March
1,
2001
Donald
R.
Lynam
Vice
President,
Air
Conservation
Ethyl
Corporation
330
South
Fourth
Street
Richmond,
VA
23219­
4304
Dear
Dr.
Lynam,

On
November
16,
2000,
the
Ethyl
Corporation
(
Ethyl)
submitted
to
the
Environmental
Protection
Agency
(
EPA)
a
draft
emission
characterization
study
protocol
for
MMT,
as
required
under
the
Alternative
Tier
2
Health
Effects
Testing
Requirements.
These
requirements
were
finalized
in
the
notification
received
by
Ethyl
on
May
25,
2000
("
the
notification").
As
you
know,
the
notification
requires
EPA
review
and
approval
of
these
protocols.
In
this
letter,
we
are
transmitting
to
you
our
comments
on
the
protocols
you
submitted.

The
protocol
should
clearly
state
that
the
objective
of
the
protocol
is
to
develop
additional
data
regarding
manganese
(
Mn)
particulate
speciation
characterization
and
the
Mn
emission
rate
that
results
from
using
MMT
in
the
combustion
of
gasoline,
and
is
not
to
provide
data
on
gaseous
emissions.
As
noted
on
p.
32
of
the
notification,
"
this
speciation
test
program
is
not
designed
or
intended
to
address
the
effect
of
MMT
use
on
emissions
of
any
regulated
gaseous
pollutants.
...
EPA
has
determined
that
this
study
cannot
be
construed
as
identifying
or
measuring
the
gaseous
emission
products
of
MMT,
the
effect
of
MMT
on
gaseous
emissions,
or
the
effects
of
the
emission
products
of
MMT
on
the
performance
of
emission
control
devices
or
systems."

We
recommend
that
the
test
fuel
composition
specifications
be
modified.
First,
we
agree
that
it
is
appropriate
to
use
low
sulfur
fuel
since
it
would
be
more
representative
of
U.
S.
gasoline
in
the
future.
Second,
we
recommend
that
the
base
fuel
not
contain
MTBE
at
11
percent
by
volume
concentration.
Two
of
the
peer
reviewers
of
the
draft
protocol
pointed
out
that
it
is
possible
that
MTBE
will
be
reduced
as
an
oxygenate
in
the
future.
One
peer
reviewer
further
states
that
because
of
this
possible
reduced
use
of
MTBE,
its
use
for
this
test
program
may
be
inappropriate.
Moreover,
we
disagree
with
Ethyl's
contention
that
the
MTBE
concentration
specified
would
not
affect
Mn
particle
generation
or
speciation,
as
we
do
not
believe
that
­
2­

adequate
testing
exists
to
allow
such
a
conclusion
to
be
reached.
Third,
Ethyl's
previous
emission
characterization
study,
entitled,
"
Characterization
of
Manganese
Particulates
from
Vehicles
using
MMT
Fuel"
dated
September
10,
1997,
used
Howell
EEE
certification
fuel
with
no
oxygenates.
In
order
to
compare
the
results
of
the
new
emissions
characterization
study
to
the
results
of
the
1997
study,
we
believe
it
would
be
best
if
differences
between
the
test
fuels
in
these
two
programs
were
kept
to
a
minimum.
Therefore,
we
believe
the
best
choice
of
test
fuel
would
be
non­
oxygenated
test
fuel.
While
it
is
our
understanding
that
non­
oxygenated
test
fuel
is
available
without
MTBE,
it
now
has
a
somewhat
lower
sulfur
level
than
the
fuel
used
in
the
1997
study.
In
order
to
keep
the
differences
to
a
minimum
between
the
test
fuel
used
in
this
study
compared
to
the
fuel
used
in
the
1997
study,
we
believe
that
it
is
appropriate
to
adjust
the
test
fuel
in
this
study
to
a
40
parts
per
million
by
weight
maximum
sulfur
content
using
a
non­
naturally
occurring
sulfur
additive.

