Exhaust and Crankcase Emission Factors 

for Nonroad Engine Modeling  

Compression-Ignition 
Exhaust and Crankcase Emission Factors 


for Nonroad Engine Modeling 
	

Compression-Ignition
 

NR-009d
 

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. 

EPA-420-R-10-018 

NR-009d 

July 2010 
Exhaust and Crankcase Emission Factors 

for Nonroad Engine Modeling-­

Compression-Ignition 

Report No. NR-009d 

July 2010
 

Assessment and Standards Division
 

EPA, Office of Transportation and Air Quality
 

Purpose 

This report describes and documents exhaust emission factors used for compression 

ignition (CI) engines in the U.S. Environmental Protection Agency’s (EPA) final 

NONROAD2008a emission inventory model. The term “compression ignition” is synonymous 

with “diesel” for the purposes of this report. Pollutants covered include hydrocarbons (HC), 

carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), carbon dioxide (CO2), 

and sulfur dioxide (SO2). Brake specific fuel consumption (BSFC), which is a fuel rate 

measurement, is also discussed. All PM emissions are assumed to be smaller than 10 microns 

(PM10) and 97% of the PM is assumed to be smaller than 2.5 microns (PM2.5). The NONROAD 

Reporting Utility allows the user to select which of these two size ranges is reported. Relative to 

the previous April 2004 version of this report, this version has been updated to include the Tier 3 

standards for recreational marine diesel engines, along with technology name changes for this 

source category. 

This report covers zero-hour, steady-state emission factors, transient adjustment factors, 

and deterioration factors for all diesel-fueled engines. Adjustments to emission rates due to 

variations in fuel sulfur level are also included. There are no additional adjustments to CI 

emissions for temperature, altitude, or for other fuel parameters. Crankcase HC emission factors 

are also covered in this report. Emission factors for spark ignition engines (including gasoline 

and natural gas/propane) are covered in a separate report, NR-010f. 

Zero-mile, steady-state emission factors for HC, CO, NOx, PM, and BSFC will be 

discussed first, followed by adjustments (where applicable) to account for transient operation, 

deterioration, and variations in fuel sulfur level. Derivation of CO2 and SO2 emission factors 

follows. Crankcase HC emission factors are then discussed. This is followed by a discussion of 

the PM2.5 fraction of PM10 used in the Reporting Utility. 

Introduction 

The NONROAD model estimates air pollution from more than 80 types of compression 

ignition (CI) and spark ignition (SI) nonroad sources including such items as lawnmowers, 

motorboats, portable generators and construction equipment. By bringing together information 

on equipment populations, equipment use, and emission factors, the NONROAD model 

1
 
estimates mass emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), 

sulfur dioxide (SO2), particulate matter (PM) and carbon dioxide (CO2) for specific states and 

counties for past and future years, providing a flexible tool that can be applied to a wide variety 

of air quality modeling and planning functions. 

The NONROAD calculations rely on emission factors--estimates of the amount of 

pollution emitted by a particular type of equipment during a unit of use. Typically, emission 

factors for nonroad sources are reported in grams per horsepower-hour (g/hp-hr), but they also 

may be reported in grams per mile, grams per hour, and grams per gallon. The CI emission 

factors in the NONROAD model are reported in g/hp-hr and are based on emissions test data 

where available, adjusted when necessary to account for in-use operation that differs from the 

typical test conditions. These emission factors are stored in NONROAD’s data input files. 

NONROAD adjusts these emission factors as necessary to account for the effects of fuel sulfur. 

Emission changes with the age of the engine, often called ‘deterioration,’ are also applied by the 

model. 

If comments on this document or other information gathered during stakeholder and peer 

review cause us to refine the CI emission factors, we will document the changes in a subsequent 

report. 

Emission Standards 

In addition to estimating emissions from uncontrolled engines, the NONROAD model is 

designed to account for the effect of federal emissions standards. NONROAD will not cover 

California emission standards or proposed federal standards that are not yet final. 

NONROAD2008a accounts for emission factors under five regulations that establish up to four 

tiers of emission standards: 

•	 “Determination of Significance for Nonroad Sources and Emission Standards for New 

Nonroad Compression Ignition Engines at or above 37 Kilowatts.” This rule establishes 

“Tier 1” standards for CI engines at or above 50 hp (37 kW). [1] 

•	 “Control of Emissions from Nonroad Diesel Engines.” This rule lists “Tier 1” and “Tier 

2” standards for CI engines below 50 hp, and “Tier 2” and “Tier 3 ” standards for engines 

of 50 hp and greater. [2] 

•	 “Control of Emissions From Nonroad Large Spark-Ignition Engines and Recreational 

Engines (Marine and Land-Based).” This rule establishes “Tier 2” equivalent standards 

for recreational marine diesel engines over 50 hp. [3] 

•	 “Control of Emissions from Nonroad Diesel Engines and Fuel.” This rule establishes 

“Tier 4" standards for CI engines covering all hp categories, and also regulates diesel fuel 

sulfur content. [4] 

2
 
•	 “Control of Emissions of Air Pollution From Locomotive Engines and Marine 

Compression Ignition Engines Less Than 30 Liters per Cylinder; Republication.” This 

rule establishes “Tier 3" standards for recreational marine diesel engines. [5] 

The emission standards with the affected model years and the corresponding model tech 

types are provided in Table 1. Table 1 covers all CI engines except recreational marine engines. 

The standards and emission factors for recreational marine CI engines are discussed separately. 

Tech types are defined for unique sets of standards and/or certification fuel sulfur levels. The 

certification fuel sulfur levels will be discussed in more detail later in this report. 

Along with the new engine standards listed in Table 1, there are flexibility allowances for 

equipment manufacturers. Under the Percentage Phase-in Allowance provision, a manufacturer 

may exempt up to a cumulative total of eighty percent of the production over the first seven 

years a new standard applies. This applies separately to each regulatory power category. The 

engines used in such exempted equipment will only have to meet the previous standard, which is 

either the Tier 1 standard in the case of equipment at or above 50 hp, or unregulated in the case 

of equipment under 50 hp. For categories of engines where there is an overlap in standards (this 

only occurs in equipment at or above 50 hp), the standard for the exempted equipment continues 

to be the Tier 1 standard. The following example illustrates the percent exemptions applied 

during the introduction of Tier 2 and Tier 3 standards for equipment <100 to 175 hp. For this 

example, the standard for the exempted equipment is the Tier 1 standard. 

2002 100% Tier 1 

2003 20% Tier 1; 80% Tier 2 

2004 20% Tier 1; 80% Tier 2 

2005 10% Tier 1; 90% Tier 2 

2006 10% Tier 1; 90% Tier 2 

2007 10% Tier 1; 90% Tier 3 

2008 10% Tier 1; 90% Tier 3 

2009 100% Tier 3 

Total exemption: 80% 

For the purposes of emissions modeling, we assumed that the manufacturers took full 

advantage of the Percentage Phase-in Allowance provisions. The resulting technology 

distributions by hp category and model year are provided in Appendix A, Table A1. 

3
 
Table 1. Nonroad CI Engine Emission Standardsa 

Engine Power 

(hp) Model Years Regulation 

Emission Standards (g/hp-hr) NONROAD 

HC Tech Types b NMHC+NOx CO NOx PM 

<11 2000-2004 Tier 1 7.8 6.0 0.75 T1 

2005-2007 Tier 2 5.6 6.0 0.60 T2 

2008+ Tier 4 0.30 T4A, T4B e 

‡11 to <25 2000-2004 Tier 1 7.1 4.9 0.60 T1 

2005-2007 Tier 2 5.6 4.9 0.60 T2 

2008+ Tier 4 0.30 T4A, T4B e 

‡25 to <50 1999-2003 Tier 1 7.1 4.1 0.60 T1 

2004-2007 Tier 2 5.6 4.1 0.45 T2 

2008-2012 Tier 4 

transitional 

0.22 

T4A 

2013+ Tier 4 final 3.5 0.02 T4 

‡50 to <75 1998-2003 Tier 1 6.9 T1 

2004-2007 Tier 2 5.6 3.7 0.30 T2 

2008-2012 Tier 3 c 3.5 3.7 T3 

2008-2012 Tier 4 

transitional c 

0.22 T4A 

2013+ Tier 4 final 3.5 0.02 T4 

‡75 to <100 1998-2003 Tier 1 6.9 T1 

2004-2007 Tier 2 5.6 3.7 0.30 T2 

2008-2011 Tier 3 3.5 3.7 T3B 

2012-2013 Tier 4 

transitional 

0.14 

(50%) d 

0.30 

(50%) 

0.01 50% T4 

50% T4N 

2014+ Tier 4 final 0.14 0.30 0.01 T4N 

‡100 to <175 1997-2002 Tier 1 6.9 T1 

2003-2006 Tier 2 4.9 3.7 0.22 T2 

2007-2011 Tier 3 3.0 3.7 T3 

2012-2013 Tier 4 

transitional 

0.14 

(50%) 

0.30 

(50%) 

0.01 50% T4 

50% T4N 

2014+ Tier 4 final 0.14 0.30 0.01 T4N 

‡175 to <300 1996-2002 Tier 1 1.0 8.5 6.9 0.4 T1 

2003-2005 Tier 2 4.9 2.6 0.15 T2 

2006-2010 Tier 3 3.0 2.6 T3 

2011-2013 Tier 4 

transitional 

0.14 

(50%) 

0.30 

(50%) 

0.01 50% T4 

50% T4N 

2014+ Tier 4 final 0.14 0.30 0.01 T4N 

‡300 to <600 1996-2000 Tier 1 1.0 8.5 6.9 0.4 T1 

4
 
Engine Power 

(hp) Model Years Regulation 

Emission Standards (g/hp-hr) NONROAD 

HC Tech Types b NMHC+NOx CO NOx PM 

2001-2005 Tier 2 4.8 2.6 0.15 T2 

2006-2010 Tier 3 3.0 2.6 T3 

2011-2013 Tier 4 

transitional 

0.14 

(50%) 

0.30 

(50%) 

0.01 50% T4 

50% T4N 

2014+ Tier 4 final 0.14 0.30 0.01 T4N 

‡600 to £750 1996-2001 Tier 1 1.0 8.5 6.9 0.4 T1 

2002-2005 Tier 2 4.8 2.6 0.15 T2 

2006-2010 Tier 3 3.0 2.6 T3 

2011-2013 Tier 4 

transitional 

0.14 

(50%) 

0.30 

(50%) 

0.01 50% T4 

50% T4N 

2014+ Tier 4 final 0.14 0.30 0.01 T4N 

>750 except 

generator sets 

2000-2005 Tier 1 1.0 8.5 6.9 0.4 T1 

2006-2010 Tier 2 4.8 2.6 0.15 T2 

2011-2014 Tier 4 

transitional 

0.30 2.6 0.075 

T4 

2015+ Tier 4 final 0.14 2.6 0.03 T4N 

Generator sets 

>750 to £1200 

2000-2005 Tier 1 1.0 8.5 6.9 0.4 T1 

2006-2010 Tier 2 4.8 2.6 0.15 T2 

2011-2014 Tier 4 

transitional 

0.30 2.6 0.075 

T4 

2015+ Tier 4 final 0.14 0.5 0.02 T4N 

Generator sets 

>1200 

2000-2005 Tier 1 1.0 8.5 6.9 0.4 T1 

2006-2010 Tier 2 4.8 2.6 0.15 T2 

2011-2014 Tier 4 

transitional 

0.30 0.5 0.075 

T4 

2015+ Tier 4 final 0.14 0.5 0.02 T4N 

a The standards for recreational marine diesel engines are provided in Table 9.
 b Tier 4 standards are in the form of NMHC.
 c For 50 to <75 hp engines, a Tier 3 NOx standard of 3.5 g/hp-hr was promulgated, beginning in 2008. The Tier 4 transitional
 

standard also begins in 2008; it leaves the Tier 3 NOx standard unchanged and adds a 0.22 g/hp-hr PM standard.
 d Percentages are model year sales fractions required to comply with the indicated NOx and NMHC standards, for model years
 

where less than 100 percent is required.
 e The T4A tech type is used in 2008-2012. The T4B tech type is used in 2013+.
 

5
 
Methodology for Calculation of Emission Factors in NONROAD 

For HC, CO, and NOx, the exhaust emission factor for a given diesel equipment type in a 

given model year/age is calculated as follows: 

EF adj ( HC , CO , NOx ) = EF ss · TAF · DF [Equation 1] 

where:
 

EFadj = final emission factor used in model, after adjustments to account for transient operation
 

and deterioration (g/hp-hr) 

EFss = zero-hour, steady-state emission factor (g/hp-hr) 

TAF = transient adjustment factor (unitless) 

DF = deterioration factor (unitless) 

The zero-hour, steady-state emission factors (EFss) are mainly a function of model year and 

horsepower category, which defines the technology type. The transient adjustment factors 

(TAFs) vary by equipment type. The deterioration factor (DF) is a function of the technology 

type and age of the engine. 

Since PM emissions are dependent on the sulfur content of the fuel the engine is burning, 

the equation used for PM is slightly modified from equation [1] as follows: 

EF adj ( PM ) = EF ss · TAF · DF · S PMadj [Equation 2] 

where: 

SPM adj = adjustment to PM emission factor to account for variations in fuel sulfur content 

(g/hp-hr) 

PM and SO2 are the only diesel pollutants that are dependent on fuel sulfur content. 

For BSFC, there is no deterioration applied, so the equation is simplified to: 

EF adj ( BSFC ) = EF ss · TAF [Equation 3] 

Emission factors for CO2 and SO2 are calculated based on brake-specific fuel 

consumption; therefore, the model does not require CO2 or SO2 emission factor input files. The 

equations for computing these emissions are discussed in detail later in this report. 

Crankcase HC emissions are simply a fraction (2%) of exhaust HC emissions for Tier 3 

and earlier engines. [6] For Tier 4 engines, zero crankcase emissions are assumed. Crankcase 

emissions are discussed in more detail later in this report. 

For ease of reference, the model inputs for EFss, TAFs, and DFs are included with the 

technology model year fractions in Appendix A. 

6
 
Zero-Hour, Steady State Emission Factors (EFss)--HC, CO, NOx , PM, and BSFC 

This section describes the steady-state fuel consumption and emission factors for HC, 

CO, NOx , and PM. These emission factors are listed in Table A2 in Appendix A. We have used 

engine model year and horsepower as categories to group NONROAD emission factors. These 

groupings are consistent with emission standards for CI engines with two minor exceptions. One 

exception is that the pre-control engines have been split into two groups, pre-1988 MY engines, 

and 1988 MY to Tier 1 engines. The pre-1988 MY engines are referred to as “Base” engines and 

the 1988 MY to Tier 1 engines are referred to as “Tier 0” engines. This distinction was made 

based on data indicating a difference in emission rates. The other exception is a minor difference 

in the horsepower categories used in NONROAD versus those used for standard setting. The 

NONROAD horsepower categories follow the general formula, x<hp£y, whereas the CI 

standards generally follow the formula, x£hp<y. By making this minor modification, the 

NONROAD CI horsepower categories are consistent with those used for spark ignition 

equipment. Perhaps in the future, emission factors may be distinguished by technologies such as 

turbo-charging, fuel metering pumps, and cylinder size; however, there are not enough emissions 

data at present to support such distinctions in NONROAD emission factors. 

As mentioned previously, fuel sulfur levels affect PM emissions. NONROAD users can 

adjust for local (episodic) fuel sulfur levels. In the absence of local information, suggested 

nationwide average fuel properties are provided in Table 2. [7] 

The adjustment for fuel sulfur is made relative to the default certification fuel sulfur level 

in the model. The national average for nonroad diesel estimated as of 1997 is 3300 ppm [8], and 

the Tier 1 and pre-control emission factors in NONROAD’s input files are adjusted to be 

consistent with this default fuel sulfur level. The available Tier 2 emission factors are intended to 

be consistent with a default fuel sulfur level of 0.20 mass percent, in order to attain a 0.15 g/hphr PM standard. Where emission tests were known to have been performed with fuels with other 

sulfur contents, the test results have been adjusted, as described in Appendix C. 

The default certification fuel sulfur levels in the model for Tier 3 and Tier 4 engines are 

provided in Table 3. In addition to adjusting for local fuel sulfur levels, the model allows the 

user to input alternative default certification diesel fuel sulfur levels for Tier 2 and later engines. 

This option will be described in more detail in a later section of the report. 

7
 
Table 2. Suggested Nationwide Average Diesel Fuel Sulfur Content 

Year 

Diesel Sulfur (ppm) 

Land Marine 

2000 2284 2640 

2001 2284 2635 

2002 2284 2637 

2003 2284 2637 

2004 2284 2637 

2005 2284 2637 

2006 2242 2588 

2007 1139 1332 

2008 351 435 

2009 351 435 

2010 165 319 

2011 32 236 

2012 32 124 

2013 32 44 

2014 20 52 

2015 11 56 

2016 11 56 

2017 11 56 

2018 11 55 

2019 11 55 

2020+ 11 55 

8
 
Table 3. Default Certification Diesel Fuel Sulfur Content for Tier 3 and Tier 4 Engines 

Engine Power Model Years Regulation NONROAD 

Tech Types 

Modeled Default Fuel 

Sulfur Content (ppm) 

hp £ 75 2008-2012 Tier 4 transitional T4A 500 

2013+ Tier 4 T4B, T4 15 

75 < hp £ 100 2008-2011 Tier 3 transitional a T3B 500 

2012+ Tier 4 transitional 

and final T4, T4N 15 

100 < hp £ 175 2007-2011 Tier 3 T3 2000 

2012+ Tier 4 transitional 

and final T4, T4N 15 

175 < hp £ 750 2006-2010 Tier 3 T3 2000 

2011+ Tier 4 transitional 

and final T4, T4N 15 

hp > 750 2011+ Tier 4 transitional 

and final T4, T4N 15 

a Since the Tier 3 standard begins in 2008, it is assumed that this new technology introduction will allow 

manufacturers to take advantage of the availability of 500 ppm fuel that year. 

Due to lack of data, the brake-specific fuel consumption (BSFC) for the 1988-and-later 

pre-control (Tier 0) engines is used for all engines, both earlier pre-control engines and later 

engines subject to emissions standards. The derivation of the BSFC values is described in 

Appendix C. While it is likely that fuel consumption varies between these categories, there is 

not sufficient data available at this time for EPA to specify alternate values. 

There is little test data available on nonroad engines. In developing the emission factors 

for NONROAD, we have considered data from various sources. The basis for the emission 

factors by model year/hp category is described below and summarized in Table 4 thru Table 7. 

Base (Pre-1988), Engines £50 hp: 

There are no known tests of pre-1988 CI engines of less than or equal to 50 hp. Thus, 

NONROAD will use the same emission factors as for the 1988 through Tier 1 years for engines 

of this size described below. 

9
 
Table 4. Summary of the Basis for the HC Zero-Hour Steady-State CI Emission Factors in NONROAD2008a 

HP 

HC g/hp-hr 

Tier 0a T0 Basis Tier 1 T1 Basis Tier 2b T2 Basisc Tier 3b T3 Basisc Tier 4f T4 Basis 

>0 to 11 1.5 OFFROAD 0.7628 cert 0.5508d (5) 10% default margin from 0.6 equivalent std 

(since T1 EF exceeds T2 std, cannot be used) na 0.5508 Same as T2 

>11 to 16 1.7 OFFROAD 0.4380 cert 0.4380 (3) Same as T1 

(since T1 EF still below 0.6 T2 equivalent std) na 0.4380 Same as T2 

>16 to 25 1.7 OFFROAD 0.4380 cert 0.4380 (3) Same as T1 

(since T1 EF still below 0.6 T2 equivalent std) na 0.4380 Same as T2 

>25 to 50 1.8 OFFROAD 0.2789 cert 0.2789 (3) Same as T1 

(since T1 EF still below 0.6 T2 equivalent std) na 0.1314d 8% margin from 0.14 eqv std 

>50 to 75 0.99 EF data 0.5213 cert 0.3672d (5) 10% default margin from 0.4 equivalent std 

(since T1 EF exceeds T2 std, cannot be used) 0.1836d (5) 10% margin from 0.2 eqv std 0.1314d 8% margin from 0.14 eqv std 

>75 to 100 0.99 EF data 0.5213 cert 0.3672d (5) 10% default margin from 0.4 equivalent std 

(since T1 EF exceeds T2 std, cannot be used) 0.1836d (5) 10% margin from 0.2 eqv std 0.1314d 8% margin from 0.14 standard 

>100 to 175 0.68 EF data 0.3384 cert 0.3384 (3) Same as T1 

(since T1 EF still below 0.4 T2 equivalent std) 0.1836d (5) 10% margin from 0.2 eqv std 0.1314d 8% margin from 0.14 standard 

>175 to 300 0.68 EF data 0.3085 cert 0.3085 (3) Same as T1 

(since T1 EF still below 0.4 T2 equivalent std) 0.1836d (5) 10% margin from 0.2 eqv std 0.1314d 8% margin from 0.14 standard 

>300 to 600 0.68 EF data 0.2025 cert 0.1669 cert 0.1669 (3) Same as T2 0.1314d 8% margin from 

0.14 standard 

>600 to 750 0.68 EF data 0.1473 cert 0.1669 (1 and 2) Same as the >300 to 600hp category. 

Rationale: 

a) All these HP categories meet same 0.3 HC 

eqv std. 

b) The NOx T1 EFs exceed the T2 std. To meet 

NOx T2, changes are likely to increase HC. 

c) EF based on actual cert data. 

0.1669 (3) Same as T2 0.1314d 8% margin from 

0.14 standard 

>750 except 

gen sets 0.68 EF data 0.2861 cert 0.1669 na 0.1314d,e 8% margin from 

0.14 standard 

Gen sets >750 

to 1200 0.68 EF data 0.2861 cert 0.1669 na 0.1314d,e 8% margin from 

0.14 standard 

Gen sets 

>1200 0.68 EF data 0.2861 cert 0.1669 na 0.1314d,e 8% margin from 

0.14 standard 

a Tier 0 represents 1988+ MY engines for MYs prior to Tier 1. Separate EFs are also provided for Base (pre-1988 MY) engines. For 50hp engines, Base EF = Tier 0 EF. For >50hp engines,
 

the Base EFs vary by application, so are not provided in this table.

b The Tier 2 and Tier 3 standards are expressed as a combined NMHC + NOx standard. The NMHC assumed fractions of these combined standards are taken from the RIA. The resulting
 

NMHC portion of the combined standard is referred to here as the “equivalent” standard.
 c Numbers in parentheses correspond to the option selected, which is briefly described here. For more details regarding the options, consult the text.
 d An adjustment of 1.02 (1/0.984) is also applied to convert from NMHC to THC, since the standards apply to NMHC. This adjustment is described in report NR-002b.
 e For >750 hp engines, there is also a transitional Tier 4 NMHC standard of 0.30 g/hp-hr in 2011-2014. The corresponding HC EF in NONROAD is 0.2815 g/hp-hr.
 f Tier 4 emission factors are considered to be transient, rather than steady-state.
 

10
 
Table 5. Summary of the Basis for the CO Zero-Hour Steady-State CI Emission Factors in NONROAD2008a 

HP CO g/hp-hr 

Tier 0a T0 Basis Tier 1 T1 Basis Tier 2 T2 Basisb Tier 3 T3 Basisb Tier 4d T4 Basis 

>0 to 11 5 OFFROAD 4.1127 cert 4.1127 Same as T1 (since T1 EF still below T2 std) na 4.1127 Same as T1 

>11 to 16 5 OFFROAD 2.1610 cert 2.1610 Same as T1 (since T1 EF still below T2 std) na 2.1610 Same as T1 

>16 to 25 5 OFFROAD 2.1610 cert 2.1610 Same as T1 (since T1 EF still below T2 std) na 2.1610 Same as T1 

>25 to 50 5 OFFROAD 1.5323 cert 1.5323 Same as T1 (since T1 EF still below T2 std) na 0.153c 90% reduction 

>50 to 75 3.49 EF data 2.3655 cert 2.3655 Same as T1 (since T1 EF still below T2 std) 2.3655 Same as T1 0.237c 90% reduction 

>75 to 100 3.49 EF data 2.3655 cert 2.3655 Same as T1 (since T1 EF still below T2 std) 2.3655 Same as T1 0.237 90% reduction 

>100 to 175 2.7 EF data 0.8667 cert 0.8667 Same as T1 (since T1 EF still below T2 std) 0.8667 Same as T1 0.087 90% reduction 

>175 to 300 2.7 EF data 0.7475 cert 0.7475 Same as T1 (since T1 EF still below T2 std) 0.7475 Same as T1 0.075 90% reduction 

>300 to 600 2.7 EF data 1.3060 cert 0.8425 cert 0.8425 Same as T2 0.084 90% reduction 

>600 to 750 2.7 EF data 1.3272 cert 1.3272 Same as T1 (since T1 EF still below T2 std) 1.3272 Same as T1 0.133 90% reduction 

>750 except 

gen sets 2.7 EF data 0.7642 cert 0.7642 Same as T1 (since T1 EF still below T2 std) na 0.076 90% reduction 

Gen sets >750 

to 1200 2.7 EF data 0.7642 cert 0.7642 Same as T1 (since T1 EF still below T2 std) na 0.076 90% reduction 

Gen sets 

>1200 2.7 EF data 0.7642 cert 0.7642 Same as T1 (since T1 EF still below T2 std) na 0.076 90% reduction 

a Tier 0 represents 1988+ MY engines for MYs prior to Tier 1. Separate EFs are also provided for Base (pre-1988 MY) engines. For 50hp engines, Base EF = Tier 0 EF.
 

For >50hp engines, the Base EFs vary by application, so are not provided in this table.
 

b The Tier 2 and Tier 3 CO emission factors are based on application of option 2, the carryover of emission factors derived from nonroad certification data. For more detail
 

regarding this option, consult the text.
 

c For >25 to 75 hp engines, CO emissions for engines meeting the Tier 4 transitional PM standard of 0.22 g/hp-hr in 2008-2012 are unchanged from Tier 1. In 2013+, when
 

the Tier 4 PM standard of 0.02 g/hp-hr takes effect, the corresponding CO EFs are reduced by 90 percent.
 

d Tier 4 emission factors are considered to be transient, rather than steady-state.
 

11
 
eqv s

Table 6. Summary of the Basis for the NOx Zero-Hour Steady-State CI Emission Factors in NONROAD2008a 

HP 

NOx g/hp-hr 

Tier 0a T0 Basis Tier 1 T1 Basis Tier 2b T2 Basisc Tier 3b T3 Basisc Tier 4e T4 Basis 

>0 to 11 10 OFFROAD 5.2298 cert 4.3 (4) 14% hwy margin from 5.0 equivalent std 

(since T1 EF exceeds T2 std, cannot be used) na 4.3 Same as T2 

>11 to 16 8.5 OFFROAD 4.4399 cert 4.4399 (3) Same as T1 

(since T1 EF still below 5.0 T2 equivalent std) na 4.4399 Same as T2 

>16 to 25 8.5 OFFROAD 4.4399 cert 4.4399 (3) Same as T1 

(since T1 EF still below 5.0 T2 equivalent std) na 4.4399 Same as T2 

>25 to 50 6.9 OFFROAD 4.7279 cert 4.7279 (3) Same as T1 

(since T1 EF still below 5.0 T2 equivalent std) na 3.0 Same as >50 

to 75 

>50 to 75 8.30 EF data 5.5988 cert 4.7 (5) 10% default margin from 5.2 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) 3.0 (5) 10% margin from 3.3 eqv std 3.0 Same as T3 

>75 to 100 8.30 EF data 5.5988 cert 4.7 (5) 10% default margin from 5.2 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) 3.0 (5) 10% margin from 3.3 eqv std 0.276 8% margin from 0.3 std 

>100 to 175 8.38 EF data 5.6523 cert 4.1 (5) 10% default margin from 4.5 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) 2.5 (5) 10% margin from 2.8 eqv std 0.276 8% margin from 0.3 std 

>175 to 300 8.38 EF data 5.5772 cert 4.0 (4) 10.5% hwy margin from 4.5 T2 equivalent std 

(since T1 EF exceeds T2 std, cannot be used) 2.5 (4) 10.5% hwy 

margin from 2.8 

td 

0.276 8% margin 

from 0.3 std 

>300 to 600 8.38 EF data 6.0153 cert 4.3351 cert (real data preferred even though margin 

from 4.5 eqv T2 std <10%) 2.5 (5) 10% margin from 2.8 eqv std 0.276 8% margin from 0.3 std 

>600 to 750 8.38 EF data 5.8215 cert 4.1 (5) 10% default margin from 4.5 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) 2.5 (5) 10% margin from 2.8 eqv std 0.276 8% margin from 0.3 std 

>750 except 

gen sets 8.38 EF data 6.1525 cert 4.1 (5) 10% default margin from 4.5 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) na 2.392 8% margin from 2.6 std 

Gen sets >750 

to 1200 8.38 EF data 6.1525 cert 4.1 (5) 10% default margin from 4.5 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) na 0.460d 8% margin 

from 0.5 std 

Gen sets 

>1200 8.38 EF data 6.1525 cert 4.1 (5) 10% default margin from 4.5 T2 equiv std 

(since T1 EF exceeds T2 std, cannot be used) na 0.460 8% margin from 0.5 std 

a Tier 0 represents 1988+ MY engines for MYs prior to Tier 1. Separate EFs are also provided for Base (pre-1988 MY) engines. For 50hp engines, Base EF = Tier 0 EF. For >50hp engines, the Base EFs vary by
 

application, so are not provided in this table.

b The Tier 2 and Tier 3 standards are expressed as a combined NMHC + NOx standard. The NOx assumed fractions of these combined standards are taken from the RIA. The resulting NOx portion of the combined
 

standard is referred to here as the “equivalent” standard.
 c Numbers in brackets correspond to the option selected, which is briefly described here. For more details regarding the options, consult the text. The derivation of the highway-based compliance margins are discussed
 

in Appendix E.

d For generator sets >750 to 1200hp, there is also a transitional Tier 4 NOx standard of 2.6 g/hp-hr in 2011-2014. The corresponding NOx EF is 2.39 g/hp-hr.
 e Tier 4 emission factors are considered to be transient, rather than steady-state.
 

12
 
Table 7. Summary of the Basis for the PM10 Zero-Hour Steady-State CI Emission Factors in NONROAD2008a 

HP 

PM10 g/hp-hr 

Tier 0a T0 Basis Tier 1 T1 Basis Tier 2 T2 Basisb Tier 3 T3 Basisb Tier 4e T4 Basis 

>0 to 11 1 OFFROAD 0.4474 cert 0.50 

(1) The NOx T1 EF exceeds the T2 std. To meet 

NOx T2, changes are likely to increase PM. The 

T2 PM EF is therefore expected to be greater 

than 0.44 (T1 EF) and less than 0.60 (T2 std); 

0.50 chosen as a reasonable value. 

na 0.28 8% margin 

from 0.3 std 

>11 to 16 0.9 OFFROAD 0.2665 cert 0.2665 (3) Same as T1 (since T1 EF still below T2 std) na 0.28 8% margin 

from 0.3 std 

>16 to 25 0.9 OFFROAD 0.2665 cert 0.2665 (3) Same as T1 (since T1 EF still below T2 std) na 0.28 8% margin 

from 0.3 std 

>25 to 50 0.8 OFFROAD 0.3389 cert 0.3389 (3) Same as T1 (since T1 EF still below T2 std) na 0.0184c 8% margin 

from 0.02 std 

>50 to 75 0.722 EF data 0.4730 0.24 (4) 20% highway-based margin from std 

(since T1 EF exceeds T2 std, cannot be used) 0.30 (1) T3 std 0.0184c 8% margin 

from 0.02 std 

>75 to 100 0.722 EF data 0.4730 0.24 (4) 20% highway-based margin from std 

(since T1 EF exceeds T2 std, cannot be used) 0.30 (1) T3 std 0.0092 8% margin from 0.01 std 

>100 to 175 0.402 EF data 0.2799 0.18 (4) 20% highway-based margin from std 

(since T1 EF exceeds T2 std, cannot be used) 0.22 (1) T3 std 0.0092 8% margin from 0.01 std 

>175 to 300 0.402 EF data 0.2521 cert 0.1316 

(2) T2 EF for >300 to 600hp category applied to 

these hp categories. Rationale: All four hp 

categories meet same PM std. Also, T2 EF of 

0.1316 based on actual certification data. 

0.15 (1) T3 std 0.0092 8% margin 

from 0.01 std 

>300 to 600 0.402 EF data 0.2008 cert 0.1316 0.15 (1) T3 std 0.0092 8% margin 

from 0.01 std 

>600 to 750 0.402 EF data 0.2201 cert 0.1316 0.15 (1) T3 std 0.0092 8% margin 

from 0.01 std 

>750 except 

gen sets 0.402 EF data 0.1934 cert 0.1316 na 0.0276d 8% margin 

from 0.03 std 

Gen sets >750 

to 1200 0.402 EF data 0.1934 cert 0.1316 na 0.0184d 8% margin 

from 0.02 std 

Gen sets 

>1200 0.402 EF data 0.1934 cert 0.1316 na 0.0184d 8% margin 

from 0.02 std a Tier 0 represents 1988+ MY engines for MYs prior to Tier 1. Separate EFs are also provided for Base (pre-1988 MY) engines. For 50hp engines, Base EF = Tier 0 EF. For >50hp engines,
 

the Base EFs vary by application, so are not provided in this table.

b Numbers in brackets correspond to the option selected, which is briefly described here. For more details regarding the options, consult the text. The derivation of the highway-based
 

compliance margins are discussed in Appendix E.
 c For >25 to 75 hp engines, there is also a transitional Tier 4 PM standard of 0.22 g/hp-hr in 2008-2012. The corresponding PM EF in NONROAD is 0.20 g/hp-hr.
 d For all engines >750 hp, there is also a transitional Tier 4 PM standard of 0.075 g/hp-hr in 2011-2014. The corresponding PM EF in NONROAD is 0.069 g/hp-hr.
 e Tier 4 emission factors are considered to be transient, rather than steady-state.
 

13
 
Base (Pre-1988), Engines > 50 hp: 

For pre-1988 CI engines of greater than 50 hp, NONROAD’s steady-state emission 

factors are based on the emission factors used in the Nonroad Engine and Vehicle Emission 

Study (NEVES) [6]. The sources of the emission factors used in NEVES are described in 

Appendix B. The emission factors vary by application. However, NEVES includes an 

adjustment for in-use operation. Since NONROAD uses a different in-use adjustment factor than 

NEVES (see Appendix F), the NEVES adjustment is removed to determine pre-1988 average 

steady-state emissions. 

Because the testing fuel is generally unknown, we assume that the NEVES PM factors 

are appropriate for the default certification fuel sulfur content of 0.33 wt.% sulfur used in 

NONROAD. 

A conversion from gram per gallon to gram per horsepower-hr was made to NEVES 

emission rates for the greater than 50 horsepower engines for the diesel recreational marine 

categories; inboard, outboard, and sailboat auxiliary. Outboard and sailboat auxiliary engines 

above 50 hp were converted from the NEVES gram per gallon to gram per horsepower using the 

higher fuel consumption of 0.408 lbs/hp-hr and 7.1 lbs/gallon fuel density because these engines 

are primarily less than 100 hp. The NEVES emission rate for inboard engines was converted 

using the lower fuel consumption rate of 0.367 lbs/hp-hr because these engines are primarily 

above 100 horsepower. 

Tier 0 (1988 to Tier 1), Engines £50 hp 

For 1988-and-later pre-control engines less than or equal to 50 hp, we will use the 

emission factors described in the documentation for ARB’s OFF-ROAD model. [9] We have 

combined the direct injection and indirect injection factors using the technology fractions listed 

in the Regulatory Impact Analysis (RIA) for the emission standards. [10] Again, because the 

sulfur content of fuels used in generating these emission factors is unknown, we have assumed 

that the PM emission factors are appropriate for the default certification fuel sulfur level of 0.33 

weight percent. 

Tier 0 (1988 to Tier 1), Engines >50 hp 

Recent studies have indicated that, in general, emission rates from Tier 0 engines greater 

than 50 hp are lower than for Tier 0 engines less than or equal to 50 hp. For these engines, we 

will use emission factors calculated from recent studies. A summary of the emission data from 

these studies is provided in Appendix C. As explained in Appendix C, a correction for fuel 

sulfur content is applied. 

Tier 1 Engines , all hp categories 

The NONROAD model’s emission factors for Tier 1 engines are based on EPA 

certification data. The certification data are described in Appendix D. 

Tier 2 Engines, >300 to 600 hp 

Since EPA certification data are available for this hp category, the emission factors are 

14
 
based on analysis of the certification data, as described in Appendix D. 

Tier 2 Engines £300 hp and > 600 hp and Tier 3 Engines 

Since the Tier 2 standard for the 600 to 750 hp category began in 2002, and the Tier 2 

standard for the 100 to 300 hp category began in 2003, Tier 2 certification data for these 

categories are now available; however, these recent certification data were not yet available at 

the time these emission factors were developed. As a result, we developed five alternative 

options for calculating zero mile, steady-state emission factors for these engines. These options 

were considered in the order they are presented here. 

(1)	 Examine likely impacts of expected technology changes. In this option, we consider 

offsetting changes to PM and HC with implementation of stricter emission standards for 

NOx. This includes assigning the applicable standard as the PM emission factor without 

applying a compliance margin. The compliance margin is the percent difference between 

a standard and average emissions at certification for engines manufactured under that 

standard. 

(2)	 Assign an emission factor from another hp category. In this option, we assume that an 

emission factor based on certification data is applicable to another hp category and is 

preferable to applying a compliance margin to the applicable nonroad standard. 

(3)	 Continue to use the Tier 1 or Tier 2 emission factors derived from the nonroad 

certification data. In this option, we assume that manufacturers will maintain current 

emission levels, e.g., design technologies, if they appear adequate to achieve compliance 

while maintaining some margin of safety. Under this option, we would assume that 

emission factors remain at the same levels used for Tier 1 or Tier 2 engines. 

This option was only considered if the compliance margin (percent difference) between 

the proposed emission factor and the applicable nonroad standard was at least 10%. We 

based this lower bound (10%) on average highway-certification compliance margins for 

NOx, assuming that it represents progressive highway certification experience for a 

“controlling pollutant,” i.e., a pollutant for which the necessity to achieve compliance 

drives innovation in engine design or control technology. 

(4)	 Reduce the applicable nonroad standard by a compliance margin derived from 

certification test results for analogous highway engines. We expect that the control of 

emissions from nonroad engines will follow a course similar to that experienced for 

highway engines, since we believe that as standards for nonroad engines become more 

stringent, manufacturers will adopt technologies similar to those already introduced in 

highway engines. Based on this expectation, we calculated compliance margins using 

highway standards and corresponding highway certification test results. In this 

discussion, we will refer to compliance margins calculated for highway engines as 

“highway-certification compliance margins” (HCCM). The derivation of the HCCMs is 

discussed in detail in Appendix E. An HCCM is only considered for use if it is greater 

15
 
than or equal to 10% and less than 75%. 

(5)	 Apply a default compliance margin of 10%. In this option, we assume that on average, 

manufacturers will maintain a minimum compliance margin. This margin is based on 

average highway certification compliance margins for NOx, the pollutant appearing to 

drive measures to achieve compliance in highway diesel engines. A default compliance 

margin was considered when the highway-based compliance margins were outside the 

acceptable range. With this option, the applicable nonroad standard is simply reduced by 

10%. 

The Agency regulates HC and NOx under a combined standard for all Tier 2 and Tier 3 

engines. Thus, in order to apply compliance margins for these pollutants, where applicable, we 

split the combined standard into pollutant-specific components for HC and NOx. These are 

presented in Table 8. 

For each pollutant in Tiers 2 and 3, we evaluated one or more of these five options for 

each horsepower category. The specific options selected for each pollutant and Tier are 

presented in Table 4 thru Table 7 and summarized below: 

HC:	 Tier 2: For categories less than 300 hp, we continued to use the Tier 1 nonroad 

certification results (option 3) or applied the default compliance margin (option 5) on an 

individual basis by horsepower category to give nonroad compliance margins of at least 

10%. We did not use the highway-certification compliance margins because the highway 

HC standards have not driven technology development; as a result, the HC standards are 

unrelated to the certification values. 

For the two hp categories greater than 600 hp, we assigned the emission factor for the 

300-600 hp category. The rationale, which applies options 1 and 2, is threefold: 1) all 

three hp categories meet the same HC equivalent standard, 2) the use of certification data 

is preferable to applying a compliance margin, and 3) changes necessary to meet the Tier 

2 NOx standard for the 600-750 hp category are likely to increase HC, so a slight increase 

in HC emissions from Tier 1 to Tier 2 for this hp category is not unexpected. 

Tier 3: We continued to use the Tier 2 nonroad certification results (option 3) or applied 

the default compliance margin (option 5) to give nonroad compliance margins of at least 

10%. We ruled out use of highway-certification compliance margins (option 4) for the 

same reason as for Tier 2. 

CO:	 Tiers 2 and 3: We continued to use the Tier 1 nonroad certification results (option 2) for 

all horsepower categories in Tiers 2 and 3. Highway-certification compliance margins 

(option 4) were very large (>90%), and as with HC, give implausibly low emission 

factors in Tiers 2 and 3. 

16
 
Table 8. Tier 2 and Tier 3 Combined and Estimated Pollutant-Specific Emissions
 

Standards for Nonroad Diesel Engines1
 

Power Range 

(hp) 

Combined Standard 

HC+NOx 

(g/hp-hr) 

Estimated 

Pollutant-Specific 

HC 

(g/hp-hr) 

Estimated 

Pollutant-Specific 

NOx 

(g/hp-hr) 

Tier 2 Tier 3 Tier 2 Tier 3 Tier 2 Tier 3 

< 11 5.6 0.6 5.0 

‡11 to <25 5.6 0.6 5.0 

‡25 to <50 5.6 0.6 5.0 

‡50 to <100 5.6 3.5 0.4 0.2 5.2 3.3 

‡100 to <175 4.9 3.0 0.4 0.2 4.5 2.8 

‡175 to <300 4.9 3.0 0.4 0.2 4.5 2.8 

‡300 to <600 4.8 3.0 0.3 0.2 4.5 2.8 

‡600 to <750 4.8 3.0 0.3 0.2 4.5 2.8 

‡750 4.8 0.3 4.5 

1 Pollutant-specific components have no regulatory significance and are derived to facilitate 

modeling analyses. 

Basis for Pollutant-Specific HC and NOx Emission Standards: 

Tier 2 <50 hp: As in the RIA [10], EPA assumes minimum HC emissions of 0.6 g/hp-hr based on 

ARB data on indirect injection (IDI) engines under 25 hp. This rate is then subtracted from the 

combined HC+NOx standard to split the standard into single pollutant emission factors. 

Tier 2 ‡50 hp: As in the RIA [10], the proposed European NOx standard is used to split the 

combined HC+NOx standard into single pollutant emission factors. 

