Seasonal and Monthly Activity Allocation Fractions for Nonroad Engine Emissions Modeling

Seasonal and Monthly Activity Allocation Fractions
For Nonroad Engine Emissions Modeling

Report No. NR-004
December 9, 1997

Greg Janssen
and
Rich Wilcox

Nonroad Engine Emission Modeling Team
Assessment and Modeling Division
EPA, Office of Mobile Sources
Introduction
The Nonroad Engine Emission Modeling Team (NEEMT) is developing a national
nonroad air emissions inventory model called NONROAD. The model uses estimates of annual
activity for each equipment type, e.g., generally expressed in terms of hours of operations or
gallons of fuel used per year, to calculate yearly emission inventories. It will also calculate
inventories on a seasonal (i.e., summer, fall, winter, spring), monthly, or daily (i.e., week or
weekend day) basis by allocating annual activity to these smaller time periods. This
memorandum documents the seasonal and monthly activity allocation fractions used by the
model. Daily activity allocation fractions are addressed in a separate technical memorandum.
The NEEMT currently considers these fractions to be final inputs for the beta version of
NONROAD.

The remainder of this memorandum is organized into two parts. The first part contains a
basic description of the overall approach and sources of information that are used to develop the
requisite temporal allocation fractions. The second part explains how this information is used
and describes the final default values for each state.

Background

The NONROAD model allocates annual activity for the various equipment categories to
each month of the year based on the general climate and geographic location of the state and the
time of year in which the equipment is used. Seasonal inventories are computed by combining
the monthly activity fractions that comprise each of the four seasons as shown in Table 1.

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                                         Table 1
                            Season and Month Correspondence
Season
Summer
Fall
Winter
Spring
Month
June, July, and August
September, October, and November
December, January, and February
March, April, and May
       The monthly activity allocation fractions used in NONROAD were derived from the
seasonal activity factors contained in the November 1991 Nonroad Engine and Vehicle Emission
Study1 (NEVES) and monthly activity factors contained in a technical report for the California
Air Resources Board (CARB) nonroad emissions model - OFFROAD.2 The NEEMT decided to
develop the activity allocation fractions based on these two documents as final default values for
the beta version of NONROAD. To the best of the NEEMT's current knowledge, these two
sources of information represent the most comprehensive work that has been done to date
concerning the distribution of activity by season and month for a broad range of nonroad
equipment categories on a statewide (CARB) and nationwide (EPA) basis. EPA recognizes that
states and other users of NONROAD may have more  detailed information on their local activity
levels by season and month.  Such users of NONROAD may substitute activity allocation
fractions derived for a state,  county, or air quality management district based on surveys or other
studies for any of the equipment categories.

       The data from NEVES can be found in Appendix L, Tables L-02, L-03, and L-04 of that
document, which contain percentages of activity for summer and winter use only (Attachment
I).3 More specifically, Table L-02 contains summer and winter activity allocations for
agricultural, construction, industrial, lawn and garden (excluding chainsaws),
snowblower/snowmobile, commercial marine, airport service, logging (including chainsaws),
and light commercial equipment. These percentages were derived from a paper written by Hare
          Environmental Protection Agency, Office of Air and Radiation. Nonroad Engine and Vehicle Emission Study,
          21A-2001, November 1991.

          Energy and Environmental Analysis. Documentation of Input Factors For the New Off-Road Mobile Source
          Emissions Inventory Model - Draft. Prepared for the California Air Resources Board, August 1995.  OFFROAD
          was formerly know as MVOFF
          The derivation of allocation factors for the fall and spring using the NEVES summer and winter values is
          explained in the next section.

-------
and Springer,41987 state implementation plan (SIP) inventories, and the CARB Technical
Support Document for proposed regulations applicable to lawn and garden equipment.5 Separate
summer and winter activity allocations for these general equipment categories are provided for
three climatological and geographical regions (cold/northern, medium/central, and
warm/southern). These regions are defined by the average January temperature and latitude
criteria shown in Table 2.

