Revised
4/
21/
03
1
OFFROAD
Modeling
Change
Technical
Memo
SUBJECT:
Addition
of
Evaporative
Emissions
for
Small
Off­
Road
Engines
LEAD:
Walter
Wong
Summary
The
OFFROAD
model
is
used
to
estimate
the
contributions
of
emissions
of
various
equipment
types
to
the
overall
off­
road
emissions
inventory.
With
the
exception
of
gas
cans,
the
OFFROAD
model
does
not
currently
account
for
evaporative
hydrocarbons.
This
is
primarily
due
to
the
lack
of
test
data.

In
support
of
pending
regulation,
however,
Air
Resources
Board
(
ARB
or
Board)
staff
has
performed
a
number
of
evaporative
tests
of
small
off­
road
equipment.
In
addition,
a
research
project
performed
by
the
Automotive
Testing
Laboratories
(
ATL)
for
the
ARB
entitled
"
Collection
of
Evaporative
Emissions
Data
from
Off­
Road
Equipment",
has
recently
been
completed.
It
is
the
information
from
these
projects
that
serve
as
the
basis
for
the
proposed
modification
to
the
off­
road
emissions
inventory.

This
change
is
estimated
to
result
in
an
increase
in
the
off­
road
evaporative
emissions
inventory
of
31.2
tons
per
day
of
reactive
organic
gases
(
ROG),
statewide
in
2010.
By
the
year
2020,
the
evaporative
emissions
inventory
is
estimated
to
increase
to
34.3
tons
per
day,
statewide.

Regulations
for
the
control
of
evaporative
emission
from
the
SORE
category
are
estimated
to
result
in
a
31
percent
reduction
in
ROG
from
this
category,
statewide
in
2010
and
a
64
percent
reduction
by
the
year
2020.

Background
Small
off­
road
engines
(
SORE)
are
less
than
25
horsepower
and
are
used
in
equipment
that
falls
into
several
of
the
OFFROAD
categories.
Small
off­
road
engines
are
used
in
handheld
(
HH)
and
non­
handheld
(
NHH),
preempted
(
P)
and
non­
preempted
(
NP)
equipment
in
the
following
categories:
Light
Commercial,
Agricultural,
Logging,
Airport
Ground
Support
and
Transport
Refrigeration
Units.
However,
the
majority
is
used
in
the
Lawn
and
Garden
Equipment
category.
A
full
listing
of
SORE
equipment
can
be
found
in
Appendix
A.
Table
1
(
below)
rank
orders
the
top
ten
SORE
equipment
types
according
to
the
percentage
of
the
overall
SORE
population.
Revised
4/
21/
03
2
Table
1.
Top
Ten
SORE
Equipment
Types
by
Population
(
2000)

Equipment
Category
Population
%
of
SORE
Lawn
Mowers
Lawn
&
Garden
2,513,937
44.7
Trimmers/
Edgers/
Brush
Cutters
Lawn
&
Garden
8,631,88
15.4
Chainsaws
Lawn
&
Garden
601,336
10.7
Leaf
Blowers/
Vacuums
Lawn
&
Garden
408,593
7.3
Tillers
Lawn
&
Garden
281,444
5.0
Generator
Sets
Light
Commercial
258,639
4.6
Snow
blowers
Lawn
&
Garden
97,662
1.7
Front
Mowers
Lawn
&
Garden
85,476
1.5
Wood
Splitters
Lawn
&
Garden
72,789
1.3
Pumps
Light
Commercial
59,681
1.1
The
exhaust
emissions
inventory
for
small
off­
road
engines
was
last
presented
and
approved
by
the
Board
in
1998.
Several
characteristics
of
the
SORE
inventory
presented
at
that
time,
including
equipment
population
and
activity,
are
common
to
both
the
exhaust
and
evaporative
emission
inventories.

Methodology
The
evaporative
emissions
inventory
is
segregated
into
four
distinct
processes:

1.
Diurnal
emissions
occur
when
rising
ambient
temperatures
cause
fuel
evaporation
from
engines
and
gas
tanks
throughout
the
day.

2.
Hot
soaks
are
evaporative
losses
that
occur
immediately
after
the
engine
is
turned
off.
The
cause
of
evaporation
is
the
heat
of
the
engine.

3.
Running
losses
are
evaporative
emissions
that
occur
while
the
equipment
is
being
operated.

4.
Resting
loses,
like
diurnal
emissions,
occur
while
the
equipment
is
not
being
used.
Unlike
diurnal
events,
the
ambient
temperature
is
either
stable
or
declining
during
a
resting
loss
event.
These
losses
are
mainly
due
to
the
permeation
of
hydrocarbon
molecules
through
plastic
and
rubber
equipment
components.

The
basic
equations
for
estimating
the
evaporative
emissions
are
displayed
below:

Diurnal/
Resting
(
tpd)
=
Population
*
Emission
Rate
*
Temp/
RVP
Correction
Hot
Soak
(
tpd)
=
Population
*
Percent
Usage
*
Emission
Rate
*
RVP
Correction
Running
Loss
(
tpd)
=
Population
*
Percent
Usage
*
Activity
*
Emission
Rate
*
RVP
Correction
Revised
4/
21/
03
3
Where
tpd
is
Tons
per
day,
Population
is
equipment
and
age
specific,
Emission
Rate
is
expressed
in
grams
per
hour
for
running
loss,
grams
per
event
for
hot
soaks,
and
grams
per
day
for
diurnal
and
resting
losses,
Percent
Usage
is
the
percent
of
the
equipment
population
in
use
in
a
given
period,
Activity
is
equipment
usage
in
hours
per
day,
RVP
is
the
Reid
Vapor
Pressure
of
the
fuel
and
the
Temp/
RVP
Correction
is
a
multiplicative
correction
factor
to
adjust
the
basic
emission
rate
with
respect
to
standardized
test
conditions.