Tier 3: NONROAD follows the RIA [10] in using engineering judgment to assume minimum HC 

emissions of 0.2 g/hp-hr. This rate is then subtracted from the combined HC+NOx standard to 

split the standard into single pollutant emission factors. 

NOx: Tier 2: We applied highway-certification compliance margins (option 4), continued to use 

17
 
the Tier 1 nonroad certification results (option 3) or applied the default compliance 

margin (option 5) on an individual basis by horsepower category to give compliance 

margins of at least 10%. 

Tier 3: We applied the highway certification compliance margin (option 4) or the default 

compliance margin (option 5) for all horsepower categories. Nonroad certification results 

(option 3) did not provide adequate compliance margins. 

PM:	 Tier 2: We applied the first four options on an individual basis by horsepower category to 

give compliance margins of at least 10%. The highway-certification compliance margin 

used for the 50-100 hp and 100-175 hp categories was 20%. 

Tier 3: Tier 3 PM emission factors were set equal to the appropriate nonroad standards. 

To meet the NOx Tier 3 standards, technological changes are likely to increase PM; 

therefore, compliance margins were not applied to PM (option 1). 

Tier 4 Engines 

For these engines, an 8% compliance margin was applied to the standards. This 

compliance margin was derived from data for highway diesel vehicles and used in the HD2007 

rulemaking. 

The resulting zero-hour, steady-state emission factors for all Tiers and pollutants are 

shown in Table A2 in Appendix A. 

Recreational Marine and Underground Mining Emission Factors 

Recreational marine CI engines under 50 hp are subject to the Tier 1 and Tier 2 CI engine 

standards in the October 1998 rule. (2) Tier 2 standards for recreational marine CI engines over 

50 hp were established by the November 2002 rule. (3) More recently, Tier 3 standards were 

promulgated for all recreational marine engines [5], so the emission factor inputs used for these 

engines do not exactly follow those presented in Table 4 thru Table 7. The emission standards 

for this category are provided in Table 9. Table 10 shows the base and controlled recreational 

marine emission factors in NONROAD2008a. The technology type names have also been 

revised to differentiate marine CI from other CI engines. 

Although underground mining equipment emissions are not controlled by EPA, there 

have been controls imposed by the Occupational Safety and Health Administration (OSHA). 

The OSHA standards do not directly follow the form used for the NONROAD model, but they 

are considered approximately equivalent to the EPA Tier 2 standards for land-based CI 

equipment. Therefore, the NONROAD model simply uses the NEVES uncontrolled emission 

factors for Base, Tier 0, and Tier 1 underground mining inputs, and then applies the Tier 2 

emission factors from Table 4 thru Table 7 for all newer engines. 

18
 
 

 

 

 

 

 

Table 9. Emission Standards for Recreational Marine Diesel Engines 

Engine 

Power (hp) 

Engine 

Displacement 

(L/cyl) 

Model 

Year 

Start Regulation 

Emission Standards (g/hp-hr) 

NONROAD 

Tech Types 

NMHC 

+NOx 

HC 

+NOx CO PM 

<11 <0.9 2000 Tier 1 7.8 6.0 0.75 T1M 

2005 Tier 2 5.6 6.0 0.60 T2M 

2009 Tier 3 5.6 6.0 0.30 T3M 

≥11 to <25 <0.9 2000 Tier 1 7.1 4.9 0.60 T1M 

2005 Tier 2 5.6 4.9 0.60 T2M 

2009 Tier 3 5.6 4.9 0.30 T3M 

≥25 to <50 <0.9 1999 Tier 1 7.1 4.1 0.60 T1M 

2004 Tier 2 5.6 4.1 0.45 T2M 

2009 Tier 3 5.6 4.1 0.22 T3M 

2014 Tier 3 3.5 4.1 0.15 T4M 

≥50 to 

<100 

<0.9 2007 Tier 2 5.6 4.1 0.30 T2M 

2009 Tier 3 5.6 4.1 0.22 T3M 

2014 Tier 3 3.5 4.1 0.22 T4M 

≥100 <0.9 2007 Tier 2 5.6 4.1 0.30 T2M 

2012 Tier 3 4.3 4.1 0.11 T3M 

0.9≤ disp <1.2 2006 Tier 2 5.4 4.1 0.22 T2M 

2013 Tier 3 4.3 4.1 0.10 T3M 

1.2≤ disp <2.5 2006 Tier 2 5.4 4.1 0.15 T2M 

2014 Tier 3 4.3 4.1 0.10 T2M 

2.5≤ disp <3.5 2009 Tier 2 5.4 4.1 0.15 T2M 

2013 Tier 3 4.3 4.1 0.09 T3M 

≥3.5 2009 Tier 2 5.4 4.1 0.15 T2M 

2012 Tier 3 4.3 4.1 0.08 T3M 

19
 
 

Table 10. NONROAD Model EF Inputs for Recreational Marine Diesel Engines 

Engine Power 

(hp) 

Model 

Year Start Tech Type Emission Factor Modeling Inputs (g/hp-hr) BSFC 

HC CO NOx PM (lb/hp-hr) 

hp £ 11 Pre-2000 BaseM 1.50 5.00 10.00 1.00 0.408 

2000 T1M 0.76 4.11 5.23 0.45 

2005 T2M 0.68 4.11 4.39 0.38 

2009 T3M 0.43 4.11 4.39 0.24 

11 < hp £ 25 Pre-2000 BaseM 1.70 5.00 8.50 0.90 0.408 

2000 T1M 0.44 2.16 4.44 0.27 

2005 T2M 0.21 2.16 3.63 0.19 

2009 T3M 0.21 2.16 3.63 0.19 

25 < hp £ 50 Pre-1999 BaseM 1.80 5.00 6.90 0.80 0.408 

1999 T1M 0.28 1.53 4.73 0.34 

2004 T2M 0.54 1.53 3.71 0.23 

2009 T3M 0.41 1.53 3.71 0.18 

2014 T4M 0.41 1.53 2.32 0.18 

50 < hp £ 100 Pre-2007 BaseM 0.22 0.95 6.67 0.16 0.408 

2007 T2M 0.20 0.95 3.82 0.13 

2009 T3M 0.20 0.95 3.82 0.13 

2014 T4M 0.20 0.95 2.39 0.13 

100 < hp £ 175 Pre-2006 BaseM 0.22 0.95 6.67 0.16 0.367 

2006 T2M 0.20 0.95 3.82 0.13 

2012 T3M 0.13 0.95 3.34 0.088 

175 < hp £ 300 Pre-2006 BaseM 0.22 0.95 6.67 0.16 0.367 

2006 T2M 0.25 0.95 4.46 0.090 

2013 T3M 0.22 0.95 3.90 0.080 

300 < hp £ 750 Pre-2006 BaseM 0.22 0.95 6.67 0.16 0.367 

2006 T2M 0.33 0.95 4.42 0.082 

2014 T3M 0.29 0.95 3.98 0.072 

750 < hp ≤1200 Pre-2006 BaseM 0.22 0.95 6.67 0.16 0.367 

2006 T2M 0.33 0.95 4.42 0.082 

2013 T3M 0.29 0.95 3.98 0.072 

>1200 Pre-2009 BaseM 0.22 0.95 6.67 0.16 0.367 

2009 T2M 0.33 0.95 4.42 0.082 

2012 T3M 0.29 0.95 3.98 0.064 

20
 
Transient Adjustment Factors--HC, CO, NOx, PM, and BSFC 

Nonroad engines are primarily tested with steady-state tests. However, the steady-state 

operation typically used for emission testing is not always representative of the operation of 

engines in many nonroad applications. Some of the differences can be due to load or engine 

speed, and other differences can be due to transient demands. We will apply “transient 

adjustment factors” (“TAFs”) to the steady-state emission factors previously described. TAFs 

are applied to the Base, Tier 0, Tier 1, Tier 2, and Tier 3 emission factors. Transient emission 

control is expected to be an integral part of all Tier 4 engine design considerations. As a result, 

TAFs are not applied to the emission factors for Tier 4 engines (i.e., the model applies a TAF of 

1.0). 

We calculate the TAF as the ratio of the transient emission factor (EFtrans) to the 

corresponding steady-state (ISO-C1) emission factor (EFss): 

EF trans TAF = 

EF ss 

Transient adjustment factors may be greater than or less than 1.0. 

The derivation and application of the TAFs, including the test data used, are described in 

more detail in Appendix F. 

Table A3 presents the resulting TAFs assigned to each equipment application. The 

steady-state emission factors given in Table A2 were then multiplied by the appropriate TAFs to 

create NONROAD’s emission factor input files for CI engines. 

Deterioration Factors--HC, CO, NOx, and PM 

The NONROAD model addresses the effects of deterioration in the inventory calculation 

by multiplying a zero hour emission factor for each category of engine by a deterioration factor, 

DF (see equation 1 above). DF varies as a function of engine age. The following equation is 

used to calculate DF as a function of engine age: 

DF = 1 + A * (Age Factor)b for Age Factor £ 1 [Equation 4] 

DF = 1 + A for Age Factor > 1 

where: Age Factor = fraction of median life expended = (cumulative hours * load factor) 

median life at full load, in hours 

A, b = constants for a given pollutant/technology type; b£ 1. 

Deterioration is capped at the end of an engine’s median life (age factor =1), under the 

21
 
assumption that an engine deteriorates to a point where any increased deterioration is offset by 

maintenance. 

The constants A and b can be varied to approximate a wide range of deterioration 

patterns. “A” can be varied to reflect differences in maximum deterioration. For example, 

setting A equal to 2.0 would result in emissions at the engine’s median life being three times the 

emissions when new (DF = 1 + 2). The shape of the deterioration function is determined by the 

second constant, “b.” This constant can be set at any level between zero and 1.0. For 

compression-ignition engines, b is always equal to 1.0. This results in a linear deterioration 

pattern, in which the rate of deterioration is constant throughout the median life of an engine. 

Due to lack of deterioration data for nonroad compression-ignition engines, the 

deterioration factors are based on data derived from highway engines. The derivation of the 

constant “A” for compression-ignition engines is described in Appendix G and the resulting 

deterioration factors (i.e., the constants “A”) are given in Table A4. 

Sulfur Adjustment for PM Emissions (SPMadj) 

Since PM emissions are dependent on the sulfur content of the fuel, an adjustment (SPM 

adj) is subtracted from the PM emission factor to account for variations in fuel sulfur content (see 

equation 2 above). SPM adj corrects PM emissions from the default fuel sulfur level to the 

episodic fuel sulfur level and is calculated using the following equation: 

SPM adj = BSFC * 453.6 * 7.0 * soxcnv * 0.01 * (soxbas - soxdsl) [Equation 5] 

where: SPM adj = PM sulfur adjustment (g/hp-hr) 

BSFC = in-use adjusted brake-specific fuel consumption (lb fuel/hp-hr) 

453.6 = conversion from lb to grams 

7.0 = grams PM sulfate/grams PM sulfur 

soxcnv = grams PM sulfur/grams fuel sulfur consumed 

0.01= conversion from percent to fraction 

soxbas = default certification fuel sulfur weight percent 

soxdsl = episodic fuel sulfur weight percent (specified by user) 

The soxcnv term represents the fraction of diesel fuel sulfur converted to PM. This varies 

by technology type. Soxcnv is equal to 0.02247 for the Base, T0, T1, T2, T3, T3B, T4A, and 

T4B technology types. For Tier 4 engines meeting stringent PM standards below 0.1 g/hp-hr, 

soxcnv is equal to 0.30. This applies to the T4 and T4N technology types. If the soxcnv value 

for a technology type is not provided in the opt file, the default value used in the model is 

0.02247. Derivation of the soxcnv term is described in Appendix C. 

Values for the soxbas term vary by technology type and were discussed previously. If the 

soxbas value for a technology type is not provided in the opt file, the default value used in the 

model is 0.33 weight percent for diesel engines. 

22
 
The model also allows the user to input alternative default certification diesel fuel sulfur 

levels (soxbas) for Tier 2 and Tier 3 engines. This is a feature added to the opt file, but not 

available through the GUI; therefore, this feature can only be exercised by changing the opt file. 

Sample Calculation--EF adj 

The following example illustrates how emission factors are calculated in NONROAD. 

Example: Calculate the PM emission factor for a three year old 100-175 hp diesel excavator in 

2003. The episodic diesel fuel sulfur level is 2500 ppm. (In NONROAD, three year old 

equipment in 2003 translates to equipment made in model year 2001, since the calendar year of 

interest is assigned age =1 year). 

Needed inputs:	 For 100-175 hp, MY2001 = Tier 1 (from Table 1) 

100-175 hp, Tier 1 PM EFss = 0.2799 g/hp-hr (from Table A2) 

Excavator, Tier 1 PM TAF = 1.23 (from Table A3) 

Tier 1 PM Deterioration “A” = 0.473 (from Table A4) 

The deterioration factor, DF, is calculated as: 

DF = 1 + A*(cumulative hours * load factor) [Equation 4] 

median life at full load, in hours 

where:	 Diesel excavator activity = 1092 hours/year (from activity.dat input file) 

Diesel excavator load factor = 0.59 (from activity.dat input file) 

Diesel excavator median life = 4667 hours (from us.pop input file) 

Cumulative hours = age * activity = 3*1092 = 3276 hours 

Substituting the above values into the equation yields: 

DF = 1 + 0.473*(3276 * 0.59) = 1 + 0.473 * 0.414 = 1.196
 

4667
 

The sulfur adjustment factor, SPM adj, is calculated as: 

SPM adj = BSFC * 453.6 * 7.0 * soxcnv * 0.01 * (soxbas - soxdsl) [Equation 5] 

where: BSFC = 100-175 hp BSFCss * Excavator BSFC TAF = 0.367*1.01 = 0.371 

(BSFCss from Table A2 and BSFC TAF from Table A3) 

soxcnv = 0.02247 

soxbas = 0.3300 

23
 
soxdsl = 0.2500 

Substituting the values into the equation yields: 

SPM adj = 0.371* 453.6 * 7.0 * 0.02247 * 0.01 * (0.33 - 0.25) = 0.0212 g/hp-hr 

The resulting adjusted emission factor is calculated as follows: 

EF adj(PM) = EFss * TAF * DF - SPMadj
 

= (0.2799 * 1.23 * 1.196) - 0.0212
 

= 0.39 g/hp-hr
 

Emission Factors--CO2 and SO2 

Emission factors for CO2 and SO2 are rarely measured, instead they typically are 

calculated based on brake-specific fuel consumption (BSFC). 

The NONROAD model uses in-use adjusted BSFC to compute CO2 emissions directly, 

as shown in the equation below. The carbon that goes to exhaust HC emissions is subtracted as 

the correction for unburned fuel. This does not require a CO2 emission factors input file. 

CO2 = (BSFC * 453.6 - HC) * 0.87 * (44/12) [Equation 6] 

where 

CO2 is in g/hp-hr 

BSFC is the in-use adjusted fuel consumption in lb/hp-hr 

453.6 is the conversion factor from pounds to grams 

HC is the in-use adjusted hydrocarbon emissions in g/hp-hr 

0.87 is the carbon mass fraction of diesel
 

44/12 is the ratio of CO2 mass to carbon mass
 

The model does not require an SO2 emission factors input file either. EPA will calculate 

SO2 emission factors as shown in the equation below. 

SO2 = (BSFC * 453.6* (1 - soxcnv) - HC) * 0.01 * soxdsl * 2 [Equation 7] 

where 

SO2 is in g/hp-hr 

BSFC is the in-use adjusted fuel consumption in lb/hp-hr 

453.6 is the conversion factor from pounds to grams 

soxcnv is the fraction of fuel sulfur converted to direct PM 

HC is the in-use adjusted hydrocarbon emissions in g/hp-hr 

0.01 is the conversion factor from weight percent to weight fraction 

soxdsl is the episodic weight percent of sulfur in nonroad diesel fuel 

24
 
2 is the grams of SO2 formed from a gram of sulfur 

This equation includes corrections for the fraction of sulfur that is converted to direct PM 

and for the fraction of sulfur remaining in unburned fuel. This equation assumes that the 

unburned fuel, as indicated by HC emissions, has the same sulfur level as the base fuel. 

Note that BSFC for the pre-control (Tier 0) engines is used for all engines in the model. 

As a result, related emissions of CO2 and SO2 will change very little with the advent of new 

emission reduction technologies. Minor changes will result as HC emissions are changed, since 

the carbon that goes to exhaust HC is subtracted in the CO2 and SO2 equations. For diesel 

engines, this adjustment is insubstantial. 

Crankcase HC Emission Factors 

Crankcase emissions are those emissions that escape from the combustion chamber past 

the piston rings into the crankcase. For diesel engines with open crankcases, NONROAD 

assumes the crankcase HC emission factor is equal to 2.0% of the exhaust HC emission factor. 

This applies for all Tier 3 and prior engines. This estimate was obtained from NEVES [6], and is 

based on data from on-highway engines. These percentages are applied to the final calculated 

exhaust emission factors, so the resulting crankcase emission factors include the same percentage 

deterioration as used for exhaust HC. For Tier 4 engines, zero crankcase emissions are assumed. 

Crankcase emission factors for all fuel types are discussed in NR-012d, “Nonroad Evaporative 

Emission Rates.” 

PM2.5 Fraction of PM10 

The NONROAD PM emission factor files and PM model output include all PM. For 

diesel engines, all PM emissions are assumed to be smaller than 10 microns (PM10). The 

NONROAD Reporting Utility allows the user to select whether to report results for PM10 or 

PM2.5 (smaller than 2.5 microns). If PM2.5 is selected, an adjustment of 0.97 is applied to the 

PM10 output. This is an updated estimate, based on an analysis of size distribution data for diesel 

engines. [11] 

25
 
References 

[1] EPA, “Control of Air Pollution; Determination of Significance for Nonroad Sources and 

Emission Standards for New Nonroad Compression Ignition Engines At or Above 37 Kilowatts,” 

59 FR 31306, June 17, 1994. 

[2] EPA, “ Control of Emissions of Air Pollution From Nonroad Diesel Engines,” 63 FR 56967, 

October 23, 1998. 

[3] EPA, “Control of Emissions From Nonroad Large Spark-Ignition Engines and Recreational 

Engines (Marine and Land-Based); Final Rule,” 67 FR 68241, November 8, 2002. 

[4] EPA, “Control of Emissions of Air Pollution From Nonroad Diesel Engines and Fuel; Final 

Rule,” 69 FR 38958, June 29, 2004. 

[5] EPA, “Control of Emissions of Air Pollution From Locomotive Engines and Marine 

Compression-Ignition Engines Less Than 30 Liters per Cylinder; Republication,” (Final Rule), 

73 FR 37096, June 30, 2008. 

[6] EPA, “Nonroad Engine and Vehicle Emission Study” (NEVES), U.S. EPA, Office of Air 

and Radiation, 21A-2001. November, 1991. 

[7] EPA, “Suggested Nationwide Average Fuel Properties,” U.S. EPA, Office of Transportation 

and Air Quality, EPA-420-B-09-018, April 2009. 

[8] Korotney, David. “Estimates for In-Use Nonroad Diesel Fuel Levels,” Memorandum to 

Docket A-96-40. July 1, 1997. 

[9] EEA, “Documentation of Input Factors for the New Off-Road Mobile Source Emissions 

Inventory Model,” (“Inputs...”) Energy and Environmental Analysis, Inc. for California Air 

Resources Board. February, 1997. 

[10] EPA, “Final Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel 

Engines,” August, 1998. 

[11] Cantrell, Bruce. “Recommended Revision of the Fraction of Diesel Particulate Emissions 

Mass Less Than 2.5 Microns in Size,” Memorandum to Docket A-2001-28, Document IV-B-21. 

October 17, 2003. 

26
 
Appendix A 

CI Inputs for NONROAD2008a: 

Technology Distributions
 

Zero-Hour, Steady-State Emission Factors
 

Transient Adjustment Factors
 

Deterioration Factors
 

A1
 
Table A1. Nonroad CI Technology Distributions by HP Category and Model Yeara 

Engine Power 

(hp) Model Year 

Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 Tier 3 Tier 3B Tier 4A Tier 4B Tier 4 Tier 4N 

≤25 Pre-1988 1.000 

1988-1999 1.000 

2000-2001 0.200 0.800 

2002-2004 0.100 0.900 

2005 0.100 0.900 

2006-2007 1.000 

2008-2012 1.000 

2013+ 1.000 

>25 to 50 Pre-1988 1.000 

1988-1998 1.000 

1999-2000 0.200 0.800 

2001-2003 0.100 0.900 

2004 0.100 0.900 

2005-2007 1.000 

2008-2012 1.000 

2013+ 1.000 

>50 to 75 Pre-1998 1.000 

1988-1997 1.000 

1998-2003 1.000 

2004-2005 0.200 0.800 

2006-2007 0.100 0.900 

2008-2009 0.100 0.900 

2010-2012 1.000 

2013+ 1.000 

A2
 
Table A1. Nonroad CI Technology Distributions by HP Category and Model Year (cont.)a 

Engine Power 

(hp) Model Year 

Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 Tier 3 Tier 3B Tier 4A Tier 4B Tier 4 Tier 4N 

>75 to 100 Pre-1998 1.000 

1988-1997 1.000 

1998-2003 1.000 

2004-2005 0.200 0.800 

2006-2007 0.100 0.900 

2008-2009 0.100 0.900 

2010-2011 1.000 

2012-2013 0.500 0.500 

2014+ 1.000 

>100 to 175 Pre-1998 1.000 

1988-1996 1.000 

1997-2002 1.000 

2003-2004 0.200 0.800 

2005-2006 0.100 0.900 

2007-2008 0.100 0.900 

2009-2011 1.000 

2012-2013 0.500 0.500 

2014+ 1.000 

>175 to 300 Pre-1988 1.000 

1988-1995 1.000 

1996-2002 1.000 

2003-2004 0.200 0.800 

2005 0.100 0.900 

2006-2008 0.100 0.900 

2009-2010 1.000 

2011-2013 0.500 0.500 

2014+ 1.000 

A3
 
Table A1. Nonroad CI Technology Distributions by HP Category and Model Year (cont.)a 

Engine Power 

(hp) Model Year 

Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 Tier 3 Tier 3B Tier 4A Tier 4B Tier 4 Tier 4N 

>300 to 600 Pre-1988 1.000 

1988-1995 1.000 

1996-2000 1.000 

2001-2002 0.200 0.800 

2003-2005 0.100 0.900 

2006 0.100 0.900 

2007-2010 1.000 

2011-2013 0.500 0.500 

2014+ 1.000 

>600 to 750 Pre-1988 1.000 

1988-1995 1.000 

1996-2001 1.000 

2002-2003 0.200 0.800 

2004-2005 0.100 0.900 

2006-2007 0.100 0.900 

2008-2010 1.000 

2011-2013 0.500 0.500 

2014+ 1.000 

>750 Pre-1988 1.000 

1988-1999 1.000 

2000-2005 1.000 

2006-2007 0.300 0.700 

2008 0.200 0.800 

2009-2010 1.000 

2011-2014 1.000 

2015+ 1.000 

a Used in NONROAD2008a for all nonroad diesel equipment with the exception of recreational marine engines 

and underground mining equipment; these are presented in separate tables. The technology fractions are 

contained in the tech-exh.dat model file. Blank cells have a technology fraction of 0.000. 

b Base = pre-control, pre-1988 MY engines. Tier 0 = pre-control 1988+ MY engines prior to Tier 1. 

A4
 
Table A2. Recreational Marine CI Technology Distributions by HP Category and Model Yeara 

Engine Power 

(hp) 

Model Year Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 Tier 3 Tier 4c 

≤25 Pre-1988 1.000 

1988-1999 1.000 

2000 0.200 0.800 

2001-2004 0.100 0.900 

2005-2006 0.100 0.900 

2007-2008 1.000 

2009+ 1.000 

>25 to 50 Pre-1988 1.000 

1988-1998 1.000 

1999 0.200 0.800 

2000-2003 0.100 0.900 

2004-2005 0.100 0.900 

2006-2008 1.000 

2009-2013 1.000 

2014+ 1.000 

>50 to 100 Pre-2007 1.000 

2007-2008 1.000 

2009-2013 1.000 

2014+ 1.000 

>100 to 175 Pre-2006 1.000 

2006-2011 1.000 

2012+ 1.000 

>175 to 300 Pre-2006 1.000 

2006-2012 1.000 

2013+ 1.000 

>300 to 750 Pre-2006 1.000 

A5
 
c 

Table A2. Recreational Marine CI Technology Distributions by HP Category and Model Year (cont.)a 

Engine Power 

(hp) 

Model Year Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 Tier 3 Tier 4c 

2006-2013 1.000 

2014+ 1.000 

>750 to 1200 Pre-2006 1.000 

2006-2012 1.000 

2013+ 1.000 

>1200 Pre-2009 1.000 

2009-2011 1.000 

2012+ 1.000 

a The technology fractions are contained in the tech-exh.dat model file. Blank cells have a technology fraction 

of 0.000. 

b Base = pre-control, pre-1988 MY engines. Tier 0 = pre-control 1988+ MY engines prior to Tier 1. 

This source category is not subject to Tier 4 standards. Some horsepower categories are subject to two phases 

of the Tier 3 standard; the second phase is referred to as Tier 4. 

A6
 
Table A3. Underground Mining Equipment
 

Technology Distributions by HP Category and Model Yeara
 

Engine Power 

(hp) 

Model Year Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 

≤25 Pre-1988 1.000 

1988-1999 1.000 

2000-2001 1.000 

2002-2004 1.000 

2005 0.100 0.900 

2006+ 1.000 

>25 to 50 Pre-1988 1.000 

1988-1998 1.000 

1999-2000 1.000 

2001-2003 1.000 

2004 0.100 0.900 

2005+ 1.000 

>50 to 100 Pre-1988 1.000 

1988-1997 1.000 

1998-2003 1.000 

2004-2005 0.200 0.800 

2006-2007 0.100 0.900 

2008-2009 0.100 0.900 

2010+ 1.000 

>100 to 175 Pre-1988 1.000 

1988-1996 1.000 

1997-2002 1.000 

2003-2004 0.200 0.800 

2005-2006 0.100 0.900 

2007-2008 0.100 0.900 

A7
 
Table A3. Underground Mining Equipment
 

Technology Distributions by HP Category and Model Year (cont.)a
 

Engine Power 

(hp) 

Model Year Fraction of Population in Each Technology Type 

Baseb Tier 0b Tier 1 Tier 2 

2009+ 1.000 

>175 to 300 Pre-1988 1.000 

1988-1995 1.000 

1996-2002 1.000 

2003-2004 0.200 0.800 

2005 0.100 0.900 

2006-2008 0.100 0.900 

2009+ 1.000 

>300 to 600 Pre-1988 1.000 

1988-1995 1.000 

1996-2000 1.000 

2001-2002 0.200 0.800 

2003-2005 0.100 0.900 

2006 0.100 0.900 

2007+ 1.000 

>600 to 750 Pre-1988 1.000 

1988-1995 1.000 

1996-2001 1.000 

2002-2003 0.200 0.800 

2004-2005 0.100 0.900 

2006-2007 0.100 0.900 

2008+ 1.000 

>750 Pre-1988 1.000 

1988-1999 1.000 

2000-2005 1.000 

2006-2007 0.300 0.700 

2008 0.200 0.800 

2009+ 1.000 

a The technology fractions are contained in the tech-exh.dat model file. Blank cells have a technology fraction 

of 0.000. 

b Base = pre-control, pre-1988 MY engines. Tier 0 = pre-control 1988+ MY engines prior to Tier 1. 

A8 
Table A4. Zero-Hour, Steady-State Emission Factors for Nonroad CI Enginesa 

Engine 

Power (hp) 

Technology 

Type 

BSFC 

(lb/hp-hr) 

Emission Factors (g/hp-hr) 

HC CO NOx PM 

>0 to 11 Base 0.408b 1.5 5.0 10.0 1.0 

Tier 0 1.5 5.0 10.0 1.0 

Tier 1 0.7628 4.1127 5.2298 0.4474 

Tier 2 0.5508 4.1127 4.3 0.50 

Tier 4A 0.5508 4.1127 4.3 0.28 

Tier 4B 0.5508 4.1127 4.3 0.28 

>11 to 16 Base 0.408 1.7 5.0 8.5 0.9 

Tier 0 1.7 5.0 8.5 0.9 

Tier 1 0.4380 2.1610 4.4399 0.2665 

Tier 2 0.4380 2.1610 4.4399 0.2665 

Tier 4A 0.4380 2.1610 4.4399 0.28 

Tier 4B 0.4380 2.1610 4.4399 0.28 

>16 to 25 Base 0.408 1.7 5.0 8.5 0.9 

Tier 0 1.7 5.0 8.5 0.9 

Tier 1 0.4380 2.1610 4.4399 0.2665 

Tier 2 0.4380 2.1610 4.4399 0.2665 

Tier 4A 0.4380 2.1610 4.4399 0.28 

Tier 4B 0.4380 2.1610 4.4399 0.28 

>25 to 50 Base 0.408 1.8 5.0 6.9 0.8 

Tier 0 1.8 5.0 6.9 0.8 

Tier 1 0.2789 1.5323 4.7279 0.3389 

Tier 2 0.2789 1.5323 4.7279 0.3389 

Tier 4A 0.2789 1.5323 4.7279 0.20 

Tier 4 0.1314 0.153 3.0000 0.0184 

>50 to 75 Base 0.408 Vary by application, see NEVES 

Tier 0 0.99 3.49 6.9 0.722 

Tier 1 0.5213 2.3655 5.5988 0.4730 

Tier 2 0.3672 2.3655 4.7 0.24 

Tier 4A 0.1836 2.3655 3.0 0.20 

Tier 4 0.1314 0.237 3.00 0.0184 

A9
 
Table A4. Zero-Hour, Steady-State Emission Factors for Nonroad CI Engines (cont.)a 

Engine 

Power (hp) 

Technology 

Type 

BSFC 

(lb/hp-hr) 

Emission Factors (g/hp-hr) 

HC CO NOx PM 

>75 to 100 Base 0.408 Vary by application, see NEVES 

Tier 0 0.99 3.49 6.9 0.722 

Tier 1 0.5213 2.3655 5.5988 0.4730 

Tier 2 0.3672 2.3655 4.7 0.24 

Tier 3B 0.1836 2.3655 3.0 0.20 

Tier 4 0.1314 0.237 3.00 0.0092 

Tier 4N 0.1314 0.237 0.276 0.0092 

>100 to 175 Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.3384 0.8667 5.6523 0.2799 

Tier 2 0.3384 0.8667 4.1 0.18 

Tier 3 0.1836 0.8667 2.5 0.22 

Tier 4 0.1314 0.087 2.50 0.0092 

Tier 4N 0.1314 0.087 0.2760.402 0.0092 

>175 to 300 Base 0.367 Vary by application, see NE0.2799VES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.3085 0.7475 5.5772 0.2521 

Tier 2 0.3085 0.7475 4.0 0.1316 

Tier 3 0.1836 0.7475 2.5 0.15 

Tier 4 0.1314 0.075 2.50 0.0092 

Tier 4N 0.1314 0.075 0.276 0.0092 

>300 to 600 Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.2025 1.3060 6.0153 0.2008 

Tier 2 0.1669 0.8425 4.3351 0.1316 

Tier 3 0.1669 0.8425 2.5 0.15 

Tier 4 0.1314 0.084 2.50 0.0092 

Tier 4N 0.1314 0.084 0.276 0.0092 

>600 to 750 Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.1473 1.3272 5.8215 0.2201 

A10
 
Table A4. Zero-Hour, Steady-State Emission Factors for Nonroad CI Engines (cont.)a 

Engine 

Power (hp) 

Technology 

Type 

BSFC 

(lb/hp-hr) 

Emission Factors (g/hp-hr) 

HC CO NOx PM 

Tier 2 0.1669 1.3272 4.1 0.1316 

Tier 3 0.1669 1.3272 2.5 0.15 

Tier 4 0.1314 0.133 2.50 0.0092 

Tier 4N 0.1314 0.133 0.276 0.0092 

>750 except 

generator 

sets 

Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.2861 0.7642 6.1525 0.1934 

Tier 2 0.1669 0.7642 4.1 0.1316 

Tier 4 0.2815 0.7642 2.392 0.069 

Tier 4N 0.1314 0.076 2.392 0.0276 

Gen sets 

>750 to 1200 

Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.2861 0.7642 6.1525 0.1934 

Tier 2 0.1669 0.7642 4.1 0.1316 

Tier 4 0.2815 0.7642 2.392 0.069 

Tier 4N 0.1314 0.076 0.460 0.0184 

Gen sets 

>1200 

Base 0.367 Vary by application, see NEVES 

Tier 0 0.68 2.70 8.38 0.402 

Tier 1 0.2861 0.7642 6.1525 0.1934 

Tier 2 0.1669 0.7642 4.1 0.1316 

Tier 4 0.2815 0.7642 0.460 0.069 

Tier 4N 0.1314 0.076 0.460 0.0184 

a

Prior to listing in NONROAD input files, these ISO-C1 emission factors are adjusted for in-use operation as explained in 

Appendix F. The emission factors in the input files are rounded to two decimal places. The emission factors for 

recreational marine CI engines are provided in Table 10. Underground mining equipment inputs are just the Base (NEVES) 

and Tier 2 values from this table. 

b

BSFC for engines <50 hp is assumed to be the same as 50-100 hp engines 

A11
 
Table A5. Transient Adjustment Factors by Equipment Type for Nonroad CI Equipment a 

SCC Equipment Type Cycle TAF 

Assignment 

HC CO NOx PM BSFC 

Base-T3 Base-T3 Base, T0-T2 Tier 3 Base, T0-T2 Tier 3 Base-T3 

2270001000 Recreational Vehicles All Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270001020 Recreational Vehicles Snowmobiles None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270001030 Recreational Vehicles All Terrain Vehicles None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270001040 Recreational Vehicles Minibikes None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270001050 Recreational Vehicles Golf Carts None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270001060 Recreational Vehicles Speciality Vehicle Carts Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270002003 Construction Equipment Pavers Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002006 Construction Equipment Tampers/Rammers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002009 Construction Equipment Plate Compactors None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002015 Construction Equipment Rollers Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002018 Construction Equipment Scrapers Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002021 Construction Equipment Paving Equipment Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002024 Construction Equipment Surfacing Equipment Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002027 Construction Equipment Signal Boards None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002030 Construction Equipment Trenchers Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002033 Construction Equipment Bore/Drill Rigs None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002036 Construction Equipment Excavators Excavator Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002039 Construction Equipment Concrete/Industrial Saws Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002042 Construction Equipment Cement & Mortar Mixers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002045 Construction Equipment Cranes None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002048 Construction Equipment Graders Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002051 Construction Equipment Off-highway Trucks Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002054 Construction Equipment Crushing/Proc. Equipment None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270002057 Construction Equipment Rough Terrain Forklifts RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002060 Construction Equipment Rubber Tire Loaders RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002063 Construction Equipment Rubber Tire Dozers Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002066 Construction Equipment 

Tractors/Loaders/Backhoes 

Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270002069 Construction Equipment Crawler Dozer Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002072 Construction Equipment Skid Steer Loaders SSLoader Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270002075 Construction Equipment Off-Highway Tractors Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270002078 Construction Equipment Dumpers/Tenders Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270002081 Construction Equipment Other Construction Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

A12
 
Table A5. Transient Adjustment Factors by Equipment Type for Nonroad CI Equipment a 

SCC Equipment Type Cycle TAF 

Assignment 

HC CO NOx PM BSFC 

Base-T3 Base-T3 Base, T0-T2 Tier 3 Base, T0-T2 Tier 3 Base-T3 

Equipment 

2270003010 Industrial Equipment Aerial Lifts Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270003020 Industrial Equipment Forklifts RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270003030 Industrial Equipment Sweepers/Scrubbers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270003040 Industrial Equipment Other General Industrial 

Equipment 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270003050 Industrial Equipment Other Material Handling 

Equipment 

Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270003060 Industrial Equipment AC\Refrigeration None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270003070 Terminal Tractors Crawler Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270004000 Lawn & Garden Equipment ALL None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004010 Lawn & Garden Equipment Lawn mowers 

(Residential) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004011 Lawn & Garden Equipment Lawn mowers 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004015 Lawn & Garden Equipment Rotary Tillers < 6 HP None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004016 Lawn & Garden Equipment Rotary Tillers < 6 HP 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004020 Lawn & Garden Equipment Chain Saws < 6 HP None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004021 Lawn & Garden Equipment Chain Saws < 6 HP 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004025 Lawn & Garden Equipment Trimmers/Edgers/Brush 

Cutters 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004026 Lawn & Garden Equipment Trimmers/Edgers/Brush 

Cutters (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004030 Lawn & Garden Equipment Leafblowers/Vacuums None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004031 Lawn & Garden Equipment Leafblowers/Vacuums 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004035 Lawn & Garden Equipment Snowblowers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004036 Lawn & Garden Equipment Snowblowers 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004040 Lawn & Garden Equipment Rear Engine Riding 

Mowers 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004041 Lawn & Garden Equipment Rear Engine Riding 

Mowers (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004045 Lawn & Garden Equipment Front Mowers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

A13
 
Table A5. Transient Adjustment Factors by Equipment Type for Nonroad CI Equipment a 

SCC Equipment Type Cycle TAF 

Assignment 

HC CO NOx PM BSFC 

Base-T3 Base-T3 Base, T0-T2 Tier 3 Base, T0-T2 Tier 3 Base-T3 

2270004046 Lawn & Garden Equipment Front Mowers 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004050 Lawn & Garden Equipment Shredders < 6 HP None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004051 Lawn & Garden Equipment Shredders < 6 HP 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004055 Lawn & Garden Equipment Lawn & Garden 

Tractors 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004056 Lawn & Garden Equipment Lawn & Garden 

Tractors (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004060 Lawn & Garden Equipment Wood Splitters None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004061 Lawn & Garden Equipment Wood Splitters 

(Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004065 Lawn & Garden Equipment Chippers/Stump 

Grinders 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004066 Lawn & Garden Equipment Chippers/Stump 

Grinders (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004071 Lawn & Garden Equipment Commercial Turf 

Equipment (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004075 Lawn & Garden Equipment Other Lawn & Garden 

Equipment 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270004076 Lawn & Garden Equipment Other Lawn & Garden 

Equipment (Commercial) 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270005010 Farm Equipment 2-Wheel Tractors AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005015 Farm Equipment Agricultural Tractors AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005020 Farm Equipment Combines AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005025 Farm Equipment Balers AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005030 Farm Equipment Agricultural Mowers AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005035 Farm Equipment Sprayers AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005040 Farm Equipment Tillers > 6 HP AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005045 Farm Equipment Swathers AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005050 Farm Equipment Hydro Power Units None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270005055 Farm Equipment Other Agricultural Equipment AgTractor Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270005060 Farm Equipment Irrigation Sets None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270006000 Light Commercial ALL None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270006005 Light Commercial Generator Sets None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

A14
 
Table A5. Transient Adjustment Factors by Equipment Type for Nonroad CI Equipment a 

SCC Equipment Type Cycle TAF 

Assignment 

HC CO NOx PM BSFC 

Base-T3 Base-T3 Base, T0-T2 Tier 3 Base, T0-T2 Tier 3 Base-T3 

2270006010 Light Commercial Pumps None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270006015 Light Commercial Air Compressors None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270006020 Light Commercial Gas Compressors None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270006025 Light Commercial Welders ArcWelder Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270006030 Light Commercial Pressure Washers None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2270007005 Logging Equipment Chain Saws > 6 HP RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270007010 Logging Equipment Shredders > 6 HP RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270007015 Logging Equipment Forest Equipment RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270008005 Airport Service Equipment Airport Support 

Equipment 

RTLoader Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

2270009010 Other Underground Mining Equipment Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

2270010010 Other Oil Field Equipment None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2282020005 Recreational Pleasure Craft, Inboards None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2282020010 Recreational Pleasure Craft, Outboards None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2282020015 Recreational Pleasure Craft, Personal Water Craft None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2282020025 Recreational Pleasure Craft, Sailboat Aux. 

Outboard 

None None 1.00 1.00 1.00 1.00 1.00 1.00 1.00 

2285002015 Railway Maintenance Backhoe Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

a TAFs are not applied to the emission factors for Tier 4 engines (i.e., the model applies a TAF of 1.0). “Base-T3” in this table refers to Tier 3 and prior engines. 

A15
 
Table A6. Deterioration Factors for Nonroad Diesel Engines 

Pollutant 

Relative Deterioration Factor (A) 

(% increase/%useful life) 

Base/Tier 0 Tier 1 Tier 2 Tier 3+ 

HC 0.047 0.036 0.034 0.027 

CO 0.185 0.101 0.101 0.151 

NOx 0.024 0.024 0.009 0.008 

PM 0.473 0.473 0.473 0.473 

DF =1+A*(fraction of useful life expended)B 

B = 1 for diesel nonroad engines 

A16
 
Appendix B
 

Sources of Previous Emission Factors for
 

Nonroad Compression Ignition Engines
 

There is little test data available on nonroad engines. Table B1 lists the data sources used 

for EPA’s Nonroad Engine and Vehicle Study’s (NEVES) diesel emission factors. Published in 

November, 1991, NEVES was mandated by Congress to determine whether nonroad sources 

made a significant contribution to urban air pollution. It covers HC, CO, NOx, PM, SOx and 

other pollutants. It provides inventories for 19 ozone and 16 CO nonattainment areas. 

Table B1. Data sources for NEVES Diesel Emission Factors 

Application Emissions Test 

Data Source 

Notes 

Lawn and Garden and 

Light Commercial 

None NEVES emission factors 

were based on factors for 

“continuous service diesel < 

50 hp” SwRI, 1991, which 

are based on Radian, 1988 

factors for truck/container 

refrigeration units. 

Agriculture Cal/ERT, 1982 

Construction EMA 

SwRI, 1973 

Cal/ERT, 1982 

NEVES emission factors 

were based on EMA when 

possible. For PM and for 

applications not available 

from EMA, factors were 

taken from AP-42, which 

relies on Cal/ERT for most 

emission factors and on 

SwRI, 1973 for PM and 

SOx. 

Logging (skidders) EMA 

Industrial and 

Airport Service Equipment 

SwRI, 1973 

Recreational Marine 

(Inboard) 

NMMA 

B1
 
Table B2 lists the data sources used for California’s Air Resources Board (ARB) 

OFFROAD diesel emission factors. OFFROAD is designed to estimate nonroad emissions for 

the state of California only. A version of this model was released in late summer 1997. It covers 

HC, CO, NOx, PM, SO2, and CO2. The studies listed in the tables are described below. 

Table B2. Data sources for ARB OFFROAD Diesel Emission Factors 

Horsepower Class Emissions Test 

Data Source 

Notes 

0-15 hp Manufacturers’ data-­

2 Yanmar engines 

1 Deutz engine 

15-25 hp Manufacturers (ARB OffRoad Equipment Study, 

1990) 

25-50 hp Manufacturers Submissions 

(ARB Off-Road Equipment 

Study, 1990 ) 

50-125 hp Manufacturers (CA HD 

Construction Study, 1988) 

125-250 

250+ 

Manufacturers (CA HD 

Construction Study, 1988) 

ARB factors on all engines 

from 125 hp and above are 

based on the same data, but 

the weighting between turbocharged and naturally 

aspirated engines is different 

in the two horsepower 

categories listed here. 

