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.

### 

### 

### 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

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 off-road 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 65^o^F to a high of 105^o^F, 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 95^o^F. The resulting evaporative emissions were
monitored minute by minute for three hours.

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       **Hot      **Running Loss**
                                   Loss**          Soak**     

  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]{.underline} 

## 

## 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.

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**

+--------+---------------+------+-------+---------+--------+--------+
| **\    | **\           | **\  | **\   | **Di    | **Res  | **T    |
| ID**   | M             | Ye   | Str   | urnal** | ting** | otal** |
|        | anufacturer** | ar** | ata** |         |        |        |
|        |               |      |       | **(g    | **(g/  | **(g/  |
|        |               |      |       | /day)** | day)** | 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   |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Toro          | 99   | New   | 3.55    | 2.00   | 5.55   |
| ower10 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Murray        | 01   | New   | 5.61    | 3.16   | 8.77   |
| ower11 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Briggs &      | 01   | New   | 1.82    | 1.03   | 2.85   |
| ower12 | Stratton      |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Briggs &      | 01   | New   | 1.65    | 0.93   | 2.58   |
| ower13 | Stratton      |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Tecumseh      | 01   | New   | 2.08    | 1.17   | 3.25   |
| ower14 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Tecumseh      | 01   | New   | 2.26    | 1.27   | 3.53   |
| ower15 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Honda         | 01   | New   | 1.62    | 0.91   | 2.53   |
| ower16 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Honda         | 01   | New   | 1.60    | 0.90   | 2.50   |
| ower17 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Toro          | 90   | Used  | 1.47    | 0.83   | 2.30   |
| ower18 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Sears         | 94   | Used  | 2.27    | 1.27   | 3.54   |
| ower19 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Builders Best | 73   | Old   | 2.52    | 1.42   | 3.94   |
| ower20 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Murray        | ?    | Used  | 2.64    | 1.48   | 4.12   |
| ower21 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Murray        | 99   | Used  | 4.52    | 2.54   | 7.06   |
| ower22 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+
| M      | Toro          | 89   | Old   | 15.35   | 8.64   | 23.99  |
| ower23 |               |      |       |         |        |        |
+--------+---------------+------+-------+---------+--------+--------+

**"?" 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).

### 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.

![](media/image1.wmf)

# 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).

![](media/image2.wmf)

## 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
  ------------------ ------------- -------- --------- ----------- --------- ---------

# 

# 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**  | *               | **Y   | **       | **Hot     | **Ru    |
|         | *Manufacturer** | ear** | Strata** | Soak**    | nning** |
|         |                 |       |          |           |         |
|         |                 |       |          | **(g      | **(     |
|         |                 |       |          | /event)** | 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 &        | 01    | New      | 0.52      |         |
|         | Stratton        |       |          |           |         |
+---------+-----------------+-------+----------+-----------+---------+
| Mower13 | Briggs &        | 01    | New      | 0.67      |         |
|         | Stratton        |       |          |           |         |
+---------+-----------------+-------+----------+-----------+---------+
| 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                          **Running              
                     Soak**                         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
  ------------------ --------- ---------- --------- ----------- ---------- ---------

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

+------------+-------------+-------------+-------------+-------------+
|            | *           | *           | **Average** | **W         |
|            | *Summertime | *Summertime |             | intertime** |
|            | (65-105F)** | (65-105F)** | *           |             |
|            |             |             | *(50-90F)** | *           |
|            | **7.0 RVP** | **9.5 RVP** |             | *(48-69F)** |
|            |             |             | **9.5 RVP** |             |
|            |             |             |             | **7.0 RVP** |
+------------+-------------+-------------+-------------+-------------+
| ####       | **Diurnal   |             |             |             |
|  Equipment | (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        |             |
+------------+-------------+-------------+-------------+-------------+

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, 65^o^F to 105^o^F) 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      **Diurnal**   **Resting**   **Running**   **Total**
                         soak**                                               

  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
  ------------ --------- ---------- ------------- ------------- ------------- -----------

# 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**         | **Red    | *           | **Imp         |
|                            | uction** | *Standard** | lementation** |
+----------------------------+----------+-------------+---------------+
|                            |          |             |               |
+----------------------------+----------+-------------+---------------+
| Handheld                   | 30%      |             | 2005          |
+----------------------------+----------+-------------+---------------+
| Non Handheld Class I       |          | 1.0         | 2006          |
| (65-225cc)                 |          | grams/day   | Lawnmower     |
|                            |          |             |               |
|                            |          |             | 2007 Other    |
+----------------------------+----------+-------------+---------------+
| Non Handheld Class II      |          | 2.0         | 2008          |
| (\>225cc)                  |          | grams/day   |               |
+----------------------------+----------+-------------+---------------+

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.

