12  feet in  length  should  be  allowed  provided
they  are  heated to 235  + 15F  (113 +  8C) prior to  the  start
of  testing  and  during any periods of  the test when the  engine
is  off.   Heating of the duct  should  be  allowed during  the  test
for  any  length  of  duct,  provided the temperature of   the  duct

wall does not  exceed  250F (121C).   If insulated,  long,  heated
ducts are employed, provisions  should be made either  to  remove
the  insulation during engine operation  or  if  necessary to cool
the duct to  prevent duct wall temperature  exceeding  250F.   As
an  alternative,  the  mixing  duct  may be essentially eliminated
by  moving  the  mixing point  of the  dilution  air   and exhaust
gases to  a  point  immediately adjacent  to  the  vehicle tailpipe
or engine exhaust.

Issue:      Vehicle  Preconditioning  for  Evaporative  Emissions

Summa ry o f the Is sue:

     EPA    proposed    that    vehicle    preconditioning    for
methanol-fueled   vehicles   be   the   same  as   that  presently
specified for gasoline-fueled  vehicles.   EPA  requested comment,
however,  on   whether   or   not   a   different   preconditioning
procedure  should   be   employed   for  methanol-fueled  vehicles
because   of   potential  variability   in   evaporative  emission
results  stemming  from  relative  differences  in  the  affinity
between  the  charcoal  in the  canister  for methanol  fuel  vapor
vs. gasoline vapor.

Summary of the Comments:

     Comments on this  issue were  provided by Ford  and General
Motors.    Ford   felt   that   canister   purging    during   the
preconditioning   drive   is   heavily   influenced    by  vehicle
operation and storage  conditions prior to the initiation of the
preconditioning   drive.   Ford    felt,   therefore,    that   any
alternative  preconditioning  provisions should  be  allowed  for
all  vehicles  whether  methanol  or  gasoline  fueled  to preclude
unrepresentative     purging     requirements     during     the
preconditioning  drive.

     GM  felt  that  fuel  type should not  dictate the  degree of
vehicle  preconditioning.  GM  felt  that  preconditioning should
approximate a typical  day of vehicle usage and  that the current
preconditioning  procedure is inadequate.

Analysis  of Comments:

     Neither  Ford  nor  GM  provided any  information  indicating
that  the purge/load characteristics of an  evaporative control
system  for a  methanol-fueled vehicle  would be  different  than
those  for a gasoline-fueled  vehicle.   It  appears  reasonable to
conclude,  therefore,   that  any  differences  which  may  exist
between  the relative  affinity  of  the  charcoal  in the  canister
for  methanol  fuel  vapors and  gasoline vapors will  be  accounted
for   in   the  design   of the  evaporative  control   systems on
methanol-fueled   vehicles.   Comments   by  Ford  and  GM on  the
appropriateness  of the preconditioning procedure  fall outside
of  the scope of  this  proposal  and are, therefore,  not  analyzed


     Since   no   information  was  provided   in   support   of
preconditioning    procedures    for   methanol-fueled    vehicles
different to   those   used   for  gasoline-fueled   vehicles,  the
preconditioning  procedures,  as proposed,  should  be retained.


Issue:     Lean Flammability Limit in SHED

Summary of theIssue:

     EPA proposed  the  use of  the same upper limit  (15,000  ppm
C) for  the concentration of combustible materials  in the  SHED
for  testing  of  methanol-fueled  vehicles  as  is  used  in  the
testing  of gasoline-fueled  vehicles.   Use  of  a  common  limit
value for  both types of  fuel was judged to be desirable  because
while it would provide about the  same  safety  margin  relative to
the lean flammability  limit  for  both fuels,  it  would also avoid
the introduction of  a new  factor which  could  cause  confusion
during the performance of tests.