Population
and
Activity
The
population
and
activity
estimates
used
in
this
analysis
were
obtained
from
the
Booz­
Allen
Hamilton
(
BAH)
report
entitled
"
Off­
Road
Mobile
Equipment
Emission
Inventory
Estimate",
the
Power
System
Research
(
PSR)
database
of
manufacturer's
factory
production
and
surveys,
and
input
provided
by
small
offroad
equipment
manufacturers
and
their
consultants.

The
population
growth
rates
were
obtained
from
the
California
State
University,
Fullerton
(
CSUF)
study
entitled
"
A
Study
to
Develop
Projected
Activity
for
Non­
Road
Mobile
Categories
in
California,
1970­
2020".
In
this
study,
growth
in
the
equipment
population
is
linked
to
number
of
households.

The
estimates
of
population
and
activity
used
in
this
analysis
are
the
same
as
those
presented
to,
and
approved
by
the
Board
in
1998.
A
more
detailed
discussion
of
the
development
of
these
estimates
can
be
found
in
ARB
Mail­
out
#
98­
04
(
http://
www.
arb.
ca.
gov/
msei/
off­
road/
pubs.
htm).

Emission
Rates
Evaporative
emissions
are
quantified
by
placing
the
equipment
within
a
sealed
enclosure
(
a
shed)
and
measuring
the
concentration
of
hydrocarbons
emitted
over
a
predetermined
period
of
time.

The
baseline
testing
for
diurnal
and
resting
loss
emissions
was
performed
using
California
Phase
2
gasoline
with
an
RVP
of
7.0,
over
a
24
hour
period
using
an
episodic
summertime
temperature
profile.
This
temperature
excursion
from
a
low
of
65oF
to
a
high
of
105oF,
is
the
same
as
that
used
to
certify
on­
road
motor
vehicles.

Hot
Soak
emissions
were
measured
after
operating
each
piece
of
equipment
for
15
minutes
after
which
the
equipment
was
placed
in
a
shed
at
a
constant
temperature
of
95oF.
The
resulting
evaporative
emissions
were
monitored
minute
by
minute
for
three
hours.
Revised
4/
21/
03
4
In
order
to
measure
running
loss
emissions,
the
equipment
must
be
operated
(
according
to
the
specific
equipment
type)
within
the
shed
enclosure.
Exhaust
emissions
must
be
routed
outside
of
the
shed
in
order
to
ensure
that
only
evaporative
hydrocarbons
are
measured.

Table
2
lists
the
number
of
pieces
of
equipment
tested
by
the
ARB
and
their
contractors.

Table
2.
Equipment
Tested
for
Baseline
Emissions
Equipment
Type
Diurnal
Resting
Loss
Hot
Soak
Running
Loss
Lawnmower
23
23
23
4
Trimmer/
Edger
8
8
8
1
Leaf
blower
3
3
3
0
Chainsaw
3
3
3
0
Tractor
4
4
3
0
Tiller
1
1
1
0
Generator
4
4
3
2
ATV
*
4
4
4
2
Forklift
*
2
2
2
2
*
Although
all
terrain
vehicles
(
ATVs)
and
forklifts
are
not
included
in
the
SORE
category,
these
data
were
used
as
surrogates
for
some
SORE
equipment
types
that
were
not
tested.

Because
lawnmowers
dominate
the
SORE
category,
lawnmowers
were
tested
more
often
than
any
other
equipment
type.
For
simplicity,
the
discussion
of
the
evaporative
emissions
inventory
development
will
focus
primarily
on
lawnmowers.

Basic
Emission
Rates
Diurnal
and
Resting
Losses
The
Basic
Emission
Rate
(
BER)
consists
of
two
parts:
a
zero
hour
and
a
deterioration
rate.
The
zero
hour
emission
rate
is
the
emissions
of
the
equipment
when
it
is
brand
new.
The
deterioration
rate
is
the
rate
at
which
emissions
increase
due
to
usage
and
is
modeled
as
a
function
of
the
age
of
the
equipment.

Table
3
segregates
the
lawnmower
test
fleet
into
three
strata
by
age,
namely
"
new",
"
used"
and
"
old"
equipment.
New
lawnmowers
were
those
purchased
by
ARB
or
their
contractors
that
had
not
been
previously
operated
in
customer
service.
These
test
results
were
averaged
to
estimate
the
zero
hour
emission
rate
of
lawnmowers.
Revised
4/
21/
03
5
The
used
lawnmowers
were
randomly
obtained
from
customer
service
and
are
assumed
to
be
representative
of
the
in­
use
lawnmower
fleet.
The
test
results
of
these
mowers
were
averaged
to
establish
a
deterioration
factor.
Finally,
the
emission
rates
of
the
old
lawnmowers
were
averaged
to
estimate
the
emission
of
lawnmowers
at
the
end
of
their
lives.