Table 2
Seasonal Activity Allocation Fraction Regions Defined by Hare and Springer
Region
Cold/Northern
Medium/C entral
Warm/Southern
Average January
Temperature (°F)
<35°
35° -44°
>45°
Latitude
43 ° and north
37° to 43°
37° and south
Table L-03 contains summer and winter activity allocations for recreational marine
equipment from a boat usage survey done for the National Marine Manufacturers Association
(NMMA).6 The factors in this table are arranged into eight geographical regions: Northeast,
Southeast, Mid-Atlantic Coast, Great Lakes, Southwest, Rocky Mountains, Northwest, and West
Coast.

Table L-04 contains summer and winter activity allocations for recreational equipment
from a survey done for the Motorcycle Industry Council (MIC).7 Table L-04 lists twelve regions.
However, the list of regions was subsequently found to be in error, based on a list received from
the MIC that defines the geographical regions used for its survey. The corrected information was
used in the development of the allocation scheme for the NONROAD model.

The MIC organized the seasonal activity usage results into four regions (East, Midwest,
South, West), which the MIC further divided into eight subregions: New England and Middle
Hare, C.T., andKJ. Springer. Exhaust Emissions from Uncontrolled Vehicles and Related Equipment Using
Combustion Engines, Part 5, No. APRD-1494. San Antonio, TX: Southwest Research Institute, October 1973.

California Air Resources Board. Technical Support Documents for California Exhaust Emission Standards and
Test Procedures for 1994 and Subsequent Model Year Utility and Lawn and Garden Equipment Engines.
Attachment C to CARB Mailout #90-64. El Monte, CA:State of California, December 1991.

Irwin Broh & Associates, Inc. NMMA Boat Usage Survey. Prepared for the National Marine Manufacturers
Association, Des Plaines, IL, August 1991.
Burke Marketing Research. 1990 Survey of Motorcycle Ownership and Usage: Final Results Waves 1-12,
Volume II. Conducted for the Motorcycle Industry Council, Inc. May 1991.

-------
Atlantic8 (East); East Central and West Central (Midwest); Southeast and Southwest (South); and
Rocky Mountains and Pacific (West). In Table L-04, the allocations for the main regions are
averages of the two subregions that form each of the main regions.

The CARB model has activity allocations for the State of California, which are expressed
in monthly form (Attachment 2). The allocation fractions are described in the OFFROAD
model's technical support document. The CARB factors differ from those contained in NEVES
for agriculture, construction, industrial, lawn and garden, snowblowers/snowmobile, and
recreational equipment. The CARB technical document did not contain allocations for certain
categories (i.e., commercial and recreational marine9), and it differed from NEVES in that it
contained separate factors for tillers, chainsaws less than or equal to five horsepower and
transportation refrigeration units. CARB and NEVES had equivalent allocations for the
remaining categories where usage was judged to be essentially uniform over the year. As
described in the next section, the CARB allocation factors are used directly in NONROAD to
model emissions in the State of California.

Methodology/Results

NEVES-Based Regional Activity Allocations

Because each of the seasonal allocation tables in NEVES contains different numbers and
types of geographical regions, composite regions were created for use in NONROAD by
geographically matching the less defined regions from Tables L-02 and L-03 to those in Table L-
04. This correspondence is shown in Table 3. The resulting ten composite regions represent an
attempt to reconcile and link the regions defined in each of the three tables so that they are
geographically coherent and compatible.
In NEVES, Middle Atlantic was changed to be Mid-Atlantic Coast. However, in the documentation of the
geographic definitions received from the MIC, it is labeled at Middle Atlantic.

C)
For commercial marine, as well as aircraft and locomotives, baseline emissions in tons per day were directly
entered into the OFFROAD model and a growth factor was used to project emissions into the future. Therefore,
seasonal activity allocation fractions were not needed. No explanation is given for why no seasonal activity
allocation fractions are listed for recreational marine equipment