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.

![](media/image3.wmf)

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)**

+------------+-------+---+--------+-------+--------+----------+-------+
| **         | **    | * |        | *     | **Res  | **R      | **To  |
| Scenario** | Pop** | * |        | *Diur | ting** | unning** | tal** |
|            |       | H |        | nal** |        |          |       |
|            |       | o |        |       |        |          |       |
|            |       | t |        |       |        |          |       |
|            |       | s |        |       |        |          |       |
|            |       | o |        |       |        |          |       |
|            |       | a |        |       |        |          |       |
|            |       | k |        |       |        |          |       |
|            |       | * |        |       |        |          |       |
|            |       | * |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | **    |   |        |       |        |          |       |
|            | Basel |   |        |       |        |          |       |
|            | ine** |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Lawnmower  | 28    |   | 1.38   | 3.74  | 3.65   | 3.61     | 12.38 |
|            | 79569 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Chainsaw   | 6     |   | 0.09   | 0.16  | 0.13   | 0.13     | 0.51  |
|            | 88119 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Trimmer    | 9     |   | 0.16   | 0.31  | 0.26   | 0.10     | 0.83  |
|            | 88730 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | **Co  |   |        |       |        |          |       |
|            | ntrol |   |        |       |        |          |       |
|            | led** |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| 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  |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | #     |   |        |       |        |          |       |
|            | ##### |   |        |       |        |          |       |
|            | ## Pe |   |        |       |        |          |       |
|            | rcent |   |        |       |        |          |       |
|            |  Redu |   |        |       |        |          |       |
|            | ction |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Lawnmower  |       |   | 35%    | 39%   | 39%    | 25%      | 35%   |
+------------+-------+---+--------+-------+--------+----------+-------+
| Chainsaw   |       |   | 22%    | 13%   | 15%    | 31%      | 20%   |
+------------+-------+---+--------+-------+--------+----------+-------+
| Trimmer    |       |   | 25%    | 16%   | 15%    | 20%      | 18%   |
+------------+-------+---+--------+-------+--------+----------+-------+

**Table 13. Baseline and Controlled Evaporative Inventory Estimates**

**(Tons per Day -- Annual Average in 2020)**

+------------+-------+---+--------+-------+--------+----------+-------+
| **         | **    | * |        | *     | **Res  | **R      | **To  |
| Scenario** | Pop** | * |        | *Diur | ting** | unning** | tal** |
|            |       | H |        | nal** |        |          |       |
|            |       | o |        |       |        |          |       |
|            |       | t |        |       |        |          |       |
|            |       | s |        |       |        |          |       |
|            |       | o |        |       |        |          |       |
|            |       | a |        |       |        |          |       |
|            |       | k |        |       |        |          |       |
|            |       | * |        |       |        |          |       |
|            |       | * |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | **    |   |        |       |        |          |       |
|            | Basel |   |        |       |        |          |       |
|            | ine** |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Lawnmower  | 32    |   | 1.57   | 4.24  | 4.13   | 4.09     | 14.03 |
|            | 63808 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Chainsaw   | 7     |   | 0.11   | 0.18  | 0.15   | 0.14     | 0.58  |
|            | 79318 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| Trimmer    | 11    |   | 0.18   | 0.35  | 0.29   | 0.12     | 0.94  |
|            | 20663 |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | **Co  |   |        |       |        |          |       |
|            | ntrol |   |        |       |        |          |       |
|            | led** |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| 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  |
+------------+-------+---+--------+-------+--------+----------+-------+
|            | #     |   |        |       |        |          |       |
|            | ##### |   |        |       |        |          |       |
|            | ## Pe |   |        |       |        |          |       |
|            | rcent |   |        |       |        |          |       |
|            |  Redu |   |        |       |        |          |       |
|            | ction |   |        |       |        |          |       |
+------------+-------+---+--------+-------+--------+----------+-------+
| 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     **0.30**       **0.34**       **0.23**         **32%**
  Co**                                                               

  **South Coast AB**  **11.72**      **13.25**      **9.02**         **32%**

  **San Francisco     **4.97**       **5.62**       **3.84**         **32%**
  AB**                                                               

  **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      **Diurnal**   **Resting**   **Running**   **Total**
                           soak**                                               

                 **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%
  -------------- --------- ---------- ------------- ------------- ------------- -----------

**[Modeling Change]{.underline}**

The test results for equipment types other than lawnmowers are displayed
in Table 16.

