Air and Radiation EPA420-R-05-017
December 2005
United NR-004c
Environmental Protection
Agency
Seasonal and Monthly
Activity Allocation
Fractions for Nonroad
Engine Emissions Modeling
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EPA420-R-05-017
December 2005
for
NR-004C
Assessment and Standards Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
NOTICE
This technical report does not necessarily represent final EPA decisions or positions.
It is intended to present technical analysis of issues using data that are currently available.
The purpose in the release of such reports is to facilitate the exchange of
technical information and to inform the public of technical developments which
may form the basis for a final EPA decision, position, or regulatory action.
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Introduction
The United States Environmental Protection Agency (EPA) has developed 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., weekday or
weekend day) basis by allocating annual activity to these smaller time periods. This report
documents the seasonal and monthly activity allocation fractions used by the model. Daily
activity allocation fractions are addressed in a separate technical report. The only substantive
change from draft NONROAD2004 is the seasonal allocation of construction equipment,
described in the Methodology/Results section below. Seasonal inputs have also been added for
Puerto Rico and the U.S. Virgin Islands, simply by assigning them to the Southeast region and
using those existing values. The EPA currently considers these seasonal fractions to be final
inputs for the draft NONROAD2005 model.
The remainder of this report 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 draft NONROAD2005 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.
Table 1
Season and Month Correspondence
Season
Summer
Fall
Winter
Spring
Month
June, July, and August
September, October, and November
December, January, and February21
March, April, and May
When running the model for the winter season, it assumes January, February, and December all in the same year, rather
than the preceding December.
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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 EPA decided to
develop the activity allocation fractions based on these two documents as default values for the
NONROAD model. To the best of the EPA'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. The 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
l).b 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
and Springer,3 1987 state implementation plan (SIP) inventories, and the CARB Technical
Support Document for proposed regulations applicable to lawn and garden equipment.4 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/Central
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
The derivation of allocation factors for the fall and spring using the NEVES summer and winter values is explained in
the next section.
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(NMMA).5 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).6 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 NONROAD.
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
Atlantic0 (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 C ARE 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 marined), 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 for most equipment
categories in the draft NONROAD2005 to model emissions in the State of California.
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.
Tor 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
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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.
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.
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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.
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 seasonal 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. Recreational marine
was 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.
Construction Value-Based Regional Activity Allocations
The one industry segment that has been updated from the NEVES and CARB-based
approaches described above is construction equipment. The county level construction dollar
value data7 that EPA acquired to update the geographic allocations for draft NONROAD20058
also included a breakout of construction expenditures by month. For consistency with the other
seasonal inputs and to minimize effects of any potentially anomolous data at the individual state
and month level, EPA aggregated these data into the seasons defined in Table 1 and the regions
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defined in Table 5. The main change in these seasonal allocations relative to prior versions of
NONROAD is a decrease in the difference between summer and winter activities. The new data
indicate that a greater portion of construction activity occurs in winter months than was the case
with the older data.
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Table 4
Monthly Seasonal Activity Allocation Fractions
(Based mostly on Tables L-02, L-03, and L-04 in Appendix L in NEVES, but construction is based on 2003 value of construction)
Northeast/New England
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.059
0.067
0.020
0.333
0.083
0.083
0.083
0.003
0.047
February
0.020
0.059
0.067
0.020
0.333
0.083
0.083
0.083
0.003
0.047
March
0.073
0.093
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
April
0.073
0.093
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
May
0.073
0.093
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
June
0.167
0.095
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.146
July
0.167
0.095
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.146