Table
3.
Evaporative
Emissions
Test
Results
ID
Manufacturer
Year
Strata
Diurnal
(
g/
day)
Resting
(
g/
day)
Total
(
g/
day)
Mower1
Lawn
Boy
01
New
1.32
0.74
2.06
Mower2
Craftsman
01
New
1.40
0.79
2.19
Mower3
Craftsman
01
New
1.44
0.81
2.25
Mower4
Yard
Machine
01
New
1.46
0.82
2.28
Mower5
Yard
Machine
01
New
1.57
0.88
2.45
Mower6
Yard
Machine
01
New
1.57
0.88
2.45
Mower7
Honda
01
New
1.60
0.90
2.50
Mower8
Honda
00
New
2.03
1.14
3.17
Mower9
Scott's
01
New
2.27
1.27
3.54
Mower10
Toro
99
New
3.55
2.00
5.55
Mower11
Murray
01
New
5.61
3.16
8.77
Mower12
Briggs
&
Stratton
01
New
1.82
1.03
2.85
Mower13
Briggs
&
Stratton
01
New
1.65
0.93
2.58
Mower14
Tecumseh
01
New
2.08
1.17
3.25
Mower15
Tecumseh
01
New
2.26
1.27
3.53
Mower16
Honda
01
New
1.62
0.91
2.53
Mower17
Honda
01
New
1.60
0.90
2.50
Mower18
Toro
90
Used
1.47
0.83
2.30
Mower19
Sears
94
Used
2.27
1.27
3.54
Mower20
Builders
Best
73
Old
2.52
1.42
3.94
Mower21
Murray
?
Used
2.64
1.48
4.12
Mower22
Murray
99
Used
4.52
2.54
7.06
Mower23
Toro
89
Old
15.35
8.64
23.99
"?"
The
Model
Year
of
equipment
could
not
be
determined
Useful
Life
is
defined
as
the
age
at
which
fifty
percent
of
the
originally
sold
equipment
population
still
exists.
For
lawnmowers,
this
is
assumed
to
be
seven
years,
however,
some
equipment
is
assumed
to
remain
in
use
for
as
long
as
twice
the
defined
useful
life.

Therefore,
the
test
data
was
used
to
establish
three
emission
points
in
the
life
of
the
lawnmower
fleet;
"
new"
for
year
zero,
"
used"
for
the
useful
life
definition
of
seven
years,
and
"
old"
for
the
end
of
equipment
life
which
for
lawnmowers
is
fourteen
years.
Linear
deterioration
was
assumed
between
each
point
(
See
Table
4).
Revised
4/
21/
03
6
Table
4.
Estimated
Lawnmower
Emission
Rates
Age
Diurnal
(
g/
day)
Resting
Loss
(
g/
day)
0
2.05
1.15
7
2.72
1.53
14
8.94
5.03
Figure
1
graphically
displays
the
proposed
lawnmower
emission
and
deterioration
rates
for
diurnal
and
resting
losses.

Figure
1.
Lawnmower
Diurnal/
Resting
Loss
Deterioration
0.000
2.000
4.000
6.000
8.000
10.000
0
5
10
15
Age,
years
(
g/
day)
Baseline
Diurnal
(
g/
day)
Baseline
Resting
Loss
(
g/
day)

Liquid
Leakers
The
emissions
estimates
at
fourteen
years
are
the
averages
of
two
lawnmowers
(
mowers
20
and
23),
one
of
which,
mower
23,
was
found
to
have
a
liquid
fuel
leak.
Because
the
deterioration
rates
beyond
year
seven
are
highly
influenced
by
the
emissions
of
this
liquid
leaker,
staff
surveyed
a
number
of
lawnmower
repair
shops
and
requested
manufacturer's
input
to
determine
how
often
these
types
of
problems
occur.

Although
it
was
confirmed
that
lawnmowers
with
fuel
leaks
are
not
uncommon,
it
was
not
possible
to
determine
the
incidence
with
accuracy.
Staff
found
no
compelling
reason
to
exclude
mower
23
from
this
analysis.
However,
by
using
this
data
at
the
end
of
equipment
life,
the
impact
is
minimized
because
the
majority
of
mowers
(
91%)
are
assumed
to
be
age
seven
or
newer
at
any
given
time.
Only
0.1%
of
mowers
are
assumed
to
reach
the
age
of
fourteen
(
See
Figure
2).
Revised
4/
21/
03
7
Figure
2.
Lawnmower
Population
Distribution
by
Age
0.0%
5.0%
10.0%
15.0%

0
5
10
15
Age,
years
%
of
Fleet
Basic
Emission
Rates
for
Other
Equipment
Types
The
emission
factors
for
chainsaws,
tractors
and
ATVs
were
estimated
in
the
same
manner
described
above
for
lawnmowers
given
that
a
clear
pattern
of
deterioration
between
new
and
used
equipment
could
be
discerned.

In
cases
where
deterioration
could
not
be
discerned
because
of
the
lack
of
data
or
high
variability
in
test
results,
straight
averages
of
the
emission
rates
were
used
across
all
years.
Table
5
lists
the
estimated
zero
hour
(
ZHR),
useful
life
(
UL),
and
end
of
life
(
END),
diurnal
and
resting
loss
evaporative
emission
rates
for
all
tested
equipment
types.