-------
                                        Table 3
      Mapping of Seasonal Activity Allocation Regions From NEVES to NONROAD
NEVES
General
Equipment
Table L-02
Cold/Northern
Medium/Central
Warm/Southern
NEVES
Recreational Marine
Table L-03
Northeast, Great Lakes,
Northwest, Rocky Mountains
Mid-Atlantic Coast, West
Coast
Southeast, Southwest
NEVES
Recreational Equipment
Table L-04
Midwest, New England,
Rocky Mountains, East
Central
Mid-Atlantic Coast, West
Central, Pacific,
South, Southeast, Southwest
NONROAD
Composite
Regions
Northeast/New England,
Great Lakes/Midwest,
Rocky Mountains,
Northwest
Middle Atlantic, West
Coast, Central West
Southeast, Southwest,
South Central
       There were two exceptions in regard to the general method of defining the regions
discussed above. The first involved a decision to leave out the East Central region found in
Table L-04 for recreation equipment from the composite regions because the region that it
defined could be included in and reasonably characterized by the Great Lakes/Midwest region.

       The second exception pertained to the allocation factors used for the general equipment
categories included in the Rocky Mountains category for NONROAD. In Table L-02, the
general equipment categories used in this geographic area would have been classified as
Medium/Central by the criteria previously shown in Table 2. This classification may seem
reasonable since the Rocky Mountains region is generally located in the central part of the U.S.
However, the climatic conditions found in most of the Rocky Mountains more closely resemble
the northern part of the U.S. than the central section of the country. Therefore, NONROAD uses
the Cold/Northern seasonal activity allocation factors from Table L-02 for the general equipment
categories included in the Rocky Mountains category. This rationale is also supported by Table
L-01 in NEVES, which classified the nonattainment  area of Denver as being within a cold
region.
10
       Since the seasonal allocation factors for all of the categories except recreational
equipment were arranged in more general regions than the ten composite regions described
above, these values were used multiple times based on the matching strategy in Table 3. For
example, the cold/northern fractions from Table L-02 are used in the Northeast/New England,
Midwest/Great Lakes, Rocky Mountains, and Northwest regions.
       10
          Regional and Seasonal Designations, Table L-01, NEVES Appendices, p. L-2

                                           5

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Because the allocation tables in NEVES include only summer and winter factors, it was
also necessary to develop allocations for the remaining two seasons. These allocations were
determined by taking the sum of the summer and winter allocation percentages for each
equipment category and geographical region represented in the NEVES tables, and subtracting
this value from one hundred. The resulting value was then divided by two to obtain the fall and
spring allocation percentages.

The monthly allocation fractions required by NONROAD can be computed from the
NEVES-based seasonable allocation percentages by first dividing the seasonal percentages for
each equipment category and region described above by 100 to convert from percentile to
fractional form. Second, each seasonal allocation fraction was then divided by three to produce
the allocation fraction for each month of the respective season (Table 1). The resulting monthly
allocation fractions by equipment category for all regions except the West Coast, which is
described below, are shown in Table 4.

This approach assumes that the four seasons are contained in specific three month
periods, within which usage in each category is constant. For example, this results in
NONROAD apportioning the use of snow-related equipment to December, January, and
February because these are defined as the winter months. However, it is common knowledge
that significant snow can occur in late fall and early spring in certain areas. While the NEVES-
based method does not optimally reflect such conditions, in the absence of more specific regional
or local data, the method provides a reasonable and logical approximation of the seasonal
impacts on nonroad equipment usage for a national emission inventory model.

CARB-Based Regional Activity Allocations

An exception to the NEVES-based approach described above resulted from using the
available fractions from the CARB OFFROAD technical support document for the State of
California, which is represented in NONROAD by the West Coast region. Commercial and
recreational marine were not included in the CARB model, so NONROAD uses allocations
derived from NEVES. The resulting monthly allocation fractions by equipment category for the
West Coast and for each of the other regions are shown in Table 4, starting on the next page.