August
0.167
0.095
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.146
September
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
October
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
November
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.070
December
0.020
0.059
0.067
0.020
0.333
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
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.061
0.067
0.020
0.333
0.083
0.083
0.083
0.000
0.027
February
0.020
0.061
0.067
0.020
0.333
0.083
0.083
0.083
0.000
0.027
March
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
April
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
May
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
June
0.167
0.099
0.100
0.167
0.000
0.083
0.083
0.083
0.233
0.153
July
0.167
0.099
0.100
0.167
0.000
0.083
0.083
0.083
0.233
0.153
August
0.167
0.099
0.100
0.167
0.000
0.083
0.083
0.083
0.233
0.153
September
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
October
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
November
0.073
0.086
0.083
0.073
0.000
0.083
0.083
0.083
0.050
0.077
December
0.020
0.061
0.067
0.020
0.333
0.083
0.083
0.083
0.000
0.027
Rocky Mountains
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.066
0.067
0.020
0.333
0.083
0.083
0.083
0.000
0.027
February
0.020
0.066
0.067
0.020
0.333
0.083
0.083
0.083
0.000
0.027
March
0.073
0.079
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
April
0.073
0.079
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
May
0.073
0.079
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
June
0.167
0.100
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.147
July
0.167
0.100
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.147
August
0.167
0.100
0.100
0.167
0.000
0.083
0.083
0.083
0.230
0.147
September
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
October
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
November
0.073
0.089
0.083
0.073
0.000
0.083
0.083
0.083
0.052
0.080
December
0.020
0.066
0.067
0.020
0.333
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
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.072
0.083
0.020
0.333
0.083
0.083
0.083
0.007
0.040
February
0.020
0.072
0.083
0.020
0.333
0.083
0.083
0.083
0.007
0.040
March
0.090
0.079
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
April
0.090
0.079
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
May
0.090
0.079
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
June
0.133
0.098
0.083
0.133
0.000
0.083
0.083
0.083
0.190
0.137
July
0.133
0.098
0.083
0.133
0.000
0.083
0.083
0.083
0.190
0.137
August
0.133
0.098
0.083
0.133
0.000
0.083
0.083
0.083
0.190
0.137
September
0.090
0.085
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
October
0.090
0.085
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
November
0.090
0.085
0.083
0.090
0.000
0.083
0.083
0.083
0.068
0.078
December
0.020
0.072
0.083
0.020
0.333
0.083
0.083
0.083
0.007
0.040
Southeast
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.078
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.057
February
0.020
0.078
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.057
March
0.100
0.080
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
April
0.100
0.080
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
May
0.100
0.080
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
June
0.113
0.089
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.117
July
0.113
0.089
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.117
August
0.113
0.089
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.117
September
0.100
0.086
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
October
0.100
0.086
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
November
0.100
0.086
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.080
December
0.020
0.078
0.083
0.020
0.333
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
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment*
January
0.020
0.069
0.067
0.020
0.333
0.083
0.083
0.083
0.016
0.043
February
0.020
0.069
0.067
0.020
0.333
0.083
0.083
0.083
0.016
0.043
March
0.073
0.081
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
April
0.073
0.081
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
May
0.073
0.081
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
June
0.167
0.102
0.100
0.167
0.000
0.083
0.083
0.083
0.190
0.143
July
0.167
0.102
0.100
0.167
0.000
0.083
0.083
0.083
0.190
0.143
August
0.167
0.102
0.100
0.167
0.000
0.083
0.083
0.083
0.190
0.143
September
0.073
0.080
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
October
0.073
0.080
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
November
0.073
0.080
0.083
0.073
0.000
0.083
0.083
0.083
0.063
0.073
December
0.020
0.069
0.067
0.020
0.333
0.083
0.083
0.083
0.016
0.043
West Coast
Note: West Coast table uses CARB OFFROAD Seasonal Activity Allocation Fractions except for marine and construction.
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine*
Recreational Equipment
January
0.054
0.072
0.083
0.057
0.200
0.083
0.083
0.083
0.023
0.060
February
0.054
0.072
0.083
0.067
0.200
0.083
0.083
0.083
0.023
0.060
March
0.086
0.088
0.083
0.086
0.180
0.083
0.083
0.083
0.075
0.070
April
0.086
0.088
0.083
0.086
0.060
0.083
0.083
0.083
0.075
0.080
May
0.108
0.088
0.083
0.095
0.020
0.083
0.083
0.083
0.075
0.090
June
0.108
0.090
0.083
0.095
0.000
0.083
0.083
0.083
0.160
0.100
July
0.108
0.090
0.083
0.095
0.000
0.083
0.083
0.083
0.160
0.100
August
0.108
0.090
0.083
0.095
0.000
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
0.075
0.090
October
0.075
0.083
0.083
0.086
0.000
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
0.075
0.090
December
0.054
0.072
0.083
0.067
0.200
0.083
0.083
0.083
0.023
0.070
' CARB OFFROAD did not have marine seasonal allocation fractions, so NEVES data are used for these.