Table
5.
Basic
Evaporative
Emission
Rates
(
grams/
day)

Equipment
Type
Diurnal
Resting
Loss
ZHR
UL
END
ZHR
UL
END
Chainsaw
0.44
0.49
0.54
0.21
0.23
0.25
Lawnmower
2.05
2.72
8.94
1.15
1.53
5.03
Tractor
5.93
8.33
10.73
3.33
4.69
6.05
ATV
8.14
10.3
12.51
2.43
3.06
3.68
Trimmer/
Edger
0.63
0.63
0.63
0.30
0.30
0.30
Leaf
blower
1.07
1.07
1.07
0.51
0.51
0.51
Tiller
2.89
2.89
2.89
1.24
1.24
1.24
Generator/
Welder
12.04
12.04
12.04
2.29
2.29
2.29
Forklift
30.61
30.61
30.61
5.40
5.40
5.40
Revised
4/
21/
03
8
Hot
Soak
and
Running
Losses
Table
6
(
below)
displays
the
hot
soak
and
running
loss
evaporative
emissions
results
for
the
fleet
of
tested
lawnmowers.
The
same
methodology
used
in
establishing
the
basic
emission
rates
for
diurnal
and
resting
losses
was
used
to
derive
the
hot
soak
estimates.
Again,
where
data
permitted,
both
a
zero
hour
and
deterioration
rate
were
established,
otherwise
a
straight
average
of
all
data
by
equipment
type
was
used
(
See
Table
7).

Table
6.
Hot
Soak
and
Running
Loss
Test
Data
ID
Manufacturer
Year
Strata
Hot
Soak
(
g/
event)
Running
(
g/
hr)
Mower1
Lawn
Boy
01
New
0.41
Mower2
Craftsman
01
New
0.58
Mower3
Craftsman
01
New
0.55
Mower4
Yard
Machine
01
New
0.41
Mower5
Yard
Machine
01
New
0.61
Mower6
Yard
Machine
01
New
0.63
Mower7
Honda
01
New
0.48
Mower8
Honda
00
New
0.89
0.81
Mower9
Scott's
01
New
0.58
2.60
Mower10
Toro
99
New
0.72
Mower11
Murray
01
New
2.18
Mower12
Briggs
&
Stratton
01
New
0.52
Mower13
Briggs
&
Stratton
01
New
0.67
Mower14
Tecumseh
01
New
0.70
Mower15
Tecumseh
01
New
0.75
Mower16
Honda
01
New
0.47
Mower17
Honda
01
New
0.39
Mower18
Toro
90
Used
1.56
Mower19
Sears
94
Used
1.06
27.03
Mower20
Builders
Best
73
Old
0.87
Mower21
Murray
?
Used
0.70
Mower22
Murray
99
Used
1.00
Mower23
Toro
89
Old
2.88
12.10
"?"
The
Model
Year
of
equipment
could
not
be
determined
Table
7.
Hot
Soak
and
Running
Loss
Basic
Emission
Rates
Equipment
Type
Hot
Soak
Running
Loss
New
Used
Old
New
Used
Old
Chainsaw
0.12
0.34
0.56
Lawnmower
0.68
1.08
1.88
1.7
15.0
28.2
Tractor
1.23
2.09
2.95
ATV
2.40
3.60
4.80
11.3
11.3
11.3
Trimmer/
Edger
0.29
0.29
0.29
0.58
0.58
0.58
Leaf
blower
0.15
0.15
0.15
Tiller
0.57
0.57
0.57
Generator/
Welder
3.24
3.24
3.24
1.80
19.5
37.1
Forklift
10.5
10.5
10.5
4.61
4.61
4.61
Revised
4/
21/
03
9
The
difficulty
associated
with
measuring
running
losses
resulted
in
few
pieces
of
equipment
being
tested.
Separate
running
loss
rates
were
established
for
lawnmowers,
ATVs,
trimmers,
generators,
and
forklifts.
No
deterioration
rates
were
estimated
for
running
losses
with
the
exception
of
lawnmowers
and
generators.

For
lawnmowers,
two
emission
rates
were
created.
A
new
engine
rate
was
established
by
averaging
the
test
results
of
mowers
8
and
9.
A
used
rate
was
established
by
averaging
the
test
results
of
mowers
19
and
23.
The
used
rate
represents
the
average
emissions
of
a
nine
year
old
mower,
the
average
age
of
mowers
19
and
23.

Because
the
SORE
category
includes
more
equipment
types
than
those
tested,
staff
used
the
test
results
(
including
ATVs
and
forklifts)
in
order
to
estimate
the
emissions
for
other
equipment
in
the
SORE
category.
The
emission
rate
assignment
was
based
upon
engine
size,
equipment
characteristics,
and
usage.
The
mapping
strategy
is
included
in
Appendix
B.

In
ARB's
research
project,
two
forklifts,
a
1995
Komatsu
and
a
1987
Toyota
were
tested.
The
initial
test
of
the
Toyota
revealed
an
extremely
high
running
loss
emission
rate
of
195
grams
per
hour.
This
rate
can
be
directly
compared
to
the
Komatsu
that
had
an
emission
rate
of
2
grams
per
hour.

The
problem
with
the
Toyota's
engine
was
diagnosed
and
repaired
and
upon
retest,
the
emissions
were
reduced
to
7
grams
per
hour.
Staff
chose
to
use
the
lower
emission
rate
in
establishing
the
emission
factor
for
forklifts
given
that
this
result
seemed
to
better
typify
the
emissions
of
these
engines.

RVP/
Temperature
Correction
Factors
In
order
to
account
for
spatial,
temporal,
and
seasonal
variations
in
ambient
temperature
and
dispensed
fuel
properties,
correction
factors
for
RVP
and
temperature
needed
to
be
developed.
To
determine
the
magnitude
of
the
effects
of
these
parameters,
a
subset
of
the
SORE
equipment
was
tested
using
different
temperature
profiles
and
fuels
(
See
Table
8).