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                      Table 4
  Monthly Seasonal Activity Allocation Fractions
(Based on Tables L-02, L-03, and L-04 in Appendix L in NEVES)
Equipment Category January
Agricultural 0.020
Construction 0.033
Industrial 0.067
Lawn and Garden excl. chainsaws 0.020
Snowblowers/Snowmobiles 0.333
Commercial Marine 0.083
Airport Service 0.083
Logging (incl. chainsaws) 0.083
Light Commercial 0.083
Recreational Marine 0.003
Recreational Equipment 0.047
February
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.003
0.047
March
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
Northeast/New
April May
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
England
June
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.146
July
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.146
August
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.146
September
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
October
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
November
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.070
December
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.003
0.047

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Table 4 Continued
Great Lakes/Midwest
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.000
0.027

Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.000
0.027
February March
0.020 0.073
0.033 0.078
0.067 0.083
0.020 0.073
0.333 0.000
0.083 0.083
0.083 0.083
0.083 0.083
0.083 0.083
0.000 0.050
0.027 0.077

February March
0.020 0.073
0.033 0.078
0.067 0.083
0.020 0.073
0.333 0.000
0.083 0.083
0.083 0.083
0.083 0.083
0.083 0.083
0.000 0.052
0.027 0.080
April
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.050
0.077
Rocky
April
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.080
May
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.050
0.077
June
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.233
0.153
July
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.233
0.153
August
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.233
0.153
September
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.050
0.077
October
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.050
0.077
November
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.050
0.077
December
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.000
0.027
Mountains
May
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.080
June
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.147
July
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.147
August
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.230
0.147
September
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.080
October
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.080
November
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.052
0.080
December
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.000
0.027

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Table 4 Continued
Mid-Atlantic
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.007
0.040

Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.057
February
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.007
0.040

February
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.057
March
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078

March
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
April
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078

April
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
May
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078
Southeast
May
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
June
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.190
0.137

June
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.117
July
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.190
0.137

July
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.117
August
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.190
0.137

August
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.117
September
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078

September
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
October
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078

October
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
November
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.068
0.078

November
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.080
December
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.007
0.040

December
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.057

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Table 4 Continued
Northwest
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment*
January February
0.020 0.020
0.033 0.033
0.067 0.067
0.020 0.020
0.333 0.333
0.083 0.083
0.083 0.083
0.083 0.083
0.083 0.083
0.016 0.016
0.043 0.043
March
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
April
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
May
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
June
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.190
0.143
July
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.190
0.143
August
0.167
0.143
0.100
0.167
0.000
0.083
0.083
0.083
0.083
0.190
0.143
September
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
October
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
November
0.073
0.078
0.083
0.073
0.000
0.083
0.083
0.083
0.083
0.063
0.073
December
0.020
0.033
0.067
0.020
0.333
0.083
0.083
0.083
0.083
0.016
0.043
West Coast
Note: West Coast table uses CARB OFFROAD Seasonal
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine*
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine*
Recreational Equipment
January February
0.054 0.054
0.083 0.083
0.083 0.083
0.057 0.067
0.200 0.200
0.083 0.083
0.083 0.083
0.083 0.083
0.083 0.083
0.023 0.023
0.060 0.060
Activity Allocation Fractions except
March
0.086
0.083
0.083
0.086
0.180
0.083
0.083
0.083
0.083
0.075
0.070
CARB MVOFF doesn't have marine seasonal allocation fractions,
April
0.086
0.083
0.083
0.086
0.060
0.083
0.083
0.083
0.083
0.075
0.080
so NEVES
May
0.108
0.083
0.083
0.095
0.020
0.083
0.083
0.083
0.083
0.075
0.090
for marine.
June
0.108
0.083
0.083
0.095
0.000
0.083
0.083
0.083
0.083
0.160
0.100

July
0.108
0.083
0.083
0.095
0.000
0.083
0.083
0.083
0.083
0.160
0.100

August
0.108
0.083
0.083
0.095
0.000
0.083
0.083
0.083
0.083
0.160
0.100

September
0.108
0.083
0.083
0.095
0.000
0.083
0.083
0.083
0.083
0.075
0.090

October
0.075
0.083
0.083
0.086
0.000
0.083
0.083
0.083
0.083
0.075
0.090

November
0.054
0.083
0.083
0.076
0.140
0.083
0.083
0.083
0.083
0.075
0.090

December
0.054
0.083
0.083
0.067
0.200
0.083
0.083
0.083
0.083
0.023
0.070
data are used for these.
       10

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Table 4 Continued
Central West
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.027

Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Commercial Marine
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.040
February
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.027

February
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.040
March
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080

March
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
April
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080

April
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
May
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080
Southwest
May
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
June
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.160
0.147

June
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.123
July
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.160
0.147

July
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.123
August
0.133
0.127
0.083
0.133
0.000
0.083
0.083
0.083
0.083
0.160
0.147

August
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.123
September
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080

September
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
October
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080

October
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
November
0.090
0.078
0.083
0.090
0.000
0.083
0.083
0.083
0.083
0.075
0.080

November
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.085
December
0.020
0.050
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.027

December
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.040
       11

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Table 4 Continued
Equipment Category January
Agricultural 0.020
Construction 0.067
Industrial 0.083
Lawn and Garden (excl. chainsaws) 0.020
Snowblowers/Snowmobiles 0.333
Commercial Marine 0.083
Airport Service 0.083
Logging (incl. chainsaws) 0.083
Light Commercial 0.083
Recreational Marine 0.023
Recreational Equipment 0.050
February
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.050
March
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
South Central
April May
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
June
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.120
July
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.120
August
0.113
0.110
0.083
0.113
0.000
0.083
0.083
0.083
0.083
0.160
0.120
September
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
October
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
November
0.100
0.078
0.083
0.100
0.000
0.083
0.083
0.083
0.083
0.075
0.082
December
0.020
0.067
0.083
0.020
0.333
0.083
0.083
0.083
0.083
0.023
0.050
       12

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As a general practice, EPA welcomes and encourages the use of locally-derived activity
allocation data in place of national or regional default data. It is the NEEMT's judgement that
state or local agencies, such as CARB, are usually in a better position than EPA to collect, assess,
and/or develop local nonroad activity-oriented data that more realistically mirror local conditions.
In the specific case of California, NONROAD's use of the CARB fractions will help to ensure
that EPA's NONROAD model produces compatible results with those from California's
OFFROAD model when NONROAD is run for California. If possible, EPA will incorporate
data from other local sources in future model revisions when such information becomes
available.

Assignment of Region Activity Allocations to States

The final task involves assigning states to each of the regions. These assignments are
shown in Table 5. As mentioned above, California is the only state apportioned to the West
Coast region. Many of the other states have logical assignments. However, some states do not
clearly belong in a particular region because they span more than one of the defined regions
and/or have several climatic tendencies that resemble more than one region. New York could be
included in the Great Lakes/Midwest, Northeast/New England, or Middle Atlantic regions.
Pennsylvania could be included in the Great Lakes/Midwest or Middle Atlantic regions.
Wyoming could be included in the Central West, Rocky Mountain, or Northwest regions. In
these cases, the NEEMT's best judgement was used based on general knowledge of the state's
climate, general geographical position, and information from the NEVES report. Alaska, which
has two CO nonattainment areas (Fairbanks and Anchorage), presented another problem. It
should have its own unique seasonal allocation fraction data. However, lacking this data, it
seemed logical to classify it as a Midwest/Great Lakes state, since the climatic conditions in
Alaska bear the closest resemblance to the states assigned to that region.
13

-------
                                     Table 5




Mapping of States to Regions Used For Defining Monthly Activity Allocation Fractions

1.
2.
o
J.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.

State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Missouri
Mississippi
Montana
State
Region
Southeast
Great Lakes/Midwest*
Southwest
South Central
West Coast
Rocky Mountains
Mid-Atlantic
Mid-Atlantic
Southeast
Southeast
West Coast
Northwest
Great Lakes/Midwest
Great Lakes/Midwest
Great Lakes/Midwest
Central West
South Central
Southeast
Northeast/New England
Mid-Atlantic
Northeast/New England
Great Lakes/Midwest
Great Lakes/Midwest
Great Lakes/Midwest
Southeast
Northwest
Region
                                      14