10
-------
Table 4 Continued
Central West
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.070
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.027
February
0.020
0.070
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.027
March
0.090
0.089
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
April
0.090
0.089
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
May
0.090
0.089
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
June
0.133
0.094
0.083
0.133
0.000
0.083
0.083
0.083
0.160
0.147
July
0.133
0.094
0.083
0.133
0.000
0.083
0.083
0.083
0.160
0.147
August
0.133
0.094
0.083
0.133
0.000
0.083
0.083
0.083
0.160
0.147
September
0.090
0.080
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
October
0.090
0.080
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
November
0.090
0.080
0.083
0.090
0.000
0.083
0.083
0.083
0.075
0.080
December
0.020
0.070
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.027
Southwest
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden excl. chainsaws
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.075
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.040
February
0.020
0.075
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.040
March
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
April
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
May
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
June
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.123
July
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.123
August
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.123
September
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
October
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
November
0.100
0.084
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.085
December
0.020
0.075
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.040
11
-------
Table 4 Continued
South Central
Equipment Category
Agricultural
Construction
Industrial
Lawn and Garden (excl. chainsaws)
Snowblowers/Snowmobiles
Airport Service
Logging (incl. chainsaws)
Light Commercial
Recreational Marine
Recreational Equipment
January
0.020
0.068
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.050
February
0.020
0.068
0.083
0.020
0.333
0.083
0.083
0.083
0.023
0.050
March
0.100
0.092
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
April
0.100
0.092
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
May
0.100
0.092
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
June
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.120
July
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.120
August
0.113
0.091
0.083
0.113
0.000
0.083
0.083
0.083
0.160
0.120
September
0.100
0.082
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
October
0.100
0.082
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
November
0.100
0.082
0.083
0.100
0.000
0.083
0.083
0.083
0.075
0.082
December
0.020
0.068
0.083
0.020
0.333
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 EPA's judgment 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, the 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 it 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 Regional Activity Allocations to States
The final task involves assigning states to each of the regions. These assignments are shown
in Table 5. The West Coast region consists of California (since most of the seasonal allocation data
comes from CARB) and Hawaii (due to lack of other specific data, and assuming that at least
southern California has some similarity to Hawaii). 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 EPA's best judgment 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 Fraction
FIPS
1.
2.
4.
5.
6.
8.
9.
10.
11.
12.
13.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia (Washington, D.C.)
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
Region
Southeast
Great Lakes/Midwest*
Southwest
South Central
West Coast
Rocky Mountains
Mid-Atlantic
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
Southeast
Great Lakes/Midwest
Northwest
Central West
Central West
14
-------
FIPS
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
44.
45.
46.
47.
48.
49.
50.
51.
53.
54.
55.
56.
72.
78.
State
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
West Virginia
Wisconsin
Wyoming
Puerto Rico
Virgin Islands
Region
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
Great Lakes/Midwest
Rocky Mountains
Southeast*
Southeast*
* Although Alaska should have unique seasonal adjustment fractions, for the purpose of default data, Alaska has been
assigned to the Midwest/Great Lakes profile because of a lack of data at this time. Similarly, Puerto Rico and the U.S.
Virgin Islands have been assigned to the Southeast regional profile due to lack of data specific to those territories.
National Average Seasonal and Monthly Activity Allocations
Since seasonal activity fractions can vary considerably with region, they are most useful
when performing state or county level model runs. However, the NONROAD model does have the
capability to model seasonal and monthly emissions for a nationwide scenario, even though such
results would lack the seasonal specificity of state or county level runs. To estimate national average
seasonal and monthly activity allocations the monthly activity allocations were used as described
15
-------
below. The resulting values are included in the SEASON.DAT input data file with the region
designation of "US."
Due to the different seasonal activity allocations and different geographic allocations of the
various types of equipment, the national average seasonal allocations are calculated as follows. Any
set of equipment that has the same temporal and geographic allocations can be handled together,
which is why there are not more than about 75 different types of equipment for this purpose.
1) Do twelve "50STATE" model runs (one for each month of the year) including all equipment
types to generate activity (and emission) estimates for each state for each month for every type of
equipment. Use the same temperature and fuel properties for all runs, since the seasonal allocation
factors are just meant to allocate activity, regardless of emissions.
2) Aggregate the activity outputs from Step 1 across all states by SCC and month. This yields one
activity value for each SCC and month (approximately 75 x 12 = 900).
3) Also aggregate those activity outputs across all states and months by SCC to get one national
annual total activity value for each SCC (approximately 75 values).
4) For each of the equipment types listed in SEASON.DAT find the ratio of each month's activity
from Step 2 to the annual total from Step 3.
5) In the /MONTHLY/ packet of SEASON.DAT, in the "US" section for the US total allocations,
put the twelve monthly ratios from Step 4 into each appropriate line (using the global SCC where
possible, such as 2270002000 for all diesel construction equipment, or individual SCCs where
necessary due to equipment specific temporal activity profiles).
16
-------
References
1. Environmental Protection Agency, Office of Air and Radiation. Nonroad Engine and Vehicle
Emission Study. 21A-2001, November 1991.
2. 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
3. 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.
4. 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.
5. Irwin Broh & Associates, Inc. NMMA Boat Usage Survey. Prepared for the National Marine
Manufacturers Association, Des Plaines, IL, August 1991.
6. 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.
7. Construction valuation data for 2003 purchased by EPA from McGraw-Hill Construction
(formerly F.W. Dodge Company).
8. Geographic Allocation of State Level Nonroad Engine Population Data to the County Level,
NONROAD model report NR-014d, 2005.
17
-------
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
A-l
-------
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
A-2
-------
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(<5HP)
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
A-3
------- |