Table
8.
Temperature
/
RVP
Test
Results
Summertime
(
65­
105F)
7.0
RVP
Summertime
(
65­
105F)
9.5
RVP
Average
(
50­
90F)
9.5
RVP
Wintertime
(
48­
69F)
7.0
RVP
Equipment
Diurnal
(
Grams
per
Day)
Mower
3
1.44
0.41
Mower
8
2.03
2.66
1.50
Resting
Loss
(
Grams
per
Day)
Mower
3
0.81
0.43
Mower
8
1.14
1.37
1.13
Revised
4/
21/
03
10
In
analyzing
this
data
for
temperature
effects,
the
measured
emissions
given
a
specific
fuel
formulation
were
evaluated
each
hour
in
terms
of
the
change
in
emissions
as
a
function
of
the
change
in
temperature.
For
RVP,
the
emission
results
over
a
set
diurnal
temperature
profile
were
compared
across
fuel
types.

Each
hour's
emissions
were
normalized
dividing
by
the
emissions
obtained
under
standard
conditions
(
7
RVP,
65oF
to
105oF)
to
obtain
the
percent
change.
Finally,
a
general
linear
model
was
used
to
find
the
variables
that
best
fit
the
data.
The
resulting
statistical
analysis
indicated
that
a
multi­
variable
polynomial
equation
was
best
for
both
a
diurnal
and
resting
loss
correction
factor
(
See
below).

Diurnal/
Resting
Loss
Temperature/
RVP
Correction
Factor
=
(
A)
hr
+
(
B)
RVP
+
(
C)
Temp
+
(
D)
dtemp
+
(
E)
temp*
dtemp
+
(
F)
temp*
hr
+
(
G)
temp*
rvp
+
(
H)
dtemp*
hr
+
(
I)
dtemp*
rvp
+
intercept
Where:
hr
is
the
duration
of
the
soak
in
hours
RVP
is
the
Reid
Vapor
Pressure
of
the
fuel
temp
is
the
starting
temperature
dtemp
is
the
change
in
temperature
Table
9
shows
the
Temperature/
RVP
correction
factors
that
result
from
the
use
of
the
statewide
annual
average,
summer
and
winter
temperature
profiles
from
the
EMFAC
on­
road
emissions
inventory
model.

Table
9.
Temperature/
RVP
Correction
Factors
Profile
Diurnal
Resting
Loss
Summer
Average
0.55
0.80
Winter
Average
0.30
0.74
Annual
Average
0.45
0.78
Estimated
Baseline
Inventory
for
Lawnmowers
Using
the
basic
emission
rates
and
correction
factors
described
above,
the
baseline
inventory
for
lawnmower
was
calculated.
The
results
are
shown
in
Table
10
below.

Table
10.
Statewide
Lawnmower
Evaporative
Emissions
Inventory
(
Tons
per
Day
 
Annual
Average)

Year
Pop
Hot
soak
Diurnal
Resting
Running
Total
1999
2472640
1.19
3.21
3.13
3.10
10.63
2010
2789569
1.38
3.74
3.65
3.61
12.38
2020
3263809
1.57
4.24
4.13
4.09
14.03
Revised
4/
21/
03
11
Proposed
Regulatory
Action
The
Board
will
soon
consider
taking
action
to
control
evaporative
emissions
from
equipment
in
the
SORE
category.
This
regulation,
if
adopted,
would
require
compliance
either
in
terms
of
a
percent
reduction
from
uncontrolled
emission
levels
or
with
a
set
gram
per
day
diurnal
+
resting
loss
standard
throughout
the
useful
life
of
the
equipment
(
See
Table
11).

Table
11.
Proposed
Diurnal
+
Resting
Loss
Evaporative
Standards
Equipment
Type
Reduction
Standard
Implementation
Handheld
30%
2005
Non
Handheld
Class
I
(
65­
225cc)
1.0
grams/
day
2006
Lawnmower
2007
Other
Non
Handheld
Class
II
(>
225cc)
2.0
grams/
day
2008
In
estimating
the
potential
benefits
of
such
a
standard
for
lawnmowers,
staff
adjusted
the
basic
evaporative
emission
rates
in
the
following
manner:

1.
Assuming
compliance
with
a
1.0
gram
standard
in
use
(
for
example),
the
seven
year,
or
"
used",
emission
rates
for
diurnal
and
resting
loss
were
lowered,
proportionately,
until
the
resulting
sum
was
equal
to
1.0
gram.

2.
Manufacturers
routinely
allow
for
deterioration
in
emissions
during
the
useful
life
of
the
equipment.
This
"
compliance
margin"
is
designed
to
assure
that
the
standards
are
not
exceeded
in­
use.
Assuming
a
compliance
margin
of
twenty
percent,
the
zero
hour
emission
rate
was
set
at
0.8
gram
per
day
of
diurnal
+
resting
loss.

3.
Assuming
that
beyond
the
useful
life
of
the
equipment,
deterioration
in
the
fleet
will
be
equivalent
to
that
in
the
uncontrolled
fleet,
the
baseline
assumption
of
deterioration
was
used
to
establish
the
"
old"
or
end
of
life
emission
rate.
Linear
deterioration
was
assumed
between
emission
rate.

4.
Although
not
specified
directly,
based
on
testing
of
prototype
equipment,
a
70%
reduction
in
hot
soak
emissions
and
a
50%
reduction
in
running
losses
are
anticipated
for
equipment
complying
with
the
proposed
standards.
These
reductions
were
applied
to
the
basic
emission
rates
in
order
to
estimate
the
benefits
of
control.
Revised
4/
21/
03
12
A
comparison
of
baseline
emission
rates
for
lawnmowers
and
those
modeled
to
comply
with
a
1.0
gram
per
day
standard
are
displayed
in
Figure
3
below
for
diurnal
+
resting
loss.
For
other
pieces
of
equipment
required
to
meet
the
1.0
or
2.0
gram
per
day
standard,
a
revised
zero
hour
and
deterioration
rate
was
calculated
using
the
same
methodology
as
outlined
for
lawnmowers.