Description and Citations of Sources used for Previous Emission Factors 

Radian, 1988. Radian’s estimates of HC, CO, NOx and PM for truck/container refrigeration units 

are not based on testing, but on Radian’s estimates for “typical small direct injection and indirect 

injection diesel engines.” (Weaver, C.S., “Feasibility and Cost Effectiveness of Controlling 

Emissions from Diesel Engines in Rail, Marine, Construction, Farm and Other Mobile OffHighway Equipment.” Final Report by Radian Corporation for U.S. EPA, Office of Policy 

Analysis, under contract 68-01-7288, February, 1988.) 

B2
 
SwRI, 1973. Southwest Research Institute tested 8 diesel engines for HC, CO, NOx and PM. 

Emissions of SOx were calculated for no. 2 diesel fuel assuming sulfur content of 0.22%. BSFC 

is not stated. The emissions tests were given different weightings to estimate industrial, 

construction and farm equipment emission factors. (Hare, C.T and K.J. Springer. Exhaust 

Emission from Uncontrolled Vehicles and Related Equipment Using Internal Combustion 

Engines, Final Report, Part 5, Heavy Duty Farm, Construction and Agricultural Engines. San 

Antonio TX: Southwest Research Institute, October 1973.) 

EMA. Emission factors for 17 applications based on unknown number of tests, unknown 

horsepower engines. Engine vintage unknown, but data was submitted by the Engine 

Manufacturers Association to EPA prior to NEVES (1991). (Listed in NEVES table I-06.) 

Cal/ERT, 1982. Data from 13 engine manufacturers representing 391 models of construction 

equipment. Raw data was aggregated by an accounting firm prior to analysis and reporting. 

(Environmental Research and Technology, Inc. “Feasibility, Cost and Air Quality Impact of 

Potential Emission Control Requirements on Farm, Construction and Industrial Equipment in 

California”, Document PA841, sponsored by the Farm and Industrial Equipment Institute, 

Engine Manufacturers Association, and Construction Industry Manufacturers Association, May 

1982.) 

NMMA. The National Marine Manufacturers Association submitted data to EPA on HC, CO, 

NOx and BSFC for 3 diesel inboard motors. Engine vintage unknown, but data was submitted to 

EPA prior to NEVES (1991). (NEVES, Table I-11(e).) 

ARB Off-Road Study, 1990. A study of lawn and garden and utility emissions. (Manufacturer 

Submissions to ARB on Exhaust Emission Standards for Utility and Lawn and Garden 

Equipment Engines. California ARB, October 1990. EPA requests assistance in locating this 

study) 

ARB Heavy Duty Construction Study, 1988.1 Reports HC, NOx and PM emission factors based 

on emission information from four manufacturers. Does not include information on test 

programs. It is not clear how data collected in the study was used to create the inputs for the 

ARB model. (Energy and Environment Analysis, Inc. “ Feasibility of Controlling Emissions 

from Off-Road, Heavy-Duty Construction Equipment.” Final Report to the California Air 

Resources Board. Arlington, VA, December 1988.) 

B3
 
Appendix C
 

1988-1995 (Tier 0) Zero-Hour, Steady-State Emission Factors and
 

Fuel Sulfur Adjustment for Nonroad Compression Ignition Engines
 

Introduction 

EPA’s 1991 Nonroad Engine and Vehicle Emission Study (NEVES) (1) used emission 

factors for diesel engines based primarily on tests of older engines. All the NEVES particulate 

matter (PM) emission factors are from tests conducted in 1972 and many of the other emissions 

factors in NEVES are based on data from tests prior to 1982. 

To better characterize emissions from more recent, pre-control engines, EPA analyzed 

available emission test data on 1988-1995 nonroad diesel engines. This analysis provides the 

basis for NONROAD pre-control emission factors for 1988-and-later engines greater than 50 hp, 

as described in the main body of this report. The analysis indicated a significant difference in 

emissions based on engine power. Engines between 50 and 100 horsepower in general had 

higher emissions and fuel consumption than engines larger than 100 horsepower. Table C1 

summarizes these results. 

Table C1. Average Emission Test Results for 1988 to 1995 Model Year Engines 

Engine 

(Reference) 

HC 

(g/hp-hr) 

CO 

(g/hp-hr) 

NOx 

(g/hp-hr) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

Average (50 

to 100 hp) 

0.99 3.49 8.30 0.722 0.408 

Average 

(>=100 hp) 

0.68 2.70 8.38 0.402 0.367 

A summary of test results for individual engines is presented in Table C2. Note that 

testing was conducted using the current certification test procedure, also known as ISO-C1. The 

procedure uses eight steady-state modes weighted by time to produce one number in units such 

as grams per horsepower-hour. EPA adjusted this test data to account for differences between 

the test fuel and typical in-use fuel sulfur levels of 0.33 wt. percent as explained below. 

C1
 
Table C2. Summary of ISO-C1 Emission Results for 1988 through 1995 Engines 

7076 (7) 

Engine 

(Reference) 

Model 

Year 

Age 

(Hrs) 

Fuel 

Sulfur 

(wt. %) 

Power 

Level 

(hp) 

HC 

(g/hp-hr) 

CO 

(g/hp-hr) 

NOx 

(g/hp-hr) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

Ford New 

Holland (2) 

1991 0 0.26 127 1.02 7.70 7.48 1.10 0.358 

John Deere 

7068T (2) 

1990 0 0.26 139 0.45 2.98 11.74 0.41 0.349 

Volvo TD 

71G (avg. of 

2) (3) 

1984 0 0.046 144 0.47 1.64 12.68 0.149 0.373 

Volvo TD73 

KBE (avg. of 

2) (3) 

1992 0 0.046 139 0.64 0.85 4.52 0.12 0.386 

Weterbeke 

32BEDA (4) 

1995 0 0.033 95 1.95 7.43 7.99 1.50 0.484 

Caterpillar 

3176B (4) 

1995 0 0.033 451 0.09 2.94 6.37 0.213 0.358 

Cummins 

KTA19-M3 

(4) 

1995 0 0.033 599 0.68 3.26 8.78 0.257 0.359 

Caterpillar 

3306 

(Nonroad) (5) 

1990 0 0.26 285 1.1 1.4 6.5 0.18 0.354 

Cummins 4BT 

(Nonroad) (5) 

1990 0 0.26 100 0.8 2.1 11 0.39 0.365 

John Deere 

4039D (6) 

1991 0 0.25 72 0.6 3.5 7.2 0.59 0.385 

Caterpillar 

3116 (7) 

1991 2,511 0.28 201 0.07 2.51 9.38 0.406 0.352 

0.035 0.350 

Caterpillar 

3054 (7) 

1991 1,964 0.28 85 0.66 1.00 7.53 0.387 0.393 

0.035 0.340 

John Deere 

4039 (7) 

1994 2,265 0.28 86 0.41 2.17 11.22 0.384 0.389 

0.035 0.256 

John Deere 1993 3,300 0.28 174 0.53 2.05 10.22 0.250 0.385 

C2
 
Engine 

(Reference) 

Model 

Year 

Age 

(Hrs) 

Fuel 

Sulfur 

(wt. %) 

Power 

Level 

(hp) 

HC 

(g/hp-hr) 

CO 

(g/hp-hr) 

NOx 

(g/hp-hr) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

0.035 0.205 

Consolidated 

Diesel 

6TA-830 (7) 

1990 4,370 0.28 226 0.86 1.50 6.53 0.397 0.365 

0.035 0.338 

John Deere 

6619 (7) 

1993 4,970 0.28 275 0.82 4.69 7.29 0.662 0.397 

0.035 0.556 

Consolidated 

Diesel 4039 

(7) 

1988 3,570 0.28 71 1.32 3.37 7.57 0.581 0.389 

0.035 0.484 

Caterpillar 

3306 (7) 

1990 6,700 0.28 278 1.27 1.46 6.52 0.248 0.373 

0.035 0.245 

Average 

(50 to 100 hp) 

0.33 0.99 3.49 8.30 0.722* 0.408 

Average 

(>=100 hp) 

0.33 0.68 2.70 8.38 0.402* 0.367 

* Adjusted to the national average fuel sulfur level of 0.33 weight percent 

Fuel Sulfur Adjustment 

PM emissions from diesel engines are highly dependent on the sulfur content of the fuel 

the engine is burning. PM emissions from diesel engines are generally comprised of unburned or 

partially burned fuel, engine oil, and sulfur compounds. When the engine burns fuel, the fuel 

sulfur is oxidized to both sulfur dioxide and sulfur trioxide. The sulfur trioxide rapidly absorbs 

water to form hydrated sulfuric acid which condenses and is collected on filters as particulate 

matter (PM) during emission testing. 

Because the sulfur content of diesel fuel can vary considerably, it is important to account 

for fuel sulfur in establishing emission factors for PM. To adjust emission test data to the default 

sulfur level used in NONROAD (0.33 wt. percent), EPA followed the approach described below. 

EPA measured particulate emissions from nine nonroad diesel engines using fuel with 

two different sulfur levels, a typical highway diesel fuel at a sulfur level of 0.035 weight percent 

and a typical nonroad diesel fuel doped to a sulfur level of 0.28 weight percent to simulate more 

closely the average nonroad diesel fuel sulfur level of 0.33 weight percent. (8) Data from eight 

of the engines is listed in Table C2, above. In addition, the study included a 1997 John Deere 

nonroad engine. This engine is not shown in Table C2 because it is certified for the Tier 1 

C3
 
emission regulations and should not be used to determine an overall emission factor for precontrol engines. Test results from this study (including all 9 engines tested) were used to 

determine the emission adjustment associated with fuel sulfur level. Other fuel parameter 

differences such as cetane and fuel distillation that might also have affected particulate emissions 

were ignored for this analysis. 

The study found that emissions of all pollutants were reduced by using highway fuel as 

compared to the nonroad fuel; however, only the average PM reduction was statistically 

significant at the 90% confidence level. 

The particulate sulfur emission rate should be proportional to the fuel consumption and 

the fuel sulfur level. By dividing the difference in particulate emissions by the difference in fuel 

sulfur consumption, EPA calculated the average effect of fuel sulfur levels on PM emissions for 

the nine engines, as shown in Table C3 below. 

Table C3. Effects of Fuel Sulfur on PM Emissions 

Engine 

MY 

Fuel Sulfur 

(wt percent) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

Delta 

PM 

(g/hp-hr) 

Delta Fuel 

Sulfur 

Consumed* 

(g/hp-hr) 

Delta PM 

/ Delta 

Sulfur 

Cat 3116 

Cat 3116 

1991 

1991 

0.280 

0.035 

0.406 

0.350 

0.352 

0.352 

0.056 0.391 0.143 

Cat 3054 

Cat 3054 

1991 

1991 

0.280 

0.035 

0.387 

0.340 

0.393 

0.393 

0.047 0.437 0.107 

Deere 4039 

Deere 4039 

1994 

1994 

0.280 

0.035 

0.384 

0.256 

0.389 

0.389 

0.128 0.432 0.296 

Deere 7076 

Deere 7076 

1993 

1993 

0.280 

0.035 

0.250 

0.205 

0.385 

0.385 

0.045 0.428 0.105 

ConDsl 6TA-830 

ConDsl 6TA-830 

1990 

1990 

0.280 

0.035 

0.397 

0.338 

0.365 

0.365 

0.059 0.405 0.146 

Deere 6619 

Deere 6619 

1993 

1993 

0.280 

0.035 

0.662 

0.556 

0.397 

0.397 

0.106 0.441 0.240 

Con Dsl 4039 

Con Dsl 4039 

1988 

1988 

0.280 

0.035 

0.581 

0.484 

0.389 

0.389 

0.097 0.432 0.225 

Cat 3306 

Cat 3306 

1990 

1990 

0.280 

0.035 

0.248 

0.245 

0.373 

0.373 

0.003 0.415 0.007 

Deere 6101 

Deere 6101 

1997 

1997 

0.280 

0.035 

0.186 

0.129 

0.350 

0.350 

0.057 0.389 0.147 

Average: 0.1573 

* Delta fuel sulfur consumed (g S/hp-hr) = 0.01*(0.280-0.035)*BSFC*453.6 g/lb 

C4
 
The value of 0.1573 is the average change in PM emissions per change in grams of fuel 

sulfur consumed. The change in PM emissions would be due to PM sulfate, so this can also be 

expressed as the change in PM sulfate emissions per change in grams of fuel sulfur consumed. 

We assume that PM sulfate is H2SO4:7H20 (sulfuric acid hydrated seven times). For PM 

sulfate, there is 7.0 grams sulfate per gram sulfur. Therefore, 0.1573 ‚7 = 0.02247 grams PM 

sulfur per gram fuel sulfur consumed, which is the fraction of fuel sulfur converted to PM. In the 

NONROAD model, the change in PM emissions per change in grams of fuel sulfur consumed is 

expressed as the term, “soxcnv * 7,” where soxcnv is the fraction of fuel sulfur converted to PM 

and 7 is the grams sulfate PM per gram sulfur. Soxcnv is equal to 0.02247 and soxcnv * 7 is 

equal to 0.157 for diesel equipment not equipped with advanced oxidation catalyst technologies. 

This applies to the Base, Tier 0, Tier 1, Tier 2, Tier 3, Tier 3B, Tier 4A, and Tier 4B technology 

types in NONROAD. 

Consistent with our analysis in the Heavy-Duty (HD) 2007 highway rule, we have 

assumed that the conversion of fuel sulfur to sulfate emissions for engines equipped with 

advanced oxidation catalyst technologies (e.g., catalyzed diesel particulate filters) will be 30 

percent. As a result, soxcnv is equal to 0.30 for the Tier 4 and Tier 4N technology types in 

NONROAD. The balance (70 percent) of the fuel sulfur is assumed to be emitted as SO2. The 

memo to EPA Air Docket A-99-06 Item II-B-32 documents the analysis from the HD 2007 

rulemaking. Extensive discussion of diesel fuel sulfur oxidation to sulfate PM can be found in 

Chapter 3 of the HD 2007 Final Regulatory Impact Analysis (RIA) and in Chapter 4 of the 

nonroad Tier 4 RIA. The 30 percent conversion of fuel sulfur to sulfate represents an assumed 

average rate; sulfur conversion rates can vary widely depending upon operating conditions and 

catalyst technology. 

The above analysis of engine test data provided the constant “A” in the equation below, 

which describes the adjustment made to correct PM emissions from the test fuel sulfur level to 

the default sulfur level of 0.33 weight percent. 

PMBase = PM + BSFC * A * (0.0033 - Fuel Sulfur) 

where 

PMBase = PM emissions with default fuel, in g/hp-hr 

PM = PM emissions with test fuel, in g/hp-hr 

BSFC = Brake Specific Fuel Consumption in g/hp-hr 

A = 0.157 g PM/hp-hr/Weight Fraction sulfur/BSFC 

0.0033= the default weight fraction of fuel sulfur for nonroad diesel 

Fuel Sulfur = Weight Fraction of sulfur in test fuel 

EPA then used this equation for all tests listed in Table C2 to correct PM emissions from 

the test-fuel sulfur level to a fuel sulfur level of 0.33 wt.% before computing the averages listed 

in Table C1 and at the bottom of Table C2. Since the engines tested are pre-Tier 4 technologies, 

the constant “A” value of 0.157 was used in the equation. 

C5
 
References 

(1)“Nonroad Engine and Vehicle Emission Study” (NEVES), U.S. EPA, Office of Air and 

Radiation, 21A-2001. November, 1991. 

(2) Doorlag, M. and M. Samulski. “Heavy-Duty Engine Testing Report: Non-Road Engine 

Configurations, Test Results 1991" EPA Technical Report, 1991. 

(3) Hedbom, A. “Emission tests of two Volvo//VME Heavy Duty Off Road Engines.” 

Motortestcenter, Hanige, Sweden. MTC 9307A. March. 1994. 

(4) Carroll, J.N. and C. M. Urban. “Emission Testing of Nonroad Compression Ignition 

Engines.” Draft Final Report. Southwest Research Institute, 6886-802. September 1995. 

(5) Fritz, S. G., “Dynamometer Testing of Heavy-Duty Diesel Engines to Support 

Non-Road Regulations,” SwRI Report No. 08-3426-010, Work Assignment 0-10 of 

EPA Contract No. 68-C0-0014 (September 1991). 

(6) Smith, Michael. “Dynamometer Testing of Nonroad Diesel Engines to Support Nonroad 

Regulations.” Southwest Research Institute, 08-4855-150, EPA Docket A-91-24, June 1992. 

(7) Fritz, S. G. and M.E. Starr, “Emission Factors for Compression Ignition Nonroad Engines 

Operated on Number 2 Highway and Nonroad Diesel Fuel,” Southwest Research Institute. EPA 

contract # 68-C5-0077, SwRI 08-7601-822, March 1998. 

(8) Korotney, David. “Estimates for In-Use Nonroad Diesel Fuel Levels,” Memorandum to 

Docket A-96-40. July 1, 1997. 

C6
 
Appendix D
 

Certification Data for Nonroad Compression Ignition Engines
 

Certification data were available and therefore used to develop zero-mile, steady-state 

emission factors for Tier 1 engines in all hp categories and Tier 2 engines in the >300 to 600 hp 

category. Certification data were extracted from the database as of October, 2001. Official test 

results (OTR values) obtained with the nonroad 8-mode test procedure were used. Note that 

emissions for some engines exceed the applicable standards if the engine families are part of the 

Average Banking and Trading (ABT) program. 

Tests were conducted with fuel meeting either diesel nonroad or diesel on-highway 

specifications. For tests conducted on the Tier 1 engines with diesel on-highway fuel, the PM 

emissions were adjusted from 350 ppm to 3300 ppm sulfur (the default diesel sulfur level used in 

NONROAD), using the equation described in Appendix C. For tests conducted on the Tier 2 

engines with diesel on-highway fuel, the PM emissions were adjusted from 350 ppm to 2000 

ppm. An estimate of brake-specific fuel consumption is required to calculate the adjustment. If 

the fuel rate for a certification test was reported, the engine-specific BSFC was calculated and 

used directly. If the fuel rate was not reported, the default BSFC values in NONROAD were 

used to calculate the adjustment. 

The certification data were grouped by model year and by hp category. Sales-weighted 

emission averages were calculated for each model year/hp category. Then, for each hp category, 

a straight average of the applicable model year data was used. 

For categories less than 50 hp, the Tier 1 standard for HC and NOx is expressed as a 

combination of HC and NOx (HC+NOx, refer to Table 1). As a result, most of the certification 

data for these engines is provided as the sum of HC and NOx, although there are some data 

reported for HC and NOx separately. To obtain separate HC and NOx emission factors for 

categories less than 50 hp, HC fractions of HC+NOx emissions were calculated for those tests 

which reported both HC and HC+NOx emission factors. The average HC fraction was then 

calculated and multiplied by the sales-weighted average HC+NOx emission factor to obtain an 

HC emission factor (referred to as HC calc in the tables). The remaining fraction of the 

HC+NOx emission factor was assigned as the NOx emission factor (referred to as NOx calc in 

the tables). This was done for each model year and for each of the hp categories less than 50 hp 

(i.e., 0-11 hp, 11-25 hp, 25-50 hp). 

Table D1 presents a summary of the results, as well as the sample sizes for each 

pollutant/model year/hp category. The numbers in bold are those used in the model. Tables D2­

D7 present the individual engine emissions data and sales weightings for each model year and hp 

category. The engine identification and specific sales information have been removed. For 

categories less than 50 hp, the HC fractions, HC calc emission factors, and NOx calc emission 

factors are also provided. The HC calc and NOx calc emission factors are used in the model. 

D1
 
Table D1. Summary of Certification Data for Nonroad Compression Ignition Engines* 

>0 to 11 hp 

g/hp-hr HC NOx HC+NOx CO PM HC frac HC calc NOx calc 

2000 0.692103 5.170337 5.966223 4.051366 0.452858 0.113196 0.675351 5.290871 

2001 0.828378 5.073763 6.018891 4.174066 0.44201 0.141247 0.850153 5.168738 

average 0.760241 5.12205 5.992557 4.1127 0.4474 0.7628 5.2298 

sample size HC NOx HC+NOx CO PM 

2000 4 6 20 20 20 

2001 5 5 19 19 19 

total 9 11 39 39 39 

>11 to 25 hp 

g/hp-hr HC NOx HC+NOx CO PM HC frac HC calc NOx calc 

2000 0.489983 3.749647 4.9489 2.207041 0.289982 0.081156 0.401631 4.547269 

2001 0.447831 4.109521 4.80692 2.114884 0.242992 0.09869 0.474395 4.332525 

average 0.468907 3.929584 4.87791 2.1610 0.2665 0.4380 4.4399 

sample size HC NOx HC+NOx CO PM 

2000 9 10 40 39 40 

2001 16 16 43 43 43 

total 25 26 83 82 83 

>25 to 50 hp 

g/hp-hr HC NOx HC+NOx CO PM HC frac HC calc NOx calc 

1999 0.496458 4.558405 4.983359 1.54213 0.35614 0.047095 0.23469 4.748669 

2000 0.452946 4.893606 5.083919 1.522782 0.331337 0.056039 0.284899 4.79902 

2001 0.472917 4.469647 4.952901 1.532028 0.329222 0.064006 0.317014 4.635887 

average 0.474107 4.640553 5.006726 1.5323 0.3389 0.2789 4.7279 

sample size HC NOx HC+NOx CO PM 

1999 11 15 72 72 72 

2000 14 22 95 96 96 

2001 25 35 103 104 104 

total 50 72 270 272 272 

D2
 
Table D1. Summary of Certification Data for Nonroad Compression Ignition Engines (cont)* 

>50 to 100 hp 

g/hp-hr HC NOx HC+NOx CO PM 

1998 0.528845 5.682411 4.235576 2.753546 0.472055 

1999 0.517642 5.613376 6.569501 2.34687 0.452553 

2000 0.46289 5.494892 4.235576 2.047055 0.460428 

2001 0.575867 5.604515 5.976957 2.314372 0.506824 

average 0.5213 5.5988 5.254402 2.3655 0.4730 

sample size HC NOx HC+NOx CO PM 

1998 18 71 1 21 19 

1999 27 91 3 33 31 

2000 35 104 1 38 36 

2001 40 127 3 47 43 

total 120 393 8 139 129 

>100 to 175 hp 

g/hp-hr HC NOx HC+NOx CO PM 

1997 0.297479 5.599201 0.745072 0.281314 

1998 0.355336 5.743938 0.961288 0.276378 

1999 0.35159 5.749792 0.93731 0.270345 

2000 0.33246 5.593736 0.68581 0.282059 

2001 0.355107 5.574714 1.003922 0.28934 

average 0.3384 5.6523 0.8667 0.2799 

sample size HC NOx HC+NOx CO PM 

1997 29 43 0 29 25 

1998 25 52 0 27 24 

1999 25 59 0 27 25 

2000 27 61 0 29 28 

2001 34 69 0 37 36 

total 140 284 0 149 138 

>175 to 300 hp 

g/hp-hr HC NOx HC+NOx CO PM 

1996 0.331633 5.667602 0.834876 0.239994 

1997 0.307044 5.723983 0.819777 0.24542 

1998 0.316321 5.574079 0.722968 0.262486 

1999 0.314974 5.549376 0.695869 0.257528 

2000 0.26631 5.441729 4.54 0.666725 0.240685 

2001 0.314765 5.506545 4.203295 0.744633 0.266622 

average 0.3085 5.5772 4.371648 0.7475 0.2521 

sample size HC NOx HC+NOx CO PM 

1996 44 44 0 44 44 

1997 43 43 0 43 43 

1998 72 72 0 72 72 

1999 71 71 0 71 71 

2000 64 64 2 64 64 

2001 86 86 6 88 88 

total 380 380 8 382 382 

D3
 
hp

Table D1. Summary of Certification Data for Nonroad Compression Ignition Engines 

(cont)* 

>300 to 600 

g/hp-hr HC NOx HC+NOx CO PM 

1996 0.260521 6.264393 1.353145 0.195978 

1997 0.1553 5.865363 1.431343 0.213156 

1998 0.209071 6.126551 1.289223 0.198893 

1999 0.201521 6.04976 1.201752 0.192703 

2000 0.186024 5.77026 5.24 1.254546 0.203148 

average 0.2025 6.0153 5.24 1.3060 0.2008 

2001Tier 2 0.1669 4.3351 4.345348 0.8425 0.1316 

sample size HC NOx HC+NOx CO PM 

1996 40 40 0 40 40 

1997 35 35 0 35 35 

1998 48 48 0 48 48 

1999 55 55 0 55 55 

2000 51 51 1 51 51 

2001 14 14 35 35 35 

total 243 243 36 264 264 

>600 to 750 

g/hp-hr HC NOx HC+NOx CO PM 

1996 0.174804 6.063537 1.502117 0.242149 

1997 0.135125 5.872338 1.571034 0.236991 

1998 0.190719 5.866023 1.277422 0.205116 

1999 0.118392 5.723896 1.361031 0.227162 

2000 0.126821 5.790567 1.368105 0.225632 

2001 0.138065 5.612418 3.975047 0.883305 0.183773 

average 0.1473 5.8215 3.975047 1.3272 0.2201 

sample size HC NOx HC+NOx CO PM 

1996 11 11 0 11 11 

1997 10 10 0 10 10 

1998 12 12 0 12 12 

1999 13 13 0 13 13 

2000 15 15 0 15 15 

2001 16 16 3 17 17 

total 77 77 3 78 78 

D4
 
Table D1. Summary of Certification Data for Nonroad Compression Ignition Engines 

(cont)* 

>750 hp 

g/hp-hr HC NOx HC+NOx CO PM 

2000 0.25906 6.252638 0.727419 0.183308 

2001 0.313093 6.052394 0.800887 0.203589 

average 0.2861 6.1525 0.7642 0.1934 

sample size HC NOx HC+NOx CO PM 

2000 16 16 0 16 16 

2001 18 18 0 18 18 

total 34 34 0 34 34 

* Values in bold are used in NONROAD. All are Tier 1 emission factors, with the exception that 

both Tier 1 and Tier 2 emission factors are provided for the >300 to 600 hp category. 

D5
 
Table D2. 1996 MY Certification Data 

175 to 300 hp Emission Factors (g/hp-hr) 

Rated HP HC NOx CO PM Sales wgt 

261 0.47 6.06 0.89 0.27 0.0005 

248 0.34 5.31 1.04 0.35 0.0005 

215 0.32 5.51 0.55 0.33 0.0628 

260 0.44 5.81 0.70 0.27 0.0398 

240 0.29 5.38 0.49 0.27 0.0545 

260 0.37 5.73 1.30 0.31 0.0177 

225 0.41 5.70 0.84 0.15 0.0862 

275 0.11 4.56 1.25 0.18 0.0174 

258 0.05 6.34 0.89 0.22 0.0064 

275 0.08 4.93 1.80 0.25 0.0034 

220 0.11 6.16 0.89 0.20 0.0563 

200 0.26 5.12 0.60 0.22 0.0910 

215 0.32 5.51 0.55 0.33 0.1054 

260 0.44 5.80 0.70 0.27 0.0652 

240 0.29 5.38 0.49 0.27 0.0362 

255 0.46 6.11 0.52 0.20 0.0014 

296 0.31 6.41 0.96 0.18 0.0005 

196 0.28 5.44 0.65 0.21 0.0074 

287 0.33 5.94 1.16 0.21 0.1080 

263 0.43 6.13 2.68 0.24 0.0322 

275 0.46 6.51 1.19 0.15 0.0273 

216 0.59 6.20 1.55 0.20 0.0262 

293 0.09 6.20 0.46 0.12 0.0018 

261 0.30 4.38 0.69 0.23 0.0050 

194 0.30 6.26 0.80 0.17 0.0024 

280 0.25 4.03 0.56 0.18 0.0005 

241 0.41 6.44 1.11 0.26 0.0036 

193 0.60 6.69 0.85 0.28 0.0025 

215 0.32 5.51 0.55 0.33 0.0136 

240 0.29 5.38 0.49 0.27 0.0362 

189 0.31 5.40 0.92 0.16 0.0020 

252 0.22 6.23 0.30 0.17 0.0058 

273 0.31 4.46 0.48 0.08 0.0009 

248 0.34 5.31 1.04 0.35 0.0005 

275 0.10 4.14 0.78 0.13 0.0028 

210 0.16 6.85 1.47 0.17 0.0043 

225 0.11 6.63 0.57 0.06 0.0014 

228 0.36 5.45 0.59 0.21 0.0504 

182 0.42 6.43 0.87 0.32 0.0072 

207 0.44 6.59 1.15 0.36 0.0045 

188 0.37 5.51 0.63 0.18 0.0018 

235 0.31 6.18 0.52 0.13 0.0018 

201 0.42 5.38 0.63 0.16 0.0018 

255 0.43 6.43 0.76 0.20 0.0027 

Sales-wgt EF 0.331633 5.667602 0.834876 0.239994 1.0000 

Sample Size 44 44 44 44 

D6
 
Table D2. 1996 MY Certification Data (cont.) 

300 to 600 hp Emission Factors (g/hp-hr) 

Rated HP HC NOx CO PM Sales wgt 

335 0.27 5.51 0.74 0.28 0.0013 

543 2.24 5.66 0.54 0.24 0.0010 

300 0.28 6.13 0.81 0.28 0.0249 

330 0.34 5.27 1.07 0.28 0.0075 

362 0.16 5.49 1.57 0.13 0.3220 

425 0.09 6.38 2.18 0.08 0.0155 

500 0.17 8.19 2.24 0.13 0.0078 

455 0.12 5.48 0.82 0.17 0.0039 

542 0.07 6.05 1.43 0.31 0.0959 

300 0.08 5.78 0.43 0.05 0.0093 

397 0.19 4.65 1.35 0.19 0.0216 

535 0.08 5.79 2.10 0.34 0.0186 

515 0.05 6.05 1.44 0.21 0.0180 

300 0.31 5.50 0.41 0.22 0.0052 

480 0.17 6.85 1.16 0.17 0.0833 

525 0.25 6.36 0.45 0.15 0.0104 

375 0.40 6.03 1.51 0.20 0.0339 

337 0.41 5.99 1.31 0.22 0.0170 

300 0.51 8.03 1.28 0.21 0.1823 

313 0.10 6.55 0.49 0.14 0.0039 

440 0.39 6.55 0.43 0.18 0.0052 

568 0.37 6.46 2.17 0.37 0.0124 

350 0.78 6.32 1.30 0.37 0.0357 

400 0.10 6.28 0.49 0.14 0.0129 

412 0.35 6.51 1.76 0.30 0.0039 

322 0.23 5.00 0.87 0.23 0.0026 

563 0.18 4.56 0.48 0.18 0.0078 

305 0.24 6.29 0.72 0.29 0.0044 

335 0.19 5.78 0.41 0.10 0.0003 

349 0.20 5.41 0.34 0.15 0.0016 

526 0.17 6.06 0.60 0.16 0.0003 

493 0.16 5.89 0.95 0.20 0.0005 

573 0.14 5.86 0.62 0.17 0.0005 

571 0.31 3.98 0.48 0.11 0.0026 

308 0.28 5.68 0.45 0.18 0.0021 

335 0.27 5.51 0.74 0.28 0.0023 

543 0.22 5.66 0.54 0.25 0.0037 

300 0.07 4.54 0.51 0.15 0.0052 

300 0.07 6.35 0.52 0.04 0.0078 

369 0.24 5.43 0.51 0.14 0.0052 

Sales-wgt EF 0.260521 6.264393 1.353145 0.195978 1.0000 

Sample Size 40 40 40 40 

D7
 
Table D2. 1996 MY Certification Data (cont.) 

600 to 750 hp Emission Factors (g/hp-hr) 

Rated HP HC NOx CO PM Sales wgt 

750 0.07 5.90 1.29 0.22 0.1010 

750 0.07 5.84 0.90 0.16 0.0056 

750 0.08 6.01 1.92 0.30 0.1330 

750 0.35 5.80 1.48 0.29 0.0859 

660 0.05 6.24 0.83 0.14 0.1627 

740 0.10 5.53 1.63 0.33 0.1324 

640 0.10 5.62 0.83 0.19 0.0056 

730 0.05 5.04 0.99 0.18 0.0960 

600 0.46 6.86 1.46 0.23 0.1403 

710 0.25 6.64 2.42 0.27 0.1347 

740 0.24 5.85 1.37 0.21 0.0028 

Sales-wgt EF 0.174804 6.063537 1.502117 0.242149 1.0000 

Sample Size 11 11 11 11 

D8
 
Table D3. 1997 MY Certification Data 

100 to 175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

100 0.35 6.08 0.70 0.28 0.0015 0.0011 0.0015 0.0015 

125 0.23 6.21 0.47 0.16 0.0087 0.0069 0.0087 0.0090 

165 0.36 4.95 0.75 0.31 0.1552 0.1226 0.1552 0.1597 

110 6.06 0.0000 0.0174 0.0000 0.0000 

165 6.24 0.0000 0.0915 0.0000 0.0000 

166 4.95 0.0000 0.0022 0.0000 0.0000 

100 0.35 6.08 0.70 0.30 0.0102 0.0080 0.0102 0.0104 

125 0.23 6.21 0.47 0.16 0.1001 0.0790 0.1001 0.1030 

165 0.36 4.95 0.75 0.31 0.2320 0.1833 0.2320 0.2388 

114 0.39 4.88 0.88 0.0038 0.0030 0.0038 0.0000 

141 0.39 4.97 2.30 0.0057 0.0045 0.0057 0.0000 

134 0.33 6.59 1.15 0.17 0.0218 0.0172 0.0218 0.0224 

168 0.43 6.52 1.25 0.17 0.0044 0.0034 0.0044 0.0045 

110 0.75 6.18 2.60 0.41 0.0058 0.0046 0.0058 0.0060 

158 0.51 6.26 1.28 0.38 0.0247 0.0195 0.0247 0.0254 

153 5.65 0.0000 0.0206 0.0000 0.0000 

134 6.51 0.0000 0.0041 0.0000 0.0000 

103 6.26 0.0000 0.0069 0.0000 0.0000 

106 6.01 0.0000 0.0018 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0022 0.0017 0.0022 0.0022 

125 0.23 6.21 0.47 0.16 0.0015 0.0011 0.0015 0.0015 

165 0.36 4.95 0.75 0.31 0.0537 0.0424 0.0537 0.0552 

162 0.62 6.11 0.90 0.29 0.0035 0.0028 0.0035 0.0036 

130 5.58 0.0000 0.0115 0.0000 0.0000 

134 6.08 0.0000 0.0183 0.0000 0.0000 

131 5.18 0.0000 0.0115 0.0000 0.0000 

157 0.12 6.55 1.15 0.13 0.0125 0.0099 0.0125 0.0128 

168 0.11 6.63 0.57 0.06 0.0091 0.0072 0.0091 0.0094 

108 0.17 5.99 0.37 0.17 0.0242 0.0191 0.0242 0.0249 

166 0.38 6.21 0.56 0.22 0.0182 0.0143 0.0182 0.0187 

121 0.68 6.11 1.22 0.18 0.0085 0.0067 0.0085 0.0087 

108 0.20 5.63 0.70 0.32 0.2393 0.1890 0.2393 0.2463 

103 6.19 0.0000 0.0128 0.0000 0.0000 

172 0.13 5.31 0.45 0.25 0.0258 0.0204 0.0258 0.0266 

130 0.64 6.70 1.23 0.36 0.0004 0.0003 0.0004 0.0004 

102 6.68 0.0000 0.0023 0.0000 0.0000 

172 6.23 0.0000 0.0069 0.0000 0.0000 

117 6.23 0.0000 0.0023 0.0000 0.0000 

173 0.54 6.57 1.83 0.42 0.0029 0.0023 0.0029 0.0030 

122 0.07 5.75 1.06 0.34 0.0029 0.0023 0.0029 0.0030 

122 0.12 4.12 0.64 0.0030 0.0024 0.0030 0.0000 

161 0.23 5.96 0.83 0.0160 0.0126 0.0160 0.0000 

161 0.34 5.26 1.05 0.19 0.0029 0.0023 0.0029 0.0030 

Sales-wgt EF 0.297479 5.599201 0.745072 0.281314 1.0000 1.0000 1.0000 1.0000 

Sample Size 29 43 29 25 

D9
 
Table D3. 1997 MY Certification Data (cont.) 

175 to 300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

261 0.47 6.06 0.89 0.27 0.0048 0.0048 0.0048 0.0048 

248 0.34 5.31 1.04 0.35 0.0060 0.0060 0.0060 0.0060 

280 0.47 5.47 0.52 0.23 0.1439 0.1439 0.1439 0.1439 

260 0.37 5.73 1.30 0.39 0.0282 0.0282 0.0282 0.0282 

246 0.34 5.27 1.07 0.36 0.0056 0.0056 0.0056 0.0056 

225 0.41 5.70 0.84 0.22 0.1444 0.1444 0.1444 0.1444 

220 0.11 6.16 0.89 0.27 0.1523 0.1523 0.1523 0.1523 

275 0.11 4.56 1.25 0.26 0.0489 0.0489 0.0489 0.0489 

205 0.19 5.96 1.73 0.25 0.0060 0.0060 0.0060 0.0060 

260 0.08 6.48 0.82 0.29 0.0854 0.0854 0.0854 0.0854 

275 0.08 4.93 1.80 0.32 0.0116 0.0116 0.0116 0.0116 

280 0.47 5.47 0.52 0.23 0.0059 0.0059 0.0059 0.0059 

260 0.46 6.11 0.52 0.27 0.0104 0.0104 0.0104 0.0104 

188 0.50 5.29 1.31 0.37 0.0045 0.0045 0.0045 0.0045 

296 0.23 4.78 0.72 0.21 0.0013 0.0013 0.0013 0.0013 

264 0.64 6.38 2.37 0.41 0.0085 0.0085 0.0085 0.0085 

250 0.10 6.41 0.54 0.12 0.0040 0.0040 0.0040 0.0040 

189 0.43 6.65 1.04 0.34 0.0053 0.0053 0.0053 0.0053 

261 0.30 4.38 0.69 0.23 0.0240 0.0240 0.0240 0.0240 

194 0.30 6.26 0.80 0.17 0.0133 0.0133 0.0133 0.0133 

189 0.37 5.87 0.76 0.28 0.0069 0.0069 0.0069 0.0069 

241 0.41 6.44 1.11 0.26 0.0115 0.0115 0.0115 0.0115 

227 0.51 6.72 1.07 0.31 0.0101 0.0101 0.0101 0.0101 

193 0.60 6.69 0.85 0.28 0.0051 0.0051 0.0051 0.0051 

296 0.42 5.77 0.82 0.25 0.0008 0.0008 0.0008 0.0008 

234 0.31 4.22 0.51 0.08 0.0027 0.0027 0.0027 0.0027 

248 0.34 5.31 1.04 0.35 0.0044 0.0044 0.0044 0.0044 

247 0.57 6.13 0.69 0.17 0.0011 0.0011 0.0011 0.0011 

240 0.35 5.36 0.54 0.23 0.0053 0.0053 0.0053 0.0053 

225 0.14 6.73 0.64 0.16 0.0008 0.0008 0.0008 0.0008 

228 0.36 5.45 0.59 0.21 0.1289 0.1289 0.1289 0.1289 

253 0.55 4.64 1.10 0.29 0.0133 0.0133 0.0133 0.0133 

182 0.42 6.43 0.87 0.29 0.0027 0.0027 0.0027 0.0027 

207 0.44 6.59 1.15 0.36 0.0027 0.0027 0.0027 0.0027 

183 0.54 6.63 0.81 0.34 0.0016 0.0016 0.0016 0.0016 

227 0.35 0.63 0.51 0.27 0.0016 0.0016 0.0016 0.0016 

272 0.35 6.44 1.09 0.23 0.0027 0.0027 0.0027 0.0027 

255 0.25 5.85 0.40 0.13 0.0373 0.0373 0.0373 0.0373 

255 0.25 6.22 1.10 0.14 0.0250 0.0250 0.0250 0.0250 

188 0.37 5.51 0.60 0.18 0.0053 0.0053 0.0053 0.0053 

235 0.31 6.41 0.54 0.13 0.0053 0.0053 0.0053 0.0053 

201 0.42 5.38 0.63 0.16 0.0053 0.0053 0.0053 0.0053 

255 0.43 6.43 0.76 0.20 0.0053 0.0053 0.0053 0.0053 

Sales-wgt EF 0.307044 5.723983 0.819777 0.245420 1.0000 1.0000 1.0000 1.0000 

Sample Size 43 43 43 43 

D10
 
Table D3. 1997 MY Certification Data (cont.) 

300 to 600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

335 0.27 5.51 0.74 0.28 0.0004 0.0004 0.0004 0.0004 

543 0.22 5.66 0.54 0.24 0.0035 0.0035 0.0035 0.0035 

425 0.09 6.38 2.18 0.16 0.0282 0.0282 0.0282 0.0282 

300 0.28 6.13 0.81 0.36 0.0339 0.0339 0.0339 0.0339 

397 0.19 4.65 1.35 0.19 0.0261 0.0261 0.0261 0.0261 

362 0.16 5.49 1.57 0.21 0.4232 0.4232 0.4232 0.4232 

373 0.17 8.19 2.24 0.21 0.0141 0.0141 0.0141 0.0141 

455 0.12 5.48 0.82 0.17 0.0023 0.0023 0.0023 0.0023 

599 0.04 6.59 2.67 0.33 0.1521 0.1521 0.1521 0.1521 

492 0.05 6.24 0.83 0.14 0.0052 0.0052 0.0052 0.0052 

535 0.08 5.79 2.10 0.34 0.0065 0.0065 0.0065 0.0065 

559 0.07 5.84 0.90 0.16 0.0004 0.0004 0.0004 0.0004 

300 0.08 5.78 0.43 0.13 0.0173 0.0173 0.0173 0.0173 

307 0.10 6.52 0.51 0.14 0.0069 0.0069 0.0069 0.0069 

430 0.38 6.58 0.43 0.18 0.0177 0.0177 0.0177 0.0177 

425 0.08 6.44 0.76 0.16 0.0355 0.0355 0.0355 0.0355 

413 0.35 6.51 1.76 0.29 0.0140 0.0140 0.0140 0.0140 

590 0.34 6.40 0.72 0.23 0.0002 0.0002 0.0002 0.0002 

313 0.18 4.56 0.48 0.18 0.0121 0.0121 0.0121 0.0121 

305 0.24 6.29 0.72 0.29 0.0089 0.0089 0.0089 0.0089 

493 0.16 4.26 1.04 0.30 0.0024 0.0024 0.0024 0.0024 

426 0.31 3.98 0.48 0.11 0.0040 0.0040 0.0040 0.0040 

308 0.28 5.68 0.45 0.20 0.0019 0.0019 0.0019 0.0019 

335 0.27 5.51 0.74 0.28 0.0115 0.0115 0.0115 0.0115 

543 0.22 5.66 0.54 0.16 0.0275 0.0275 0.0275 0.0275 

308 0.38 5.70 0.39 0.18 0.0002 0.0002 0.0002 0.0002 

330 0.07 5.07 0.44 0.12 0.0270 0.0270 0.0270 0.0270 

320 0.12 7.41 0.51 0.08 0.0008 0.0008 0.0008 0.0008 

300 0.08 5.62 0.45 0.12 0.0121 0.0121 0.0121 0.0121 

381 0.21 6.55 0.61 0.08 0.0403 0.0403 0.0403 0.0403 

496 0.13 6.12 0.28 0.07 0.0379 0.0379 0.0379 0.0379 

369 0.24 6.50 0.51 0.14 0.0081 0.0081 0.0081 0.0081 

526 0.45 5.59 0.67 0.11 0.0081 0.0081 0.0081 0.0081 

315 0.34 5.48 0.79 0.13 0.0081 0.0081 0.0081 0.0081 

362 0.37 5.29 0.82 0.12 0.0016 0.0016 0.0016 0.0016 

Sales-wgt EF 0.155300 5.865363 1.431343 0.213156 1.0000 1.0000 1.0000 1.0000 

Sample Size 35 35 35 35 

D11
 
Table D3. 1997 MY Certification Data (cont.) 