Summary ofthe Comments:

     Ford  and  GM  provided  comments  on  this  subject.   Ford
supported  continued  utilization  of  the   15,000  ppm  C  safety
limit  in the  SHED since  a  4:1  safety factor  beyond the  lean
flammability   limit   for   pure   methanol    corresponds   to   a
concentration  of  approximately 17,500  ppm C.   Ford  pointed out
that  a  different  monitor  would,  however,  have to  be  employed
with  methanol  fuel because  present  monitors  are  insensitive to

     GM did not believe that there will be  any  explosion hazard
in a  SHED during  an  evaporative emission test with M-100 fuel
because   the   boiling   point  of  pure  methanol   (148F)   is
significantly higher than the  normally experienced maximum tank
temperature of 90-92F.   GM  felt that use of M-85  fuel could
increase   organic  levels  in  the  SHED but  not  to  dangerous
levels.   GM  pointed   out  that  the  FID   used  to  measure  VOC
concentrations  in  the   SHED  would  provide  warning  of  high
concentrations.  A combustible gas  sensor  should,  however, be
used  to monitor  concentrations  in  the SHED.   While GM did not
believe  that  a safety  hazard  will develop  in the SHED,  GM was
somewhat   concerned  about   the   development  of  an  explosive
mixture  inside of  the vehicle  fuel tank when M-100 is the fuel.

Analysis of Comments:

      Analysis  suggests that the  commenrers are correct  in  that
it is unlikely that a hazardous  mixture could  develop in a  SHED
during  testing and that continued utilization of  a 15,000 ppm  C
upper  limit would provide a  reasonable safety margin  relative
to the  lower  flammability limit  for  the fuels  used  in  testing.
Good  laboratory  practice,  as  pointed out by Ford and GM,  will
necessitate  the  use of  combustible  mixture  monitors  which  are
sensitive  to  the vapors being  monitored.

     GM's  comment  pertaining  to  the  development of  explosive
mixtures  in the  fuel  tanks  of  vehicles  using  M-100  fuel  is
relevant to  the safe  operation  of these  vehicles  both  on the
street  and during testing.   Since  there is  a  potential hazard
posed by  these vehicles  during  road operation,  it  is expected
that  manufacturers  will  resolve  this possible hazard prior  to
testing a  vehicle.   It is also expected  that laboratories will
use  good  practice  in  preventing  ignition  sources beyond the
vehicle  manufacturer's  control   from entering  a  closed  fuel
tank.   Incorporation  of  additional  safety  precautions into the
test procedures does not, therefore, appear to be necessary.


     An  upper  concentration  limit  of  15,000  ppm   C  for
combustible  materials  in  the  SHED  should  be  retained  as  a
warning note  in the regulations.   Laboratories should use good
engineering  practice  both  in the selection  of combustible gas
monitors sensitive  to  the materials being  monitored and in the
handling  of methanol-fueled  vehicles.    These  precautions will
ensure  the safety  of  laboratory personnel  during testing  of
methanol-fueled vehicles.


Issue:      Test Fuel Specification

Summary of the Issue:

     EPA proposed  that  methanol fuel used  in  emissions  testing
be  representative  of  commercially  available  methanol  fuel.
This  was   necessary   to   ensure  that   emissions  would   be
representative  of  vehicle   operation  in   the   real   world.
Recognizing  that  methanol-fueled  vehicles  were   at  an  early
stage of development and that,  as a result,  manufacturers'  fuel
specifications  for  those  vehicles  that   will  ultimately  be
marketed have not yet been determined, EPA chose  not  to  propose
a detailed  specification for methanol test  fuel.   EPA proposed
that a  fuel must  contain  a  minimum  of  50  percent methanol  by
volume before that fuel could be classified as methanol fuel.

Summary of the Comments:

     Comments   on  this   issue  were   provided   by  thirteen
organizations.    The   organizations   were:    California   Air
Resources  Board,   Chevron,   Chrysler,   Department  of  Energy,
Engine   Manufacturers   Association,   Ford,   General   Motors,
Manufacturers   of   Emission   Controls  Association,  Oxygenated
Fuels  Association,  State  of  New  York,   Nissan,  Toyota  and