Figure
3.
Lawnmower
Diurnal
+
Resting
Loss
0.000
5.000
10.000
15.000
0
5
10
15
Age,
years
(
g/
day)
Baseline
Controlled
Using
the
revised
emission
rates
as
described
above,
an
alternative
inventory
can
be
calculated
and
compared
to
the
baseline
to
estimate
the
benefits
of
the
proposed
regulation.
This
analysis
is
displayed
for
various
equipment
types
in
Tables
12
and
13
for
calendar
years
2010
and
2020,
for
various
areas
of
the
state
in
Table
14
and
for
the
overall
inventory
in
Table
15.

Table
12.
Baseline
and
Controlled
Evaporative
Inventory
Estimates
(
Tons
per
Day
 
Annual
Average
in
2010)

Scenario
Pop
Hot
soak
Diurnal
Resting
Running
Total
Baseline
Lawnmower
2879569
1.38
3.74
3.65
3.61
12.38
Chainsaw
688119
0.09
0.16
0.13
0.13
0.51
Trimmer
988730
0.16
0.31
0.26
0.10
0.83
Controlled
Lawnmower
0.90
2.28
2.22
2.70
8.10
Chainsaw
0.07
0.14
0.11
0.09
0.41
Trimmer
0.12
0.26
0.22
0.08
0.68
Percent
Reduction
Lawnmower
35%
39%
39%
25%
35%
Chainsaw
22%
13%
15%
31%
20%
Trimmer
25%
16%
15%
20%
18%
Revised
4/
21/
03
13
Table
13.
Baseline
and
Controlled
Evaporative
Inventory
Estimates
(
Tons
per
Day
 
Annual
Average
in
2020)

Scenario
Pop
Hot
soak
Diurnal
Resting
Running
Total
Baseline
Lawnmower
3263808
1.57
4.24
4.13
4.09
14.03
Chainsaw
779318
0.11
0.18
0.15
0.14
0.58
Trimmer
1120663
0.18
0.35
0.29
0.12
0.94
Controlled
Lawnmower
0.47
1.29
1.26
2.05
5.07
Chainsaw
0.05
0.13
0.10
0.07
0.35
Trimmer
0.09
0.25
0.20
0.06
0.60
Percent
Reduction
Lawnmower
70%
70%
69%
50%
64%
Chainsaw
55%
28%
33%
50%
40%
Trimmer
50%
29%
31%
50%
36%

Table
14.
Baseline
and
Controlled
Evaporative
Emissions
for
Various
areas
of
the
State
(
Annual
Average
­
Tons
per
Day)

Year
2000
Year
2010
Area
Baseline
Baseline
Controlled
%
Diff
Santa
Barbara
Co
0.30
0.34
0.23
32%
South
Coast
AB
11.72
13.25
9.02
32%
San
Francisco
AB
4.97
5.62
3.84
32%
San
Joaquin
AB
2.38
2.69
1.84
32%
Sacramento
AB
1.99
2.25
1.54
32%

Table
15.
Baseline
and
Controlled
Evaporative
Inventory
Estimates
(
Tons
per
Day
 
Annual
Average)

Scenario
Pop
Hot
soak
Diurnal
Resting
Running
Total
Year
1999
Baseline
5529142
5.26
8.83
5.50
7.52
27.11
Year
2010
Baseline
6417962
6.02
10.72
7.18
8.66
32.58
Controlled
3.94
7.16
4.85
6.50
22.45
Reduction
2.08
3.56
2.33
2.16
10.13
%
Reduction
35%
33%
32%
25%
31%
Year
2020
Baseline
7209465
6.51
11.71
7.98
9.51
35.71
Controlled
2.02
3.12
2.65
4.76
12.55
Reduction
4.49
8.59
5.33
4.75
23.16
%
Reduction
69%
73%
67%
50%
65%
Revised
4/
21/
03
14
Modeling
Change
The
test
results
for
equipment
types
other
than
lawnmowers
are
displayed
in
Table
16.