600 to 750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

740 0.04 5.67 1.57 0.25 0.3355 0.3355 0.3355 0.3355 

750 0.08 6.01 1.92 0.30 0.0205 0.0205 0.0205 0.0205 

740 0.10 5.53 1.63 0.33 0.0169 0.0169 0.0169 0.0169 

640 0.10 5.62 0.83 0.19 0.0319 0.0319 0.0319 0.0319 

743 0.05 5.04 0.99 0.18 0.1004 0.1004 0.1004 0.1004 

750 0.07 5.90 1.29 0.22 0.0771 0.0771 0.0771 0.0771 

600 0.26 6.02 1.78 0.24 0.1597 0.1597 0.1597 0.1597 

710 0.25 6.64 2.42 0.27 0.1643 0.1643 0.1643 0.1643 

750 0.13 5.89 1.07 0.13 0.0479 0.0479 0.0479 0.0479 

748 0.30 6.04 0.45 0.24 0.0456 0.0456 0.0456 0.0456 

Sales-wgt EF 0.135125 5.872338 1.571034 0.236991 1.0000 1.0000 1.0000 1.0000 

Sample Size 10 10 10 10 

D12
 
Table D4. 1998 MY Certification Data 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

67 6.40 0.0000 0.0071 0.0000 0.0000 

79 5.74 0.0000 0.0024 0.0000 0.0000 

96 5.81 0.0000 0.0006 0.0000 0.0000 

80 0.48 7.61 4.32 0.56 0.2600 0.0914 0.2581 0.0000 

67 0.75 6.35 1.96 0.34 0.1418 0.0499 0.1408 0.0000 

80 0.72 5.78 3.26 0.51 0.2786 0.0979 0.2765 0.0000 

98 0.71 6.30 1.68 0.21 0.0009 0.0003 0.0009 0.0000 

62 6.23 0.0000 0.0012 0.0000 0.0000 

57 6.20 0.0000 0.0012 0.0000 0.0000 

59 6.56 0.0000 0.0310 0.0000 0.0000 

84 5.74 0.0000 0.0413 0.0000 0.0000 

64 5.92 0.0000 0.0049 0.0000 0.0000 

82 5.23 0.0000 0.0605 0.0000 0.0000 

53 6.32 0.0000 0.0175 0.0000 0.0000 

72 6.30 0.0000 0.0006 0.0000 0.0000 

78 6.22 0.0000 0.0001 0.0000 0.0000 

52 4.59 0.0000 0.0208 0.0000 0.0000 

50 4.14 0.0000 0.0036 0.0000 0.0000 

51 0.60 6.68 3.04 0.63 0.0004 0.0001 0.0004 0.0000 

55 0.39 6.16 0.98 0.28 0.0118 0.0042 0.0117 0.0000 

64 0.43 5.62 2.17 0.60 0.0254 0.0089 0.0252 0.0000 

73 0.29 5.35 1.08 0.52 0.0118 0.0042 0.0117 0.0000 

56 0.48 4.88 0.46 0.27 0.0016 0.0006 0.0016 0.0000 

79 0.55 5.25 2.47 0.55 0.0258 0.0091 0.0256 0.0000 

91 0.42 6.63 1.32 0.54 0.0133 0.0047 0.0132 0.0000 

59 6.65 0.0000 0.0170 0.0000 0.0000 

62 6.23 0.0000 0.0012 0.0000 0.0000 

80 0.72 5.78 3.26 0.51 0.0051 0.0018 0.0050 0.0000 

98 0.71 6.30 1.68 0.21 0.0009 0.0003 0.0009 0.0000 

59 4.37 0.0000 0.0042 0.0000 0.0000 

56 4.18 0.0000 0.0148 0.0000 0.0000 

86 5.42 0.0000 0.0047 0.0000 0.0000 

93 4.71 0.0000 0.0030 0.0000 0.0000 

72 4.31 0.0000 0.0059 0.0000 0.0000 

54 0.55 6.31 2.42 0.0077 0.0027 0.0076 0.0000 

65 0.05 4.18 4.24 0.90 0.0010 0.0003 0.0010 1.0000 

54 2.62 0.0000 0.0057 0.0000 0.0000 

50 4.38 0.0000 0.0190 0.0000 0.0000 

89 5.98 0.0000 0.0066 0.0000 0.0000 

72 4.63 0.0000 0.0145 0.0000 0.0000 

78 6.05 0.0000 0.0101 0.0000 0.0000 

52 6.32 0.0000 0.0060 0.0000 0.0000 

67 0.14 4.94 1.07 0.45 0.1213 0.0426 0.1204 0.0000 

92 0.27 5.62 0.99 0.27 0.0834 0.0293 0.0828 0.0000 

55 2.62 0.0000 0.0015 0.0000 0.0000 

85 2.18 0.0000 0.0018 0.0000 0.0000 

D13
 
Table D4. 1998 MY Certification Data 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

59 5.90 0.0000 0.0006 0.0000 0.0000 

58 3.23 0.0000 0.0297 0.0000 0.0000 

52 6.62 0.0000 0.0125 0.0000 0.0000 

64 5.13 0.0000 0.0064 0.0000 0.0000 

60 6.06 0.0000 0.0297 0.0000 0.0000 

96 5.09 0.0000 0.0861 0.0000 0.0000 

72 6.30 0.0000 0.0025 0.0000 0.0000 

68 5.85 0.0000 0.0772 0.0000 0.0000 

68 6.44 0.0000 0.0504 0.0000 0.0000 

80 0.86 5.40 4.00 0.64 0.0091 0.0032 0.0091 0.0000 

59 4.33 0.0000 0.0036 0.0000 0.0000 

84 6.14 0.0000 0.0012 0.0000 0.0000 

94 5.75 0.0000 0.0003 0.0000 0.0000 

82 4.84 1.22 0.44 0.0000 0.0011 0.0032 0.0000 

60 5.87 3.96 0.39 0.0000 0.0006 0.0017 0.0000 

62 6.19 1.69 0.30 0.0000 0.0009 0.0026 0.0000 

75 3.87 0.0000 0.0046 0.0000 0.0000 

58 3.91 0.0000 0.0069 0.0000 0.0000 

54 5.40 0.0000 0.0003 0.0000 0.0000 

67 4.89 0.0000 0.0148 0.0000 0.0000 

80 4.80 0.0000 0.0006 0.0000 0.0000 

60 4.12 0.0000 0.0042 0.0000 0.0000 

70 5.59 0.0000 0.0006 0.0000 0.0000 

56 5.23 0.0000 0.0018 0.0000 0.0000 

58 5.12 0.0000 0.0033 0.0000 0.0000 

Sales-wgt 

EF 

0.528 

845 

5.682 

411 

4.23557 

6 

2.7535 

46 

0.4720 

55 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 18 71 1 21 19 

D14
 
Table D4. 1998 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

167 0.34 5.26 1.05 0.18 0.0003 0.0003 0.0003 0.0003 

108 6.47 0.0000 0.0009 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.1104 0.0940 0.1101 0.1112 

125 0.23 6.21 0.47 0.16 0.0041 0.0035 0.0041 0.0042 

165 0.36 4.95 0.75 0.31 0.0647 0.0551 0.0645 0.0652 

110 6.06 0.0000 0.0062 0.0000 0.0000 

165 6.24 0.0000 0.0336 0.0000 0.0000 

166 4.95 0.0000 0.0029 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.1765 0.1504 0.1760 0.1779 

125 0.23 6.21 0.47 0.16 0.0537 0.0457 0.0535 0.0541 

165 0.36 4.95 0.75 0.31 0.1891 0.1611 0.1886 0.1906 

158 6.53 0.0000 0.0018 0.0000 0.0000 

109 6.41 0.0000 0.0018 0.0000 0.0000 

133 6.44 0.0000 0.0018 0.0000 0.0000 

172 6.48 0.0000 0.0018 0.0000 0.0000 

114 0.52 6.54 1.18 0.0014 0.0012 0.0014 0.0000 

141 3.71 0.0000 0.0018 0.0000 0.0000 

135 0.40 5.70 1.75 0.29 0.2535 0.2160 0.2528 0.2555 

155 6.39 0.0000 0.0021 0.0000 0.0000 

124 6.60 0.0000 0.0068 0.0000 0.0000 

103 6.22 0.0000 0.0310 0.0000 0.0000 

158 6.26 0.0000 0.0077 0.0000 0.0000 

103 0.57 6.26 1.58 0.39 0.0033 0.0028 0.0033 0.0033 

153 0.51 5.65 0.49 0.26 0.0126 0.0108 0.0126 0.0127 

106 6.01 0.0000 0.0095 0.0000 0.0000 

144 6.61 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0085 0.0072 0.0085 0.0086 

125 0.23 6.21 0.47 0.16 0.0012 0.0010 0.0012 0.0012 

165 0.36 4.95 0.75 0.31 0.0140 0.0119 0.0140 0.0141 

114 5.87 0.0000 0.0049 0.0000 0.0000 

148 0.16 6.58 0.70 0.13 0.0003 0.0003 0.0003 0.0003 

168 0.34 6.17 0.63 0.13 0.0002 0.0002 0.0002 0.0002 

162 0.62 6.11 0.90 0.28 0.0006 0.0005 0.0006 0.0006 

108 6.11 0.0000 0.0137 0.0000 0.0000 

113 4.41 0.0000 0.0020 0.0000 0.0000 

108 0.17 5.99 0.37 0.17 0.0555 0.0473 0.0553 0.0559 

121 0.68 6.11 1.22 0.18 0.0117 0.0100 0.0117 0.0118 

166 0.38 6.21 0.56 0.22 0.0196 0.0167 0.0195 0.0197 

118 6.30 0.0000 0.0006 0.0000 0.0000 

103 6.19 0.0000 0.0070 0.0000 0.0000 

103 0.53 5.30 1.24 0.51 0.0018 0.0015 0.0018 0.0018 

100 0.57 5.50 1.35 0.47 0.0024 0.0020 0.0023 0.0024 

102 6.68 0.0000 0.0027 0.0000 0.0000 

127 5.38 0.0000 0.0009 0.0000 0.0000 

117 6.23 0.0000 0.0009 0.0000 0.0000 

172 6.23 0.0000 0.0027 0.0000 0.0000 

D15
 
Table D4. 1998 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

173 0.54 6.57 1.83 0.42 0.0032 0.0027 0.0032 0.0032 

123 4.12 0.64 0.0000 0.0015 0.0018 0.0018 

122 0.07 5.75 1.06 0.44 0.0021 0.0018 0.0021 0.0022 

142 5.92 1.33 0.31 0.0000 0.0010 0.0011 0.0011 

138 6.68 0.0000 0.0004 0.0000 0.0000 

161 0.23 5.96 0.83 0.0092 0.0078 0.0092 0.0000 

Sales-wgt 

EF 0.355336 5.743938 0.961288 0.276378 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 25 52 27 24 

D16
 
Table D4. 1998 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

257 0.43 6.43 0.76 0.20 0.0002 0.0002 0.0002 0.0002 

261 0.47 6.06 0.89 0.27 0.0013 0.0013 0.0013 0.0013 

248 0.34 5.31 1.04 0.35 0.0011 0.0011 0.0011 0.0011 

200 0.26 5.13 0.60 0.22 0.0124 0.0124 0.0124 0.0124 

215 0.32 5.51 0.55 0.32 0.0184 0.0184 0.0184 0.0184 

260 0.44 5.82 0.70 0.27 0.0222 0.0222 0.0222 0.0222 

240 0.29 5.38 0.49 0.27 0.0222 0.0222 0.0222 0.0222 

278 0.13 4.70 0.51 0.15 0.0061 0.0061 0.0061 0.0061 

280 0.47 5.47 0.52 0.23 0.0160 0.0160 0.0160 0.0160 

275 0.11 4.56 1.26 0.26 0.0049 0.0049 0.0049 0.0049 

205 0.19 5.96 1.73 0.25 0.0056 0.0056 0.0056 0.0056 

260 0.17 6.48 0.82 0.29 0.0108 0.0108 0.0108 0.0108 

290 0.10 5.60 2.19 0.32 0.0030 0.0030 0.0030 0.0030 

260 0.42 6.16 1.30 0.39 0.0018 0.0018 0.0018 0.0018 

225 0.41 5.70 0.84 0.22 0.0253 0.0253 0.0253 0.0253 

275 0.04 4.76 0.31 0.14 0.0013 0.0013 0.0013 0.0013 

200 0.26 5.13 0.60 0.22 0.0726 0.0726 0.0726 0.0726 

215 0.32 5.51 0.55 0.32 0.0749 0.0749 0.0749 0.0749 

260 0.44 5.82 0.70 0.27 0.0616 0.0616 0.0616 0.0616 

240 0.29 5.38 0.49 0.27 0.0738 0.0738 0.0738 0.0738 

284 0.41 5.76 0.52 0.22 0.0042 0.0042 0.0042 0.0042 

200 0.19 4.05 0.92 0.28 0.0016 0.0016 0.0016 0.0016 

253 0.34 6.58 0.57 0.21 0.0016 0.0016 0.0016 0.0016 

188 0.50 5.29 1.31 0.37 0.0007 0.0007 0.0007 0.0007 

256 0.46 6.11 0.52 0.27 0.0016 0.0016 0.0016 0.0016 

296 0.23 4.78 0.72 0.21 0.0002 0.0002 0.0002 0.0002 

261 0.47 6.06 0.89 0.27 0.0002 0.0002 0.0002 0.0002 

220 0.20 5.87 0.72 0.27 0.0050 0.0050 0.0050 0.0050 

234 0.19 5.45 0.62 0.25 0.0104 0.0104 0.0104 0.0104 

196 0.28 5.44 0.65 0.28 0.3023 0.3023 0.3023 0.3023 

197 0.23 5.52 0.75 0.29 0.0074 0.0074 0.0074 0.0074 

263 0.43 6.13 2.68 0.31 0.0040 0.0040 0.0040 0.0040 

294 0.38 5.99 0.95 0.23 0.1154 0.1154 0.1154 0.1154 

280 0.49 6.14 2.52 0.31 0.0157 0.0157 0.0157 0.0157 

294 0.64 6.38 2.37 0.40 0.0007 0.0007 0.0007 0.0007 

283 0.09 6.38 0.51 0.12 0.0020 0.0020 0.0020 0.0020 

196 0.35 6.52 0.95 0.36 0.0006 0.0006 0.0006 0.0006 

240 0.29 4.88 0.73 0.23 0.0056 0.0056 0.0056 0.0056 

187 0.26 5.99 0.73 0.15 0.0026 0.0026 0.0026 0.0026 

189 0.37 5.87 0.76 0.35 0.0016 0.0016 0.0016 0.0016 

241 0.41 6.44 1.11 0.34 0.0028 0.0028 0.0028 0.0028 

227 0.51 6.72 1.07 0.33 0.0006 0.0006 0.0006 0.0006 

193 0.60 6.69 0.85 0.28 0.0010 0.0010 0.0010 0.0010 

296 0.38 6.19 0.54 0.22 0.0002 0.0002 0.0002 0.0002 

255 0.42 5.77 0.82 0.26 0.0006 0.0006 0.0006 0.0006 

200 0.26 5.13 0.60 0.22 0.0036 0.0036 0.0036 0.0036 

D17
 
Table D4. 1998 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

215 0.32 5.51 0.55 0.32 0.0049 0.0049 0.0049 0.0049 

240 0.29 5.38 0.49 0.27 0.0052 0.0052 0.0052 0.0052 

189 0.31 5.40 0.92 0.21 0.0010 0.0010 0.0010 0.0010 

252 0.22 6.23 0.30 0.23 0.0027 0.0027 0.0027 0.0027 

211 0.37 5.42 0.57 0.22 0.0004 0.0004 0.0004 0.0004 

253 0.23 5.28 0.47 0.27 0.0002 0.0002 0.0002 0.0002 

231 0.32 4.69 0.46 0.15 0.0005 0.0005 0.0005 0.0005 

260 0.18 6.35 0.73 0.15 0.0016 0.0016 0.0016 0.0016 

275 0.14 5.38 0.48 0.14 0.0002 0.0002 0.0002 0.0002 

248 0.34 5.31 1.04 0.35 0.0001 0.0001 0.0001 0.0001 

247 0.57 6.13 0.69 0.17 0.0004 0.0004 0.0004 0.0004 

225 0.11 6.63 0.57 0.13 0.0028 0.0028 0.0028 0.0028 

210 0.12 6.55 1.15 0.20 0.0048 0.0048 0.0048 0.0048 

225 0.14 6.73 0.64 0.16 0.0018 0.0018 0.0018 0.0018 

228 0.37 5.46 0.60 0.21 0.0294 0.0294 0.0294 0.0294 

190 0.66 6.08 1.56 0.40 0.0005 0.0005 0.0005 0.0005 

268 0.44 6.50 0.50 0.30 0.0024 0.0024 0.0024 0.0024 

182 0.42 6.43 0.87 0.30 0.0004 0.0004 0.0004 0.0004 

207 0.44 6.59 1.15 0.36 0.0004 0.0004 0.0004 0.0004 

217 0.36 5.49 1.00 0.22 0.0004 0.0004 0.0004 0.0004 

183 0.54 6.63 0.81 0.34 0.0002 0.0002 0.0002 0.0002 

227 0.35 0.63 0.51 0.27 0.0002 0.0002 0.0002 0.0002 

244 0.19 6.30 1.66 0.36 0.0016 0.0016 0.0016 0.0016 

272 0.35 6.44 1.09 0.23 0.0016 0.0016 0.0016 0.0016 

255 0.25 5.89 0.40 0.13 0.0056 0.0056 0.0056 0.0056 

255 0.25 6.22 1.10 0.14 0.0033 0.0033 0.0033 0.0033 

Sales-wgt 

EF 0.316321 5.574079 0.722968 0.262486 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 72 72 72 72 

D18
 
Table D4. 1998 MY Certification Data (cont.) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

310 0.34 5.48 0.79 0.13 0.0011 0.0011 0.0011 0.0011 

373 0.24 6.50 0.51 0.14 0.0011 0.0011 0.0011 0.0011 

335 0.27 5.51 0.74 0.28 0.0002 0.0002 0.0002 0.0002 

543 0.22 5.66 0.54 0.24 0.0016 0.0016 0.0016 0.0016 

300 0.08 5.78 0.43 0.13 0.0036 0.0036 0.0036 0.0036 

425 0.90 6.38 2.17 0.16 0.0514 0.0514 0.0514 0.0514 

300 0.28 6.13 0.81 0.36 0.0118 0.0118 0.0118 0.0118 

330 0.33 5.28 1.07 0.36 0.0111 0.0111 0.0111 0.0111 

397 0.19 5.24 1.35 0.29 0.0040 0.0040 0.0040 0.0040 

362 0.16 5.49 1.57 0.21 0.2369 0.2369 0.2369 0.2369 

500 0.13 6.10 1.67 0.17 0.0257 0.0257 0.0257 0.0257 

455 0.12 5.48 0.82 0.17 0.0029 0.0029 0.0029 0.0029 

599 0.04 6.59 2.67 0.33 0.0715 0.0715 0.0715 0.0715 

350 0.22 6.52 1.17 0.20 0.1676 0.1676 0.1676 0.1676 

525 0.25 6.36 0.45 0.15 0.0032 0.0032 0.0032 0.0032 

480 0.17 6.85 1.16 0.18 0.1718 0.1718 0.1718 0.1718 

336 0.14 5.48 0.45 0.15 0.0070 0.0070 0.0070 0.0070 

375 0.40 6.03 2.02 0.28 0.0012 0.0012 0.0012 0.0012 

336 0.41 5.99 1.31 0.30 0.0084 0.0084 0.0084 0.0084 

399 0.18 5.33 0.91 0.14 0.0285 0.0285 0.0285 0.0285 

339 0.21 5.72 0.92 0.15 0.0020 0.0020 0.0020 0.0020 

517 0.17 5.74 0.37 0.13 0.0630 0.0630 0.0630 0.0630 

401 0.23 6.02 0.50 0.14 0.0090 0.0090 0.0090 0.0090 

313 0.13 6.38 0.59 0.15 0.0077 0.0077 0.0077 0.0077 

420 0.36 6.65 0.47 0.18 0.0118 0.0118 0.0118 0.0118 

425 0.08 6.44 0.76 0.15 0.0193 0.0193 0.0193 0.0193 

567 0.28 5.65 2.26 0.33 0.0010 0.0010 0.0010 0.0010 

586 0.20 4.64 0.45 0.18 0.0029 0.0029 0.0029 0.0029 

329 0.26 6.38 0.61 0.19 0.0018 0.0018 0.0018 0.0018 

590 0.34 6.40 0.72 0.23 0.0001 0.0001 0.0001 0.0001 

306 0.24 6.29 0.72 0.37 0.0086 0.0086 0.0086 0.0086 

493 0.16 4.26 1.04 0.30 0.0037 0.0037 0.0037 0.0037 

335 0.19 5.78 0.41 0.18 0.0002 0.0002 0.0002 0.0002 

375 0.22 5.72 0.32 0.20 0.0014 0.0014 0.0014 0.0014 

525 0.17 6.06 0.60 0.23 0.0002 0.0002 0.0002 0.0002 

493 0.16 5.89 0.95 0.28 0.0004 0.0004 0.0004 0.0004 

572 0.14 5.86 0.62 0.24 0.0004 0.0004 0.0004 0.0004 

571 0.31 3.98 0.48 0.17 0.0021 0.0021 0.0021 0.0021 

531 0.36 5.01 0.40 0.16 0.0021 0.0021 0.0021 0.0021 

327 0.22 6.39 0.46 0.14 0.0021 0.0021 0.0021 0.0021 

327 0.24 6.11 0.48 0.13 0.0021 0.0021 0.0021 0.0021 

308 0.30 5.67 0.45 0.18 0.0018 0.0018 0.0018 0.0018 

335 0.27 5.51 0.74 0.28 0.0027 0.0027 0.0027 0.0027 

543 0.02 5.66 0.54 0.24 0.0064 0.0064 0.0064 0.0064 

330 0.07 5.07 0.44 0.10 0.0068 0.0068 0.0068 0.0068 

330 0.04 5.64 0.40 0.16 0.0114 0.0114 0.0114 0.0114 

D19
 
Table D4. 1998 MY Certification Data (cont.) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

381 0.21 6.55 0.61 0.08 0.0167 0.0167 0.0167 0.0167 

496 0.13 6.12 0.28 0.07 0.0021 0.0021 0.0021 0.0021 

Sales-wgt 

EF 0.209071 6.126551 1.289223 0.198893 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 48 48 48 48 

Table D4. 1998 MY Certification Data (cont.) 

600-750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

660 0.10 6.03 0.54 0.13 0.0630 0.0630 0.0630 0.0630 

640 0.11 5.62 0.83 0.19 0.0132 0.0132 0.0132 0.0132 

740 0.10 5.53 1.62 0.33 0.0350 0.0350 0.0350 0.0350 

600 0.26 6.02 1.78 0.24 0.2955 0.2955 0.2955 0.2955 

606 0.16 6.01 0.58 0.12 0.1128 0.1128 0.1128 0.1128 

725 0.16 5.88 0.84 0.12 0.0855 0.0855 0.0855 0.0855 

750 0.07 5.84 0.90 0.16 0.0210 0.0210 0.0210 0.0210 

750 0.07 5.90 1.29 0.22 0.1089 0.1089 0.1089 0.1089 

750 0.06 4.48 1.43 0.24 0.0389 0.0389 0.0389 0.0389 

750 0.35 5.80 1.48 0.30 0.1322 0.1322 0.1322 0.1322 

750 0.13 5.89 1.06 0.13 0.0855 0.0855 0.0855 0.0855 

740 0.24 5.85 1.37 0.28 0.0086 0.0086 0.0086 0.0086 

Sales-wgt 

EF 0.190719 5.866023 1.277422 0.205116 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 12 12 12 12 

D20
 
Table D5. 1999 MY Certification Data 

25-50 hp Emission Factors (g/hp-hr) Sales Weighting 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HC+NOx* wgt 

34 5.21 1.44 0.38 0.0000 0.0000 0.0107 0.0107 0.0107 

36 3.12 1.31 0.40 0.0000 0.0000 0.0011 0.0011 0.0011 

45 5.95 0.48 0.26 0.0000 0.0000 0.0011 0.0011 0.0011 

50 6.14 0.0000 0.1061 0.0000 0.0000 0.0000 

38 6.69 1.92 0.32 0.0000 0.0000 0.0113 0.0113 0.0113 

35 5.68 1.74 0.21 0.0000 0.0000 0.0282 0.0282 0.0282 

39 6.58 1.84 0.11 0.0000 0.0000 0.0068 0.0068 0.0068 

47 5.84 1.35 0.09 0.0000 0.0000 0.0056 0.0056 0.0056 

28 3.76 1.24 0.20 0.0000 0.0000 0.0025 0.0025 0.0025 

33 3.65 0.87 0.17 0.0000 0.0000 0.0033 0.0033 0.0033 

40 4.50 0.62 0.20 0.0000 0.0000 0.0013 0.0013 0.0013 

47 3.38 0.87 0.27 0.0000 0.0000 0.0007 0.0007 0.0007 

27 5.66 1.62 0.56 0.0000 0.0000 0.0008 0.0008 0.0008 

29 4.11 1.16 0.35 0.0000 0.0000 0.0310 0.0310 0.0310 

40 2.78 1.62 0.42 0.0000 0.0000 0.0507 0.0507 0.0507 

45 4.04 0.87 0.38 0.0000 0.0000 0.0158 0.0158 0.0158 

28 3.57 2.65 0.43 0.0000 0.0000 0.0017 0.0017 0.0017 

27 0.17 4.29 4.46 1.25 0.52 0.038763 0.0019 0.0014 0.0003 0.0003 0.0003 

37 0.16 3.56 3.72 2.30 0.60 0.043011 0.0027 0.0020 0.0004 0.0004 0.0004 

32 0.26 4.22 4.49 1.61 0.54 0.058036 0.0360 0.0262 0.0048 0.0048 0.0048 

27 0.09 3.95 4.04 0.82 0.42 0.022277 0.0046 0.0034 0.0006 0.0006 0.0006 

39 0.14 4.59 4.74 0.90 0.45 0.029598 0.0115 0.0084 0.0016 0.0016 0.0016 

34 0.16 3.30 3.46 0.68 0.30 0.046243 0.0028 0.0020 0.0004 0.0004 0.0004 

35 0.56 4.54 5.10 1.52 0.48 0.109804 0.8386 0.6112 0.1127 0.1127 0.1127 

34 0.08 4.56 4.64 0.90 0.40 0.017241 0.0616 0.0449 0.0083 0.0083 0.0083 

40 0.69 6.18 6.88 1.62 0.25 0.100868 0.0046 0.0034 0.0006 0.0006 0.0006 

34 4.59 0.92 0.42 0.0000 0.0000 0.0001 0.0001 0.0001 

46 3.79 0.68 0.33 0.0000 0.0000 0.0008 0.0008 0.0008 

34 3.80 0.98 0.54 0.0000 0.0000 0.0058 0.0058 0.0058 

47 0.12 6.71 6.83 0.74 0.30 0.01757 0.0042 0.0031 0.0006 0.0006 0.0006 

38 6.16 1.66 0.41 0.0000 0.0000 0.0451 0.0451 0.0451 

26 4.64 1.30 0.28 0.0000 0.0000 0.0011 0.0011 0.0011 

31 3.80 1.16 0.36 0.0000 0.0000 0.0163 0.0163 0.0163 

42 3.84 0.77 0.24 0.0000 0.0000 0.0047 0.0047 0.0047 

26 4.46 0.96 0.35 0.0000 0.0000 0.0417 0.0417 0.0417 

41 4.81 0.75 0.25 0.0000 0.0000 0.0008 0.0008 0.0008 

31 5.27 0.74 0.19 0.0000 0.0000 0.0118 0.0118 0.0118 

31 5.11 0.80 0.26 0.0000 0.0000 0.0662 0.0662 0.0662 

37 4.47 0.80 0.29 0.0000 0.0000 0.1936 0.1936 0.1936 

40 0.18 4.99 5.17 0.94 0.48 0.034632 0.0315 0.0230 0.0042 0.0042 0.0042 

30 2.79 3.06 0.46 0.0000 0.0000 0.0013 0.0013 0.0013 

38 3.62 2.13 0.51 0.0000 0.0000 0.0025 0.0025 0.0025 

25 5.78 3.66 0.43 0.0000 0.0000 0.0045 0.0045 0.0045 

33 2.37 1.58 0.53 0.0000 0.0000 0.0017 0.0017 0.0017 

30 5.29 1.50 0.33 0.0000 0.0000 0.0008 0.0008 0.0008 

D21
 
Table D5. 1999 MY Certification Data 

25-50 hp Emission Factors (g/hp-hr) Sales Weighting 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HC+NOx* wgt 

35 5.48 1.61 0.36 0.0000 0.0000 0.0025 0.0025 0.0025 

40 5.53 2.57 0.22 0.0000 0.0000 0.0025 0.0025 0.0025 

44 5.56 1.69 0.34 0.0000 0.0000 0.0017 0.0017 0.0017 

44 5.96 2.39 0.19 0.0000 0.0000 0.0017 0.0017 0.0017 

38 6.00 1.25 0.36 0.0000 0.0000 0.0001 0.0001 0.0001 

30 6.51 3.22 0.50 0.0000 0.0000 0.0034 0.0034 0.0034 

39 4.73 1.01 0.34 0.0000 0.0000 0.0021 0.0021 0.0021 

35 6.27 2.35 0.48 0.0000 0.0000 0.0118 0.0118 0.0118 

44 6.19 1.09 0.53 0.0000 0.0000 0.0225 0.0225 0.0225 

34 3.53 3.55 1.22 0.54 0.0000 0.0458 0.0085 0.0085 0.0085 

49 3.20 3.31 1.29 0.40 0.0000 0.0917 0.0169 0.0169 0.0169 

49 4.85 0.0000 0.0275 0.0000 0.0000 0.0000 

28 5.78 3.61 0.40 0.0000 0.0000 0.0152 0.0152 0.0152 

30 5.82 2.93 0.35 0.0000 0.0000 0.0026 0.0026 0.0026 

33 5.76 2.74 0.28 0.0000 0.0000 0.0596 0.0596 0.0596 

41 5.97 1.35 0.49 0.0000 0.0000 0.0006 0.0006 0.0006 

29 5.82 2.82 0.25 0.0000 0.0000 0.0070 0.0070 0.0070 

37 6.76 1.71 0.40 0.0000 0.0000 0.0007 0.0007 0.0007 

37 6.03 2.59 0.35 0.0000 0.0000 0.0098 0.0098 0.0098 

30 6.07 3.01 0.38 0.0000 0.0000 0.0169 0.0169 0.0169 

45 5.85 3.21 0.45 0.0000 0.0000 0.0423 0.0423 0.0423 

38 5.79 3.23 0.39 0.0000 0.0000 0.0011 0.0011 0.0011 

48 6.00 1.56 0.44 0.0000 0.0000 0.0001 0.0001 0.0001 

34 5.94 1.87 0.34 0.0000 0.0000 0.0507 0.0507 0.0507 

46 6.01 2.54 0.20 0.0000 0.0000 0.0039 0.0039 0.0039 

41 5.76 2.79 0.33 0.0000 0.0000 0.0041 0.0041 0.0041 

48 6.25 1.59 0.28 0.0000 0.0000 0.0002 0.0002 0.0002 

27 3.04 0.98 0.40 0.0000 0.0000 0.0036 0.0036 0.0036 

39 5.53 1.96 0.26 0.0000 0.0000 0.0015 0.0015 0.0015 

Sales-wgt 

EF 0.4965 4.5584 4.9834 1.5421 0.3561 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 11 15 72 72 72 0.047095 

Calc HC* 0.2347 

Calc NOx* 4.7487 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D22
 
Table D5. 1999 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

67 6.40 0.0000 0.0035 0.0000 0.0000 0.0000 

79 5.74 0.0000 0.0007 0.0000 0.0000 0.0000 

96 5.81 0.0000 0.0005 0.0000 0.0000 0.0000 

80 0.48 7.61 4.32 0.56 0.1942 0.0652 0.0000 0.1802 0.1814 

67 0.75 6.35 1.96 0.34 0.1177 0.0395 0.0000 0.1092 0.1100 

75 0.70 5.68 2.28 0.49 0.1618 0.0544 0.0000 0.1502 0.1512 

80 0.72 5.78 3.26 0.51 0.0647 0.0217 0.0000 0.0601 0.0605 

56 0.46 5.71 2.19 0.29 0.0309 0.0104 0.0000 0.0287 0.0289 

75 0.70 5.68 2.28 0.49 0.0486 0.0163 0.0000 0.0451 0.0454 

98 0.71 6.30 1.68 0.21 0.0008 0.0003 0.0000 0.0008 0.0008 

62 6.23 0.0000 0.0010 0.0000 0.0000 0.0000 

57 6.20 0.0000 0.0010 0.0000 0.0000 0.0000 

55 5.80 0.0000 0.0010 0.0000 0.0000 0.0000 

59 6.56 0.0000 0.0216 0.0000 0.0000 0.0000 

84 5.74 0.0000 0.0306 0.0000 0.0000 0.0000 

59 0.89 8.82 3.55 0.84 0.0099 0.0033 0.0000 0.0092 0.0092 

74 5.82 0.0000 0.0045 0.0000 0.0000 0.0000 

82 5.23 0.0000 0.0552 0.0000 0.0000 0.0000 

53 6.32 0.0000 0.0280 0.0000 0.0000 0.0000 

56 6.70 2.22 0.34 0.0000 0.0000 0.9552 0.0655 0.0660 

60 6.16 0.0000 0.0173 0.0000 0.0000 0.0000 

72 6.30 0.0000 0.0018 0.0000 0.0000 0.0000 

56 5.21 0.0000 0.0040 0.0000 0.0000 0.0000 

70 5.02 0.0000 0.0005 0.0000 0.0000 0.0000 

96 6.32 0.0000 0.0006 0.0000 0.0000 0.0000 

74 3.22 0.0000 0.0049 0.0000 0.0000 0.0000 

78 6.22 0.0000 0.0000 0.0000 0.0000 0.0000 

52 4.59 0.0000 0.0148 0.0000 0.0000 0.0000 

50 4.14 0.0000 0.0030 0.0000 0.0000 0.0000 

52 0.17 5.22 1.18 0.45 0.0049 0.0016 0.0000 0.0045 0.0045 

54 0.69 4.15 1.45 0.36 0.0183 0.0062 0.0000 0.0170 0.0171 

51 0.60 6.68 3.04 0.63 0.0003 0.0001 0.0000 0.0003 0.0003 

61 0.46 6.07 1.33 0.32 0.0121 0.0041 0.0000 0.0112 0.0113 

64 0.43 5.62 2.17 0.60 0.0056 0.0019 0.0000 0.0052 0.0052 

73 0.24 4.79 0.87 0.52 0.0110 0.0037 0.0000 0.0102 0.0103 

56 0.48 4.88 0.46 0.27 0.0003 0.0001 0.0000 0.0003 0.0003 

63 0.52 6.27 1.67 0.57 0.0118 0.0040 0.0000 0.0109 0.0110 

71 0.55 5.27 2.17 0.57 0.0236 0.0079 0.0000 0.0219 0.0221 

91 0.42 6.63 1.32 0.54 0.0287 0.0096 0.0000 0.0266 0.0268 

59 6.65 0.0000 0.0230 0.0000 0.0000 0.0000 

80 0.72 5.78 3.26 0.51 0.0044 0.0015 0.0000 0.0041 0.0041 

98 0.71 6.30 1.68 0.21 0.0008 0.0003 0.0000 0.0008 0.0008 

56 0.46 5.71 2.19 0.29 0.0002 0.0001 0.0000 0.0002 0.0002 

59 4.37 0.0000 0.0022 0.0000 0.0000 0.0000 

56 4.18 0.0000 0.0148 0.0000 0.0000 0.0000 

86 5.42 0.0000 0.0089 0.0000 0.0000 0.0000 

D23
 
Table D5. 1999 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

93 4.71 0.0000 0.0074 0.0000 0.0000 0.0000 

72 4.31 0.0000 0.0119 0.0000 0.0000 0.0000 

54 0.55 6.31 2.42 0.0060 0.0020 0.0000 0.0056 0.0000 

58 0.08 3.32 3.41 0.89 0.0011 0.0004 0.0149 0.0010 0.0000 

59 3.34 0.0000 0.0002 0.0000 0.0000 0.0000 

54 2.62 0.0000 0.0047 0.0000 0.0000 0.0000 

79 5.06 0.0000 0.0002 0.0000 0.0000 0.0000 

50 4.09 0.80 0.25 0.0000 0.0000 0.0299 0.0020 0.0021 

57 4.46 0.0000 0.0061 0.0000 0.0000 0.0000 

55 2.91 0.0000 0.0014 0.0000 0.0000 0.0000 

51 5.35 0.0000 0.0083 0.0000 0.0000 0.0000 

87 5.92 0.0000 0.0058 0.0000 0.0000 0.0000 

52 6.32 0.0000 0.0050 0.0000 0.0000 0.0000 

89 6.40 0.0000 0.0005 0.0000 0.0000 0.0000 

67 0.14 4.94 1.07 0.45 0.1378 0.0463 0.0000 0.1279 0.1288 

92 0.27 5.62 0.99 0.27 0.0902 0.0303 0.0000 0.0837 0.0842 

58 3.00 0.0000 0.0012 0.0000 0.0000 0.0000 

85 2.18 0.0000 0.0013 0.0000 0.0000 0.0000 

59 5.90 0.0000 0.0010 0.0000 0.0000 0.0000 

58 3.23 0.0000 0.0247 0.0000 0.0000 0.0000 

81 5.43 0.0000 0.0059 0.0000 0.0000 0.0000 

52 6.62 0.0000 0.0104 0.0000 0.0000 0.0000 

64 5.13 0.0000 0.0049 0.0000 0.0000 0.0000 

60 6.06 0.0000 0.0247 0.0000 0.0000 0.0000 

96 5.09 0.0000 0.1503 0.0000 0.0000 0.0000 

68 5.85 0.0000 0.0652 0.0000 0.0000 0.0000 

68 6.34 0.0000 0.0420 0.0000 0.0000 0.0000 

80 0.83 6.00 3.19 0.63 0.0063 0.0021 0.0000 0.0059 0.0059 

80 0.86 5.40 4.00 0.64 0.0079 0.0027 0.0000 0.0074 0.0074 

59 4.33 0.0000 0.0030 0.0000 0.0000 0.0000 

84 6.14 0.0000 0.0010 0.0000 0.0000 0.0000 

94 5.75 0.0000 0.0003 0.0000 0.0000 0.0000 

82 4.84 1.22 0.44 0.0000 0.0010 0.0000 0.0029 0.0029 

62 6.06 3.96 0.39 0.0000 0.0000 0.0000 0.0001 0.0001 

100 6.27 0.87 0.41 0.0000 0.0003 0.0000 0.0007 0.0007 

62 6.19 1.69 0.30 0.0000 0.0003 0.0000 0.0007 0.0007 

75 3.87 0.0000 0.0020 0.0000 0.0000 0.0000 

58 3.91 0.0000 0.0022 0.0000 0.0000 0.0000 

54 5.40 0.0000 0.0001 0.0000 0.0000 0.0000 

67 4.89 0.0000 0.0163 0.0000 0.0000 0.0000 

80 4.80 0.0000 0.0005 0.0000 0.0000 0.0000 

56 5.23 0.0000 0.0020 0.0000 0.0000 0.0000 

58 5.12 0.0000 0.0004 0.0000 0.0000 0.0000 

60 4.12 0.0000 0.0025 0.0000 0.0000 0.0000 

70 5.59 0.0000 0.0049 0.0000 0.0000 0.0000 

93 5.35 0.0000 0.0005 0.0000 0.0000 0.0000 

100 5.73 0.0000 0.0002 0.0000 0.0000 0.0000 

D24
 
50-100 hp 

Rated HP HC 

Table D5. 1999 MY Certification Data (cont.) 