     Four   commenters   expressed   the   opinion  that   EPA's
establishment of methanol  test  fuel specifications would not be
appropriate  at this  time.  Chevron  suggested that,   initially,
the  test   fuel   specification  should   be   provided   by  the
vehicle/engine   manufacturer   with  later   development   of   a
specification   corresponding   to   commercial   methanol  fuel.
Similarly,  VW  stated  that,   in the  short  term,   vehicle/engine
manufacturers  must specify  the fuel  because  only the fuel for
which  the  vehicle is  designed  can be  used.   Flexibility  in
selecting the  fuel  must be provided to facilitate  research into
the  development of the optimum fuel  and engine combination.  In
the  long term  a  precise fuel  specification,  representative of
commercial  fuel,  must  be  developed.   SMA recommended that test
fuel   correspond   to   the   fuel   specified   by   the   engine
manufacturer  for  its  production engines.  GM  also believed that
certification  fuel should be the fuel for  which the vehicle is
designed  and  which,   in  GM's  opinion,   would  also   be   the
commercial  fuel.   GM stated that M-85 and  M-100  are  distinctly
different   fuels   from  the  perspective  of  vehicle  design  and
should  not  be  viewed  as different grades of  methanol  fuel.

     Eight  of the commenters (CARB,  Chrysler, DOE, Ford, MECA,
OFA,  Nissan  and  Toyota)  believed  that EPA should establish a
fuel specification as  part of  the  rulemaking.  Reasons  provided
by  the  commenters  for  this position are  given below.

     A  fuel  specification would  provide  vehicle  and  engine
manufacturers with  a basis for making  engineering decisions on
fuel system and engine design.  Vehicle design  parameters  are
dependent  on fuel  specification,  and  a range of  M-50 through
M-100 is too broad  for design  purposes.  Further,  it  would be
unwise for  manufacturers  to  invest resources on the development
of  a vehicle for  a  fuel of the manufacturers'  choice  when that
fuel  may   not  be   used   commercially.   Methanol  fuel  which
contains  a  different  percentage  mix of methanol  and gasoline
than  the  vehicle  was  designed for  could  adversely  affect an
emission  control  system.   Also certain  additives  to  methanol
fuel  designed   to   enhance   startup   and   performance  could
adversely   affect   emission   control   performance  of  vehicles
designed to  a different fuel specification.

     A  fuel  specification would  also  provide  fuel   suppliers
with  a  single design  target  and prevent proliferation of fuel
specifications.   Finally,  a fuel  specification would  establish
limits  on  fuel  contaminants  which  would   cause  engine  wear,
corrosion,    and   materials   compatibility    problems    (e.g.,
chlorine,  sodium).   OFA provided,  in tabular  form,  a proposed
specification for methanol fuel showing limits for  contaminants
such as  chloride, organic  sulfur,  iron,  sodium  and  other metals.

     Nissan recommended the specification  of a single  test  fuel
which  must  contain gasoline  or  other  additives  to  achieve  a
visible  flame in  the event of  a  fire and to  ensure cold start
performance.   More  specific  fuels   which  were  recommended by
other  commenters  were  M-85  and  M-100.  The  commenters  taking
these  positions  and  the  reasons  for  their positions were as

            Ford  is   using  M-85  (15  percent  unleaded  gasoline)
            because  the gasoline content is  expected to provide
            a visible flame in  the event of  a fire,  to  aid in
            cold  starting   and  cold  weather  driveability,  to
            provide   RVP   equal  to  that of   indolene,  and  to
            provide  fuel  tank  vapor  concentration  richer  than
            the  combustible   limit.   While   M-85  is   presently
            being    used    by   Ford,   Ford   felt   that  other
            formulations may offer future  advantages and  should
            be allowed.

     -      Chrysler  recommended M-85, using 15 percent standard
            test  gasoline, since  it  will probably be  available
            as commercial  methanol  fuel.

            OFA  recommended M-85  on  an  interim basis  since  the
            majority of work  has  been  performed  on this  fuel.
            Establishment  of  a  final  specification  would  follow
            as more  knowledge  was gained.


           DOE  recommended  both  M-100  ("neat  chemical-grade"
           methanol)  and M-85 containing  15  percent  high-octane
           indolene by volume.

     -     CARS recommended M-85 for spark  ignition  engines  and
           M-100 for compression ignition engines.