Table
16.
Evaporative
Emission
Test
Results
for
Other
Equipment
ID
Manufacturer
Year
Strata
Diurnal
(
g/
day)
Resting
(
g/
day)
Hot
Soak
(
g/
event)
Running
(
g/
hour)
Chainsaw1
Husqvarna
2001
New
0.24
0.11
0.10
Chainsaw2
Echo
2001
New
0.64
0.30
0.15
Chainsaw3
McCulloch
1989
Used
0.54
0.25
0.56
Leafblower1
Shindaiwa
2001
New
1.21
0.57
0.11
Leafblower2
Stihl
2001
New
1.16
0.55
0.22
Leafblower3
Echo
2001
New
0.85
0.40
0.11
Tiller
Maxim
Used
2.89
1.24
0.57
Tractor1
Murray
2001
New
3.81
2.14
1.25
Tractor2
Snapper
2001
New
4.57
2.57
1.22
Tractor3
Toro
Used
8.33
4.69
2.09
Tractor4
Toro
2001
New
9.40
5.29
N/
A
Trimmer1
Power
Trim
2001
New
0.92
0.43
1.20
Trimmer2
Echo
2001
New
0.46
0.22
0.07
Trimmer3
Honda
2001
New
0.49
0.23
0.07
Trimmer4
Echo
2001
New
0.62
0.29
0.08
Trimmer4
Ryobi
Used
0.55
0.26
0.13
Trimmer5
Stihl
1999
New
0.73
0.35
0.17
Trimmer5
McCulloch
Used
0.36
0.17
0.40
Trimmer6
Makita
1999
Used
0.92
0.43
0.23
0.58
Generator1
Honda
1995
Used
6.79
1.29
4.64
19.45
Generator2
Coleman
2001
New
12.63
2.41
2.72
1.80
Generator3
Tsurumi
Used
6.21
1.18
2.36
Generator4
Coleman
Used
22.54
4.29
N/
A
ATV1
Honda
1983
Used
13.13
3.85
2.24
ATV2
Yamaha
2001
New
12.21
3.58
2.64
21.35
ATV3
Suzuki
2001
New
4.14
1.22
2.16
1.25
ATV4
Kawasaki
1988
Used
11.90
3.50
4.96
Forklift1
Komatsu
1995
Used
40.19
7.90
13.54
1.83
Forklift2
Toyota
1987
Used
21.03
3.71
7.43
7.39
*
*
This
engine
was
originally
tested
at
195.4
g/
hour.
However,
the
engine
was
malfunctioning
and
was
repaired.
The
retest
result
was
used
in
the
analysis.
Revised
4/
21/
03
15
The
model
will
be
modified
to
accept
evaporative
emission
rates
for
all
four
processes
for
each
gasoline­
powered
equipment
type.
The
emission
rates
will
take
the
form
of
a
zero
hour
rate,
and
one
or
more
deterioration
rates
as
a
function
of
equipment
age.

In
equation
form,
the
baseline
emission
factors
are:

Emission
Rate
=
[
ZHR+
DR1*
Age]
where
Age<=
Useful
Life
Emission
Rate
=
[
ZHR
+
DR1*
UL+
DR2*(
Age­
UL)]
where
Age
>
Useful
Life
ZHR
=
Zero
Hour
Rate
or
Intercept
DRx
=
Deterioration
Rate
(
1
or
2)
Age
=
Age
of
the
Equipment
in
years
(
Calendar
Year
 
Model
Year)
UL
=
Useful
Life
(
years)

Table
17.
Basic
Emission
Rates
for
Diurnal
and
Resting
Loss
(
grams/
day)
Diurnal
Resting
Loss
Equipment
Type
ZHR
DR1
DR2
ZHR
DR1
DR2
Useful
Life
Chainsaw
0.44
0.010
0.010
0.21
0.004
0.004
5
Lawnmower
2.05
0.096
0.889
1.15
0.054
0.500
7
Tractor
5.93
0.343
0.343
3.33
0.194
0.194
7
ATV
8.14
0.360
0.360
2.43
0.105
0.105
6
Trimmer/
Edger
0.63
0.000
0.000
0.30
0.000
0.000
5
Leaf
blower
1.07
0.000
0.000
0.51
0.000
0.000
5
Tiller
2.89
0.000
0.000
1.24
0.000
0.000
7
Generator/
Welder
12.04
0.000
0.000
2.29
0.000
0.000
12
Forklift
30.61
0.000
0.000
5.40
0.000
0.000
7
Table
18.
Basic
Emission
Rates
for
Hot
Soak
and
Running
Loss
Hot
Soak
(
g/
event)
Running
Loss
(
g/
hr)
Equipment
Type
ZHR
DR1
DR2
ZHR
DR1
DR2
Chainsaw
0.12
0.044
0.044
0.58
0.000
0.000
Lawnmower
0.65
0.071
0.071
1.71
1.894
1.894
Tractor
1.23
0.123
0.123
1.71
1.894
1.894
ATV
2.40
0.200
0.200
11.3
0.000
0.000
Trimmer/
Edger
0.29
0.000
0.000
0.58
0.000
0.000
Leaf
blower
0.15
0.000
0.000
0.58
0.000
0.000
Tiller
0.57
0.000
0.000
1.71
1.894
1.894
Generator/
Welder
3.24
0.000
0.000
1.80
1.470
1.470
Forklift
10.5
0.000
0.000
4.61
0.000
0.000
For
running
losses,
lawnmower
emission
rates
will
be
used
as
a
surrogate
for
tractors
and
tillers.
The
emissions
of
trimmers
will
be
used
as
a
surrogate
for
chainsaws
and
leaf
blowers.
Revised
4/
21/
03
16
Evaporative
emissions
will
be
calculated
each
hour
in
order
to
account
for
the
percentage
of
equipment
that
is
either
in­
use
or
idle,
and
the
change
in
ambient
temperature.
Regional
and
seasonal
variations
will
be
reflected
through
changes
in
activity
and
the
use
of
Temperature/
RVP
correction
factors.

The
Temperature/
RVP
correction
factor
equation
is:

Diurnal/
Resting
Loss
Temperature/
RVP
Correction
Factor
=
(
A)
hr
+
(
B)
RVP
+
(
C)
Temp
+
(
D)
dtemp
+
(
E)
temp*
dtemp
+
(
F)
temp*
hr
+
(
G)
temp*
rvp
+
(
H)
dtemp*
hr
+
(
I)
dtemp*
rvp
+
intercept
Temperature/
RVP
correction
factor
coefficients
for
both
diurnal
and
resting
losses
are
shown
below.