Ethyl
has
also
indicated
to
us
that
it
may
wish
to
evaluate
particulates
collected
using
oxygenated
fuels
and
the
LA4
driving
cycle
during
one
or
more
of
the
particulate
collection
intervals.
(
Although
not
required
under
the
notification,
particulate
collection
using
the
LA4
driving
cycle
was
specifically
recognized
and
permitted
under
the
notification
requirements.)
We
are
not
opposed
to
this
evaluation.
However,
if
Ethyl
chooses
to
do
an
evaluation
of
oxygenated
fuel
on
the
non­
required
LA4
driving
cycles,
EPA
would
like
the
protocols
to
reflect
that
collection
of
particulates
using
the
required
REMO/
REPO
driving
cycle
be
conducted
at
each
mileage
interval
before
particulate
collection
using
oxygenated
fuel
on
the
LA4
(
or,
at
Ethyl's
option,
on
an
additional
set
of
REMO/
REPO
driving
cycle
tests
in
lieu
of
the
LA4).
Such
an
approach
would
alleviate
concerns
that
the
use
of
the
oxygenated
fuel
might
impact
such
things
as
adaptive
learning
prior
to
the
required
REMO/
REPO
testing.
We
understand
Ethyl
is
agreeable
to
this
approach.

The
draft
emission
characterization
protocol
should
clarify
the
meaning
of
the
sentence,
"
minor
modifications
to
the
modified
SMA
test
cycle
may
be
required
to
fit
this
cycle
exactly
to
the
testing
facility."
In
particular,
the
draft
should
provide
examples
of
what
these
changes
might
be
and
indicate
that
any
significant
changes
to
the
protocol
would
need
EPA
concurrence.

The
draft
emission
characterization
protocols
should
provide
the
positive
displacement
pump
(
PDP)
specifications.
As
long
as
the
PDP
operates
at
sufficient
cubic
feet
per
minute
(
CFM),
there
should
be
no
concern
that
the
exhaust
dilution
ratio
would
be
inappropriate.
This
issue
was
raised
by
one
peer
reviewer.

The
draft
emission
characterization
protocol
should
indicate
all
the
likely
sources
of
experimental
error
and
also
indicate
how
the
uncertainty
associated
with
this
error
will
be
quantified
in
the
results.
For
example,
if
it
is
reported
that
Mn
sulfate
comprises
20
percent
of
Mn­
containing
particulate,
the
protocols
should
state
how
the
range
of
­
3­

uncertainty
around
that
number
will
be
calculated.

Finally,
the
draft
emission
characterization
protocol
states
that
four
of
the
six
vehicles
to
be
tested
will
be
Ford
products.
While
the
study
requirements
did
not
specifically
state
that
vehicles
produced
by
different
manufacturers
must
be
used,
we
believe
this
is
implicit
in
the
testing
objective
stated
in
the
notification
which
included
selecting
vehicles
for
representativeness
of
in­
use
gasoline­
fueled
vehicles.
We
recommend
that
the
vehicle
fleet
composition
be
changed
to
include
General
Motors
pickup
trucks
in
the
V­
8
portion
of
the
vehicle
test
fleet.
With
this
change,
the
test
fleet
composition
will
thus
represent
three
major
manufacturers
instead
of
two.

We
look
forward
to
Ethyl's
submission
of
the
revised
draft
protocol
as
required
under
the
notification.
If
you
have
any
questions
concerning
our
review,
please
contact
Joe
Sopata
of
my
staff
at
(
202)
564­
9034.

Sincerely,

/
s/

Robert
Larson
Acting
Director
Transportation
and
Regional
Programs
Division
cc:
J.
Michael
Davis,
ORD
Stan
Durkee,
ORD
Jim
Braddock.
ORD,
Tim
Backstrom,
OGC
Kevin
Fast,
Hunton
&
Williams