     New  York  stated  that  lacking specifications,  commercial
methanol  fuels  may not meet the  fuel  specifications  for  which
vehicles  are  designed.  New York  then queried  what parameters
would  be  employed  to  determine   the   representativeness   of
certification   methanol-fuel   with   respect   to   commercial

Analysis of Comments:

     While some of  the commenters  believed it is  too  early  for
EPA  to  establish  fuel  specifications, others  were obviously in
favor  of  the agency  moving now  to  take  that  action.   Both
arguments  have merit.  On the  one  hand  there  are numerous
aspects  of engine and  fuel design which  will not  be resolved
without  detailed  analysis   and  the  pressure of the marketplace.
This  argues   for  EPA's avoiding a detailed  specification,  and
Volkswagen's  and   Chevron's comments  recognized  this  point of
view.   On the other  hand,  as  various commenters  pointed out,
provision   of  a   specification   could   force    a   degree   of
standardization within the vehicle and  fuel industries  which
would be difficult to  otherwise presently obtain.

     Given the Agency's concern that  any  fuel  used to certify
vehicles  for  environmental  purposes be representative of  in-use
fuels,  there would  be two potential  problems  associated with
selection  of  a fuel specification before  a  market for methanol
vehicles  and  fuel is established.   First,  as  several  commenters
noted,   the   manufacturers  would   tend   to  optimize  vehicles'
emissions  performance around  the  specified  fuel.   This  is
consistent with GM's and EMA's comments  that  testing should be
done with  the fuel   for  which a  vehicle  was  designed.    GM's
comment that  M-85  and M-100  are  different  fuels,   not  just
different  grades   of  methanol,  is  a  useful  one,  demonstrating
how  important the choice of a  test  fuel  is.  From  an  emissions
perspective,  use  of  one  of these fuels  or  the other  can be
expected to  result in  significant  differences in the  fractions
of  HC,  methanol,   and  formaldehyde in  the organics, and perhaps
in  levels of  particulate emissions from diesel  engines.   From a
performance  perspective,   use  of  one  or  the  other  in a given
vehicle   will    likely    affect    cold    stability,   overall
driveability, fuel  efficiency  and  other performance  criteria.
Furthermore,  choice of one fuel or  another would likely  result
in   engine  design  modifications   to  take  advantage  of  that
formulation's  properties.    These   changes    might    affect

compression ratio, method of  ignition or ignition  assist,  even
possibly  cooling  capacity,   to  give  some  examples.   Thus,  a
specification  provided  now could  have  the  effect  of  detering
vehicle optimization  around  a fuel which might  be superior for
technical  and/or  economic reasons.   EPA's  establishment  of  a
fuel  specification  would,  under these  circumstances,  amount to
interference in the marketplace.

     Second, EPA's  establishment  of  a  specification might  also
be  at  odds with  decisions made  by fuel  suppliers,  who are not
bound  to  market  a fuel  simply  because  EPA  specifies  it for
purposes  of environmental testing.   If  such  were the case, EPA
would  need  to  change  its specifications to obtain  test results
representative of in-use emissions.

     Therefore,   the  development  of  the  in-use   fuel  market
should remain the  concern of  vehicle  manufacturers  and  fuel
suppliers.   It seems  clear that no  overwhelming logic has been
presented  to  demonstrate that  the decision  rightfully belongs
to  EPA.   As long as  vehicles are able to  comply with emission
standards   when   tested  on   the  fuels  that  are  eventually
marketed,   and  as  long  as   no  other  overriding environmental
concern not addressed by the  emission standards accompanies use
of  those  fuels,   the  Agency  should remain neutral  with  respect
to  the emerging fuel market.

     New  York's  comment that  without specifications, commercial
methanol  fuels may not  meet  the  fuel  specifications  for  which
the vehicles  are designed assumes  that the  process  described
above   will   not  take  place.    It    implies   that   vehicle
manufacturers  will market vehicles  incompatible with  available
fuel   supplies   or  that  fuel   suppliers   will  market   fuels
inappropriate  for use with the  vehicle  population.   This  logic
is  faulty  since  if manufacturers  expect  to  have to certify and
comply in-use  using  representative  fuels,   they  will  have   a
strong,   market-based   incentive  to  coordinate  with  the   fuel
suppliers   in  advance.   Such  cooperation is  common  even  with
regard to  today's   fuel  market.    The  American   Society for
Testing   and   Materials  specifications   for   gasoline   fuel
volatility  classes and  fuel  property test criteria are  salient
examples  of this.  It  is very  reasonable  to  assume  that  such
cooperation will  exist  with   regard to  an emerging methanol fuel

      New  York's  guestion regarding EPA's  intended  criteria for
selection  of  representative  fuels is  a  worthwhile one.   EPA's
goal   in choosing certification  fuels  is to  ensure that  in-use
emissions  are  below  the level  of   the  standards.   Thus, the
Agency would consider any fuel  properties that  it  would  expect
to  affect emissions.   Unfortunately, without  a  developed market
for methanol  fuels,  it is not  possible to  completely  specify
these properties  at this time.