Emission Factors (g/hp-hr) Sales Weightings 

NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

Sales-wgt 

EF 

0.51764 

2 

5.61337 

6 6.569501 

2.346 

87 0.45255 

3 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 27 91 3 33 31 

D25
 
Table D5. 1999 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

167 0.34 5.26 1.05 0.18 0.0004 0.0003 0.0004 0.0004 

108 6.47 0.0000 0.0005 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.1343 0.1074 0.1342 0.1355 

125 0.23 6.21 0.47 0.16 0.0048 0.0039 0.0048 0.0049 

155 0.38 4.23 0.75 0.35 0.1246 0.0996 0.1245 0.1257 

110 6.06 0.0000 0.0014 0.0000 0.0000 

165 6.24 0.0000 0.0373 0.0000 0.0000 

166 4.95 0.0000 0.0030 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.2077 0.1660 0.2075 0.2095 

125 0.23 6.21 0.47 0.16 0.1179 0.0942 0.1178 0.1189 

158 6.53 0.0000 0.0020 0.0000 0.0000 

109 6.41 0.0000 0.0020 0.0000 0.0000 

133 6.50 0.0000 0.0020 0.0000 0.0000 

141 4.97 0.0000 0.0020 0.0000 0.0000 

172 4.83 0.0000 0.0020 0.0000 0.0000 

168 0.11 6.17 0.63 0.13 0.0004 0.0003 0.0004 0.0004 

162 0.62 6.11 0.90 0.29 0.0004 0.0003 0.0004 0.0004 

135 0.40 5.70 1.75 0.29 0.2486 0.1987 0.2483 0.2507 

155 6.39 0.0000 0.0022 0.0000 0.0000 

108 6.55 0.0000 0.0102 0.0000 0.0000 

157 6.65 0.0000 0.0074 0.0000 0.0000 

103 0.57 6.26 1.58 0.39 0.0071 0.0056 0.0070 0.0071 

144 0.53 6.08 0.55 0.28 0.0187 0.0150 0.0187 0.0189 

144 6.61 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0100 0.0080 0.0100 0.0101 

125 0.23 6.21 0.47 0.16 0.0014 0.0011 0.0014 0.0014 

155 0.38 4.23 0.75 0.35 0.0165 0.0132 0.0165 0.0166 

114 5.87 0.0000 0.0010 0.0000 0.0000 

103 5.94 0.0000 0.0001 0.0000 0.0000 

151 5.60 0.0000 0.0002 0.0000 0.0000 

120 5.50 0.0000 0.0200 0.0000 0.0000 

144 5.80 0.0000 0.0121 0.0000 0.0000 

118 5.52 0.0000 0.0007 0.0000 0.0000 

113 4.41 0.0000 0.0050 0.0000 0.0000 

173 5.79 0.0000 0.0005 0.0000 0.0000 

108 0.17 5.99 0.37 0.17 0.0515 0.0411 0.0514 0.0519 

116 0.62 5.36 1.39 0.18 0.0101 0.0081 0.0101 0.0102 

168 0.37 5.68 0.54 0.17 0.0257 0.0206 0.0257 0.0260 

118 6.30 0.0000 0.0006 0.0000 0.0000 

164 5.92 0.0000 0.0161 0.0000 0.0000 

103 6.19 0.0000 0.0125 0.0000 0.0000 

120 5.55 0.0000 0.0453 0.0000 0.0000 

173 6.05 0.0000 0.0050 0.0000 0.0000 

115 5.77 0.0000 0.0002 0.0000 0.0000 

135 0.45 6.68 0.92 0.24 0.0009 0.0007 0.0009 0.0009 

150 0.50 5.74 1.06 0.49 0.0009 0.0007 0.0009 0.0009 

D26
 
Table D5. 1999 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

103 0.53 5.30 1.24 0.51 0.0021 0.0017 0.0021 0.0022 

130 0.63 6.61 1.21 0.36 0.0015 0.0012 0.0015 0.0015 

100 0.57 5.50 1.35 0.47 0.0028 0.0022 0.0028 0.0028 

114 6.39 0.0000 0.0030 0.0000 0.0000 

127 5.38 0.0000 0.0010 0.0000 0.0000 

117 6.23 0.0000 0.0010 0.0000 0.0000 

172 6.23 0.0000 0.0030 0.0000 0.0000 

173 0.54 6.57 1.83 0.42 0.0013 0.0010 0.0013 0.0013 

123 4.12 0.64 0.0000 0.0003 0.0003 0.0000 

122 0.07 5.75 1.06 0.43 0.0010 0.0008 0.0010 0.0010 

142 5.92 1.33 0.31 0.0000 0.0005 0.0007 0.0007 

138 6.68 0.0000 0.0005 0.0000 0.0000 

161 0.23 5.96 0.83 0.0094 0.0075 0.0093 0.0000 

Sales-wgt 

EF 0.351590 5.749792 0.937310 0.270345 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 25 59 27 25 

D27
 
Table D5. 1999 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

257 0.43 6.43 0.76 0.20 0.0002 0.0002 0.0002 0.0002 

200 0.26 5.13 0.60 0.22 0.0290 0.0290 0.0290 0.0290 

215 0.32 5.51 0.55 0.32 0.0136 0.0136 0.0136 0.0136 

260 0.44 5.82 0.70 0.27 0.0091 0.0091 0.0091 0.0091 

240 0.29 5.38 0.49 0.27 0.0091 0.0091 0.0091 0.0091 

280 0.47 5.47 0.52 0.23 0.0207 0.0207 0.0207 0.0207 

275 0.11 4.56 1.26 0.26 0.0012 0.0012 0.0012 0.0012 

205 0.19 5.96 1.73 0.25 0.0041 0.0041 0.0041 0.0041 

255 0.08 6.20 0.96 0.27 0.0108 0.0108 0.0108 0.0108 

294 0.09 5.45 2.19 0.34 0.0041 0.0041 0.0041 0.0041 

260 0.36 5.73 1.30 0.39 0.0009 0.0009 0.0009 0.0009 

225 0.41 5.70 0.84 0.22 0.0252 0.0252 0.0252 0.0252 

240 0.10 5.06 0.38 0.15 0.0414 0.0414 0.0414 0.0414 

200 0.26 5.13 0.60 0.22 0.0746 0.0746 0.0746 0.0746 

215 0.32 5.51 0.55 0.32 0.0787 0.0787 0.0787 0.0787 

260 0.44 5.82 0.70 0.27 0.0575 0.0575 0.0575 0.0575 

240 0.29 5.38 0.49 0.27 0.0828 0.0828 0.0828 0.0828 

280 0.47 5.47 0.52 0.23 0.0083 0.0083 0.0083 0.0083 

200 0.25 5.43 1.23 0.35 0.0015 0.0015 0.0015 0.0015 

253 0.34 6.58 0.57 0.20 0.0015 0.0015 0.0015 0.0015 

296 0.31 6.41 0.96 0.25 0.0015 0.0015 0.0015 0.0015 

261 0.47 6.06 0.89 0.27 0.0002 0.0002 0.0002 0.0002 

248 0.34 5.31 1.04 0.35 0.0002 0.0002 0.0002 0.0002 

275 0.14 5.38 0.48 0.14 0.0002 0.0002 0.0002 0.0002 

220 0.20 5.87 0.72 0.27 0.0043 0.0043 0.0043 0.0043 

234 0.19 5.45 0.62 0.25 0.0108 0.0108 0.0108 0.0108 

196 0.28 5.44 0.65 0.28 0.2781 0.2781 0.2781 0.2781 

197 0.23 5.52 0.75 0.29 0.0097 0.0097 0.0097 0.0097 

294 0.38 5.99 0.95 0.23 0.0988 0.0988 0.0988 0.0988 

285 0.46 6.51 1.19 0.22 0.0146 0.0146 0.0146 0.0146 

216 0.59 6.20 1.55 0.28 0.0260 0.0260 0.0260 0.0260 

285 0.47 4.59 0.73 0.26 0.0040 0.0040 0.0040 0.0040 

237 0.78 6.32 1.31 0.38 0.0002 0.0002 0.0002 0.0002 

196 0.35 6.52 0.95 0.36 0.0017 0.0017 0.0017 0.0017 

187 0.26 5.99 0.73 0.15 0.0039 0.0039 0.0039 0.0039 

186 0.34 6.28 0.69 0.23 0.0017 0.0017 0.0017 0.0017 

189 0.37 5.87 0.76 0.35 0.0011 0.0011 0.0011 0.0011 

249 0.48 6.37 1.08 0.24 0.0002 0.0002 0.0002 0.0002 

243 0.40 5.88 1.67 0.37 0.0001 0.0001 0.0001 0.0001 

241 0.41 6.44 1.11 0.34 0.0008 0.0008 0.0008 0.0008 

227 0.51 6.72 1.07 0.33 0.0034 0.0034 0.0034 0.0034 

193 0.60 6.69 0.85 0.21 0.0004 0.0004 0.0004 0.0004 

200 0.26 5.13 0.60 0.22 0.0034 0.0034 0.0034 0.0034 

215 0.32 5.51 0.55 0.32 0.0046 0.0046 0.0046 0.0046 

240 0.29 5.38 0.49 0.27 0.0049 0.0049 0.0049 0.0049 

280 0.47 5.47 0.52 0.23 0.0005 0.0005 0.0005 0.0005 

D28
 
Table D5. 1999 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

189 0.31 5.40 0.92 0.21 0.0009 0.0009 0.0009 0.0009 

252 0.22 6.23 0.30 0.23 0.0026 0.0026 0.0026 0.0026 

211 0.37 5.42 0.57 0.22 0.0003 0.0003 0.0003 0.0003 

253 0.23 5.28 0.47 0.27 0.0002 0.0002 0.0002 0.0002 

244 0.39 6.24 0.74 0.18 0.0005 0.0005 0.0005 0.0005 

247 0.57 6.13 0.69 0.17 0.0003 0.0003 0.0003 0.0003 

184 0.30 6.70 0.61 0.18 0.0010 0.0010 0.0010 0.0010 

280 0.19 5.68 0.51 0.18 0.0017 0.0017 0.0017 0.0017 

298 0.37 6.32 1.16 0.30 0.0012 0.0012 0.0012 0.0012 

225 0.11 6.63 0.57 0.13 0.0001 0.0001 0.0001 0.0001 

210 0.13 6.73 1.77 0.21 0.0019 0.0019 0.0019 0.0019 

210 0.12 6.55 1.15 0.20 0.0017 0.0017 0.0017 0.0017 

225 0.14 6.73 0.64 0.16 0.0017 0.0017 0.0017 0.0017 

286 0.39 5.07 0.50 0.20 0.0246 0.0246 0.0246 0.0246 

190 0.66 6.08 1.56 0.40 0.0005 0.0005 0.0005 0.0005 

268 0.44 6.50 0.50 0.22 0.0013 0.0013 0.0013 0.0013 

177 0.34 6.20 0.89 0.28 0.0004 0.0004 0.0004 0.0004 

182 0.42 6.43 0.87 0.30 0.0004 0.0004 0.0004 0.0004 

207 0.44 6.59 1.15 0.36 0.0004 0.0004 0.0004 0.0004 

217 0.36 5.49 1.00 0.22 0.0004 0.0004 0.0004 0.0004 

183 0.54 6.63 0.81 0.34 0.0002 0.0002 0.0002 0.0002 

227 0.35 6.34 0.51 0.27 0.0002 0.0002 0.0002 0.0002 

244 0.19 6.30 1.66 0.36 0.0015 0.0015 0.0015 0.0015 

272 0.35 6.44 1.09 0.23 0.0015 0.0015 0.0015 0.0015 

255 0.25 5.89 0.40 0.13 0.0055 0.0055 0.0055 0.0055 

Sales-wgt 

EF 0.314974 5.549376 0.695869 0.257528 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 71 71 71 71 

D29
 
Table D5. 1999 MY Certification Data (cont.) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

310 0.34 5.48 0.79 0.13 0.0011 0.0011 0.0011 0.0011 

415 0.10 4.65 0.40 0.08 0.0036 0.0036 0.0036 0.0036 

340 0.12 3.91 0.56 0.17 0.0271 0.0271 0.0271 0.0271 

300 0.08 5.78 0.43 0.13 0.0036 0.0036 0.0036 0.0036 

425 0.90 6.38 2.17 0.16 0.0522 0.0522 0.0522 0.0522 

300 0.28 6.13 0.81 0.36 0.0049 0.0049 0.0049 0.0049 

330 0.33 5.28 1.07 0.36 0.0060 0.0060 0.0060 0.0060 

397 0.19 4.65 1.35 0.19 0.0027 0.0027 0.0027 0.0027 

362 0.16 5.49 1.57 0.21 0.1859 0.1859 0.1859 0.1859 

500 0.13 6.10 1.67 0.17 0.0260 0.0260 0.0260 0.0260 

455 0.12 5.48 0.82 0.17 0.0036 0.0036 0.0036 0.0036 

599 0.04 6.59 2.67 0.33 0.0763 0.0763 0.0763 0.0763 

535 0.08 5.79 2.10 0.34 0.0060 0.0060 0.0060 0.0060 

350 0.22 6.52 1.17 0.20 0.0597 0.0597 0.0597 0.0597 

430 0.14 6.29 0.34 0.13 0.0199 0.0199 0.0199 0.0199 

480 0.17 6.85 1.16 0.18 0.1809 0.1809 0.1809 0.1809 

525 0.16 6.52 0.65 0.16 0.0109 0.0109 0.0109 0.0109 

336 0.14 5.48 0.45 0.15 0.0071 0.0071 0.0071 0.0071 

422 0.15 4.97 0.40 0.11 0.0007 0.0007 0.0007 0.0007 

563 0.14 5.11 0.40 0.11 0.0004 0.0004 0.0004 0.0004 

308 0.28 5.68 0.45 0.20 0.0016 0.0016 0.0016 0.0016 

335 0.27 5.51 0.74 0.28 0.0027 0.0027 0.0027 0.0027 

543 0.22 5.66 0.54 0.25 0.0099 0.0099 0.0099 0.0099 

336 0.37 4.65 0.68 0.25 0.0282 0.0282 0.0282 0.0282 

336 0.41 5.99 1.31 0.30 0.0072 0.0072 0.0072 0.0072 

339 0.21 5.72 0.92 0.15 0.0035 0.0035 0.0035 0.0035 

399 0.18 5.33 0.91 0.15 0.0047 0.0047 0.0047 0.0047 

517 0.17 5.74 0.37 0.13 0.0575 0.0575 0.0575 0.0575 

401 0.23 6.02 0.50 0.14 0.0158 0.0158 0.0158 0.0158 

431 0.17 5.59 0.43 0.15 0.0071 0.0071 0.0071 0.0071 

361 0.20 5.77 0.62 0.16 0.0061 0.0061 0.0061 0.0061 

350 0.08 5.74 2.10 0.15 0.0089 0.0089 0.0089 0.0089 

313 0.13 6.38 0.59 0.14 0.0116 0.0116 0.0116 0.0116 

430 0.35 6.64 0.56 0.19 0.0022 0.0022 0.0022 0.0022 

425 0.08 6.44 0.76 0.16 0.0689 0.0689 0.0689 0.0689 

586 0.20 4.64 0.45 0.18 0.0043 0.0043 0.0043 0.0043 

329 0.26 6.38 0.61 0.19 0.0025 0.0025 0.0025 0.0025 

590 0.34 6.40 0.72 0.24 0.0001 0.0001 0.0001 0.0001 

335 0.26 6.17 1.05 0.32 0.0004 0.0004 0.0004 0.0004 

306 0.24 6.29 0.72 0.37 0.0137 0.0137 0.0137 0.0137 

326 0.50 4.04 0.43 0.14 0.0010 0.0010 0.0010 0.0010 

493 0.16 4.26 1.04 0.22 0.0014 0.0014 0.0014 0.0014 

493 0.16 5.89 0.95 0.28 0.0004 0.0004 0.0004 0.0004 

335 0.19 5.78 0.41 0.18 0.0002 0.0002 0.0002 0.0002 

375 0.22 5.72 0.32 0.20 0.0038 0.0038 0.0038 0.0038 

525 0.17 6.06 0.60 0.23 0.0002 0.0002 0.0002 0.0002 

D30
 
300-600 hp 

Table D5. 1999 MY Certification Data (cont.)
 

Emission Factors (g/hp-hr) Sales Weightings
 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

571 0.31 3.98 0.48 0.17 0.0022 0.0022 0.0022 0.0022 

475 0.28 4.09 0.46 0.15 0.0022 0.0022 0.0022 0.0022 

327 0.22 6.39 0.46 0.14 0.0022 0.0022 0.0022 0.0022 

327 0.24 6.11 0.48 0.13 0.0022 0.0022 0.0022 0.0022 

330 0.07 5.07 0.44 0.10 0.0036 0.0036 0.0036 0.0036 

330 0.04 5.64 0.40 0.16 0.0116 0.0116 0.0116 0.0116 

313 0.27 6.26 0.31 0.06 0.0134 0.0134 0.0134 0.0134 

381 0.21 6.55 0.61 0.08 0.0186 0.0186 0.0186 0.0186 

496 0.13 6.12 0.28 0.07 0.0016 0.0016 0.0016 0.0016 

Sales-wgt 

EF 0.201521 6.049760 1.201752 0.192703 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 55 55 55 55 

Table D5. 1999 MY Certification Data (cont.) 

600-750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

660 0.05 6.24 0.83 0.14 0.1765 0.1765 0.1765 0.1765 

740 0.05 5.68 1.57 0.25 0.2857 0.2857 0.2857 0.2857 

640 0.11 5.62 0.83 0.19 0.0071 0.0071 0.0071 0.0071 

730 0.06 5.04 0.99 0.19 0.0903 0.0903 0.0903 0.0903 

740 0.10 5.53 1.62 0.33 0.0429 0.0429 0.0429 0.0429 

600 0.26 6.02 1.78 0.24 0.1618 0.1618 0.1618 0.1618 

686 0.20 5.70 0.65 0.30 0.0139 0.0139 0.0139 0.0139 

750 0.07 5.84 0.90 0.16 0.0113 0.0113 0.0113 0.0113 

750 0.07 5.90 1.29 0.22 0.0588 0.0588 0.0588 0.0588 

750 0.06 4.48 1.43 0.24 0.0597 0.0597 0.0597 0.0597 

750 0.35 5.80 1.48 0.30 0.0828 0.0828 0.0828 0.0828 

641 0.26 5.84 0.83 0.18 0.0046 0.0046 0.0046 0.0046 

740 0.24 5.85 1.37 0.28 0.0046 0.0046 0.0046 0.0046 

Sales-wgt
 

EF 0.118392 5.723896 1.361031 0.227162 1.0000 1.0000 1.0000 1.0000
 

Sample
 

Size 13 13 13 13
 

D31
 
Table D6. 2000 MY Certification Data 

0-11 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HC+NOx* wgt 

6 6.57 7.33 4.20 0.07 0.0000 0.1007 0.0289 0.0289 0.0289 

6 5.28 7.78 3.16 0.12 0.0000 0.0280 0.0080 0.0080 0.0080 

10 3.36 1.04 0.28 0.0000 0.0000 0.0088 0.0088 0.0088 

7 3.82 2.11 0.35 0.0000 0.0000 0.0096 0.0096 0.0096 

7 3.77 2.95 0.33 0.0000 0.0000 0.0225 0.0225 0.0225 

11 5.45 4.10 0.24 0.0000 0.0000 0.0096 0.0096 0.0096 

10 5.23 1.68 0.21 0.0000 0.0000 0.0193 0.0193 0.0193 

7 6.54 3.81 0.43 0.0000 0.0000 0.0123 0.0123 0.0123 

8 5.76 4.50 0.52 0.0000 0.0000 0.0006 0.0006 0.0006 

10 5.03 4.21 0.42 0.0000 0.0000 0.0006 0.0006 0.0006 

4 0.78 5.18 5.96 3.93 0.66 0.131414 0.1309 0.1141 0.0328 0.0328 0.0328 

7 0.71 4.82 5.53 3.83 0.57 0.128205 0.6675 0.5817 0.1672 0.1672 0.1672 

8 0.58 5.74 6.32 3.29 0.45 0.091981 0.1309 0.1141 0.0328 0.0328 0.0328 

11 0.57 5.10 5.67 3.18 0.54 0.101183 0.0706 0.0615 0.0177 0.0177 0.0177 

4 6.61 5.00 0.50 0.0000 0.0000 0.2089 0.2089 0.2089 

7 6.25 5.03 0.49 0.0000 0.0000 0.1607 0.1607 0.1607 

10 6.30 3.84 0.39 0.0000 0.0000 0.1832 0.1832 0.1832 

7 6.57 3.61 0.48 0.0000 0.0000 0.0164 0.0164 0.0164 

10 3.72 1.91 0.35 0.0000 0.0000 0.0501 0.0501 0.0501 

9 3.88 3.84 0.33 0.0000 0.0000 0.0096 0.0096 0.0096 

Sales-wgt 0.69210 4.05136 

EF 3 5.170337 5.966223 6 0.452858 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 4 6 20 20 20 0.113196 

0.67535 

Calc HC* 1 

Calc 

NOx* 5.290871 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D32
 
Table D6. 2000 MY Certification Data 

11-25 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx HC+NOx CO wgt PM wgt 

HC+NOx* wgt wgt 

19 5.02 1.36 0.45 0.0000 0.0000 0.0030 0.0032 0.0030 

17 0.58 3.79 4.37 3.82 0.57 0.131868 0.0373 0.0289 0.0051 0.0053 0.0051 

25 0.45 4.07 4.52 3.09 0.38 0.099558 0.1493 0.1156 0.0203 0.0211 0.0203 

21 4.30 1.74 0.24 0.0000 0.0000 0.0005 0.0005 0.0005 

17 5.26 1.69 0.39 0.0000 0.0000 0.0012 0.0012 0.0012 

18 5.15 0.77 0.23 0.0000 0.0000 0.0013 0.0014 0.0013 

23 3.98 1.08 0.26 0.0000 0.0000 0.0034 0.0035 0.0034 

11 4.88 1.88 0.50 0.0000 0.0000 0.0026 0.0027 0.0026 

17 4.38 2.36 0.52 0.0000 0.0000 0.0140 0.0146 0.0140 

12 5.54 2.57 0.33 0.0000 0.0000 0.0081 0.0084 0.0081 

18 1.10 4.96 0.56 0.0000 0.2254 0.0395 0.0000 0.0395 

21 3.68 1.34 0.57 0.0000 0.0000 0.0130 0.0135 0.0130 

24 3.54 1.06 0.30 0.0000 0.0000 0.0020 0.0021 0.0020 

24 5.67 1.66 0.56 0.0000 0.0000 0.0022 0.0023 0.0022 

25 6.45 1.20 0.41 0.0000 0.0000 0.0022 0.0023 0.0022 

19 3.40 0.99 0.37 0.0000 0.0000 0.0028 0.0029 0.0028 

18 0.17 5.59 5.76 0.97 0.54 0.028849 0.0033 0.0025 0.0004 0.0005 0.0004 

17 0.10 3.48 3.58 0.56 0.33 0.027933 0.1866 0.1445 0.0253 0.0264 0.0253 

25 0.11 3.38 3.49 0.56 0.30 0.030399 0.0974 0.0754 0.0132 0.0138 0.0132 

12 5.53 2.77 0.22 0.0000 0.0000 0.3139 0.3268 0.3139 

23 4.30 1.73 0.14 0.0000 0.0000 0.0810 0.0843 0.0810 

22 4.66 1.50 0.12 0.0000 0.0000 0.0253 0.0264 0.0253 

20 5.66 2.23 0.21 0.0000 0.0000 0.0041 0.0042 0.0041 

16 4.02 3.13 0.19 0.0000 0.0000 0.0003 0.0003 0.0003 

19 6.24 4.15 0.43 0.0000 0.0000 0.0223 0.0232 0.0223 

21 4.30 1.74 0.24 0.0000 0.0000 0.0046 0.0047 0.0046 

18 5.97 2.73 0.50 0.0000 0.0000 0.0152 0.0158 0.0152 

21 4.10 2.24 0.35 0.0000 0.0000 0.0101 0.0105 0.0101 

15 0.72 5.29 6.02 3.70 0.43 0.120198 0.0410 0.0318 0.0056 0.0058 0.0056 

15 0.43 5.70 6.12 2.41 0.39 0.069428 0.0784 0.0607 0.0106 0.0111 0.0106 

16 0.57 5.62 6.19 3.00 0.37 0.092771 0.0187 0.0145 0.0025 0.0026 0.0025 

22 0.77 5.17 5.94 3.04 0.45 0.129397 0.3881 0.3006 0.0527 0.0548 0.0527 

12 5.03 2.95 0.26 0.0000 0.0000 0.0010 0.0011 0.0010 

16 4.46 2.98 0.35 0.0000 0.0000 0.0450 0.0468 0.0450 

12 3.17 1.47 0.30 0.0000 0.0000 0.0505 0.0526 0.0505 

19 4.29 1.28 0.08 0.0000 0.0000 0.0284 0.0295 0.0284 

22 3.47 2.27 0.19 0.0000 0.0000 0.0374 0.0390 0.0374 

24 5.63 0.90 0.25 0.0000 0.0000 0.0837 0.0872 0.0837 

17 4.88 1.55 0.42 0.0000 0.0000 0.0398 0.0414 0.0398 

18 3.24 1.91 0.32 0.0000 0.0000 0.0061 0.0063 0.0061 

Sales-wgt 

EF 0.489983 3.749647 4.948900 2.207041 0.289982 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 9 10 40 39 40 0.081156 

Calc HC* 0.401631 

D33
 
Table D6. 2000 MY Certification Data 

11-25 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx HC+NOx CO wgt PM wgt 

HC+NOx* wgt wgt
 

Calc
 

NOx* 4.547269
 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D34
 
Table D6. 2000 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx HC+NOx CO wgt PM wgt 

HC+NOx* wgt wgt 

42 6.52 3.35 0.42 0.0000 0.0000 0.0025 0.0025 0.0025 

25 5.31 1.49 0.50 0.0000 0.0000 0.0005 0.0005 0.0005 

28 4.92 1.56 0.54 0.0000 0.0000 0.0022 0.0022 0.0022 

34 5.21 1.44 0.38 0.0000 0.0000 0.0069 0.0069 0.0069 

45 5.95 0.48 0.26 0.0000 0.0000 0.0007 0.0007 0.0007 

36 3.12 1.31 0.39 0.0000 0.0000 0.0007 0.0007 0.0007 

38 3.62 2.13 0.51 0.0000 0.0000 0.0033 0.0033 0.0033 

30 2.79 3.06 0.46 0.0000 0.0000 0.0004 0.0004 0.0004 

50 6.14 0.0000 0.1584 0.0000 0.0000 0.0000 

30 6.94 1.64 0.27 0.0000 0.0000 0.0390 0.0390 0.0390 

38 6.69 1.92 0.32 0.0000 0.0000 0.0133 0.0133 0.0133 

46 6.65 2.29 0.35 0.0000 0.0000 0.0123 0.0123 0.0123 

35 5.68 1.74 0.21 0.0000 0.0000 0.0036 0.0036 0.0036 

39 6.58 1.84 0.11 0.0000 0.0000 0.0051 0.0051 0.0051 

47 5.84 1.35 0.09 0.0000 0.0000 0.0044 0.0044 0.0044 

25 4.35 0.64 0.13 0.0000 0.0000 0.0004 0.0004 0.0004 

28 3.76 1.24 0.20 0.0000 0.0000 0.0022 0.0022 0.0022 

30 3.86 0.83 0.17 0.0000 0.0000 0.0030 0.0030 0.0030 

40 4.50 0.62 0.20 0.0000 0.0000 0.0013 0.0013 0.0013 

47 3.38 0.87 0.27 0.0000 0.0000 0.0005 0.0005 0.0005 

26 3.18 0.98 0.37 0.0000 0.0000 0.0004 0.0004 0.0004 

27 5.66 1.62 0.56 0.0000 0.0000 0.0001 0.0001 0.0001 

29 4.11 1.16 0.35 0.0000 0.0000 0.0160 0.0159 0.0159 

40 2.78 1.62 0.42 0.0000 0.0000 0.0379 0.0379 0.0379 

45 4.04 0.87 0.38 0.0000 0.0000 0.0147 0.0147 0.0147 

28 3.57 2.65 0.43 0.0000 0.0000 0.0010 0.0010 0.0010 

39 4.35 1.89 0.45 0.0000 0.0000 0.0004 0.0004 0.0004 

28 0.13 4.23 4.36 1.33 0.54 0.029817 0.0267 0.0167 0.0019 0.0019 0.0019 

37 0.16 3.56 3.72 2.30 0.58 0.041678 0.0595 0.0372 0.0043 0.0043 0.0043 

37 0.67 6.00 6.67 3.55 0.42 0.10051 0.0017 0.0010 0.0001 0.0001 0.0001 

27 0.11 4.52 4.63 0.57 0.31 0.023758 0.0017 0.0010 0.0001 0.0001 0.0001 

27 0.09 3.95 4.04 0.82 0.46 0.021308 0.0278 0.0173 0.0020 0.0020 0.0020 

37 0.85 4.85 5.56 2.55 0.38 0.149123 0.0076 0.0047 0.0005 0.0005 0.0005 

35 0.08 4.56 4.64 0.90 0.40 0.017234 0.0216 0.0135 0.0016 0.0016 0.0016 

40 0.69 6.19 6.88 1.62 0.25 0.100291 0.0056 0.0035 0.0004 0.0004 0.0004 

35 0.56 4.54 5.10 1.52 0.48 0.109804 0.7065 0.4409 0.0509 0.0509 0.0509 

46 0.04 3.75 3.79 0.68 0.33 0.010554 0.0014 0.0009 0.0001 0.0001 0.0001 

34 0.14 3.66 3.80 0.98 0.50 0.036842 0.0734 0.0458 0.0053 0.0053 0.0053 

47 0.12 6.71 6.83 0.74 0.30 0.01757 0.0050 0.0031 0.0004 0.0004 0.0004 

48 0.64 6.36 7.00 1.46 0.31 0.091429 0.0151 0.0094 0.0011 0.0011 0.0011 

38 6.16 1.66 0.41 0.0000 0.0000 0.0363 0.0363 0.0363 

26 4.64 1.30 0.28 0.0000 0.0000 0.0076 0.0076 0.0076 

31 3.80 1.16 0.36 0.0000 0.0000 0.0400 0.0400 0.0400 

42 3.84 0.77 0.24 0.0000 0.0000 0.0073 0.0073 0.0073 

26 4.46 0.96 0.35 0.0000 0.0000 0.0545 0.0545 0.0545 

D35
 
Table D6. 2000 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx HC+NOx CO wgt PM wgt 

HC+NOx* wgt wgt 

41 4.81 0.75 0.25 0.0000 0.0000 0.0009 0.0009 0.0009 

31 5.27 0.74 0.19 0.0000 0.0000 0.0309 0.0309 0.0309 

31 5.11 0.80 0.26 0.0000 0.0000 0.0582 0.0581 0.0581 

37 4.47 0.80 0.29 0.0000 0.0000 0.2108 0.2107 0.2107 

49 5.95 1.93 0.43 0.0000 0.0000 0.0018 0.0018 0.0018 

38 5.99 1.58 0.36 0.0000 0.0000 0.0018 0.0018 0.0018 

48 4.63 0.93 0.23 0.0000 0.0000 0.0031 0.0031 0.0031 

40 0.18 4.99 5.17 0.94 0.48 0.034632 0.0465 0.0290 0.0033 0.0033 0.0033 

30 2.79 3.06 0.46 0.0000 0.0000 0.0011 0.0011 0.0011 

38 3.62 2.13 0.51 0.0000 0.0000 0.0003 0.0003 0.0003 

26 2.62 1.83 0.25 0.0000 0.0000 0.0001 0.0001 0.0001 

25 5.78 3.66 0.43 0.0000 0.0000 0.0029 0.0029 0.0029 

33 2.37 1.58 0.53 0.0000 0.0000 0.0013 0.0013 0.0013 

36 5.73 6.06 1.07 0.33 0.0000 0.0441 0.0051 0.0051 0.0051 

30 5.29 1.50 0.33 0.0000 0.0000 0.0002 0.0002 0.0002 

35 5.15 5.48 1.61 0.36 0.0000 0.0157 0.0018 0.0018 0.0018 

40 4.62 5.53 2.57 0.22 0.0000 0.0236 0.0027 0.0027 0.0027 

42 6.35 1.01 0.13 0.0000 0.0000 0.0001 0.0001 0.0001 

44 4.82 5.56 1.69 0.34 0.0000 0.0157 0.0018 0.0018 0.0018 

40 6.36 1.33 0.33 0.0000 0.0000 0.0015 0.0015 0.0015 

38 6.00 1.25 0.36 0.0000 0.0000 0.0004 0.0004 0.0004 

30 6.51 3.22 0.50 0.0000 0.0000 0.0038 0.0038 0.0038 

42 6.07 0.70 0.31 0.0000 0.0000 0.0004 0.0004 0.0004 

39 4.73 1.01 0.34 0.0000 0.0000 0.0138 0.0138 0.0138 

45 5.62 1.30 0.38 0.0000 0.0000 0.0016 0.0016 0.0016 

49 4.09 0.80 0.25 0.0000 0.0000 0.0038 0.0038 0.0038 

44 6.19 1.09 0.53 0.0000 0.0000 0.0016 0.0016 0.0016 

47 5.32 5.81 2.45 0.44 0.0000 0.0693 0.0080 0.0080 0.0080 

43 6.35 2.33 0.26 0.0000 0.0000 0.0004 0.0004 0.0004 

41 6.35 0.95 0.32 0.0000 0.0055 0.0000 0.0006 0.0006 

48 6.25 1.59 0.28 0.0000 0.0000 0.0002 0.0002 0.0002 

26 5.45 2.00 0.15 0.0000 0.0000 0.0236 0.0236 0.0236 

28 5.78 3.61 0.40 0.0000 0.0000 0.0096 0.0096 0.0096 

25 5.53 2.91 0.37 0.0000 0.0000 0.0129 0.0129 0.0129 

30 5.82 2.93 0.35 0.0000 0.0000 0.0012 0.0012 0.0012 

25 5.91 3.45 0.24 0.0000 0.0000 0.0006 0.0006 0.0006 

33 5.76 2.74 0.28 0.0000 0.0000 0.0230 0.0230 0.0230 

41 5.97 1.35 0.49 0.0000 0.0000 0.0009 0.0009 0.0009 

29 5.82 2.82 0.25 0.0000 0.0000 0.0070 0.0070 0.0070 

37 6.76 1.71 0.40 0.0000 0.0000 0.0007 0.0007 0.0007 

25 6.01 3.03 0.32 0.0000 0.0000 0.0222 0.0222 0.0222 

37 6.03 2.59 0.35 0.0000 0.0000 0.0181 0.0181 0.0181 

25 6.09 3.03 0.20 0.0000 0.0000 0.0000 0.0000 0.0000 

30 6.07 3.01 0.38 0.0000 0.0000 0.0117 0.0117 0.0117 

45 5.85 3.21 0.45 0.0000 0.0000 0.0291 0.0291 0.0291 

38 5.79 3.23 0.39 0.0000 0.0000 0.0027 0.0027 0.0027 

D36
 
Table D6. 2000 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC frac of HC wgt NOx HC+NOx CO wgt PM wgt 

HC+NOx* wgt wgt 

48 6.00 1.56 0.44 0.0000 0.0000 0.0000 0.0000 0.0000 

34 5.94 1.87 0.34 0.0000 0.0000 0.0715 0.0715 0.0715 

50 4.85 0.0000 0.0435 0.0000 0.0000 0.0000 

46 6.01 2.54 0.20 0.0000 0.0000 0.0064 0.0064 0.0064 

41 5.76 2.79 0.33 0.0000 0.0000 0.0042 0.0042 0.0042 

27 3.04 0.98 0.40 0.0000 0.0000 0.0023 0.0023 0.0023 

39 5.53 1.96 0.26 0.0000 0.0000 0.0010 0.0010 0.0010 

Sales-wgt 

EF 0.452946 4.893606 5.083919 1.522782 0.331337 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 14 22 95 96 96 0.056039 

Calc HC* 0.284899 

Calc 

NOx* 4.799020 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D37
 
Table D6. 2000 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx HC+NOx CO wgt PM wgt 

wgt wgt 

67 6.40 0.0000 0.0035 0.0000 0.0000 0.0000 

79 5.74 0.0000 0.0015 0.0000 0.0000 0.0000 

96 5.81 0.0000 0.0005 0.0000 0.0000 0.0000 

80 0.48 7.61 4.32 0.56 0.1534 0.0381 0.0000 0.1520 0.1572 

67 0.75 6.35 1.96 0.34 0.0219 0.0054 0.0000 0.0217 0.0225 

75 0.70 5.68 2.28 0.49 0.1315 0.0327 0.0000 0.1303 0.1348 

85 0.48 6.14 1.03 0.35 0.0418 0.0104 0.0000 0.0415 0.0429 

56 0.46 5.71 2.19 0.29 0.0418 0.0104 0.0000 0.0415 0.0429 

75 0.70 5.68 2.28 0.49 0.0279 0.0069 0.0000 0.0276 0.0286 

98 0.71 6.30 1.68 0.21 0.0005 0.0001 0.0000 0.0005 0.0005 

62 6.23 0.0000 0.0010 0.0000 0.0000 0.0000 

57 6.20 0.0000 0.0010 0.0000 0.0000 0.0000 

55 5.80 0.0000 0.0010 0.0000 0.0000 0.0000 

64 5.92 0.0000 0.0049 0.0000 0.0000 0.0000 

82 5.23 0.0000 0.0802 0.0000 0.0000 0.0000 

53 6.32 0.0000 0.0217 0.0000 0.0000 0.0000 

83 6.47 0.0000 0.0029 0.0000 0.0000 0.0000 

65 6.20 0.0000 0.0174 0.0000 0.0000 0.0000 

84 6.79 0.0000 0.0000 0.0000 0.0000 0.0000 

68 6.70 0.0000 0.0030 0.0000 0.0000 0.0000 

51 5.38 0.0000 0.0015 0.0000 0.0000 0.0000 

56 5.21 0.0000 0.0042 0.0000 0.0000 0.0000 

78 6.22 0.0000 0.0001 0.0000 0.0000 0.0000 

52 4.59 0.0000 0.0188 0.0000 0.0000 0.0000 

50 3.43 0.0000 0.0079 0.0000 0.0000 0.0000 

52 0.17 5.22 1.18 0.45 0.0094 0.0023 0.0000 0.0093 0.0096 

51 1.44 5.79 3.90 0.38 0.0110 0.0027 0.0000 0.0109 0.0112 

54 0.69 4.15 1.45 0.36 0.0240 0.0060 0.0000 0.0238 0.0246 

51 0.60 6.68 3.04 0.63 0.0011 0.0003 0.0000 0.0011 0.0011 

55 0.39 6.16 0.98 0.28 0.0163 0.0041 0.0000 0.0162 0.0167 

64 0.43 5.62 2.17 0.60 0.0076 0.0019 0.0000 0.0075 0.0078 

76 0.29 5.35 1.08 0.51 0.0149 0.0037 0.0000 0.0148 0.0153 

51 0.41 5.34 2.22 0.64 0.0087 0.0022 0.0000 0.0086 0.0089 

56 0.48 4.88 0.46 0.27 0.0014 0.0003 0.0000 0.0014 0.0014 

83 0.49 4.80 0.76 0.34 0.0099 0.0025 0.0000 0.0098 0.0101 

91 0.42 6.63 1.32 0.54 0.0378 0.0094 0.0000 0.0375 0.0388 

79 0.55 5.25 2.47 0.55 0.0335 0.0083 0.0000 0.0332 0.0344 

86 0.46 4.98 0.83 0.38 0.0013 0.0003 0.0000 0.0013 0.0013 

86 0.35 5.09 0.67 0.21 0.0013 0.0003 0.0000 0.0013 0.0014 

53 6.56 0.0000 0.0478 0.0000 0.0000 0.0000 

51 0.05 3.56 0.75 0.20 0.0159 0.0040 0.0000 0.0158 0.0163 

78 0.49 3.77 3.00 0.52 0.0159 0.0040 0.0000 0.0158 0.0163 

74 0.76 4.70 2.06 0.32 0.0199 0.0050 0.0000 0.0197 0.0204 

80 0.72 5.78 3.26 0.51 0.0060 0.0015 0.0000 0.0059 0.0061 

98 0.71 6.30 1.68 0.21 0.0050 0.0012 0.0000 0.0049 0.0051 

D38
 
Table D6. 2000 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx HC+NOx CO wgt PM wgt 

wgt wgt 

56 0.46 5.71 2.19 0.29 0.0002 0.0001 0.0000 0.0002 0.0002 

85 0.48 6.14 1.03 0.35 0.0002 0.0001 0.0000 0.0002 0.0002 

59 4.37 0.0000 0.0119 0.0000 0.0000 0.0000 

51 5.12 0.0000 0.0005 0.0000 0.0000 0.0000 

56 4.18 0.0000 0.0114 0.0000 0.0000 0.0000 

89 3.57 0.0000 0.0178 0.0000 0.0000 0.0000 

73 3.68 0.0000 0.0124 0.0000 0.0000 0.0000 

86 5.42 0.0000 0.0104 0.0000 0.0000 0.0000 

93 4.71 0.0000 0.0114 0.0000 0.0000 0.0000 

72 4.31 0.0000 0.0054 0.0000 0.0000 0.0000 

54 0.54 6.31 2.42 0.0157 0.0039 0.0000 0.0156 0.0000 

65 0.05 4.18 4.24 0.90 0.0178 0.0044 1.0000 0.0177 0.0000 

59 3.34 0.0000 0.0003 0.0000 0.0000 0.0000 

53 4.60 0.0000 0.0015 0.0000 0.0000 0.0000 

56 5.95 0.0000 0.0005 0.0000 0.0000 0.0000 

54 2.62 0.0000 0.0048 0.0000 0.0000 0.0000 

63 5.06 0.0000 0.0006 0.0000 0.0000 0.0000 

57 4.46 0.0000 0.0052 0.0000 0.0000 0.0000 

55 2.91 0.0000 0.0014 0.0000 0.0000 0.0000 

51 5.35 0.0000 0.0154 0.0000 0.0000 0.0000 

87 5.92 0.0000 0.0154 0.0000 0.0000 0.0000 

52 6.32 0.0000 0.0050 0.0000 0.0000 0.0000 

89 6.40 0.0000 0.0025 0.0000 0.0000 0.0000 

67 0.22 5.71 1.01 0.54 0.1915 0.0476 0.0000 0.1898 0.1963 

92 0.35 6.16 1.22 0.29 0.0992 0.0247 0.0000 0.0983 0.1017 

55 2.62 0.0000 0.0012 0.0000 0.0000 0.0000 

59 5.90 0.0000 0.0012 0.0000 0.0000 0.0000 

85 2.18 0.0000 0.0013 0.0000 0.0000 0.0000 

64 5.58 0.0000 0.0124 0.0000 0.0000 0.0000 

79 6.16 0.0000 0.0067 0.0000 0.0000 0.0000 

58 3.23 0.0000 0.0109 0.0000 0.0000 0.0000 

52 6.62 0.0000 0.0097 0.0000 0.0000 0.0000 

64 5.13 0.0000 0.0045 0.0000 0.0000 0.0000 

60 6.06 0.0000 0.0258 0.0000 0.0000 0.0000 

96 5.09 0.0000 0.1312 0.0000 0.0000 0.0000 

68 5.85 0.0000 0.0669 0.0000 0.0000 0.0000 

52 5.97 0.0000 0.0421 0.0000 0.0000 0.0000 

68 6.11 0.0000 0.0099 0.0000 0.0000 0.0000 

80 0.83 6.00 3.19 0.63 0.0060 0.0015 0.0000 0.0059 0.0061 

80 0.86 5.40 4.00 0.64 0.0075 0.0019 0.0000 0.0074 0.0077 

59 3.58 0.0000 0.0030 0.0000 0.0000 0.0000 

84 6.14 0.0000 0.0010 0.0000 0.0000 0.0000 

94 5.75 0.0000 0.0003 0.0000 0.0000 0.0000 

50 5.80 1.78 0.38 0.0000 0.0008 0.0000 0.0034 0.0035 

77 0.03 3.55 0.15 0.18 0.0021 0.0005 0.0000 0.0021 0.0021 

59 5.59 0.96 0.45 0.0000 0.0010 0.0000 0.0040 0.0042 

D39
 
Table D6. 2000 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx HC+NOx CO wgt PM wgt 

wgt wgt 

100 6.27 0.87 0.33 0.0000 0.0004 0.0000 0.0015 0.0015 

75 3.87 0.0000 0.0015 0.0000 0.0000 0.0000 

58 3.91 0.0000 0.0020 0.0000 0.0000 0.0000 

54 5.40 0.0000 0.0001 0.0000 0.0000 0.0000 

67 4.89 0.0000 0.0163 0.0000 0.0000 0.0000 

80 4.80 0.0000 0.0005 0.0000 0.0000 0.0000 

56 5.23 0.0000 0.0016 0.0000 0.0000 0.0000 

58 5.12 0.0000 0.0157 0.0000 0.0000 0.0000 

60 4.12 0.0000 0.0025 0.0000 0.0000 0.0000 

70 5.59 0.0000 0.0138 0.0000 0.0000 0.0000 

58 5.72 0.0000 0.0002 0.0000 0.0000 0.0000 

95 5.10 0.0000 0.0030 0.0000 0.0000 0.0000 

100 5.73 0.0000 0.0114 0.0000 0.0000 0.0000 

Sales-wgt 0.462 5.49489 2.0470 0.4604 

EF 89 2 4.235576 6 3 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 35 104 1 38 36 