**Table 16. Evaporative Emission Test Results for Other Equipment**

+---------+-----------+----+-------+------+-------+--------+---------+
| **\     | **\       | *  | **\   | **D  | *     | **Hot  | **Ru    |
| ID**    | Manuf     | *\ | Str   | iurn | *Rest | Soak** | nning** |
|         | acturer** | Ye | ata** | al** | ing** |        |         |
|         |           | ar |       |      |       | *      | **(g/   |
|         |           | ** |       | **(  | *     | *(g/ev | hour)** |
|         |           |    |       | g/da | *(g/d | ent)** |         |
|         |           |    |       | y)** | ay)** |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Ch      | Husqvarna | 20 | New   | 0.24 | 0.11  | 0.10   |         |
| ainsaw1 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Ch      | Echo      | 20 | New   | 0.64 | 0.30  | 0.15   |         |
| ainsaw2 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Ch      | McCulloch | 19 | Used  | 0.54 | 0.25  | 0.56   |         |
| ainsaw3 |           | 89 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Leaf    | Shindaiwa | 20 | New   | 1.21 | 0.57  | 0.11   |         |
| blower1 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Leaf    | Stihl     | 20 | New   | 1.16 | 0.55  | 0.22   |         |
| blower2 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Leaf    | Echo      | 20 | New   | 0.85 | 0.40  | 0.11   |         |
| blower3 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Tiller  | Maxim     |    | Used  | 2.89 | 1.24  | 0.57   |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Murray    | 20 | New   | 3.81 | 2.14  | 1.25   |         |
| ractor1 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Snapper   | 20 | New   | 4.57 | 2.57  | 1.22   |         |
| ractor2 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Toro      |    | Used  | 8.33 | 4.69  | 2.09   |         |
| ractor3 |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Toro      | 20 | New   | 9.40 | 5.29  | N/A    |         |
| ractor4 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Power     | 20 | New   | 0.92 | 0.43  | 1.20   |         |
| rimmer1 | Trim      | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Echo      | 20 | New   | 0.46 | 0.22  | 0.07   |         |
| rimmer2 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Honda     | 20 | New   | 0.49 | 0.23  | 0.07   |         |
| rimmer3 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Echo      | 20 | New   | 0.62 | 0.29  | 0.08   |         |
| rimmer4 |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Ryobi     |    | Used  | 0.55 | 0.26  | 0.13   |         |
| rimmer4 |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Stihl     | 19 | New   | 0.73 | 0.35  | 0.17   |         |
| rimmer5 |           | 99 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | McCulloch |    | Used  | 0.36 | 0.17  | 0.40   |         |
| rimmer5 |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| T       | Makita    | 19 | Used  | 0.92 | 0.43  | 0.23   | 0.58    |
| rimmer6 |           | 99 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Gen     | Honda     | 19 | Used  | 6.79 | 1.29  | 4.64   | 19.45   |
| erator1 |           | 95 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Gen     | Coleman   | 20 | New   | 1    | 2.41  | 2.72   | 1.80    |
| erator2 |           | 01 |       | 2.63 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Gen     | Tsurumi   |    | Used  | 6.21 | 1.18  | 2.36   |         |
| erator3 |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Gen     | Coleman   |    | Used  | 2    | 4.29  | N/A    |         |
| erator4 |           |    |       | 2.54 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| ATV1    | Honda     | 19 | Used  | 1    | 3.85  | 2.24   |         |
|         |           | 83 |       | 3.13 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| ATV2    | Yamaha    | 20 | New   | 1    | 3.58  | 2.64   | 21.35   |
|         |           | 01 |       | 2.21 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| ATV3    | Suzuki    | 20 | New   | 4.14 | 1.22  | 2.16   | 1.25    |
|         |           | 01 |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| ATV4    | Kawasaki  | 19 | Used  | 1    | 3.50  | 4.96   |         |
|         |           | 88 |       | 1.90 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
|         |           |    |       |      |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Fo      | Komatsu   | 19 | Used  | 4    | 7.90  | 13.54  | 1.83    |
| rklift1 |           | 95 |       | 0.19 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+
| Fo      | Toyota    | 19 | Used  | 2    | 3.71  | 7.43   | 7.39 \* |
| rklift2 |           | 87 |       | 1.03 |       |        |         |
+---------+-----------+----+-------+------+-------+--------+---------+

\* 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.

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                        **Running             
                      (g/event)**                       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.

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]{.underline}   [Coefficients]{.underline}   [Coefficients]{.underline}

  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 105^o^F, 105^o^F will be used for
all ambient temperatures in excess of 105^o^F. 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.

### 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

### 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

**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            |
+-----------------------------------------------+----------------------+