Diurnal
Resting
Loss
Variable
Coefficients
Coefficients
A
­
0.0832099
0.032988944
B
­
0.007304156
0.041684179
C
­
8.10117E­
05
0.005296275
D
­
0.025853192
0.06209003
E
0.000175569
­
0.000459595
F
0.001980283
0.000596396
G
1.47497E­
05
­
0.000500966
H
0.001471629
0.000804361
I
0.001715214
­
0.002281295
intercept
0.05201313
­
0.40806693
Because
no
tests
were
performed
beyond
105oF,
105oF
will
be
used
for
all
ambient
temperatures
in
excess
of
105oF.
At
the
lower
extremes
of
the
temperature
range,
the
equation
may
produce
a
negative
estimate
of
emissions.
In
this
instance,
zero
emissions
will
be
assumed.

During
engine
operation
and
immediately
after,
the
heat
of
the
engine
is
the
dominant
factor
with
respect
to
vapor
generation.
Therefore,
running
loss
and
hot
soak
emission
will
be
corrected
only
for
variation
in
RVP.

Test
of
the
same
equipment
using
different
fuel
formulations
was
used
to
determine
the
affect
of
RVP.
The
results
were
normalized
to
standard
conditions
(
7.0
RVP)
to
derive
a
dimensionless
multiplier
to
the
basic
emission
rates.
Because
insufficient
information
exists
to
derive
a
separate
RVP
correction
factor
for
running
losses,
the
hot
soak
factor
will
be
applied.

RVP
correction
factor
equation
for
hot
soak
and
running
losses
=
0.30
(
RVP)
 
1.1
The
population
by
equipment
type
and
the
usage
estimates
remain
unchanged.
Revised
4/
21/
03
17
Appendix
A
SORE
EQUIPMENT
BY
CATEGORY
Lawn
and
Garden
Equipment
1.
Trimmers
/
Edgers
/
Brush
Cutters
2.
Lawn
Mowers
3.
Leaf
Blowers
4.
Rear
Engine
Riding
Mowers
5.
Front
Mowers
6.
Chainsaws
<
5
HP
7.
Shredders
<
5
HP
8.
Tillers
<
5
HP
9.
Lawn
and
Garden
Tractors
10.
Wood
Splitters
11.
Snow
Blowers
12.
Chippers
/
Stump
Grinders
13.
Commercial
Turf
Equipment
14.
Other
Lawn
and
Garden
Equipment
Light
Commercial
Equipment
1.
Generator
Sets
2.
Pumps
3.
Air
Compressors
4.
Welding
Machines
5.
Pressure
Washers
Agricultural
Equipment
1.
2­
Wheel
Tractors
2.
Agricultural
Tractors
3.
Agricultural
Mowers
4.
Combines
5.
Sprayers
6.
Balers
7.
Tillers
>
5
HP
8.
Swathers
9.
Hydro
Power
Units
10.
Other
Agricultural
Equipment
Logging
Equipment
1.
Chain
Saws
>
5
HP
2.
Shredders
>
5
HP
3.
Log
Skidders
4.
Fellers/
Bunchers
Revised
4/
21/
03
18
Appendix
A
SORE
EQUIPMENT
BY
CATEGORY
(
contiuned)

Airport
Ground
Support
Equipment
1.
Airplane
Tow
Tractors
2.
Baggage/
Cargo
Tow
Tractors
3.
Ground
Power
Units
4.
Start
Units
5.
Deicing
Units
6.
Load
Lifting
and
Handling
7.
Service
Utility
Carts
8.
Pressure
Washers
Transport
Refrigeration
Units
1.
Small
Units
<
25
HP
2.
Large
Units
>
25
HP
Revised
4/
21/
03
19
APPENDIX
B
Equipment
Surrogate
Asphalt
Pavers
Forklift
Tampers/
Rammers
Forklift
Plate
Compactors
Forklift
Rollers
Forklift
Paving
Equipment
Forklift
Surfacing
Equipment
Forklift
Signal
Boards
Forklift
Trenchers
Forklift
Bore/
Drill
Rigs
Forklift
Concrete/
Industrial
Saws
Forklift
Cement
and
Mortar
Mixers
Forklift
Crushing/
Process
Equipment
Forklift
Skid
Steer
Loaders
Forklift
Dumpers/
Tenders
Forklift
Aerial
Lifts
Forklift
Forklifts
Forklift
Sweepers/
Scrubbers
Forklift
Other
General
Industrial
Equipment
Forklift
Lawn
Mowers
Lawnmower
Tillers
Tiller
Chainsaws
<=
5
HP
Chainsaw
Trimmers/
Edgers/
Brush
Cutters
Trimmer
Leaf
Blowers/
Vacuums
Leaf
blower
Snow
blowers
Leaf
blower
Rear
Engine
Riding
Mowers
Tractor
Front
Mowers
Tractor
Shredders
<=
5
HP
Chainsaw
Lawn
&
Garden
Tractors
Tractor
Wood
Splitters
Lawnmower
Chippers/
Stump
Grinders
Lawnmower
Commercial
Turf
Equipment
Tractor
Other
Lawn
&
Garden
Equipment
Lawnmower
2­
Wheel
Tractors
ATV
Agricultural
Mowers
ATV
Sprayers
ATV
Tillers
>
5
HP
ATV
Hydro
Power
Units
Generator
Other
Agricultural
Equipment
ATV
Generator
Sets
Generator
Pumps
Generator
Air
Compressors
Generator
Welders
Generator
Pressure
Washers
Generator
Chainsaws
>
5
HP
Chainsaw
Shredders
>
5
HP
Chainsaw
Cart
Forklift
Lavatory
Cart
Forklift
Transport
Refrigeration
Units
Generator