D40
 
Table D6. 2000 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

173 0.33 6.37 0.78 0.11 0.0006 0.0004 0.0006 0.0006 

108 6.47 0.0000 0.0007 0.0000 0.0000 

143 6.09 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.2138 0.1425 0.2133 0.2164 

125 0.23 6.21 0.47 0.16 0.0077 0.0051 0.0077 0.0078 

118 0.25 4.53 0.54 0.22 0.0165 0.0110 0.0165 0.0167 

155 0.38 4.23 0.75 0.35 0.1983 0.1322 0.1979 0.2008 

110 6.06 0.0000 0.0019 0.0000 0.0000 

165 6.24 0.0000 0.0495 0.0000 0.0000 

166 4.95 0.0000 0.0040 0.0000 0.0000 

125 0.23 6.21 0.47 0.16 0.1202 0.0801 0.1200 0.1217 

118 0.25 4.53 0.54 0.22 0.0165 0.0110 0.0165 0.0167 

144 4.97 0.0000 0.0026 0.0000 0.0000 

109 6.41 0.0000 0.0026 0.0000 0.0000 

133 6.50 0.0000 0.0026 0.0000 0.0000 

168 0.11 6.17 0.63 0.13 0.0009 0.0006 0.0009 0.0009 

155 6.39 0.0000 0.0170 0.0000 0.0000 

109 6.32 0.53 0.13 0.0000 0.0000 0.0000 0.0000 

157 6.65 0.0000 0.0116 0.0000 0.0000 

121 0.49 4.30 1.23 0.28 0.0013 0.0009 0.0013 0.0013 

134 0.34 4.30 1.00 0.24 0.0007 0.0004 0.0007 0.0007 

103 0.57 6.26 1.58 0.39 0.0127 0.0085 0.0127 0.0129 

153 0.51 5.65 0.49 0.26 0.0145 0.0097 0.0145 0.0147 

164 0.47 4.67 1.06 0.23 0.0033 0.0022 0.0033 0.0033 

139 0.52 4.30 1.25 0.19 0.0012 0.0008 0.0012 0.0012 

144 6.61 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0881 0.0588 0.0880 0.0892 

125 0.23 6.21 0.47 0.16 0.0220 0.0147 0.0220 0.0223 

155 0.38 4.23 0.75 0.35 0.1102 0.0735 0.1100 0.1115 

125 5.74 0.0000 0.0134 0.0000 0.0000 

103 5.94 0.0000 0.0005 0.0000 0.0000 

151 5.60 0.0000 0.0005 0.0000 0.0000 

120 5.50 0.0000 0.0414 0.0000 0.0000 

144 5.80 0.0000 0.0494 0.0000 0.0000 

118 5.52 0.0000 0.0009 0.0000 0.0000 

113 4.41 0.0000 0.0060 0.0000 0.0000 

132 6.05 0.0000 0.0067 0.0000 0.0000 

173 5.79 0.0000 0.0027 0.0000 0.0000 

108 0.16 6.25 0.43 0.26 0.0759 0.0506 0.0757 0.0768 

116 0.57 6.43 1.45 0.33 0.0150 0.0100 0.0150 0.0152 

168 0.42 5.85 0.76 0.27 0.0382 0.0255 0.0381 0.0387 

118 6.30 0.0000 0.0008 0.0000 0.0000 

120 5.55 0.0000 0.0287 0.0000 0.0000 

103 6.19 0.0000 0.0089 0.0000 0.0000 

172 0.13 5.31 0.45 0.25 0.0180 0.0120 0.0180 0.0183 

115 5.77 0.0000 0.0067 0.0000 0.0000 

D41
 
Table D6. 2000 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

152 5.82 0.0000 0.0601 0.0000 0.0000 

103 0.53 5.30 1.24 0.51 0.0023 0.0015 0.0023 0.0023 

135 0.45 6.68 0.92 0.24 0.0010 0.0007 0.0010 0.0010 

130 0.63 6.61 1.21 0.36 0.0017 0.0011 0.0017 0.0017 

100 0.57 5.50 1.35 0.47 0.0031 0.0021 0.0031 0.0031 

114 6.39 0.0000 0.0040 0.0000 0.0000 

127 5.38 0.0000 0.0013 0.0000 0.0000 

117 6.23 0.0000 0.0013 0.0000 0.0000 

172 6.23 0.0000 0.0040 0.0000 0.0000 

173 0.54 6.57 1.83 0.42 0.0020 0.0013 0.0020 0.0020 

142 5.92 1.33 0.23 0.0000 0.0013 0.0020 0.0020 

138 6.68 0.0000 0.0014 0.0000 0.0000 

161 0.23 5.96 0.83 0.0141 0.0094 0.0141 0.0000 

130 5.05 0.0000 0.0002 0.0000 0.0000 

116 5.82 0.0000 0.0003 0.0000 0.0000 

Sales-wgt 

EF 0.332460 5.593736 0.685810 0.282059 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 27 61 29 28 

D42
 
Table D6. 2000 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

257 0.43 6.43 0.76 0.20 0.0005 0.0005 0.0000 0.0005 0.0005 

200 0.26 5.13 0.60 0.22 0.0678 0.0678 0.0000 0.0678 0.0678 

240 0.10 5.06 0.38 0.15 0.0136 0.0136 0.0000 0.0136 0.0136 

215 0.32 5.51 0.55 0.32 0.0329 0.0329 0.0000 0.0329 0.0329 

260 0.44 5.82 0.70 0.27 0.0213 0.0213 0.0000 0.0213 0.0213 

240 0.29 5.38 0.49 0.27 0.0213 0.0213 0.0000 0.0213 0.0213 

280 0.47 5.47 0.52 0.23 0.0484 0.0484 0.0000 0.0484 0.0484 

210 0.20 5.89 1.49 0.33 0.0362 0.0362 0.0000 0.0362 0.0362 

275 0.11 4.56 1.26 0.26 0.0027 0.0027 0.0000 0.0027 0.0027 

205 0.19 5.96 1.73 0.25 0.0096 0.0096 0.0000 0.0096 0.0096 

255 0.08 6.20 0.96 0.29 0.0252 0.0252 0.0000 0.0252 0.0252 

290 0.09 5.46 2.19 0.35 0.0097 0.0097 0.0000 0.0097 0.0097 

260 0.36 5.73 1.30 0.39 0.0022 0.0022 0.0000 0.0022 0.0022 

225 0.41 5.70 0.84 0.22 0.0588 0.0588 0.0000 0.0588 0.0588 

240 0.10 5.06 0.38 0.15 0.0968 0.0968 0.0000 0.0968 0.0968 

200 0.26 5.13 0.60 0.22 0.1355 0.1355 0.0000 0.1355 0.1355 

189 0.33 3.95 0.54 0.20 0.0039 0.0039 0.0000 0.0039 0.0039 

240 0.29 5.38 0.49 0.27 0.1936 0.1936 0.0000 0.1936 0.1936 

200 0.25 5.43 1.23 0.35 0.0034 0.0034 0.0000 0.0034 0.0034 

296 0.31 6.41 0.96 0.25 0.0034 0.0034 0.0000 0.0034 0.0034 

261 0.47 6.06 0.89 0.27 0.0002 0.0002 0.0000 0.0002 0.0002 

248 0.34 5.31 1.04 0.35 0.0002 0.0002 0.0000 0.0002 0.0002 

275 0.14 5.38 0.48 0.14 0.0014 0.0014 0.0000 0.0014 0.0014 

196 0.35 6.52 0.95 0.36 0.0037 0.0037 0.0000 0.0037 0.0037 

184 0.24 5.84 0.69 0.15 0.0215 0.0215 0.0000 0.0215 0.0215 

186 0.34 6.28 0.69 0.23 0.0017 0.0017 0.0000 0.0017 0.0017 

249 0.48 6.37 1.08 0.24 0.0001 0.0001 0.0000 0.0001 0.0001 

243 0.40 5.88 1.67 0.37 0.0002 0.0002 0.0000 0.0002 0.0002 

185 0.54 4.19 4.73 0.93 0.20 0.0004 0.0004 0.5000 0.0004 0.0004 

241 0.21 4.14 4.35 0.67 0.17 0.0004 0.0004 0.5000 0.0004 0.0004 

241 0.41 6.44 1.11 0.34 0.0024 0.0024 0.0000 0.0024 0.0024 

227 0.51 6.72 1.07 0.33 0.0055 0.0055 0.0000 0.0055 0.0055 

193 0.60 6.69 0.85 0.21 0.0010 0.0010 0.0000 0.0010 0.0010 

200 0.26 5.13 0.60 0.22 0.0194 0.0194 0.0000 0.0194 0.0194 

189 0.33 3.95 0.54 0.20 0.0039 0.0039 0.0000 0.0039 0.0039 

215 0.32 5.51 0.55 0.32 0.0194 0.0194 0.0000 0.0194 0.0194 

240 0.29 5.38 0.49 0.27 0.0116 0.0116 0.0000 0.0116 0.0116 

280 0.47 5.47 0.52 0.23 0.0020 0.0020 0.0000 0.0020 0.0020 

189 0.31 5.40 0.92 0.21 0.0014 0.0014 0.0000 0.0014 0.0014 

252 0.22 6.23 0.30 0.23 0.0092 0.0092 0.0000 0.0092 0.0092 

238 0.21 5.95 0.51 0.19 0.0006 0.0006 0.0000 0.0006 0.0006 

244 0.39 6.24 0.74 0.18 0.0011 0.0011 0.0000 0.0011 0.0011 

285 0.06 5.93 0.60 0.09 0.0009 0.0009 0.0000 0.0009 0.0009 

197 0.33 5.07 0.76 0.18 0.0044 0.0044 0.0000 0.0044 0.0044 

251 0.23 5.59 0.42 0.11 0.0072 0.0072 0.0000 0.0072 0.0072 

D43
 
Table D6. 2000 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

184 0.30 6.70 0.61 0.18 0.0023 0.0023 0.0000 0.0023 0.0023 

280 0.19 5.68 0.51 0.18 0.0039 0.0039 0.0000 0.0039 0.0039 

298 0.37 6.32 1.16 0.30 0.0029 0.0029 0.0000 0.0029 0.0029 

212 0.29 6.41 0.40 0.14 0.0035 0.0035 0.0000 0.0035 0.0035 

210 0.09 5.16 0.90 0.18 0.0070 0.0070 0.0000 0.0070 0.0070 

225 0.09 6.78 0.40 0.16 0.0058 0.0058 0.0000 0.0058 0.0058 

286 0.22 5.35 1.24 0.38 0.0304 0.0304 0.0000 0.0304 0.0304 

181 0.15 5.69 0.44 0.27 0.0127 0.0127 0.0000 0.0127 0.0127 

202 0.38 8.06 1.42 0.42 0.0009 0.0009 0.0000 0.0009 0.0009 

190 0.66 6.08 1.56 0.40 0.0007 0.0007 0.0000 0.0007 0.0007 

177 0.34 6.20 0.89 0.28 0.0026 0.0026 0.0000 0.0026 0.0026 

182 0.42 6.43 0.87 0.30 0.0009 0.0009 0.0000 0.0009 0.0009 

207 0.44 6.59 1.15 0.37 0.0009 0.0009 0.0000 0.0009 0.0009 

217 0.36 5.49 1.00 0.22 0.0018 0.0018 0.0000 0.0018 0.0018 

183 0.54 6.63 0.81 0.34 0.0009 0.0009 0.0000 0.0009 0.0009 

227 0.35 6.34 0.51 0.27 0.0009 0.0009 0.0000 0.0009 0.0009 

244 0.19 6.30 1.66 0.36 0.0035 0.0035 0.0000 0.0035 0.0035 

272 0.35 6.44 1.09 0.23 0.0035 0.0035 0.0000 0.0035 0.0035 

255 0.25 5.89 0.40 0.13 0.0087 0.0087 0.0000 0.0087 0.0087 

Sales-wgt 0.26631 5.44172 0.66672 0.24068 

EF 0 9 4.540000 5 5 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 64 64 2 64 64 

D44
 
Table D6. 2000 MY Certification Data (cont.) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

310 0.34 5.48 0.79 0.13 0.0016 0.0029 0.0016 0.0015 0.0000 

415 0.10 4.65 0.40 0.08 0.0053 0.0030 0.0053 0.0042 0.0000 

496 0.13 6.12 0.28 0.07 0.0011 0.0008 0.0011 0.0011 0.0000 

340 0.12 3.91 0.56 0.17 0.0395 0.0253 0.0395 0.0267 0.0000 

300 0.08 5.78 0.43 0.13 0.0053 0.0023 0.0053 0.0053 0.0000 

395 0.51 6.48 2.14 0.16 0.0759 0.2081 0.0759 0.0852 0.0000 

300 0.28 6.13 0.81 0.36 0.0071 0.0107 0.0071 0.0075 0.0000 

330 0.33 5.28 1.07 0.36 0.0087 0.0154 0.0087 0.0079 0.0000 

397 0.19 4.65 1.35 0.19 0.0039 0.0040 0.0039 0.0032 0.0000 

362 0.16 5.49 1.57 0.21 0.2706 0.2327 0.2706 0.2574 0.0000 

322 0.15 3.98 0.75 0.19 0.0379 0.0306 0.0379 0.0261 0.0000 

455 0.12 5.48 0.82 0.17 0.0053 0.0034 0.0053 0.0050 0.0000 

599 0.04 6.59 2.67 0.33 0.1111 0.0239 0.1111 0.1268 0.0000 

535 0.08 5.79 2.10 0.34 0.0087 0.0037 0.0087 0.0087 0.0000 

350 0.22 6.52 1.17 0.20 0.0869 0.1010 0.0869 0.0982 0.0000 

430 0.14 6.29 0.34 0.13 0.0290 0.0221 0.0290 0.0316 0.0000 

525 0.16 6.52 0.65 0.16 0.0158 0.0139 0.0158 0.0179 0.0000 

440 0.11 6.38 0.35 0.13 0.0200 0.0117 0.0200 0.0221 0.0000 

336 0.14 5.48 0.45 0.15 0.0103 0.0077 0.0103 0.0097 0.0000 

422 0.15 4.97 0.40 0.11 0.0003 0.0002 0.0003 0.0002 0.0000 

449 0.14 5.10 5.24 0.50 0.15 0.0005 0.0004 0.0005 0.0005 1.0000 

308 0.28 5.68 0.45 0.20 0.0021 0.0031 0.0021 0.0021 0.0000 

335 0.27 5.51 0.74 0.28 0.0006 0.0009 0.0006 0.0006 0.0000 

563 0.14 5.11 0.40 0.11 0.0016 0.0012 0.0016 0.0014 0.0000 

543 0.22 5.66 0.54 0.25 0.0116 0.0139 0.0116 0.0114 0.0000 

305 0.09 6.00 0.99 0.13 0.0104 0.0052 0.0104 0.0108 0.0000 

325 0.10 6.51 0.51 0.13 0.0235 0.0130 0.0235 0.0265 0.0000 

315 0.28 5.20 0.70 0.17 0.0358 0.0545 0.0358 0.0322 0.0000 

329 0.24 6.60 0.84 0.17 0.0037 0.0048 0.0037 0.0042 0.0000 

590 0.34 6.40 0.72 0.23 0.0001 0.0002 0.0001 0.0001 0.0000 

335 0.26 6.17 1.05 0.32 0.0003 0.0004 0.0003 0.0003 0.0000 

306 0.24 6.29 0.72 0.37 0.0145 0.0187 0.0145 0.0158 0.0000 

326 0.50 4.04 0.43 0.14 0.0048 0.0130 0.0048 0.0034 0.0000 

493 0.16 4.26 1.04 0.22 0.0029 0.0025 0.0029 0.0021 0.0000 

493 0.16 5.89 0.95 0.28 0.0006 0.0005 0.0006 0.0006 0.0000 

334 0.25 5.58 0.31 0.18 0.0284 0.0387 0.0284 0.0275 0.0000 

322 0.23 3.99 0.41 0.20 0.0009 0.0011 0.0009 0.0006 0.0000 

375 0.22 5.72 0.32 0.20 0.0055 0.0066 0.0055 0.0055 0.0000 

525 0.17 6.06 0.60 0.23 0.0047 0.0044 0.0047 0.0050 0.0000 

330 0.21 6.39 0.44 0.20 0.0003 0.0004 0.0003 0.0004 0.0000 

571 0.31 3.98 0.48 0.17 0.0032 0.0052 0.0032 0.0022 0.0000 

475 0.28 4.09 0.46 0.15 0.0032 0.0048 0.0032 0.0022 0.0000 

542 0.32 3.80 0.56 0.19 0.0032 0.0054 0.0032 0.0021 0.0000 

327 0.22 6.39 0.46 0.14 0.0032 0.0038 0.0032 0.0035 0.0000 

327 0.24 6.11 0.48 0.13 0.0032 0.0041 0.0032 0.0033 0.0000 

D45
 
Table D6. 2000 MY Certification Data (cont.) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

460 0.19 3.35 0.33 0.05 0.0003 0.0003 0.0003 0.0002 0.0000 

335 0.43 4.29 0.81 0.12 0.0013 0.0029 0.0013 0.0009 0.0000 

330 0.05 5.33 0.43 0.21 0.0405 0.0115 0.0405 0.0374 0.0000 

313 0.27 6.26 0.31 0.06 0.0148 0.0214 0.0148 0.0161 0.0000 

381 0.21 6.55 0.61 0.08 0.0289 0.0324 0.0289 0.0328 0.0000 

496 0.13 6.12 0.28 0.07 0.0016 0.0011 0.0016 0.0017 0.0000 

Sales-wgt 5.77026 1.25454 0.20314 

EF 0.186024 0 5.240000 6 8 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 51 51 1 51 51 

600-750 hp 

Table D6. 2000 MY Certification Data (cont.)
 

Emission Factors (g/hp-hr) Sales Weightings
 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

660 0.05 6.24 0.83 0.14 0.1743 0.1743 0.1743 0.1743 

740 0.05 5.68 1.57 0.25 0.2823 0.2823 0.2823 0.2823 

730 0.06 5.04 0.99 0.19 0.0892 0.0892 0.0892 0.0892 

740 0.10 5.53 1.62 0.33 0.0423 0.0423 0.0423 0.0423 

600 0.26 6.02 1.78 0.24 0.1598 0.1598 0.1598 0.1598 

630 0.16 4.46 0.66 0.18 0.0249 0.0249 0.0249 0.0249 

641 0.19 5.98 1.05 0.23 0.0137 0.0137 0.0137 0.0137 

740 0.24 5.85 1.37 0.28 0.0066 0.0066 0.0066 0.0066 

740 0.24 5.85 1.37 0.28 0.0066 0.0066 0.0066 0.0066 

750 0.07 5.84 0.90 0.16 0.0112 0.0112 0.0112 0.0112 

750 0.08 6.01 1.92 0.30 0.0589 0.0589 0.0589 0.0589 

750 0.35 5.80 1.48 0.30 0.0818 0.0818 0.0818 0.0818 

750 0.13 5.89 1.06 0.13 0.0357 0.0357 0.0357 0.0357 

684 0.19 5.98 0.68 0.22 0.0062 0.0062 0.0062 0.0062 

671 0.48 6.63 0.52 0.16 0.0062 0.0062 0.0062 0.0062 

Sales-wgt EF 0.126821 5.790567 1.368105 0.225632 1.0000 1.0000 1.0000 1.0000 

Sample Size 15 15 15 15 

D46
 
Table D6. 2000 MY Certification Data (cont.) 

>750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

800 0.03 6.19 0.36 0.10 0.0321 0.0321 0.0321 0.0321 

758 0.07 5.26 1.07 0.16 0.0067 0.0067 0.0067 0.0067 

1082 0.04 5.96 0.70 0.15 0.0555 0.0555 0.0555 0.0555 

1850 0.16 5.89 1.10 0.31 0.0658 0.0658 0.0658 0.0658 

2750 0.14 6.18 1.31 0.17 0.0515 0.0515 0.0515 0.0515 

1200 0.17 5.17 0.34 0.16 0.0044 0.0044 0.0044 0.0044 

2000 0.31 5.91 1.49 0.25 0.0297 0.0297 0.0297 0.0297 

1250 0.20 6.51 0.51 0.13 0.4683 0.4683 0.4683 0.4683 

1500 0.54 6.24 0.87 0.27 0.2120 0.2120 0.2120 0.2120 

1200 0.17 5.17 0.34 0.16 0.0297 0.0297 0.0297 0.0297 

899 0.21 6.02 0.53 0.15 0.0044 0.0044 0.0044 0.0044 

1230 0.12 6.03 0.67 0.26 0.0024 0.0024 0.0024 0.0024 

1874 0.38 6.15 1.36 0.15 0.0059 0.0059 0.0059 0.0059 

1207 0.23 5.45 1.26 0.24 0.0059 0.0059 0.0059 0.0059 

1026 0.26 5.07 0.70 0.18 0.0059 0.0059 0.0059 0.0059 

2346 0.40 6.04 1.39 0.26 0.0198 0.0198 0.0198 0.0198 

Sales-wgt 

EF 0.259060 6.252638 0.727419 0.183308 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 16 16 16 16 

D47
 
Table D7. 2001 MY Certification Data 

0-11 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

9 6.70 4.70 0.57 0.0000 0.0000 0.0426 0.0426 0.0426 

10 3.36 1.04 0.28 0.0000 0.0000 0.0059 0.0059 0.0059 

7 3.82 2.11 0.35 0.0000 0.0000 0.0106 0.0106 0.0106 

7 3.77 2.95 0.33 0.0000 0.0000 0.0355 0.0355 0.0355 

11 5.45 4.10 0.24 0.0000 0.0000 0.0284 0.0284 0.0284 

10 5.23 1.68 0.21 0.0000 0.0000 0.0248 0.0248 0.0248 

7 1.59 4.67 6.26 3.81 0.44 0.253454 0.2013 0.2013 0.0106 0.0106 0.0106 

8 4.09 1.09 0.44 0.0000 0.0000 0.0004 0.0004 0.0004 

4 0.78 5.18 5.96 3.93 0.66 0.131414 0.1409 0.1409 0.0075 0.0075 0.0075 

7 0.71 4.82 5.53 3.83 0.57 0.128205 0.1477 0.1477 0.0078 0.0078 0.0078 

8 0.58 5.74 6.32 3.29 0.45 0.091981 0.1409 0.1409 0.0075 0.0075 0.0075 

10 5.49 3.86 0.51 0.0000 0.0000 0.0075 0.0075 0.0075 

11 0.57 5.10 5.67 3.18 0.54 0.101183 0.3691 0.3691 0.0195 0.0195 0.0195 

4 6.61 5.00 0.50 0.0000 0.0000 0.2768 0.2768 0.2768 

7 6.25 5.03 0.49 0.0000 0.0000 0.1821 0.1821 0.1821 

10 6.30 3.84 0.39 0.0000 0.0000 0.2425 0.2425 0.2425 

7 6.57 3.61 0.48 0.0000 0.0000 0.0234 0.0234 0.0234 

10 3.72 1.91 0.35 0.0000 0.0000 0.0554 0.0554 0.0554 

9 3.88 3.84 0.33 0.0000 0.0000 0.0114 0.0114 0.0114 

Sales­ 0.8283 5.0737 6.0188 4.1740 0.4420 

wgt EF 78 63 91 66 10 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 5 5 19 19 19 0.141247 

0.8501 

Calc HC* 53 

Calc 5.1687 
 

NOx* 38
 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D48
 
Table D7. 2001 MY Certification Data (cont.) 

11-25 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

19 5.02 1.36 0.45 0.0000 0.0000 0.0029 0.0029 0.0029 

17 0.58 3.79 4.37 3.82 0.57 0.131868 0.0312 0.0312 0.0036 0.0036 0.0036 

25 0.45 4.07 4.52 3.09 0.38 0.099558 0.1248 0.1248 0.0143 0.0143 0.0143 

16 0.60 3.61 4.21 2.31 0.10 0.141844 0.0062 0.0062 0.0007 0.0007 0.0007 

21 0.30 3.77 4.07 1.72 0.20 0.073394 0.0312 0.0312 0.0036 0.0036 0.0036 

17 5.26 1.69 0.39 0.0000 0.0000 0.0004 0.0004 0.0004 

18 5.15 0.77 0.23 0.0000 0.0000 0.0005 0.0005 0.0005 

23 3.98 1.08 0.26 0.0000 0.0000 0.0024 0.0024 0.0024 

11 4.88 1.88 0.50 0.0000 0.0000 0.0027 0.0027 0.0027 

17 4.38 2.36 0.52 0.0000 0.0000 0.0037 0.0037 0.0037 

12 5.54 2.57 0.33 0.0000 0.0000 0.0021 0.0021 0.0021 

18 4.96 1.10 0.56 0.0000 0.0000 0.0301 0.0301 0.0301 

21 3.68 1.34 0.57 0.0000 0.0000 0.0064 0.0064 0.0064 

24 3.54 1.06 0.30 0.0000 0.0000 0.0014 0.0014 0.0014 

24 5.67 1.66 0.56 0.0000 0.0000 0.0020 0.0020 0.0020 

19 3.40 0.99 0.37 0.0000 0.0000 0.0031 0.0031 0.0031 

18 0.17 5.59 5.76 0.97 0.54 0.028849 0.0027 0.0027 0.0003 0.0003 0.0003 

17 0.10 3.48 3.58 0.56 0.33 0.027933 0.2702 0.2702 0.0309 0.0309 0.0309 

25 0.11 3.38 3.49 0.56 0.30 0.030399 0.1179 0.1179 0.0135 0.0135 0.0135 

12 5.53 2.77 0.22 0.0000 0.0000 0.3563 0.3563 0.3563 

20 5.66 2.23 0.21 0.0000 0.0000 0.0107 0.0107 0.0107 

23 4.30 1.73 0.14 0.0000 0.0000 0.2138 0.2138 0.2138 

22 4.66 1.50 0.12 0.0000 0.0000 0.0356 0.0356 0.0356 

16 0.60 3.61 4.21 2.31 0.10 0.142113 0.0031 0.0031 0.0004 0.0004 0.0004 

19 0.98 4.38 5.36 3.78 0.25 0.182132 0.1373 0.1373 0.0157 0.0157 0.0157 

18 1.03 5.04 6.05 3.50 0.41 0.169964 0.0811 0.0811 0.0093 0.0093 0.0093 

21 0.30 3.77 4.07 1.72 0.20 0.073154 0.0343 0.0343 0.0039 0.0039 0.0039 

21 4.10 2.24 0.35 0.0000 0.0000 0.0071 0.0071 0.0071 

17 3.62 1.57 0.30 0.0000 0.0000 0.0170 0.0170 0.0170 

23 5.34 0.68 0.22 0.0000 0.0000 0.0020 0.0020 0.0020 

15 0.72 5.29 6.02 3.70 0.43 0.120198 0.0137 0.0137 0.0016 0.0016 0.0016 

15 0.43 5.70 6.12 2.41 0.39 0.069428 0.0137 0.0137 0.0016 0.0016 0.0016 

16 0.57 5.62 6.19 3.00 0.37 0.092771 0.0069 0.0069 0.0008 0.0008 0.0008 

22 0.77 5.17 5.94 3.04 0.45 0.129397 0.0630 0.0630 0.0072 0.0072 0.0072 

22 0.37 5.17 5.53 1.58 0.32 0.066038 0.0624 0.0624 0.0071 0.0071 0.0071 

12 5.03 2.95 0.26 0.0000 0.0000 0.0011 0.0011 0.0011 

16 4.46 2.98 0.35 0.0000 0.0000 0.0323 0.0323 0.0323 

12 3.17 1.47 0.30 0.0000 0.0000 0.0355 0.0355 0.0355 

19 4.29 1.28 0.08 0.0000 0.0000 0.0217 0.0217 0.0217 

22 3.47 2.27 0.19 0.0000 0.0000 0.0276 0.0276 0.0276 

24 5.63 0.90 0.25 0.0000 0.0000 0.0351 0.0351 0.0351 

17 4.88 1.55 0.42 0.0000 0.0000 0.0280 0.0280 0.0280 

18 3.24 1.91 0.32 0.0000 0.0000 0.0043 0.0043 0.0043 

Sales­ 0.4478 4.1095 4.8069 2.1148 0.2429 

wgt EF 31 21 20 84 92 1.0000 1.0000 1.0000 1.0000 1.0000 

D49
 
Table D7. 2001 MY Certification Data (cont.)
 

11-25 hp Emission Factors (g/hp-hr) Sales Weightings
 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

Sample 

Size 16 16 43 43 43 0.09869 

0.47439 

Calc HC* 5 

Calc 4.33252 

NOx* 5 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D50
 
Table D7. 2001 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

42 6.52 3.35 0.42 0.0000 0.0000 0.0016 0.0016 0.0016 

25 5.31 1.49 0.50 0.0000 0.0000 0.0013 0.0013 0.0013 

28 4.92 1.56 0.54 0.0000 0.0000 0.0016 0.0016 0.0016 

49 4.93 0.92 0.34 0.0000 0.0000 0.0011 0.0011 0.0011 

34 5.21 1.44 0.38 0.0000 0.0000 0.0041 0.0041 0.0041 

33 0.11 4.65 4.77 0.98 0.25 0.023474 0.0149 0.0116 0.0016 0.0016 0.0016 

38 0.26 3.59 3.85 0.92 0.19 0.067829 0.0030 0.0023 0.0003 0.0003 0.0003 

30 0.16 4.00 4.17 1.17 0.26 0.039356 0.0030 0.0023 0.0003 0.0003 0.0003 

26 0.29 3.02 3.31 1.33 0.15 0.087838 0.0030 0.0023 0.0003 0.0003 0.0003 

28 0.00 7.02 1.48 0.24 0.0000 0.0000 0.0350 0.0349 0.0349 

43 0.00 6.89 2.10 0.34 0.0000 0.0000 0.0119 0.0119 0.0119 

48 0.00 6.82 1.99 0.44 0.0000 0.0000 0.0110 0.0110 0.0110 

35 5.68 1.74 0.21 0.0000 0.0000 0.0013 0.0013 0.0013 

39 6.39 1.87 0.16 0.0000 0.0000 0.0024 0.0024 0.0024 

47 6.37 1.24 0.12 0.0000 0.0000 0.0024 0.0024 0.0024 

25 4.35 0.64 0.13 0.0000 0.0000 0.0001 0.0001 0.0001 

28 3.76 1.24 0.20 0.0000 0.0000 0.0047 0.0047 0.0047 

30 3.86 0.83 0.17 0.0000 0.0000 0.0033 0.0033 0.0033 

40 4.50 0.62 0.20 0.0000 0.0000 0.0025 0.0025 0.0025 

47 3.38 0.87 0.27 0.0000 0.0000 0.0006 0.0006 0.0006 

29 4.11 1.54 0.50 0.0000 0.0000 0.0008 0.0008 0.0008 

29 4.11 1.16 0.35 0.0000 0.0000 0.0156 0.0156 0.0156 

33 3.13 1.00 0.34 0.0000 0.0000 0.0495 0.0495 0.0495 

35 4.21 0.85 0.37 0.0000 0.0000 0.0204 0.0204 0.0204 

28 3.57 2.65 0.43 0.0000 0.0000 0.0029 0.0029 0.0029 

39 4.35 1.89 0.45 0.0000 0.0000 0.0009 0.0009 0.0009 

28 0.13 4.23 4.36 1.33 0.54 0.029817 0.0417 0.0324 0.0046 0.0046 0.0046 

33 0.55 4.81 5.36 2.62 0.47 0.102612 0.1204 0.0935 0.0132 0.0131 0.0131 

37 0.16 3.56 3.72 2.30 0.58 0.041678 0.0459 0.0356 0.0050 0.0050 0.0050 

37 0.67 6.00 6.67 3.55 0.42 0.10051 0.0361 0.0280 0.0039 0.0039 0.0039 

27 0.11 4.52 4.63 0.57 0.31 0.023758 0.0002 0.0001 0.0000 0.0000 0.0000 

37 0.82 4.27 5.09 3.10 0.37 0.1611 0.0387 0.0301 0.0042 0.0042 0.0042 

27 0.09 3.95 4.04 0.82 0.46 0.021308 0.0051 0.0039 0.0006 0.0006 0.0006 

49 0.51 4.59 5.10 2.85 0.50 0.1 0.0605 0.0470 0.0066 0.0066 0.0066 

35 0.08 4.56 4.64 0.90 0.40 0.017234 0.0566 0.0440 0.0062 0.0062 0.0062 

45 0.75 5.33 6.08 2.40 0.29 0.123355 0.0548 0.0426 0.0060 0.0060 0.0060 

35 0.56 4.54 5.10 1.52 0.48 0.109804 0.4172 0.3240 0.0456 0.0456 0.0456 

46 0.04 3.75 3.79 0.68 0.33 0.010554 0.0038 0.0029 0.0004 0.0004 0.0004 

34 0.14 3.66 3.80 0.98 0.50 0.036842 0.0459 0.0356 0.0050 0.0050 0.0050 

47 0.12 6.71 6.83 0.74 0.30 0.01757 0.0015 0.0012 0.0002 0.0002 0.0002 

48 0.64 6.36 7.00 1.46 0.31 0.091429 0.0042 0.0032 0.0005 0.0005 0.0005 

30 1.41 0.62 0.26 0.0000 0.0000 0.0326 0.0325 0.0325 

26 4.64 1.30 0.28 0.0000 0.0000 0.0065 0.0065 0.0065 

31 3.80 1.16 0.36 0.0000 0.0000 0.0195 0.0195 0.0195 

42 3.84 0.78 0.24 0.0000 0.0000 0.0163 0.0163 0.0163 

D51
 
Table D7. 2001 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

26 4.46 0.95 0.35 0.0000 0.0000 0.0651 0.0651 0.0651 

44 5.37 1.10 0.38 0.0000 0.0000 0.0000 0.0000 0.0000 

33 5.52 1.71 0.36 0.0000 0.0000 0.0000 0.0000 0.0000 

41 4.81 0.75 0.25 0.0000 0.0000 0.0003 0.0003 0.0003 

31 5.27 0.74 0.19 0.0000 0.0000 0.0326 0.0325 0.0325 

31 5.11 0.80 0.26 0.0000 0.0000 0.0391 0.0390 0.0390 

38 6.16 1.66 0.41 0.0000 0.0000 0.0260 0.0260 0.0260 

37 4.47 0.80 0.29 0.0000 0.0000 0.1628 0.1627 0.1627 

49 5.95 1.93 0.43 0.0000 0.0000 0.0003 0.0003 0.0003 

38 5.99 1.58 0.36 0.0000 0.0000 0.0003 0.0003 0.0003 

48 4.63 0.93 0.23 0.0000 0.0000 0.0020 0.0020 0.0020 

35 3.69 3.83 1.40 0.29 0.0000 0.0231 0.0033 0.0033 0.0033 

40 3.36 3.54 0.95 0.21 0.0000 0.0231 0.0033 0.0033 0.0033 

40 0.18 4.99 5.17 0.94 0.48 0.034632 0.0136 0.0105 0.0015 0.0015 0.0015 

38 0.26 3.59 3.85 0.93 0.19 0.068327 0.0006 0.0005 0.0001 0.0001 0.0001 

26 0.29 3.02 3.31 1.33 0.15 0.088659 0.0012 0.0009 0.0001 0.0001 0.0001 

25 0.59 4.87 5.47 1.88 0.29 0.108272 0.0143 0.0111 0.0016 0.0016 0.0016 

33 0.23 4.10 4.33 0.74 0.23 0.054045 0.0104 0.0081 0.0011 0.0011 0.0011 

36 5.26 5.58 1.87 0.28 0.0000 0.0116 0.0016 0.0016 0.0016 

35 6.03 2.07 0.21 0.0000 0.0000 0.0015 0.0015 0.0015 

31 4.68 1.10 0.16 0.0000 0.0000 0.0015 0.0015 0.0015 

41 5.65 2.45 0.24 0.0000 0.0000 0.0024 0.0024 0.0024 

42 6.35 1.01 0.13 0.0000 0.0000 0.0020 0.0020 0.0020 

30 5.12 1.98 0.43 0.0000 0.0000 0.0035 0.0035 0.0035 

42 3.24 0.94 0.33 0.0000 0.0000 0.0003 0.0003 0.0003 

39 4.73 1.01 0.34 0.0000 0.0000 0.0026 0.0026 0.0026 

45 5.62 1.30 0.38 0.0000 0.0000 0.0009 0.0009 0.0009 

49 4.00 0.64 0.24 0.0000 0.0000 0.0001 0.0001 0.0001 

43 5.12 1.98 0.43 0.0000 0.0000 0.0001 0.0001 0.0001 

35 6.27 2.35 0.48 0.0000 0.0000 0.0033 0.0033 0.0033 

44 6.19 1.09 0.45 0.0000 0.0000 0.0015 0.0015 0.0015 

34 3.53 3.55 1.22 0.53 0.0000 0.0127 0.0018 0.0018 0.0018 

49 3.20 3.31 1.29 0.40 0.0000 0.0694 0.0098 0.0098 0.0098 

47 5.44 5.83 1.86 0.44 0.0000 0.0509 0.0072 0.0072 0.0072 

43 6.35 2.33 0.34 0.0000 0.0000 0.0006 0.0006 0.0006 

30 6.09 1.99 0.46 0.0000 0.0000 0.0003 0.0003 0.0003 

26 5.45 2.00 0.15 0.0000 0.0000 0.0280 0.0280 0.0280 

28 5.78 3.61 0.40 0.0000 0.0000 0.0097 0.0097 0.0097 

25 5.53 2.91 0.37 0.0000 0.0000 0.0137 0.0137 0.0137 

30 5.82 2.93 0.35 0.0000 0.0000 0.0009 0.0009 0.0009 

25 5.91 3.45 0.24 0.0000 0.0000 0.0018 0.0018 0.0018 

33 5.76 2.74 0.28 0.0000 0.0000 0.0476 0.0476 0.0476 

41 5.97 1.35 0.49 0.0000 0.0000 0.0009 0.0009 0.0009 

29 5.82 2.82 0.25 0.0000 0.0000 0.0030 0.0030 0.0030 

37 5.40 1.73 0.50 0.0000 0.0000 0.0009 0.0009 0.0009 

25 6.01 3.03 0.32 0.0000 0.0000 0.0004 0.0004 0.0004 

D52
 
Table D7. 2001 MY Certification Data (cont.) 

25-50 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HC NOx HC+NOx CO PM HC frac of HC wgt NOx wgt HC+NOx CO wgt PM wgt 

HP HC+NOx* wgt 

37 6.03 2.59 0.35 0.0000 0.0000 0.0272 0.0272 0.0272 

25 6.09 3.03 0.20 0.0000 0.0000 0.0000 0.0000 0.0000 

30 6.07 3.01 0.38 0.0000 0.0000 0.0110 0.0110 0.0110 

45 5.85 3.21 0.45 0.0000 0.0000 0.0367 0.0367 0.0367 

38 5.79 3.23 0.39 0.0000 0.0000 0.0017 0.0017 0.0017 

48 6.00 1.56 0.44 0.0000 0.0000 0.0000 0.0000 0.0000 

34 5.94 1.87 0.34 0.0000 0.0000 0.0689 0.0689 0.0689 

46 6.01 2.54 0.20 0.0000 0.0000 0.0063 0.0062 0.0062 

41 5.76 2.79 0.33 0.0000 0.0000 0.0030 0.0030 0.0030 

48 6.25 1.59 0.28 0.0000 0.0000 0.0002 0.0002 0.0002 

27 3.04 0.98 0.40 0.0000 0.0000 0.0021 0.0021 0.0021 

39 5.53 1.96 0.26 0.0000 0.0000 0.0010 0.0010 0.0010 

30 0.17 4.01 1.17 0.26 0.040139 0.0036 0.0028 0.0000 0.0004 0.0004 

50 4.85 0.0000 0.0325 0.0000 0.0000 0.0000 

Sales­ 0.4729 4.4696 4.9529 1.5320 0.3292 

wgt EF 17 47 01 28 22 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 25 35 103 104 104 0.064006 

Calc HC* 0.317014 

Calc 4.63588
 

NOx* 7
 

* HC fraction of HC+NOx = HC ‚ (HC+NOx). The average HC fraction is not a sales-weighted average.
 

Calculated HC = ( avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

Calculated NOx = (1- avg HC fraction of HC+NOx) * (sales-wgt avg HC+NOx).
 