     It  is  recognized  that  in  the  initial   sales   years   of
methanol vehicles,  the  fuel market may  be more uncertain than
after  some  degree of market  equilibrium  and  vehicle and fuel
standardization  is  reached.   In  this  regard,  those  comments
suggesting  that  EPA  adopt  the  fuel  for  which a  vehicle  was
designed as the  test  fuel are  useful.    In  fact,  the   Agency
could take advantage of the manufacturers' understanding  of  the
emerging  fuel  market  by  requiring  manufacturers  to  recommend
test fuels  and to provide  justification  for  their selection as
reasonably  available  future fuels.  While final  specifications
should remain the responsibility of  the  Agency, this procedure
could  benefit  all  parties  concerned  through  the  increased
flexibility  it offers.   In the  longer run,  when a  fuel  market
has  been  established,  the Agency will be  able to  specify fuels
without this required input.


     Development  by EPA of one  or  more precise methanol   fuel
specifications  at  this  time  would  tend  to  focus  development
work only on the  specified  fuel(s) and could hamper development
of optimum  vehicle/fuel  designs.  Potential  fuel-to-vehicle and
vehicle-to-fuel  compatibility problems  are  more  appropriately
resolved by cooperative efforts  between the fuel  suppliers and
the vehicle manufacturers  than by EPA  interference.   EPA should
retain the  broad methanol  fuel specification  which was proposed
until  vehicle/fuel  optimization  is  completed and  commercial
methanol  fuel  specifications have  been  developed.    At that
time EPA should  act to specify representative  test fuels.

     Until  such  a time,  the Agency should require manufacturers
to   submit   recommended  test  fuel  specifications   along   with
justification   for  their   selection  as  reasonably   available
in-use fuels.    These  recommendations  would  be  used  by   the
Agency in determining test  fuels.

     1.     M.D.   Gold,  C.E.  Moulis,  EPA/OMS,  "Emission  Factor
Data  Base  for   Prototype  Light-Duty  Methanol  Vehicles,"  SAE
Paper #872055, November,  1987,

     2.     G.Z.    Whitten,   H.   Hogo,    Systems   Applications
Incorporated,  "Impact  of  Methanol  on  Smog:   A  Preliminary
Estimate," Publication No. 83044, February 1983.

     3.     G.Z.    Whitten,   N.   Yonkow,   T.C.    Myers,   Systems
Applications    Incorporated,    "Photochemical   Modeling    of
Methanol-Use  Scenarios  in  Philadelphia,"  Publication No.  EPA
460/3-86-001, 1986.

     4.     R.J.   Nichols,  J.M. Norbeck  "Assessment  of Emissions
From  Methanol-Fueled  Vehicles:   Implications  for  Ozone  Air
Quality," APCA 78th Annual Meeting, June 16-21,  1985.

     5,     "California    Methanol    Assessment.     Volume   II:
Technical Report," Chapter  6,  Jet  Propulsion Lab and California
Institute   of  Technology,   JPL  Report   No.   83-18/Vol.   II,
March 1983.

     6,     G.Z.   Whitten,  J.P.  Killus,   "Technical  Discussions
Delating   to   the  Use   of   the  Carbon-Bond  Mechanism  in
OZIPM/EKMA,"  Publication No.  EPA 450/4-84-009, 1984.

     7.     M. Wolcott, EPA/OMS,  "Ozone Effect  of  Large Scale
Methanol   Fleets,"  memorandum   to  Charles   Moulis,   EPA/OMS
November  6,  1986.