-------
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
Washington, D.C.
West Virginia
Wisconsin
Wyoming
Central West
Central West
Northeast/New England
Mid-Atlantic
Southwest
Northeast/New England
Mid-Atlantic
Great Lakes/Midwest
Great Lakes/Midwest
South Central
Northwest
Mid-Atlantic
Mid-Atlantic
Southeast
Great Lakes/Midwest
South Central
Southwest
Central West
Northeast/New England
Mid-Atlantic
Northwest
Mid-Atlantic
Mid-Atlantic
Great Lakes/Midwest
Rocky Mountains
* Although Alaska should have unique seasonal adjustment
equated with the Midwest/Great Lakes profile because of a
fractions, for the purpose of default data, Alaska has been
lack of data at this time.
                                                      15

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                       Attachment 1
        NEVES Seasonal Activity Allocation Fractions
Table L-02. Summer and Winter Percentages of Yearly Activity
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden (excl. chain saws)
Snowblowers/ Snowmobiles
Commercial Marine
Airport Service
Logging (including chain saws)
Light Commercial
Cold/Northern
Summer
(%)
50
43
30
50
0
25
25
25
25
Winter
(%)
6
10
20
6
100
25
25
25
25
Medium/Central
Summer
(%)
40
38
25
40
0
25
25
25
25
Winter
(%)
6
15
25
6
100
25
25
25
25
Warm/Southern
Summer
(%)
34
33
25
34
0
25
25
25
25
Winter
(%)
6
20
25
6
100
25
25
25
25
 Table L-03. Summer and Winter Percentages of Yearly Activity for
                Recreational Marine Equipment
Region
Northeast
Southeast
Mid- Atlantic Coast
Great Lakes
Southwest
Rocky Mountains
Northwest
West Coast
% During Summer
68
48
57
70
48
69
57
48
% During Winter
1
7
2
0
7
0
5
7

-------
    Table L-04. Summer and Winter Percentages of Yearly
            Activity for Recreational Equipment*
Region
East
Midwest
South
West
New England
Mid- Atlantic Coast
East Central
West Central
Southeast
Southwest
Rocky Mountains
Pacific
National Average
% During Summer
42
46
36
44
44
41
48
44
35
37
44
43
42
% During Winter
12
8
15
11
14
12
9
8
17
12
8
13
12
Excluding snowmobiles
                            17

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                 ATTACHMENT 2
CARB OFF-ROAD EQUIPMENT USE BY MONTH OF YEAR
Equipment Category
Recreational Vehicles
Construction Equipment
Industrial Equipment
Lawn and Garden Equipment
Farm Equipment
Light Commercial Equipment
Logging Equipment
Aircraft GSE
Transportation Refrigeration Units
Snowmobiles & Snowblowers
Chainsaws (<5 HP)
Tillers
Fraction of Annual Use
Jan
0.061
0.083
0.083
0.057
0.054
0.083
0.083
0.083
0.083
0.200
0.090
0.030
Feb
0.061
0.083
0.083
0.067
0.054
0.083
0.083
0.083
0.083
0.200
0.090
0.030
Mar
0.071
0.083
0.083
0.086
0.086
0.083
0.083
0.083
0.083
0.180
0.090
0.040
Apr
0.081
0.083
0.083
0.086
0.086
0.083
0.083
0.083
0.083
0.060
0.050
0.150
May
0.091
0.083
0.083
0.095
0.108
0.083
0.083
0.083
0.083
0.020
0.050
0.150
June
0.101
0.083
0.083
0.095
0.108
0.083
0.083
0.083
0.083
0.000
0.040
0.150
July
0.101
0.083
0.083
0.095
0.108
0.083
0.083
0.083
0.083
0.000
0.080
0.110
Aug
0.101
0.083
0.083
0.095
0.108
0.083
0.083
0.083
0.083
0.000
0.090
0.110
Sep
0.091
0.083
0.083
0.095
0.108
0.083
0.083
0.083
0.083
0.000
0.090
0.110
Oct
0.091
0.083
0.083
0.086
0.0.75
0.083
0.083
0.083
0.083
0.000
0.110
0.040
Nov
0.091
0.083
0.083
0.076
0.054
0.083
0.083
0.083
0.083
0.140
0.110
0.040
Dec
0.071
0.083
0.083
0.067
0.054
0.083
0.083
0.083
0.083
0.200
0.110
0.040
                       18

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