D53
 
Table D7. 2001 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

67 6.40 0.0000 0.0016 0.0000 0.0000 

79 5.74 0.0000 0.0004 0.0000 0.0000 

96 5.81 0.0000 0.0002 0.0000 0.0000 

80 0.48 7.61 4.32 0.56 0.0621 0.0157 0.0591 0.0608 

67 0.75 6.35 1.96 0.34 0.0036 0.0009 0.0034 0.0035 

75 0.70 5.68 2.28 0.46 0.0888 0.0224 0.0844 0.0869 

80 0.72 5.78 3.26 0.51 0.0855 0.0216 0.0813 0.0837 

56 0.62 5.83 1.63 0.41 0.0339 0.0086 0.0322 0.0332 

75 0.70 5.68 2.28 0.49 0.0586 0.0148 0.0557 0.0573 

98 0.71 6.30 1.68 0.21 0.0004 0.0001 0.0004 0.0004 

62 6.23 0.0000 0.0008 0.0000 0.0000 

57 6.20 0.0000 0.0008 0.0000 0.0000 

55 5.80 0.0000 0.0008 0.0000 0.0000 

59 6.56 0.0000 0.0045 0.0000 0.0000 

84 5.74 0.0000 0.0478 0.0000 0.0000 

59 0.89 8.82 3.55 0.84 0.1563 0.0395 0.1486 0.1530 

78 0.48 5.36 1.92 0.35 0.0858 0.0217 0.0816 0.0840 

81 0.33 6.35 2.33 0.38 0.0154 0.0039 0.0147 0.0151 

74 5.90 0.0000 0.0040 0.0000 0.0000 

59 5.90 0.0000 0.0205 0.0000 0.0000 

82 5.44 0.0000 0.0661 0.0000 0.0000 

65 5.80 0.0000 0.0179 0.0000 0.0000 

58 6.39 0.0000 0.0002 0.0000 0.0000 

87 6.39 0.0000 0.0002 0.0000 0.0000 

83 6.56 0.0000 0.0024 0.0000 0.0000 

65 6.20 0.0000 0.0143 0.0000 0.0000 

84 6.79 0.0000 0.0000 0.0000 0.0000 

79 6.32 0.0000 0.0025 0.0000 0.0000 

94 6.09 0.0000 0.0004 0.0000 0.0000 

94 6.09 0.0000 0.0004 0.0000 0.0000 

94 6.09 0.0000 0.0004 0.0000 0.0000 

51 5.38 0.0000 0.0024 0.0000 0.0000 

56 4.98 0.0000 0.0011 0.0000 0.0000 

78 6.22 0.0000 0.0000 0.0000 0.0000 

51 4.86 1.51 0.0000 0.0022 0.0084 0.0000 

60 4.06 1.73 0.0000 0.0022 0.0084 0.0000 

52 4.59 0.0000 0.0163 0.0000 0.0000 

50 3.43 0.0000 0.0094 0.0000 0.0000 

52 0.17 5.22 1.18 0.45 0.0107 0.0027 0.0101 0.0104 

51 1.44 5.79 3.90 0.38 0.0179 0.0045 0.0170 0.0175 

54 0.69 4.15 1.45 0.36 0.0100 0.0025 0.0095 0.0098 

51 0.60 6.68 3.04 0.63 0.0008 0.0002 0.0008 0.0008 

55 0.39 6.16 0.98 0.28 0.0134 0.0034 0.0127 0.0131 

64 0.43 5.62 2.17 0.60 0.0042 0.0011 0.0040 0.0041 

D54
 
Table D7. 2001 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

76 0.29 5.35 1.08 0.51 0.0092 0.0023 0.0087 0.0090 

51 0.41 5.34 2.22 0.64 0.0386 0.0098 0.0367 0.0378 

56 0.48 4.88 0.46 0.27 0.0048 0.0012 0.0046 0.0047 

83 0.49 4.80 0.76 0.34 0.0065 0.0016 0.0061 0.0063 

91 0.42 6.63 1.32 0.54 0.0172 0.0043 0.0163 0.0168 

79 0.55 5.25 2.47 0.55 0.0248 0.0063 0.0236 0.0243 

86 0.46 4.98 0.83 0.38 0.0012 0.0003 0.0011 0.0012 

86 0.35 5.09 0.67 0.21 0.0002 0.0001 0.0002 0.0002 

59 6.65 0.0000 0.0333 0.0000 0.0000 

51 0.05 3.56 0.75 0.20 0.0097 0.0024 0.0092 0.0095 

74 0.49 3.77 3.00 0.52 0.0008 0.0002 0.0008 0.0008 

74 0.76 4.70 2.06 0.32 0.0161 0.0041 0.0153 0.0158 

80 0.72 5.78 3.26 0.51 0.0018 0.0004 0.0017 0.0017 

99 0.28 4.15 0.76 0.25 0.0133 0.0034 0.0127 0.0130 

98 0.71 6.30 1.68 0.21 0.0040 0.0010 0.0038 0.0039 

56 0.62 5.83 1.63 0.41 0.0019 0.0005 0.0018 0.0018 

59 4.37 0.0000 0.0367 0.0000 0.0000 

51 5.12 0.0000 0.0004 0.0000 0.0000 

51 4.72 0.0000 0.0004 0.0000 0.0000 

56 4.18 0.0000 0.0245 0.0000 0.0000 

89 4.79 0.0000 0.0020 0.0000 0.0000 

73 4.93 0.0000 0.0020 0.0000 0.0000 

86 5.42 0.0000 0.0082 0.0000 0.0000 

93 4.71 0.0000 0.0082 0.0000 0.0000 

72 4.31 0.0000 0.0151 0.0000 0.0000 

54 0.54 6.31 2.42 0.0085 0.0021 0.0081 0.0000 

59 3.34 0.0000 0.0002 0.0000 0.0000 

51 4.78 0.0000 0.0029 0.0000 0.0000 

56 5.95 0.0000 0.0029 0.0000 0.0000 

51 3.91 0.0000 0.0031 0.0000 0.0000 

54 2.62 0.0000 0.0039 0.0000 0.0000 

63 5.06 0.0000 0.0006 0.0000 0.0000 

95 5.58 0.0000 0.0002 0.0000 0.0000 

57 4.46 0.0000 0.0046 0.0000 0.0000 

51 5.35 0.0000 0.0042 0.0000 0.0000 

87 5.92 0.0000 0.0056 0.0000 0.0000 

55 2.91 0.0000 0.0013 0.0000 0.0000 

81 5.87 0.0000 0.0001 0.0000 0.0000 

92 5.10 0.0000 0.0002 0.0000 0.0000 

52 6.32 0.0000 0.0041 0.0000 0.0000 

72 5.14 0.0000 0.0008 0.0000 0.0000 

89 6.40 0.0000 0.0020 0.0000 0.0000 

67 0.22 5.71 1.01 0.54 0.0934 0.0236 0.0888 0.0914 

92 0.35 6.16 1.22 0.29 0.0638 0.0161 0.0606 0.0624 

55 2.62 0.0000 0.0010 0.0000 0.0000 

D55
 
Table D7. 2001 MY Certification Data (cont.) 

50-100 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

85 2.18 0.0000 0.0011 0.0000 0.0000 

59 5.90 0.0000 0.0002 0.0000 0.0000 

64 5.58 0.0000 0.0102 0.0000 0.0000 

79 6.16 0.0000 0.0055 0.0000 0.0000 

55 3.22 0.0000 0.0090 0.0000 0.0000 

52 6.62 0.0000 0.0080 0.0000 0.0000 

64 5.13 0.0000 0.0037 0.0000 0.0000 

60 6.06 0.0000 0.0212 0.0000 0.0000 

96 5.09 0.0000 0.1081 0.0000 0.0000 

68 5.85 0.0000 0.0551 0.0000 0.0000 

52 5.97 0.0000 0.0347 0.0000 0.0000 

68 6.34 0.0000 0.0347 0.0000 0.0000 

80 0.83 6.00 3.19 0.63 0.0043 0.0011 0.0041 0.0042 

80 0.86 5.40 4.00 0.64 0.0051 0.0013 0.0048 0.0050 

59 3.58 0.0000 0.0025 0.0000 0.0000 

89 5.10 0.0000 0.0008 0.0000 0.0000 

94 5.75 0.0000 0.0002 0.0000 0.0000 

50 5.80 1.78 0.46 0.0000 0.0002 0.0008 0.0009 

74 0.05 4.00 0.25 0.20 0.0002 0.0000 0.0002 0.0002 

82 0.07 4.84 1.22 0.44 0.0113 0.0029 0.0107 0.0111 

60 5.87 3.96 0.31 0.0000 0.0004 0.0015 0.0016 

58 6.27 1.32 0.27 0.0000 0.0015 0.0058 0.0059 

59 5.59 0.96 0.45 0.0000 0.0003 0.0013 0.0013 

75 3.87 0.0000 0.0013 0.0000 0.0000 

58 3.91 0.0000 0.0017 0.0000 0.0000 

54 5.40 0.0000 0.0001 0.0000 0.0000 

67 4.89 0.0000 0.0135 0.0000 0.0000 

80 4.80 0.0000 0.0004 0.0000 0.0000 

56 5.23 0.0000 0.0015 0.0000 0.0000 

58 5.12 0.0000 0.0037 0.0000 0.0000 

60 4.12 0.0000 0.0032 0.0000 0.0000 

70 5.59 0.0000 0.0117 0.0000 0.0000 

57 5.72 0.0000 0.0002 0.0000 0.0000 

95 5.10 0.0000 0.0032 0.0000 0.0000 

100 5.73 0.0000 0.0144 0.0000 0.0000 

50 0.52 4.77 5.28 1.94 0.33 0.0121 0.0031 0.3000 0.0115 0.0118 

65 0.05 4.18 4.24 0.90 0.0040 0.0010 0.1000 0.0038 0.0000 

79 5.98 6.61 1.71 0.37 0.0000 0.0061 0.6000 0.0230 0.0237 

Sales-wgt 0.57586 5.60451 2.31437 0.50682 

EF 7 5 5.976957 2 4 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 40 127 3 47 43 

D56
 
Table D7. 2001 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

173 0.33 6.37 0.78 0.11 0.0003 0.0002 0.0003 0.0003 

108 6.47 0.0000 0.0002 0.0000 0.0000 

143 6.09 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0857 0.0682 0.0856 0.0863 

125 0.23 6.21 0.47 0.16 0.0057 0.0045 0.0057 0.0058 

118 0.25 4.53 0.54 0.22 0.0021 0.0017 0.0021 0.0021 

155 0.38 4.23 0.75 0.35 0.1029 0.0819 0.1027 0.1035 

110 6.06 0.0000 0.0039 0.0000 0.0000 

165 6.24 0.0000 0.0303 0.0000 0.0000 

166 4.95 0.0000 0.0003 0.0000 0.0000 

155 0.15 4.25 1.91 0.22 0.0072 0.0057 0.0072 0.0072 

100 0.35 6.08 0.70 0.28 0.1247 0.0992 0.1244 0.1255 

125 0.23 6.21 0.47 0.16 0.0623 0.0496 0.0622 0.0627 

118 0.25 4.53 0.54 0.22 0.0023 0.0018 0.0023 0.0023 

155 0.38 4.23 0.75 0.35 0.0935 0.0744 0.0933 0.0941 

158 6.53 0.0000 0.0016 0.0000 0.0000 

109 6.41 0.0000 0.0016 0.0000 0.0000 

144 4.97 0.0000 0.0016 0.0000 0.0000 

168 0.11 6.17 0.63 0.13 0.0007 0.0006 0.0007 0.0007 

135 0.40 5.70 1.75 0.29 0.2824 0.2248 0.2819 0.2842 

168 6.26 0.0000 0.0105 0.0000 0.0000 

109 6.32 0.53 0.13 0.0000 0.0001 0.0001 0.0001 

158 6.70 0.0000 0.0072 0.0000 0.0000 

119 0.58 6.20 0.63 0.17 0.0010 0.0008 0.0010 0.0010 

121 0.49 4.30 1.23 0.28 0.0011 0.0009 0.0011 0.0011 

134 0.34 4.30 1.00 0.24 0.0050 0.0040 0.0050 0.0050 

103 0.57 6.26 1.58 0.39 0.0059 0.0047 0.0059 0.0059 

153 0.51 5.65 0.49 0.26 0.0078 0.0062 0.0078 0.0079 

164 0.47 4.67 1.06 0.23 0.0017 0.0014 0.0017 0.0017 

139 0.52 4.30 1.25 0.19 0.0006 0.0005 0.0006 0.0006 

106 6.01 0.0000 0.0426 0.0000 0.0000 

144 6.61 0.0000 0.0001 0.0000 0.0000 

100 0.35 6.08 0.70 0.28 0.0457 0.0364 0.0456 0.0460 

125 0.23 6.21 0.47 0.16 0.0114 0.0091 0.0114 0.0115 

155 0.38 4.23 0.75 0.35 0.0571 0.0455 0.0570 0.0575 

125 5.74 0.0000 0.0041 0.0000 0.0000 

114 5.42 0.0000 0.0002 0.0000 0.0000 

151 5.60 0.0000 0.0000 0.0000 0.0000 

120 5.50 0.0000 0.0009 0.0000 0.0000 

144 5.80 0.0000 0.0001 0.0000 0.0000 

114 6.35 0.0000 0.0113 0.0000 0.0000 

113 4.41 0.0000 0.0060 0.0000 0.0000 

132 6.05 0.0000 0.0041 0.0000 0.0000 

173 5.79 0.0000 0.0017 0.0000 0.0000 

108 0.16 6.25 0.43 0.26 0.0407 0.0324 0.0406 0.0410 

D57
 
Table D7. 2001 MY Certification Data (cont.) 

100-175 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

116 0.57 6.43 1.45 0.33 0.0050 0.0040 0.0050 0.0051 

168 0.42 5.85 0.76 0.27 0.0199 0.0159 0.0199 0.0200 

118 6.30 0.0000 0.0005 0.0000 0.0000 

120 5.55 0.0000 0.0178 0.0000 0.0000 

103 6.19 0.0000 0.0055 0.0000 0.0000 

172 0.13 5.31 0.45 0.17 0.0094 0.0074 0.0093 0.0094 

115 5.77 0.0000 0.0041 0.0000 0.0000 

152 5.82 0.0000 0.0372 0.0000 0.0000 

103 0.53 5.30 1.24 0.51 0.0010 0.0008 0.0010 0.0010 

135 0.45 6.68 0.92 0.24 0.0004 0.0003 0.0004 0.0004 

130 0.63 6.61 1.21 0.36 0.0007 0.0006 0.0007 0.0007 

100 0.57 5.50 1.35 0.47 0.0015 0.0012 0.0015 0.0015 

114 6.39 0.0000 0.0025 0.0000 0.0000 

127 5.38 0.0000 0.0008 0.0000 0.0000 

117 6.23 0.0000 0.0008 0.0000 0.0000 

172 6.23 0.0000 0.0025 0.0000 0.0000 

173 0.54 6.57 1.83 0.42 0.0010 0.0008 0.0010 0.0010 

122 0.07 3.93 0.42 0.14 0.0001 0.0001 0.0001 0.0001 

122 0.07 5.75 1.06 0.34 0.0049 0.0039 0.0049 0.0050 

100 6.27 0.87 0.33 0.0000 0.0005 0.0006 0.0006 

142 5.92 1.33 0.23 0.0000 0.0008 0.0010 0.0010 

138 6.68 0.0000 0.0019 0.0000 0.0000 

161 0.23 5.96 0.83 0.0082 0.0065 0.0082 0.0000 

116 5.82 0.0000 0.0005 0.0000 0.0000 

Sales-wgt 

EF 0.355107 5.574714 1.003922 0.289340 1.0000 1.0000 1.0000 1.0000 

Sample Size 34 69 37 36 

D58
 
Table D7. 2001 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

272 0.32 6.24 0.62 0.10 0.0003 0.0003 0.0000 0.0003 0.0003 

257 0.43 6.43 0.76 0.20 0.0002 0.0002 0.0000 0.0002 0.0002 

200 0.26 5.13 0.60 0.22 0.0045 0.0045 0.0000 0.0045 0.0045 

240 0.10 5.06 0.38 0.15 0.0023 0.0023 0.0000 0.0022 0.0022 

240 0.07 4.06 0.50 0.16 0.0023 0.0023 0.0000 0.0022 0.0022 

215 0.32 5.51 0.55 0.32 0.0038 0.0038 0.0000 0.0037 0.0037 

260 0.44 5.82 0.70 0.27 0.0015 0.0015 0.0000 0.0015 0.0015 

240 0.29 5.38 0.49 0.27 0.0064 0.0064 0.0000 0.0063 0.0063 

280 0.47 5.47 0.52 0.23 0.0151 0.0151 0.0000 0.0149 0.0149 

210 0.20 5.89 1.49 0.33 0.0092 0.0092 0.0000 0.0091 0.0091 

275 0.11 4.56 1.26 0.26 0.0002 0.0002 0.0000 0.0002 0.0002 

205 0.19 5.96 1.73 0.25 0.0024 0.0024 0.0000 0.0024 0.0024 

255 0.08 6.20 0.96 0.29 0.0143 0.0143 0.0000 0.0141 0.0141 

290 0.09 5.46 2.19 0.35 0.0016 0.0016 0.0000 0.0016 0.0016 

205 0.39 5.95 1.19 0.31 0.0008 0.0008 0.0000 0.0007 0.0007 

190 0.55 5.64 1.44 0.32 0.0227 0.0227 0.0000 0.0225 0.0225 

240 0.10 5.06 0.38 0.15 0.0038 0.0038 0.0000 0.0037 0.0037 

200 0.26 5.13 0.60 0.22 0.0753 0.0753 0.0000 0.0745 0.0745 

189 0.33 3.95 0.54 0.20 0.0015 0.0015 0.0000 0.0015 0.0015 

215 0.32 5.51 0.55 0.32 0.0376 0.0376 0.0000 0.0372 0.0372 

260 0.44 5.82 0.70 0.27 0.0205 0.0205 0.0000 0.0203 0.0203 

240 0.29 5.38 0.49 0.27 0.0753 0.0753 0.0000 0.0745 0.0745 

280 0.47 5.47 0.52 0.23 0.0075 0.0075 0.0000 0.0074 0.0074 

240 0.07 4.06 0.50 0.16 0.0038 0.0038 0.0000 0.0037 0.0037 

200 0.25 5.43 1.23 0.35 0.0013 0.0013 0.0000 0.0013 0.0013 

296 0.31 6.41 0.96 0.25 0.0013 0.0013 0.0000 0.0013 0.0013 

255 0.36 6.45 0.72 0.24 0.0000 0.0000 0.0000 0.0000 0.0000 

261 0.47 6.06 0.89 0.27 0.0000 0.0000 0.0000 0.0000 0.0000 

248 0.34 5.31 1.04 0.35 0.0001 0.0001 0.0000 0.0001 0.0001 

275 0.14 5.38 0.48 0.14 0.0008 0.0008 0.0000 0.0008 0.0008 

220 0.20 5.87 0.72 0.27 0.0042 0.0042 0.0000 0.0041 0.0041 

234 0.19 5.45 0.62 0.25 0.0097 0.0097 0.0000 0.0096 0.0096 

196 0.28 5.44 0.65 0.28 0.4205 0.4205 0.0000 0.4161 0.4161 

199 0.27 5.70 1.05 0.32 0.0147 0.0147 0.0000 0.0146 0.0146 

294 0.38 5.99 0.95 0.23 0.0640 0.0640 0.0000 0.0633 0.0633 

285 0.46 6.51 1.19 0.22 0.0164 0.0164 0.0000 0.0163 0.0163 

216 0.59 6.20 1.55 0.28 0.0458 0.0458 0.0000 0.0453 0.0453 

285 0.47 4.59 0.73 0.26 0.0287 0.0287 0.0000 0.0284 0.0284 

237 0.78 6.32 1.30 0.38 0.0000 0.0000 0.0000 0.0000 0.0000 

189 0.43 6.65 1.04 0.34 0.0014 0.0014 0.0000 0.0014 0.0014 

194 0.31 6.28 0.81 0.17 0.0083 0.0083 0.0000 0.0083 0.0083 

288 0.62 6.62 1.69 0.36 0.0005 0.0005 0.0000 0.0005 0.0005 

186 0.34 6.28 0.69 0.23 0.0004 0.0004 0.0000 0.0004 0.0004 

249 0.48 6.37 1.08 0.24 0.0001 0.0001 0.0000 0.0001 0.0001 

D59
 
Table D7. 2001 MY Certification Data (cont.) 

175-300 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

243 0.40 5.88 1.67 0.37 0.0000 0.0000 0.0000 0.0000 0.0000 

210 0.09 5.16 0.90 0.11 0.0021 0.0021 0.0000 0.0020 0.0020 

250 0.09 5.29 0.44 0.05 0.0001 0.0001 0.0000 0.0001 0.0001 

215 0.10 6.30 0.50 0.07 0.0005 0.0005 0.0000 0.0005 0.0005 

197 0.33 4.42 0.71 0.20 0.0002 0.0002 0.0000 0.0001 0.0001 

241 0.21 4.14 0.67 0.17 0.0002 0.0002 0.0000 0.0001 0.0001 

241 0.41 6.44 1.11 0.34 0.0006 0.0006 0.0000 0.0006 0.0006 

227 0.51 6.72 1.07 0.33 0.0009 0.0009 0.0000 0.0009 0.0009 

193 0.60 6.69 0.85 0.28 0.0004 0.0004 0.0000 0.0004 0.0004 

200 0.26 5.13 0.60 0.22 0.0075 0.0075 0.0000 0.0074 0.0074 

189 0.33 3.95 0.54 0.20 0.0015 0.0015 0.0000 0.0015 0.0015 

215 0.32 5.51 0.55 0.32 0.0075 0.0075 0.0000 0.0074 0.0074 

240 0.29 5.38 0.49 0.27 0.0045 0.0045 0.0000 0.0045 0.0045 

280 0.47 5.47 0.52 0.23 0.0008 0.0008 0.0000 0.0008 0.0008 

189 0.31 5.40 0.92 0.21 0.0001 0.0001 0.0000 0.0001 0.0001 

252 0.22 6.23 0.30 0.23 0.0030 0.0030 0.0000 0.0029 0.0029 

283 0.14 4.25 0.43 0.17 0.0011 0.0011 0.0000 0.0011 0.0011 

262 0.17 5.84 0.57 0.21 0.0002 0.0002 0.0000 0.0002 0.0002 

244 0.39 6.24 0.74 0.18 0.0004 0.0004 0.0000 0.0004 0.0004 

285 0.06 5.93 0.60 0.09 0.0003 0.0003 0.0000 0.0003 0.0003 

215 0.04 4.10 0.51 0.16 0.0034 0.0034 0.0000 0.0034 0.0034 

197 0.33 5.07 0.76 0.18 0.0021 0.0021 0.0000 0.0021 0.0021 

251 0.23 5.59 0.42 0.11 0.0039 0.0039 0.0000 0.0039 0.0039 

184 0.30 6.70 0.61 0.18 0.0010 0.0010 0.0000 0.0010 0.0010 

280 0.19 5.68 0.51 0.18 0.0020 0.0020 0.0000 0.0019 0.0019 

298 0.37 6.32 1.16 0.30 0.0011 0.0011 0.0000 0.0011 0.0011 

212 0.29 6.41 0.40 0.14 0.0014 0.0014 0.0000 0.0014 0.0014 

286 0.22 5.35 1.24 0.37 0.0083 0.0083 0.0000 0.0082 0.0082 

208 0.15 4.28 0.52 0.26 0.0051 0.0051 0.0000 0.0050 0.0050 

202 0.28 6.00 1.05 0.33 0.0003 0.0003 0.0000 0.0003 0.0003 

190 0.66 6.08 1.56 0.40 0.0002 0.0002 0.0000 0.0002 0.0002 

177 0.34 6.20 0.89 0.28 0.0010 0.0010 0.0000 0.0010 0.0010 

182 0.42 6.43 0.87 0.29 0.0003 0.0003 0.0000 0.0003 0.0003 

207 0.44 6.59 1.15 0.36 0.0003 0.0003 0.0000 0.0003 0.0003 

217 0.36 5.49 1.00 0.22 0.0007 0.0007 0.0000 0.0007 0.0007 

244 0.19 6.30 1.66 0.37 0.0014 0.0014 0.0000 0.0014 0.0014 

272 0.35 6.44 1.09 0.22 0.0014 0.0014 0.0000 0.0014 0.0014 

255 0.25 5.89 0.40 0.13 0.0026 0.0026 0.0000 0.0026 0.0026 

279 4.18 0.73 0.20 0.0000 0.0000 0.8977 0.0102 0.0102 

275 0.11 4.02 4.13 0.80 0.16 0.0002 0.0002 0.0209 0.0002 0.0002 

185 0.54 4.19 4.73 0.93 0.20 0.0002 0.0002 0.0132 0.0001 0.0001 

245 4.55 0.45 0.15 0.0000 0.0000 0.0359 0.0004 0.0004 

295 0.22 4.08 4.29 0.60 0.13 0.0003 0.0003 0.0299 0.0003 0.0003 

268 0.30 4.00 4.47 0.66 0.19 0.0000 0.0000 0.0024 0.0000 0.0000 

Sales-wgt 0.31476 5.50654 4.203295 0.74463 0.26662 1.0000 1.0000 1.0000 1.0000 1.0000 

D60
 
Table D7. 2001 MY Certification Data (cont.) 

175-300 hp 

Rated HP HC 

Emission Factors (g/hp-hr) 

NOx HC+NOx CO PM HC wgt 

Sales Weightings 

NOx wgt HC+NOx CO wgt PM wgt 

EF 5 5 3 2 

wgt 

Sample 

Size 86 86 6 88 88 

D61
 
Table D7. 2001 MY Certification Data (cont.) (Tier 2 for this hp category) 

300-600 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

325 4.56 1.52 0.17 0.0000 0.0000 0.0516 0.0516 0.0516 

439 3.75 1.19 0.16 0.0000 0.0000 0.0589 0.0589 0.0589 

515 3.58 1.14 0.17 0.0000 0.0000 0.0521 0.0521 0.0521 

593 4.08 0.58 0.10 0.0000 0.0000 0.2080 0.2080 0.2080 

475 4.14 0.99 0.14 0.0000 0.0000 0.0460 0.0460 0.0460 

325 4.56 1.52 0.17 0.0000 0.0000 0.0516 0.0516 0.0516 

449 0.10 3.80 3.91 0.37 0.10 0.0036 0.0036 0.0011 0.0011 0.0011 

422 0.14 4.09 4.24 0.35 0.10 0.0279 0.0279 0.0082 0.0082 0.0082 

322 0.13 4.37 4.50 0.44 0.11 0.0110 0.0110 0.0032 0.0032 0.0032 

333 0.15 4.38 4.53 0.53 0.14 0.6951 0.6951 0.2042 0.2042 0.2042 

300 4.53 0.82 0.14 0.0000 0.0000 0.0038 0.0038 0.0038 

350 4.71 0.77 0.11 0.0000 0.0000 0.0038 0.0038 0.0038 

500 4.75 1.30 0.12 0.0000 0.0000 0.1467 0.1467 0.1467 

500 4.61 0.48 0.12 0.0000 0.0000 0.0258 0.0258 0.0258 

300 0.06 4.02 4.08 0.59 0.13 0.0239 0.0239 0.0070 0.0070 0.0070 

317 0.39 4.19 4.58 0.80 0.15 0.0150 0.0150 0.0044 0.0044 0.0044 

321 0.17 4.22 4.39 0.52 0.14 0.0389 0.0389 0.0114 0.0114 0.0114 

483 0.16 4.23 4.39 0.46 0.13 0.0235 0.0235 0.0069 0.0069 0.0069 

360 0.12 4.47 4.59 0.63 0.09 0.0030 0.0030 0.0009 0.0009 0.0009 

326 0.50 4.04 4.54 0.43 0.14 0.0022 0.0022 0.0006 0.0006 0.0006 

456 0.15 4.37 4.52 0.57 0.10 0.0070 0.0070 0.0021 0.0021 0.0021 

481 0.10 4.44 4.53 0.43 0.08 0.0036 0.0036 0.0011 0.0011 0.0011 

322 4.34 0.65 0.15 0.0000 0.0000 0.0066 0.0066 0.0066 

410 4.40 0.30 0.11 0.0000 0.0000 0.0264 0.0264 0.0264 

508 4.20 0.30 0.12 0.0000 0.0000 0.0016 0.0016 0.0016 

572 4.53 0.86 0.19 0.0000 0.0000 0.0019 0.0019 0.0019 

503 4.50 0.93 0.15 0.0000 0.0000 0.0064 0.0064 0.0064 

571 4.29 0.48 0.14 0.0000 0.0000 0.0035 0.0035 0.0035 

475 4.38 0.46 0.11 0.0000 0.0000 0.0035 0.0035 0.0035 

595 4.20 0.63 0.16 0.0000 0.0000 0.0035 0.0035 0.0035 

367 4.55 0.45 0.15 0.0000 0.0000 0.0035 0.0035 0.0035 

493 4.49 0.71 0.13 0.0000 0.0000 0.0006 0.0006 0.0006 

493 4.49 0.71 0.13 0.0000 0.0000 0.0006 0.0006 0.0006 

324 0.22 4.30 4.53 0.47 0.08 0.0100 0.0100 0.0029 0.0029 0.0029 

375 0.25 4.29 4.54 0.48 0.08 0.1354 0.1354 0.0398 0.0398 0.0398 

Sales-wgt 

EF 

0.1669 

24 

4.3351 

13 

4.34534 

8 

0.8424 

60 

0.1315 

81 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 14 14 35 35 35 

D62
 
Table D7. 2001 MY Certification Data (cont.) 

600-750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx HC+NOx CO PM HC wgt NOx wgt HC+NOx CO wgt PM wgt 

wgt 

660 0.05 6.24 0.83 0.14 0.0276 0.0276 0.0000 0.0192 0.0192 

742 0.04 6.27 0.52 0.10 0.0408 0.0408 0.0000 0.0284 0.0284 

654 0.04 6.21 1.58 0.25 0.1192 0.1192 0.0000 0.0829 0.0829 

730 0.06 5.04 0.99 0.19 0.1159 0.1159 0.0000 0.0806 0.0806 

740 0.10 5.53 1.62 0.33 0.0850 0.0850 0.0000 0.0591 0.0591 

670 0.25 6.53 1.27 0.36 0.0795 0.0795 0.0000 0.0553 0.0553 

710 0.27 6.63 2.31 0.30 0.0552 0.0552 0.0000 0.0384 0.0384 

641 0.19 5.98 1.05 0.23 0.0353 0.0353 0.0000 0.0246 0.0246 

740 0.24 5.85 1.37 0.28 0.0839 0.0839 0.0000 0.0583 0.0583 

684 0.19 5.98 0.68 0.22 0.0055 0.0055 0.0000 0.0038 0.0038 

671 0.48 6.63 0.52 0.16 0.0221 0.0221 0.0000 0.0153 0.0153 

747 0.22 4.50 0.76 0.09 0.0055 0.0055 0.0000 0.0038 0.0038 

680 3.89 0.33 0.12 0.0000 0.0000 0.7192 0.3047 0.3047 

601 0.13 4.19 4.32 0.22 0.12 0.1049 0.1049 0.1721 0.0729 0.0729 

750 0.07 5.84 0.90 0.16 0.0121 0.0121 0.0000 0.0084 0.0084 

750 0.13 5.89 1.06 0.13 0.1413 0.1413 0.0000 0.0982 0.0982 

630 0.12 3.87 3.99 0.87 0.18 0.0662 0.0662 0.1087 0.0460 0.0460 

Sales-wgt 0.13806 5.61241 0.88330 0.18377 

EF 5 8 3.975047 5 3 1.0000 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 16 16 3 17 17 

D63
 
Table D7. 2001 MY Certification Data (cont.) 

>750 hp Emission Factors (g/hp-hr) Sales Weightings 

Rated HP HC NOx CO PM HC wgt NOx wgt CO wgt PM wgt 

758 0.07 5.26 1.07 0.16 0.0052 0.0052 0.0052 0.0052 

891 0.05 6.22 0.73 0.14 0.0152 0.0152 0.0152 0.0152 

1850 0.16 5.89 1.09 0.30 0.0654 0.0654 0.0654 0.0654 

2250 0.16 6.43 1.28 0.20 0.0395 0.0395 0.0395 0.0395 

755 0.35 5.80 1.48 0.30 0.0599 0.0599 0.0599 0.0599 

1200 0.17 5.17 0.34 0.16 0.0033 0.0033 0.0033 0.0033 

2000 0.31 5.91 1.49 0.25 0.0228 0.0228 0.0228 0.0228 

1110 0.23 6.03 0.55 0.14 0.4402 0.4402 0.4402 0.4402 

1500 0.54 6.24 0.87 0.27 0.2677 0.2677 0.2677 0.2677 

1200 0.17 5.17 0.34 0.16 0.0228 0.0228 0.0228 0.0228 

899 0.21 6.02 0.53 0.15 0.0088 0.0088 0.0088 0.0088 

1230 0.12 6.03 0.67 0.26 0.0046 0.0046 0.0046 0.0046 

811 0.27 6.24 1.05 0.21 0.0152 0.0152 0.0152 0.0152 

1874 0.38 6.15 1.36 0.15 0.0024 0.0024 0.0024 0.0024 

878 0.34 5.96 0.89 0.14 0.0152 0.0152 0.0152 0.0152 

1207 0.23 5.45 1.26 0.24 0.0030 0.0030 0.0030 0.0030 

1026 0.26 5.07 0.70 0.18 0.0009 0.0009 0.0009 0.0009 

2346 0.40 6.04 1.39 0.26 0.0076 0.0076 0.0076 0.0076 

Sales-wgt 

EF 0.313093 6.052394 0.800887 0.203589 1.0000 1.0000 1.0000 1.0000 

Sample 

Size 18 18 18 18 

D64
 
Appendix E
 

Derivation of Highway-Certification Compliance Margins and Application to Nonroad
 

Compression Ignition Engines
 

Here below, we describe the derivation of the highway-certification compliance margins 

(HCCMs) in greater detail. The highway certification results used for this purpose in derivation 

of Tier 2/3 emission factors (option 4) are summarized in a report updating emission levels for 

heavy-duty highway diesel engines for use in MOBILE6 (1). The report presents results for 

light, medium, and heavy vehicle classes in model years 1988-1989 and 1991-1994. For this 

analysis, we supplemented these certification data with more recent highway certification data 

from model years 1997-2001. 

We used the highway certification results to calculate compliance margins (HCCM) for 

some highway engines for MY 1988-2001. The procedure followed several steps (refer to Table 

E1): 

(1)	 We assigned highway model-year groups, (e.g., 1991-93) to each nonroad horsepower 

category (e.g., 50-100 hp). These assignments vary for each pollutant and individual 

horsepower category. The assignments attempt to associate similar highway and nonroad 

engine technologies. We averaged results for multiple years within a model-year group. 

(2)	 We assigned nonroad engines less than 50 horsepower to the light heavy-duty diesel 

vehicle weight class (LHDD), engines in the range of 50-250 hp to the medium heavyduty diesel vehicle weight class (MHDD), and engines greater than 250 hp to the heavy 

heavy-duty diesel vehicle weight class (HHDD). Within a model-year group, these 

assignments identified subsets of certification data to represent specific nonroad 

horsepower categories. Correspondence between highway weight class (light-duty, 

medium-duty, heavy-duty) and nonroad horsepower categories follows relationships 

established by the California Air Resources Board (CARB 2000). 

(3)	 We used the highway certification data described above and assigned to the appropriate 

nonroad horsepower categories to calculate compliance margins for highway engines at 

certification: 

HS - AHC i, j i, j HCCM = i, j HS i, j 

where HCCMi,j, HSi,j and AHCi,j are the highway-certification 

compliance margin, highway standard and average certification 

emissions level, respectively, for pollutant i, and horsepower category 

j (e.g., NOx, 50-100 hp). 

While we calculated the highway-certification compliance margins for all pollutants and 

E1
 
horsepower categories, note that Table E1 presents results only for NOx and PM. We do not 

present compliance margins for HC and CO because the margins were higher than 80 percent. 

As a result, we did not use them to estimate HC and CO Tier 2/3 emission factors. 

References 

(1) EPA, “Update of Heavy-Duty Emission Levels (Model Years 1988-2004+) for Use in 

MOBILE6,” EPA420-R-99-010, April 1999. 

E2
 
Power Categori Year Group (VWC), Emission Standards

Table E1. Highway-Certification Compliance Margins by Horsepower Category 

Nonroad Engine 

es (hp) 

Highway Model­

(MYG) 

Corresponding Heavy-Duty Highway Vehicle Weight Class 

(HS), Certification Test Results (AHC) and Compliance Margins 

(HCCM) 

NOx 

VWC1 HS 

(g/hp-hr) 

AHC 2 

(g/hp-hr) 

HCCM 

(% HS) 

< 11 1991-93 LHDD 5.0 4.28 14 

11-25 1991-93 LHDD 5.0 4.28 14 

25-50 1991-93 LHDD 5.0 4.28 14 

50-100 1991-93 MHDD 5.0 4.54 9.0 

100-175 1998-2003 MHDD 4.0 3.78 5.5 

175-300 1998-2003 MHDD 4.0 3.58 10.5 

300-600 1998-2003 HHDD 4.0 3.92 2.0 

600-750 1998-2003 HHDD 4.0 3.84 4.0 

>750 1998-2003 HHDD 4.0 3.84 4.0 

PM 

< 11 1988-89 LHDD 0.6 0.44 27 

11-25 1988-89 LHDD 0.6 0.44 27 

25-50 1988-89 LHDD 0.6 0.44 27 

50-100 1991-93 MHDD 0.25 0.20 20 

100-175 1991-93 MHDD 0.25 0.20 20 

175-300 1994-97 MHDD 0.10 0.08 20 

300-600 1994-97 HHDD 0.10 0.08 20 

600-750 1994-97 HHDD 0.10 0.08 20 

>750 1994-97 HHDD 0.10 0.08 20 

1 LHDD = “light heavy-duty diesel,” MHDD = “medium heavy-duty diesel,” and HHDD = “heavy heavy-duty diesel.” 

2 Source: USEPA (1999), for NOx, Table 10 or MY 1997-2001 highway certification data; for PM, Table 11 or MY 

1997-2001highway certification data. 

E3
 
Appendix F
 

Derivation of Transient Adjustment Factors (TAFs) for
 

Nonroad Compression Ignition Engines
 

Nonroad engines often operate under conditions unlike that of the steady-state 

ISO-C1 testing procedure typically used in emissions testing. This alternate operation 

can cause a change in the emission characteristics of nonroad compression ignition (CI) 

engines. As in NEVES, the NONROAD model accounts for in-use (transient) operation 

in CI engines by applying an adjustment to emission factors generated using the ISO-C1 

(8-mode) steady-state tests. Unlike NEVES, the NONROAD model uses transient 

adjustment factors derived from emission testing designed to represent operational 

behavior of nonroad equipment. Note that the transient adjustments are not applied by 

the NONROAD model, but are applied by EPA during the creation of the NONROAD 

emission factor input files. 

TAFs are applied to the Base, Tier 0, Tier 1, Tier 2, and Tier 3 emission factors. 

Since transient emission control is expected to be an integral part of all Tier 4 engine 

design considerations, TAFs are not applied to the emission factors for Tier 4 engines 

(i.e., the model applies a TAF of 1.0). 

Development of Transient Adjustment Factors 

In NEVES, EPA adjusted the ISO-C1-derived emission factor data available at 

the time to account for in-use operation by applying a set of multipliers. These factors 

were derived from a comparison of only a few engines tested with both the ISO-C1 test 

procedure and the highway Federal Test Procedure (FTP). (1) These factors shown in 

Table F1 were applied in NEVES only to engines used in applications judged to be 

sufficiently transient in nature. 

Table F1. NEVES Test Cycle Adjustment from ISO-C1 Emission Factors 

NEVES 

Adjustment 

HC CO NOx PM 

1.4 2.0 1 1.6 

NONROAD’s steady-state emission factors for pre-1988 CI engines of greater 

than 50 hp are based on the emission factors used in the NEVES. As a result, the NEVES 

in-use adjustments were removed to determine pre-1988 average steady-state emissions 

for these engines. The TAFs described below are then applied consistently to all the 

steady-state emission factors in NONROAD, including the NEVES-derived steady-state 

emission factors. 

Since it was recognized that the highway test procedure may not simulate engine 

F1
 
behavior when used in nonroad applications, a joint EMA\EPA project was initiated to 

develop more realistic test cycles for nonroad engine emissions characterization. The 

project developed cycles to represent typical operation of an agricultural tractor, a 

crawler dozer, and a backhoe\loader. The cycles were developed from data acquired 

from instrumenting one piece of each type of equipment. This data was used to construct 

appropriate test cycles from statistical criteria developed by EMA and EPA. Southwest 

Research Institute (SwRI) then tested nine late-model nonroad engines using the steadystate ISO-C1 certification procedure and the three nonroad test cycles. (2) Later testing 

at SwRI involved three additional engines and four additional cycles (rubber-tire loader, 

skid-steer loader, arc welder, and excavator cycles). (3) A summary of the cycle specific 

emission results for each engine is given in Table F2. 

For each pollutant and test cycle, we calculate the TAF as the ratio of the transient 

emission factor (EFtrans) to the corresponding steady-state (ISO-C1) emission factor 

(EFss): 

EF trans TAF = 

EF ss 

Transient adjustment factors may be greater than or less than 1.0. 

Using the emission data in Table F2, TAFs were calculated for each engine, 

pollutant, and test cycle. The resulting TAFs for each engine are provided in Table F3. 

The TAFs for each engine were then averaged to obtain composite TAFs for each of the 

seven test cycles. These are also shown in Table F3 along with the standard deviations. 

TAFs for Tier 0 and Tier 1 engines were combined, since they were not statistically 

different, based on P values obtained from performing the Student’s t-Test. 

For this version of NONROAD, the seven average cycle TAFs were further 

binned into two categories, Hi LF and Lo LF, based on the cycle load factors. We 

thought this approach would be more defensible, given the limited data available. This 

approach is also consistent with that used to develop the new load factors in the model. 

Table F4 shows how the cycle TAFs were binned. When reviewing the cycle load 

factors, two bins emerged. A high load factor bin consisted of the following cycles: 

agricultural tractor (LF=0.78), crawler dozer (LF=0.58), rubber-tire loader (LF=0.48), 

and excavator (LF=0.53). A low load factor bin consisted of the remaining cycles: 

backhoe/loader (LF=0.21), skid-steer loader (LF=0.23), and arc welder (LF=0.19). The 

TAFs for the high load factor cycles were averaged to obtain a composite Hi LF TAF. 

Similarly, the TAFs for the low load factor cycles were averaged to obtain a composite 

Lo LF TAF. As a result, the cycle TAFs were replaced by either a Hi LF TAF or a Lo LF 

TAF, depending on the cycle assignment. 

Table F5 presents the CI TAFs used in NONROAD. The TAFs are carried over 

F2
 
from Table F4 with the exception of the Tier 3 TAFs for NOx and PM. The rationale for 

the NOx and PM Tier 3 TAFs is described in detail below. 

Transient Emission Control and Implications for Tier 3 NOx and PM TAFs 

The nonroad engine test cycle (for pre-Tier 4 engines) is a weighted 8 mode 

steady-state emission cycle without a transient test element. This is in contrast to onhighway diesel regulations which are set based on average emissions over a 20 minute 

transient test and a separate steady-state test. The absence of a transient test allows some 

additional control flexibilities for nonroad engines not available, or available at a 

diminished level, for on-highway diesel engines. The nonroad engine standards are 

therefore inherently less restrictive than otherwise equivalent on-highway emission 

standards, as explained in the following paragraphs. 