     8.    L,R.   Smith,  "Characterization  of  Exhaust Emissions
from  Alcohol-fueled  Vehicles,"  Southwest  Research  Institute,
Final  Report  for  the   Coordinating  Research  Council,   Inc.,
Project CAPE-30-81, May  1985,  NTIS No. PB85-238582/AS.

     9.     "Automotive Methanol  Vapors and Human  Health:   An
Evaluation  of Existing  Scientific  Information  and  Issues for
Future Research,"  Health  Effects  Institute,  May  1987.

     10.   J,  Braddock,   EPA/ORD,   "Methanol Escort  Emissions,"
memorandum to Paul Machiele,  EPA/OMS, April  17,  1987.

     11.   S.  Syria,   EPA/OMS,  "Methanol  Escort Idle Testing,"
memorandum   to   Charles  Gray,  Director,  EPA  Emission   Control
Technology Division, July 17,  1985.

     12.   D.E.  Seizinger,  "Influence  of  Ambient  Temperature,
Fuel Composition, and Duty Cycle on Exhaust  Emissions," NIPER,
Draft, December  1987.

     13.   Unpublished EPA data.

                      References(Cont' d. )

     14.   R.  Snow,   Northrop  Services,  Inc.,  letter  to  Jim
Garvey, EPA November 12, 1985.

     15.   Haack,  L.P.,  LaCourse,   D.L.,   and  Korniski,   T.J.
"Comparison  of  Fourier  Transform  Infrared  Spectrometry  and
2,4-Dinitrophenylhydrazine    Impinger    Techniques    for    the
Measurement  of Formaldehyde  in Vehicle Exhaust,"  Anal.  Chetn.
58(1986) pp.68-72.

     16.   Based  on  "Assessment  of Health Risks  to  Garment
Workers   and   Certain   Home   Residents    from   Exposure   to
Formaldehyde,"  EPA-Office of  Pesticides  and  Toxic  Substances,
Final Draft March 1987.

     17.   J.N.   Harris,   A.G.  Russell,  J.B.   Milford,   "Air
Quality  Implications of  Methanol  Fuel Utilization",  SAE Paper
8881198, August  1988.

     18.   Based   on   "Preliminary   Source   Assessment   for
Formaldehyde," Radian Corporation, September 3, 1985.

     19.    "Estimated  Cancer  Incidence  Rates for Selected Toxic
Air Pollutants Using Ambient  Pollution  Data,"  EPA Office of Air
Quality Planning  and Standards,  April, 1985.

     20.    "Report  on the Consensus  Workshop  on Formaldehyde,"
Environmental  Health  Perspectives,  U.S.  Dept.   of  Health  and
Human  Services,  Vol.  58,  p.323,  December 1984.

     21.    Summary   and  Analysis of  Comments  on the NPRM for
Gaseous  Emission Regulation  for  1984 and  later  Model  Year
Heavy-Duty Engines,  December  1979.

     22.    Summary   and  Analysis of  Comments  on the NPRM for
Revised  Gaseous  Emission  Regulations  for  1984  and  Later Model
Year Light-Duty Trucks  and Heavy-Duty Engines, July  1983.

     23.    Conversation  with  Richard  Shyu  of  Daimler-Benz,
April  1987.   Quoted control  system retail  replacement cost  as
75  dollars.   Manufacturer cost can be assumed  even lower.

     24.    E.U.   Goff,   J.R.   Coombs,   D.H.  Fine,   "Nitrosamine
Emissions  from Diesel  Engine Crankcases,"  SAE K801374,  October

                      References (Cont'd.)
     25.    "Use of  Heated Critical  Flow  Venturi  Sample  Probes
to    Maintain     Proportional     Flow,"     Technical    Report
EPA-AA-TEB-87-01,  1987.

     26.    S.B. Tejada,   "Evaluation of  Silica Gel  Cartridges
Coated  In Situ  with  Acidified 2,4-Dinitrophenylhydrazine  for
Sampling  Aldehydes and  Ketones in Air,"  Intern. J.  Environ.
Anal.  Chem.,  26<1986) pp.167-185

     27.    W. Adams, EPA/OMS,  "Heated  vs.  Unheated Exhaust Pipe
Correlation," memorandum  to Stanley  Syria, EPA/OMS, March, 1987.