Transient PM emission control is realized for on-highway diesel engines by 

limiting fuel injection quantities dependent upon the oxygen content available (the air to 

fuel ratio, A/F) to burn the fuel. When an on-highway diesel engine transitions from a 

low load steady-state condition to a higher load it does so by increasing the fuel injection 

rate and the air induction rate through increases in the intake manifold pressure (i.e. 

higher boost from the turbocharger) in order to maintain an A/F ratio with acceptable PM 

emissions. While the fueling rate can be changed almost instantaneously on a diesel 

engine, it takes a longer amount of time for the turbocharger to increase the air flow due 

to the inertial lag of the turbocharger and the mass of air. During the transient period 

when the turbocharger is gradually increasing the air flow, the engine control system 

limits the addition of fuel in order to prevent excess PM emissions. It is only after the air 

flow has increased to the proper amount, that the engine control system allows the fueling 

rate to rise to the level needed to deliver the desired engine torque. This control approach 

limits transient PM emissions so that the engine will pass the highway transient test. 

Absent a transient PM emissions test, the engine controller could immediately increase 

the fueling rate, providing rapid attainment of the desired torque level, but this would also 

dramatically increase PM emissions. The increase in PM emissions under transient 

conditions due to the lack of oxygen (low A/F) is exacerbated by the use of exhaust gas 

recirculation (EGR) to limit NOx emissions. This is because the recirculated gases have a 

lower oxygen content (the very reason they help to lower NOx emissions). In order to 

maintain effective PM emission control with EGR, turbocharger boost levels are 

increased (more low oxygen content air is forced in to the engine in order to give a total 

oxygen content similar to without EGR). Because of the higher boost pressure required, 

transient PM control might be expected to be worse for EGR equipped engines. For 

highway diesel engines which must meet a transient PM emission standard, these issues 

are addressed with sophisticated control systems and with the use of advanced 

turbocharger systems (i.e., variable geometry turbochargers). Absent a transient test 

procedure, these advanced systems would not necessarily be used. 

F3
 
Similarly, NOx control for on-highway diesel engines equipped with EGR 

systems are significantly constrained by the transient emission test procedure. When 

undergoing a transient event as described in the previous example, an EGR emission 

control system for on-highway engines would briefly turn off EGR in order to increase 

the fresh air flow to the system in order to limit PM emissions and increase engine torque 

response. The control system must, however, restore the EGR relatively quickly in order 

to control NOx emissions under the highway transient test procedure. Failure to do so 

would lead to higher NOx emissions. Absent a transient NOx standard, the EGR system 

could be turned off for a long period under transient operation, leading to substantially 

higher NOx emissions than what would be expected based upon a steady state emission 

test level alone. The extent of this increase in NOx emissions is dependent upon the 

degree of transient operation (the relative change in engine load). To the extent that load 

transient are less severe or not extended, the differences in the resulting NOx emissions 

would be less evident. 

The lack of a transient emission test procedure for pre-Tier 4 nonroad engines is a 

concern to the Agency, because we know that PM emissions realized in use can be 

significantly higher than the steady-state emission level set by the PM standards. 

Similarly, we have concerns that NOx emissions under transient conditions may be higher 

than indicated by the steady state emissions test and the associated standards. We are 

therefore working to develop a more comprehensive set of emission test requirements for 

nonroad engines to include a transient test element. In the absence of such a test 

procedure for Tier 3 engines, we believe that it is prudent to try to characterize these inuse emissions by increasing the TAFs applied for NOx and PM emissions for Tier 3 

engines from the level estimated for Tier 2 engines. Since Tier 3 engines are not 

available to provide test data to establish the level of adjustment required, we have 

applied engineering judgement to estimate the level of increase in emissions. For PM we 

have estimated that the TAF will increase by 20 percent due to the lack of a transient test 

and the inherent reduction in average A/F ratio values due to the use of EGR. Given the 

highly transient nature of some nonroad diesel engine applications the actual level of 

increase could be even higher. In the absence of more definitive data we believe that a 20 

percent increase in the TAF is appropriate. We intend to investigate this issue further 

when Tier 3 engines become available for testing. We also believe that the NOx TAF 

should be adjusted in a similar manner. For NOx we believe that a 10 percent increase in 

the TAF is appropriate given the characteristics of EGR systems as we understand them 

today. We believe that nonroad engine manufacturers will choose to modulate EGR rates 

during high load change transient operation in order to limit PM emissions increases. 

This will lead to an increase in NOx emission for the period that the EGR rate is 

modulated below the steady-state level. For example, a 10 percent increase in NOx 

emissions could correspond to an EGR rate of zero for 10 percent of the time (a duty 

cycle of 90 percent moderate transient and steady-state operation and 10 percent highly 

transient operation) assuming that NOx emissions double when the EGR flow is zero. 

For some applications with extreme transient operations it is conceivable that the increase 

F4
 
in emission could be even higher. As with PM, we intend to investigate the actual level 

of NOx emissions when Tier 3 engines become available. 

Applying In-use Adjustment Factors 

To apply the in-use adjustment factors listed in Table F5 to the entire CI 

equipment population, EPA matched nonroad applications with the test cycle that most 

closely represents the nonroad activity for the application. Table F6 lists the nonroad 

applications used in the NONROAD model and the in-use adjustment most representative 

of that application. If steady-state operation is typical of an application no adjustment 

was made, and the cycle adjustment is listed as ‘none’. 

Table A3 presents the resulting TAFs assigned to each equipment application. 

The steady-state emission factors given in Table A2 were then multiplied by the 

appropriate in-use adjustment factor to create NONROAD’s emission factor inputs for CI 

engines. 

Comparison with Previous Draft Versions of NONROAD 

Table F7 presents a comparison of TAF methodologies used in the various draft 

versions of NONROAD. 

References 

(1) EPA, “Nonroad Engine and Vehicle Emission Study” (NEVES), U.S. EPA, Office 

of Air and Radiation, 21A-2001. November, 1991 

(2) Fritz, S. G. and M.E. Starr, “Emission Factors for Compression Ignition Nonroad 

Engines Operated on Number 2 Highway and Nonroad Diesel Fuel,” Southwest Research 

Institute. EPA contract # 68-C5-0077, SwRI 08-7601-822, March 1998. 

(3) Starr, M.E., “Nonroad Engine Emissions Testing,” Southwest Research Institute. 

EPA contract # 68-C5-0076 and 68-C-98-169, September 1999. 

F5
 
Table F2. CI Engine Emissions Data Used to Calculate Transient Adjustment Factors 

Engine 

(reference) Tier Test Cycle HC 

(g/hp-hr) 

CO 

(g/hp-hr) 

NOx 

(g/hp-hr) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

Caterpillar 3116 (2) 0 ISO-C1 8-mode 0.07 2.51 9.38 0.406 0.352 

Agricultural Tractor 0.04 0.75 9.4 0.28 0.357 

Backhoe Loader 0.36 7.47 9.46 0.652 0.411 

Crawler Dozer 0.09 7.3 8.7 0.713 0.362 

Caterpillar 3054 (2) 0 ISO-C1 8-mode 0.66 1 7.53 0.387 0.393 

Agricultural Tractor 0.46 0.47 9.46 0.263 0.377 

Backhoe Loader 1.22 3.34 5.45 0.759 0.446 

Crawler Dozer 0.51 1.06 8.28 0.384 0.372 

John Deere 4039 (2) 0 ISO-C1 8-mode 0.41 2.17 11.22 0.384 0.389 

Agricultural Tractor 0.2 0.56 11.7 0.173 0.361 

Backhoe Loader 1 2.62 9.57 0.447 0.471 

Crawler Dozer 0.33 1.42 11.7 0.254 0.372 

John Deere 7076 (2) 0 ISO-C1 8-mode 0.53 2.05 10.22 0.25 0.385 

Agricultural Tractor 0.54 0.57 9.45 0.168 0.366 

Backhoe Loader 1.13 4.82 14.35 0.522 0.493 

Crawler Dozer 0.52 2.22 10.14 0.303 0.37 

Consolidated Diesel 

6TA-830 (2) 

0 ISO-C1 8-mode 0.86 1.5 6.53 0.397 0.365 

Agricultural Tractor 0.9 1.07 5.62 0.304 0.377 

Backhoe Loader 2.08 9.86 6.69 1.698 0.438 

Crawler Dozer 0.83 3.76 6.06 0.805 0.37 

John Deere 6619 (2) 0 ISO-C1 8-mode 0.82 4.69 7.29 0.662 0.397 

Agricultural Tractor 0.87 1.16 6.77 0.283 0.4 

Backhoe Loader 1.99 6.89 8.29 1.102 0.466 

Crawler Dozer 0.8 3.31 7.01 0.698 0.398 

Consolidated Diesel 

4039 (2) 

0 ISO-C1 8-mode 1.32 3.37 7.57 0.581 0.389 

Agricultural Tractor 0.86 2.5 7.28 0.43 0.367 

Backhoe Loader 2.89 3.31 6.52 0.725 0.436 

Crawler Dozer 1.22 2.1 7.4 0.413 0.364 

Caterpillar 3306 (2) 0 ISO-C1 8-mode 1.27 1.46 6.52 0.248 0.373 

Agricultural Tractor 1.33 0.82 6.46 0.201 0.372 

Backhoe Loader 2.3 5.14 7.22 0.813 0.415 

Crawler Dozer 1.16 2.7 6.54 0.436 0.37 

John Deere 6101 (2) 

1 ISO-C1 8-mode 0.47 0.86 5.55 0.186 0.350 

Agricultural Tractor 0.50 0.32 4.93 0.125 0.362 

Backhoe Loader 1.07 1.92 6.36 0.430 0.434 

Crawler Dozer 0.51 1.17 5.25 0.246 0.362 

John Deere 6101(same 

engine) retested (3) 

1 ISO-C1 8-mode 0.50 1.17 5.73 0.219 0.363 

Agricultural Tractor 0.46 0.44 5.16 0.130 0.355 

Backhoe Loader 0.93 1.90 6.04 0.430 0.419 

Crawler Tractor 0.47 1.14 5.50 0.250 0.357 

John Deere 6101 (same 1 ISO-C1 8-mode 0.46 0.95 5.75 0.19 

F6
 
Table F2. CI Engine Emissions Data Used to Calculate Transient Adjustment Factors 

Engine 

(reference) Tier Test Cycle HC 

(g/hp-hr) 

CO 

(g/hp-hr) 

NOx 

(g/hp-hr) 

PM 

(g/hp-hr) 

BSFC 

(lb/hp-hr) 

Agricultural Tractor 0.39 0.39 5.24 0.11 

Backhoe Loader 0.68 1.58 6.09 0.33 

Crawler Dozer 0.37 1.33 5.61 0.24 

Excavator 0.67 0.40 4.92 0.171 

John Deere 6101 

(average of three tests) 

1 ISO-C1 8-mode 0.48 0.99 5.68 0.20 0.36 

Agricultural Tractor 0.45 0.38 5.11 0.12 0.36 

Backhoe Loader 0.89 1.80 6.16 0.40 0.43 

Crawler Dozer 0.45 1.21 5.45 0.24 0.36 

Excavator 0.67 0.40 4.92 0.171 

Caterpillar 3176 (3) 1 ISO-C1 8-mode 0.08 1.78 5.51 0.183 0.333 

Agricultural Tractor 0.08 1.47 5.39 0.180 0.330 

Backhoe Loader 0.12 4.12 7.20 0.290 0.367 

Crawler Dozer 0.06 2.67 5.61 0.230 0.334 

MX270 (3) 1 ISO-C1 8-mode 0.11 0.40 4.51 0.096 0.340 

Agricultural Tractor 0.06 0.30 4.33 0.090 0.332 

Backhoe Loader 0.09 1.30 4.49 0.200 0.382 

Crawler Tractor 0.04 0.78 4.11 0.140 0.341 

Typ Rubber-Tire 0.07 1.32 4.33 0.180 0.350 

Typ Skid-Steer 0.09 0.68 4.15 0.160 0.374 

Typ Arc Welder 0.20 1.28 5.39 0.190 0.442 

MX240 (3) 1 ISO-C1 8-mode 0.06 0.51 4.32 0.116 0.351 

Agricultural Tractor 0.05 0.26 4.02 0.090 0.340 

Backhoe Loader 0.12 1.06 4.63 0.200 0.380 

Crawler Tractor 0.05 1.04 3.99 0.160 0.342 

Typ Rubber-Tire 0.09 2.07 4.18 0.250 0.368 

Typ Skid-Steer 0.13 1.00 4.25 0.210 0.379 

Typ Arc Welder 0.27 1.65 6.15 0.260 0.451 

F7
 
Table F3. CI Transient Adjustment Factors for Various Nonroad Test Cycles 

Engine Tier Test Cycle HC CO NOx PM BSFC 

Caterpillar 3116 0 Agricultural Tractor 0.57 0.30 1.00 0.69 1.01 

Backhoe Loader 5.14 2.98 1.01 1.61 1.17 

Crawler Dozer 1.29 2.91 0.93 1.76 1.03 

Caterpillar 3054 0 Agricultural Tractor 0.70 0.47 1.26 0.68 0.96 

Backhoe Loader 1.85 3.34 0.72 1.96 1.13 

Crawler Dozer 0.77 1.06 1.10 0.99 0.95 

John Deere 4039 0 Agricultural Tractor 0.49 0.26 1.04 0.45 0.93 

Backhoe Loader 2.44 1.21 0.85 1.16 1.21 

Crawler Dozer 0.80 0.65 1.04 0.66 0.96 

John Deere 7076 0 Agricultural Tractor 1.02 0.28 0.92 0.67 0.95 

Backhoe Loader 2.13 2.35 1.40 2.09 1.28 

Crawler Dozer 0.98 1.08 0.99 1.21 0.96 

Consolidated Diesel 

6TA-830 

0 Agricultural Tractor 1.05 0.71 0.86 0.77 1.03 

Backhoe Loader 2.42 6.57 1.02 4.28 1.20 

Crawler Dozer 0.97 2.51 0.93 2.03 1.01 

John Deere 6619 0 Agricultural Tractor 1.06 0.25 0.93 0.43 1.01 

Backhoe Loader 2.43 1.47 1.14 1.66 1.17 

Crawler Dozer 0.98 0.71 0.96 1.05 1.00 

Consolidated Diesel 

4039 

0 Agricultural Tractor 0.65 0.74 0.96 0.74 0.94 

Backhoe Loader 2.19 0.98 0.86 1.25 1.12 

Crawler Dozer 0.92 0.62 0.98 0.71 0.94 

Caterpillar 3306 0 Agricultural Tractor 1.05 0.56 0.99 0.81 1.00 

Backhoe Loader 1.81 3.52 1.11 3.28 1.11 

Crawler Dozer 0.91 1.85 1.00 1.76 0.99 

John Deere 6101 

(average of three tests) 

1 Agricultural Tractor 0.99 0.37 0.89 0.63 1.01 

Backhoe Loader 2.06 1.88 1.10 2.12 1.20 

Crawler Dozer 1.01 1.14 0.95 1.22 1.01 

Excavator 1.40 0.44 0.87 0.89 1.03 

Caterpillar 3176 1 Agricultural Tractor 1.00 0.83 0.98 0.98 0.99 

Backhoe Loader 1.50 2.31 1.31 1.58 1.10 

Crawler Dozer 0.75 1.50 1.02 1.26 1.00 

MX270 1 Agricultural Tractor 0.55 0.75 0.96 0.94 0.98 

Backhoe Loader 0.82 3.25 1.00 2.08 1.12 

Crawler Dozer 0.36 1.95 0.91 1.46 1.00 

Typ Rubber-Tire 0.64 3.30 0.96 1.88 1.03 

Typ Skid-Steer 0.82 1.70 0.92 1.67 1.10 

Typ Arc Welder 1.82 3.20 1.20 1.98 1.30 

MX240 1 Agricultural Tractor 0.83 0.51 0.93 0.78 0.97 

Backhoe Loader 2.00 2.08 1.07 1.72 1.08 

Crawler Dozer 0.83 2.04 0.92 1.38 0.97 

Typ Rubber-Tire 1.50 4.06 0.97 2.16 1.05 

F8
 
Table F3. CI Transient Adjustment Factors for Various Nonroad Test Cycles 

Engine Tier Test Cycle HC CO NOx PM BSFC 

Typ Skid-Steer 2.17 1.96 0.98 1.81 1.08 

Typ Arc Welder 4.50 3.24 1.42 2.24 1.28 

Average of Individual 

TAFs 

Agricultural Tractor 0.83 0.50 0.98 0.71 0.98 

Backhoe Loader 2.23 2.66 1.05 2.07 1.16 

Crawler Dozer 0.88 1.50 0.98 1.29 0.99 

Typ Rubber-Tire 1.07 3.68 0.96 2.02 1.04 

Typ Skid-Steer 1.49 1.83 0.95 1.74 1.09 

Typ Arc Welder 3.16 3.22 1.31 2.11 1.29 

Excavator 1.40 0.44 0.87 0.89 1.03 

Standard Deviation of 

TAFs 

Agricultural Tractor 0.22 0.21 0.10 0.17 0.03 

Backhoe Loader 1.02 1.49 0.19 0.88 0.06 

Crawler Dozer 0.22 0.75 0.06 0.42 0.03 

Typ Rubber-Tire 0.61 0.54 0.01 0.20 0.01 

Typ Skid-Steer 0.95 0.18 0.04 0.10 0.01 

Typ Arc Welder 1.90 0.02 0.16 0.19 0.01 

Student’s t-test: 

P value* 

T0 vs T1 

Agricultural Tractor 0.90 0.21 0.40 0.08 0.77 

Backhoe Loader 0.13 0.67 0.40 0.63 0.17 

Crawler Dozer 0.11 0.64 0.26 0.83 0.36 

* P value > 0.05 indicates that the difference between the Tier 0 and Tier 1 values is not statistically 

significant. 

F9
 
Table F4. CI Cycle Transient Adjustment Factors Binned by Load Factor Category 

Cycle Cycle 

Load 

Factors* 

Assignment HC CO NOx 

Cycle 

TAFs 

New 

TAFs 

Cycle 

TAFs 

New 

TAFs 

Cycle 

TAFs 

New 

TAFs 

None (steady-state) N/A None 1.00 1.00 1.00 1.00 1.00 1.00 

Agricultural Tractor 0.78 Hi LF 0.83 1.05 0.50 1.53 0.98 0.95 

Backhoe/Loader 0.21 Lo LF 2.23 2.29 2.66 2.57 1.05 1.10 

Crawler Dozer 0.58 Hi LF 0.88 1.05 1.50 1.53 0.98 0.95 

Rubber-Tire Loader 0.48 Hi LF 1.07 1.05 3.68 1.53 0.96 0.95 

Skid-Steer Loader 0.23 Lo LF 1.49 2.29 1.83 2.57 0.95 1.10 

Arc Welder 0.19 Lo LF 3.16 2.29 3.22 2.57 1.31 1.10 

Excavator 0.53 Hi LF 1.40 1.05 0.44 1.53 0.87 0.95 

avg Hi LF 1.05 1.53 0.95 

avg Lo LF 2.29 2.57 1.10 

Cycle Cycle 

Load 

Factors* 

Assignment PM BSFC 

Cycle TAFs New TAFs Cycle TAFs New TAFs 

None (steady-state) N/A None 1.00 1.00 1.00 1.00 

Agricultural Tractor 0.78 Hi LF 0.71 1.23 0.98 1.01 

Backhoe/Loader 0.21 Lo LF 2.07 1.97 1.16 1.18 

Crawler Dozer 0.58 Hi LF 1.29 1.23 0.99 1.01 

Rubber-Tire Loader 0.48 Hi LF 2.02 1.23 1.04 1.01 

Skid-Steer Loader 0.23 Lo LF 1.74 1.97 1.09 1.18 

Arc Welder 0.19 Lo LF 2.11 1.97 1.29 1.18 

Excavator 0.53 Hi LF 0.89 1.23 1.03 1.01 

avg Hi LF 1.23 1.01 

avg Lo LF 1.97 1.18 

* The load factors shown were obtained from engine test data and are not used directly in 

NONROAD. 

Table F5. CI Transient Adjustment Factors in Draft NONROAD2004 

Assignment HC CO NOx PM BSFC 

Base-Tier 

3 

Base-Tier 

3 

Base, 

Tiers 0-2 

Tier 3* Base, 

Tiers 0-2 

Tier 3* BaseTier 3 

avg Hi LF 1.05 1.53 0.95 1.04 1.23 1.47 1.01 

avg Lo LF 2.29 2.57 1.10 1.21 1.97 2.37 1.18 

None 1.00 1.00 1.00 1.10 1.00 1.20 1.00 

* NOx Tier 3 TAF = 1.1*(NOx Base, Tiers 0-2 TAF). PM Tier 3 TAF = 1.2*(PM Base, Tiers 0-2 TAF). 

TAFs are not applied to the emission factors for Tier 4 engines (i.e., the model applies a TAF of 1.0). 

F10
 
Table F6. CI Transient Adjustment Factor Assignments by Equipment Type 

SCC Equipment Type Representative 

Cycle 

TAF 

Assignment 

2270001000 Recreational Vehicles All Backhoe Lo LF 

2270001020 Recreational Vehicles Snowmobiles None None 

2270001030 Recreational Vehicles All Terrain Vehicles None None 

2270001040 Recreational Vehicles Minibikes None None 

2270001050 Recreational Vehicles Golf Carts None None 

2270001060 Recreational Vehicles Speciality Vehicle Carts Backhoe Lo LF 

2270002003 Construction Equipment Pavers Crawler Hi LF 

2270002006 Construction Equipment Tampers/Rammers None None 

2270002009 Construction Equipment Plate Compactors None None 

2270002015 Construction Equipment Rollers Crawler Hi LF 

2270002018 Construction Equipment Scrapers Crawler Hi LF 

2270002021 Construction Equipment Paving Equipment Crawler Hi LF 

2270002024 Construction Equipment Surfacing Equipment Crawler Hi LF 

2270002027 Construction Equipment Signal Boards None None 

2270002030 Construction Equipment Trenchers Crawler Hi LF 

2270002033 Construction Equipment Bore/Drill Rigs None None 

2270002036 Construction Equipment Excavators Excavator Hi LF 

2270002039 Construction Equipment Concrete/Industrial Saws Crawler Hi LF 

2270002042 Construction Equipment Cement & Mortar Mixers None None 

2270002045 Construction Equipment Cranes None None 

2270002048 Construction Equipment Graders Crawler Hi LF 

2270002051 Construction Equipment Off-highway Trucks Crawler Hi LF 

2270002054 Construction Equipment Crushing/Proc. Equipment None None 

2270002057 Construction Equipment Rough Terrain Forklifts RTLoader Hi LF 

2270002060 Construction Equipment Rubber Tire Loaders RTLoader Hi LF 

2270002063 Construction Equipment Rubber Tire Dozers Crawler Hi LF 

2270002066 Construction Equipment Tractors/Loaders/Backhoes Backhoe Lo LF 

2270002069 Construction Equipment Crawler Dozer Crawler Hi LF 

2270002072 Construction Equipment Skid Steer Loaders SSLoader Lo LF 

2270002075 Construction Equipment Off-Highway Tractors Crawler Hi LF 

2270002078 Construction Equipment Dumpers/Tenders Backhoe Lo LF 

2270002081 Construction Equipment Other Construction Equipment Crawler Hi LF 

2270003010 Industrial Equipment Aerial Lifts Backhoe Lo LF 

2270003020 Industrial Equipment Forklifts RTLoader Hi LF 

2270003030 Industrial Equipment Sweepers/Scrubbers None None 

2270003040 Industrial Equipment Other General Industrial Equipment None None 

2270003050 Industrial Equipment Other Material Handling Equipment Backhoe Lo LF 

F11
 
Table F6. CI Transient Adjustment Factor Assignments by Equipment Type 

SCC Equipment Type Representative 

Cycle 

TAF 

Assignment 

2270003060 Industrial Equipment AC\Refrigeration None None 

2270003070 Terminal Tractors Crawler Hi LF 

2270004000 Lawn & Garden Equipment ALL None None 

2270004010 Lawn & Garden Equipment Lawn mowers (Residential) None None 

2270004011 Lawn & Garden Equipment Lawn mowers (Commercial) None None 

2270004015 Lawn & Garden Equipment Rotary Tillers < 6 HP None None 

2270004016 Lawn & Garden Equipment Rotary Tillers < 6 HP 

(Commercial) 

None None 

2270004020 Lawn & Garden Equipment Chain Saws < 6 HP None None 

2270004021 Lawn & Garden Equipment Chain Saws < 6 HP 

(Commercial) 

None None 

2270004025 Lawn & Garden Equipment Trimmers/Edgers/Brush 

Cutters 

None None 

2270004026 Lawn & Garden Equipment Trimmers/Edgers/Brush 

Cutters (Commercial) 

None None 

2270004030 Lawn & Garden Equipment Leafblowers/Vacuums None None 

2270004031 Lawn & Garden Equipment Leafblowers/Vacuums 

(Commercial) 

None None 

2270004035 Lawn & Garden Equipment Snowblowers None None 

2270004036 Lawn & Garden Equipment Snowblowers (Commercial) None None 

2270004040 Lawn & Garden Equipment Rear Engine Riding Mowers None None 

2270004041 Lawn & Garden Equipment Rear Engine Riding Mowers 

(Commercial) 

None None 

2270004045 Lawn & Garden Equipment Front Mowers None None 

2270004046 Lawn & Garden Equipment Front Mowers (Commercial) None None 

2270004050 Lawn & Garden Equipment Shredders < 6 HP None None 

2270004051 Lawn & Garden Equipment Shredders < 6 HP 

(Commercial) 

None None 

2270004055 Lawn & Garden Equipment Lawn & Garden Tractors None None 

2270004056 Lawn & Garden Equipment Lawn & Garden Tractors 

(Commercial) 

None None 

2270004060 Lawn & Garden Equipment Wood Splitters None None 

2270004061 Lawn & Garden Equipment Wood Splitters (Commercial) None None 

2270004065 Lawn & Garden Equipment Chippers/Stump Grinders None None 

2270004066 Lawn & Garden Equipment Chippers/Stump Grinders 

(Commercial) 

None None 

2270004071 Lawn & Garden Equipment Commercial Turf Equipment 

(Commercial) 

None None 

2270004075 Lawn & Garden Equipment Other Lawn & Garden 

Equipment 

None None 

2270004076 Lawn & Garden Equipment Other Lawn & Garden 

Equipment (Commercial) 

None None 

2270005010 Farm Equipment 2-Wheel Tractors AgTractor Hi LF 

2270005015 Farm Equipment Agricultural Tractors AgTractor Hi LF 

F12
 
Table F6. CI Transient Adjustment Factor Assignments by Equipment Type 

SCC Equipment Type Representative 

Cycle 

TAF 

Assignment 

2270005020 Farm Equipment Combines AgTractor Hi LF 

2270005025 Farm Equipment Balers AgTractor Hi LF 

2270005030 Farm Equipment Agricultural Mowers AgTractor Hi LF 

2270005035 Farm Equipment Sprayers AgTractor Hi LF 

2270005040 Farm Equipment Tillers > 6 HP AgTractor Hi LF 

2270005045 Farm Equipment Swathers AgTractor Hi LF 

2270005050 Farm Equipment Hydro Power Units None None 

2270005055 Farm Equipment Other Agricultural Equipment AgTractor Hi LF 

2270005060 Farm Equipment Irrigation Sets None None 

2270006000 Light Commercial ALL None None 

2270006005 Light Commercial Generator Sets None None 

2270006010 Light Commercial Pumps None None 

2270006015 Light Commercial Air Compressors None None 

2270006020 Light Commercial Gas Compressors None None 

2270006025 Light Commercial Welders ArcWelder Lo LF 

2270006030 Light Commercial Pressure Washers None None 

2270007005 Logging Equipment Chain Saws > 6 HP RTLoader Hi LF 

2270007010 Logging Equipment Shredders > 6 HP RTLoader Hi LF 

2270007015 Logging Equipment Forest Equipment RTLoader Hi LF 

2270008005 Airport Service Equipment Airport Support Equipment RTLoader Hi LF 

2270009010 Other Underground Mining Equipment Backhoe Lo LF 

2270010010 Other Oil Field Equipment None None 

2282020005 Recreational Pleasure Craft, Inboards None None 

2282020010 Recreational Pleasure Craft, Outboards None None 

2282020015 Recreational Pleasure Craft, Personal Water Craft None None 

2282020025 Recreational Pleasure Craft, Sailboat Aux. Outboard None None 

2285002015 Railway Maintenance Backhoe Lo LF 

F13
 
Table F7. Comparison of TAF Methodology Used in Draft Versions of NONROAD 

Model Date Model 

Version 

Name 

Data as Basis 

(# of engines) 

Cycles Used Treatment 

of Tier 0 vs 

Tier 1 Data 

Ratio of 

Averages 

or Average 

of Ratios? 

TAFs Used 

and 

Assignments 

June 1998 “Original” 9 engines Ag tractor Tier 0 and Ratio of 3 cycle TAFs. 

(8 Tier 0 and 1 Backhoe Loader Tier 1 data averages One assigned 

Tier 1 engines) Crawler Dozer combined to each 

equipment type 

April 1999 “Tier 2" No TAF-related changes 

June 2000 “2007 HD 12 engines Ag tractor Tier 0 and Ratio of Revised to 

Rule” (8 Tier 0 and 4 Backhoe Loader Tier 1 data averages accomodate 

Tier 1 engines) Crawler Dozer 

RT Loader 

SS Loader 

Arc Welder 

separated; 

separate 

TAFs for 

each 

separate T0 

and T1 TAFs 

and 3 

additional 

cycles 

Nov 2000 “Final 

Finding / 

ANPRM” 

No TAF related changes relative to June 2000 version 

Oct 2001 “Pentathalon 12 engines Ag tractor Tier 0 and Average of 6 cycle TAFs. 

NPRM” (8 Tier 0 and 4 Backhoe Loader Tier 1 data ratios One assigned 

Tier 1 engines) Crawler Dozer 

RT Loader 

SS Loader 

Arc Welder 

re-combined to each 

equipment type 

March 2002 “NONROAD 12 engines Ag tractor Tier 0 and Average of 7 cycle TAFs 

April 2004 2002" and (8 Tier 0 and 4 Backhoe Loader Tier 1 data ratios binned in two 

Dec 2005 “NONROAD Tier 1 engines) Crawler Dozer combined categories: Hi 

July 2009 2004" and 

“NONROAD 

2005” and 

“NONROAD 

2008a” 

RT Loader 

SS Loader 

Arc Welder 

Excavator 

LF and Lo LF. 

One assigned 

to each 

equipment 

type. 

F14
 
Appendix G
 

Derivation of Deterioration Factors for
 

Nonroad Compression Ignition Engines
 

Deterioration factors used in emissions models are intended to account for increases 

in emissions above a new engine or vehicle’s base emissions level with time. Emissions 

can increase with time for a number of reasons including, engine wear, poor maintenance 

practices, and willful or unwitting tampering with emission control systems. Emissions 

from diesel engines increase with time (deteriorate) at a very slow rate when the engine is 

properly maintained and operated. In fact for a number of pollutants (primarily NOx), 

emission levels can actually drop slightly as the engine ages. However, anecdotal and 

emission test experience suggests that many diesel engines emit at a much higher level inuse (especially PM) than would be anticipated for a well maintained diesel engine. 

Diesel engines are extremely robust and can continue to provide adequate 

performance for a user, even when they have been poorly maintained. Unlike speed and load 

characterized performance, however, their emissions performance can decrease quite rapidly 

when the engine receives poor maintenance. Analysis and testing conducted by contractors 

to EPA and to the California Air Resources Board (CARB) have shown that these 

maintenance and tampering issues comprise the bulk of the observed increase in PM 

emissions from diesel engines in-use. (1) When CARB updated the large CI component of 

its OFFROAD model in 2000, they accounted for this increase in emissions by using 

deterioration factors developed from real world observations of in-use PM emissions 

correlated to particular engine technologies. (2) We believe that this is the appropriate 

approach for PM emission modeling in order to account for all of the possible mechanisms of 

PM deterioration. We have therefore adopted the PM deterioration factors from CARB’s 

OFFROAD model in this version of NONROAD. We averaged the highway-based LDDT, 

MHDT, and HHDT PM deterioration factors used in CARB’s OFFROAD model (0.31, 0.44, 

and 0.67, respectively) and applied the average (0.473) to all tiers. 

For HC, CO, and NOx, we have continued our practice of using deterioration factors 

developed by manufacturers based upon well maintained engines. We have done so because 

we believe that maintenance and tampering issues do not effect the emission rates of these 

pollutants as dramatically. As a result, we base the HC, CO, and NOx deterioration factors 

adopted for nonroad engines on highway certification data (zero-mile levels and lifetime 

deterioration) (3). We used the same data to derive highway compliance margins for the 

steady-state emission factor analysis. Correspondence between highway weight class (light, 

medium, heavy), highway model-year group, and nonroad horsepower categories is identical 

to that used for the steady-state emission factor analysis. 

We converted the highway engine deterioration estimates into a format applicable to 

nonroad engines, following these steps: 

(1)	 We calculated absolute deterioration rates DFabs using the zero-mile emission 

factors and lifetime deterioration estimates presented in reference (3). 

G1
 
(2)	 We converted the absolute deterioration rates DFabs (g/hp-hr2

) to relative 

deterioration rates DFrel (% emissions increase/% useful life expended). 

(3)	 We calculated a separate DFrel for each combination of pollutant, Tier, and 

horsepower category. Then to derive a single value for each Tier and pollutant, we 

simply averaged the DFrel. 

We discuss these calculations in greater detail below. 

To adapt highway-certification deterioration rates for application to nonroad engines, 

it was necessary to convert them from an absolute basis (emissions increase over engine’s 

useful life (g/hp-hr)) to a relative basis (% emissions increase/% useful life expended). This 

conversion involves relating the emissions increase over the engine’s useful life to the zerohour emission factor, in proportional terms. 

We achieved this conversion as follows. To begin, if we assume linear deterioration 

with the intercept at the zero-mile emission factor, (0 deterioration increase at 0 miles (0 

hours useful life)), it is possible to calculate the absolute slope of the line, i.e., the absolute 

deterioration rate DFabs (g/hp-hr2) (Figure 1 on next page). The required data are the absolute 

emissions increase DT (g/hp-hr) over engine’s useful life L (years) and the zero-mile emission 

factor EFzm (g/hp-hr): 

Dy (EFzm + DT ) - EFzm DT DF = =	 = abs Dx L - 0 L 

Dividing the numerator and denominator by EFzm and L, respectively, and multiplying 

each by 100 expresses the deterioration factor in percentage terms with respect to emissions 

increase and useful life, giving a relative deterioration rate DFrel (% emissions increase/% 

useful life): 

( DT 

 

 )) ·100 

Ł EF zm ł DT DF =	 = rel ( L EF zm )·100 Ł L ł

Thus, the relative deterioration rate is the quotient of the absolute emissions increase 

and the zero-mile emission factor. Tables G1-G3 present estimates of DFrel for each 

combination of pollutant, Tier and horsepower category. To derive individual values of DFrel 

for each pollutant and Tier, we calculated simple unweighted averages. 

The resulting DFrel for each pollutant and Tier are presented in Table G4. 

We intend to continue to monitor in-use PM emissions levels, and as the body of data 

increases (especially for newer engine technologies), we intend to further update the 

G2
 
deterioration factors used here. Similarly, if we learn that deterioration rates for other 

pollutants also increase significantly in-use, we will update those factors as well. 

References 

(1) Engine, Fuel and Emissions Engineering, Inc., “Modeling Deterioration in Heavy-Duty 

Diesel Particulate Emissions,” report prepared for U.S. Environmental Protection Agency, 

1998. 

(2) ARB, “Public Meeting to Consider Approval of the Emissions Inventory of Off-Road 

Large Compression-Ignited (CI) Engines (>25HP),” January 2000. 

(3) EPA, “Update of Heavy-Duty Emission Levels (Model Years 1988-2004+) for Use in 

MOBILE6,” EPA420-R-99-010, April 1999. 

Y 

time (years) 

brake specific emissions (g/hp-hr) 

L EFzm 

D T 

DFabs 

X 

Figure 1. Conceptual representation of absolute linear emissions 

deterioration over the useful life of a diesel engine. 

G3
 
Table G1. Hydrocarbon (HC) Deterioration Factors by Tier and
 

Horsepower Category
 

Nonroad 

Engine Corresponding Corresponding 

Power Highway Highway 

Categories Vehicle Weight Model-Year Corresponding Highway Certification Test Results 

(hp) Class1 Group and Deterioration Factors 

EFZM 2 

(g/hp-hr) 

DT 

3 

(g/hp-hr) 

DFrel 4 

(%increase/% 

useful life) 

Tier 0 

< 11 LHDD 1988-89 0.64 0.02 0.031 

11-25 LHDD 1988-89 0.64 0.02 0.031 

25-50 LHDD 1988-89 0.64 0.02 0.031 

50-100 MHDD 1988-89 0.66 0.05 0.068 

100-175 MHDD 1988-89 0.66 0.05 0.068 

175-300 MHDD 1988-89 0.66 0.05 0.068 

300-600 HHDD 1988-89 0.47 0.02 0.043 

600-750 HHDD 1988-89 0.47 0.02 0.043 

>750 HHDD 1988-89 0.47 0.02 0.043 

Tiers 1-3 

< 11 LHDD 1994-97 0.26 0.01 0.038 

11-25 LHDD 1994-97 0.26 0.01 0.038 

25-50 LHDD 1994-97 0.26 0.01 0.038 

50-100 MHDD 1994-97 0.31 0.00 0.000 

100-175 MHDD 1994-97 0.31 0.00 0.000 

175-300 MHDD 1994-97 0.31 0.00 0.000 

300-600 HHDD 1994-97 0.22 0.02 0.068 

600-750 HHDD 1994-97 0.22 0.02 0.068 

>750 HHDD 1994-97 0.22 0.02 0.068 

1 LHDD = “light heavy-duty diesel,” MHDD = “medium heavy-duty diesel,” and HHDD = “heavy heavy-duty diesel.”
 

2 Zero-mile emission factor, Source: USEPA 1999, Table 8.
 

3 Lifetime Deterioration (cumulative deterioration over vehicle useful life), Source USEPA 1999, Table 8.
 

4 Relative Deterioration Factor, calculated as DT/EFzm. For discussion, see text.
 

G4
 
Table G2. CO Deterioration Factors by Tier and Horsepower Category1 

Nonroad 

Engine Corresponding Corresponding 

Power Highway Highway 

Categories Vehicle Weight Model-Year Corresponding Highway Certification Test Results 

(hp) Class1 Group and Deterioration Factors 

EFZM 2 

(g/hp-hr) 

DT 

3 

(g/hp-hr) 

EFZM 2 

(g/hp-hr) 

Tier 0 

< 11 LHDD 1988-89 1.22 0.24 0.198 

11-25 LHDD 1988-89 1.22 0.24 0.198 

25-50 LHDD 1988-89 1.22 0.24 0.198 

50-100 MHDD 1988-89 1.70 0.33 0.195 

100-175 MHDD 1988-89 1.70 0.33 0.195 

175-300 MHDD 1988-89 1.70 0.33 0.195 

300-600 HHDD 1988-89 1.36 0.22 0.162 

600-750 HHDD 1988-89 1.36 0.22 0.162 

>750 HHDD 1988-89 1.36 0.22 0.162 

Tiers 1-3 

< 11 LHDD 1994-97 1.20 0.03 0.021 

11-25 LHDD 1994-97 1.20 0.03 0.021 

25-50 LHDD 1994-97 1.20 0.03 0.021 

50-100 MHDD 1994-97 0.88 0.17 0.189 

100-175 MHDD 1994-97 0.88 0.17 0.189 

175-300 MHDD 1994-97 0.88 0.17 0.189 

300-600 HHDD 1994-97 1.07 0.10 0.093 

600-750 HHDD 1994-97 1.07 0.10 0.093 

> 750 HHDD 1994-97 1.07 0.10 0.093 

1 LHDD = “light heavy-duty diesel,” MHDD = “medium heavy-duty diesel,” and HHDD = “heavy heavy-duty diesel.”
 

2 Zero-mile emission factor, Source: USEPA 1999, Table 9.
 

3 Lifetime Deterioration (cumulative deterioration over vehicle useful life), Source USEPA 1999, Table 9.
 

4 Relative Deterioration Factor, calculated as DT/EFzm. For discussion, see text.
 

G5
 
Table G3. NOx Deterioration Factors by Pollutant and Horsepower Category1 

Nonroad 

Engine Power Corresponding Corresponding 

Categories Highway Vehicle Highway Model- Corresponding Highway Certification Test Results and 

(hp) Weight Class1 Year Group Deterioration Factors 

EFZM 2 

(g/hp-hr) 

DT 

3 

(g/hp-hr) 

EFZM 2 

(g/hp-hr) 

Tier 0-1 

< 11 LHDD 1988-89 4.34 0.02 0.005 

11-25 LHDD 1988-89 4.34 0.02 0.005 

25-50 LHDD 1988-89 4.34 0.02 0.005 

50-100 MHDD 1988-89 6.43 0.16 0.025 

100-175 MHDD 1988-89 6.43 0.16 0.025 

175-300 MHDD 1988-89 6.43 0.16 0.025 

300-600 HHDD 1988-89 6.28 0.28 0.044 

600-750 HHDD 1988-89 6.28 0.28 0.044 

>750 HHDD 1988-89 6.28 0.28 0.044 

Tier 2 

< 11 LHDD 1991-93 4.28 0.01 0.003 

11-25 LHDD 1991-93 4.28 0.01 0.003 

25-50 LHDD 1991-93 4.28 0.01 0.003 

50-100 MHDD 1998-2003 4.67 0.03 0.006 

100-175 MHDD 1998-2003 4.67 0.03 0.006 

175-300 MHDD 1998-2003 4.67 0.03 0.006 

300-600 HHDD 1998-2003 4.70 0.05 0.011 

600-750 HHDD 1998-2003 4.70 0.05 0.011 

>750 HHDD 1998-2003 4.70 0.05 0.011 

Tier 3 

50-100 MHDD 1998-2003 4.67 0.03 0.006 

100-175 MHDD 1998-2003 4.67 0.03 0.006 

175-300 MHDD 1998-2003 4.67 0.03 0.006 

300-600 HHDD 1998-2003 4.70 0.05 0.011 

600-750 HHDD 1998-2003 4.70 0.05 0.011 

1 LHDD = “light heavy-duty diesel,” MHDD = “medium heavy-duty diesel,” and HHDD = “heavy heavy-duty diesel.”
 

2 Zero-mile emission factor, Source: USEPA 1999, Table 10.
 

3 Lifetime Deterioration (cumulative deterioration over vehicle useful life), Source USEPA 1999, Table 10.
 

4 Relative Deterioration Factor, calculated as DT/EFzm. For discussion, see text.
 

G6
 
Table G4. Deterioration Factors for Nonroad Diesel Engines 

Pollutant Relative Deterioration Factor (DFrel) (% increase/%useful life)1 

Base/Tier 0 Tier 1 Tier 2 Tier 3 

HC 0.047 0.036 0.034 0.027 

CO 0.185 0.101 0.101 0.151 

NOx 0.024 0.024 0.009 0.008 

PM 0.473 0.473 0.473 0.473 

1

DFrel = A in the equation: DF =1+A*(fraction of useful life expended)B 

G7