1

 The Draft NONROAD model is available at: www.epa.gov/otaq/nonrdmdl.htm.

 EPA420-F-02-044

 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

 ANN ARBOR, MI 48105

September 9, 2002

 OFFICE OF 

 AIR AND RADIATION

MEMORANDUM

SUBJECT: Emission Factors for Recreational Marine Diesel Engines

FROM: Mike Samulski

Assessment and Standards Division

TO: Docket A-2000-01

The U.S. Environmental Protection Agency (EPA) has adopted emission standards for

recreational marine diesel engines. To analyze the environmental benefits expected from these new

standards, we calculated emission factors for these engines, which are summarized in this memo.

Estimated baseline emission rates

In support of the rulemaking finalizing the recreational marine diesel engine emission standards,

EPA estimated average emission rates, given in grams per kilowatt-hour (g/kW-hr), for current

uncontrolled engines. Table 1 presents the baseline emission rates used in this analysis for new

engines and for engines deteriorated to the regulatory useful life (10 years). The emission rates are

based on data collected on 25 recreational marine engines. This data is presented in Table 2. 

Deterioration rates are based on the EPA computer model for estimating emissions from nonroad

engines.1
Table 1 - Estimated Baseline Emission Rates [g/kW-hr]

HC NOx CO PM

new engine 0.295 8.94 1.27 0.219

after 10 years 0.300 9.05 1.39 0.270

Table 2 - Emission Data from Recreational Marine Diesel Engines [g/kW-hr]

Rated Power

(kW)

Control

Management

Aftercooling HC NOx CO PM

120

132

142

162

164

170

186

209

230

235

265

276

287

321

324

336

336

447

447

474

537

820

1040

1080

1340

electronic

mechanical

mechanical

mechanical

electronic

mechanical

mechanical

mechanical

electronic

mechanical

mechanical

mechanical

electronic

mechanical

mechanical

electronic

electronic

electronic

mechanical

electronic

electronic

electronic

electronic

electronic

electronic

raw-water

raw-water

separate circuit

raw-water

raw-water

raw-water

raw-water

raw-water

raw-water

raw-water

jacket-water

raw-water

raw-water

raw-water

jacket-water

jacket-water

jacket-water

raw-water

jacket-water

raw-water

jacket-water

separate circuit

jacket-water

separate circuit

separate circuit

0.09

0.07

0.79

0.11

0.28

0.36

0.30

0.42

0.28

0.45

0.58

0.60

0.28

0.37

0.30

0.18

0.09

0.12

0.60

0.34

0.08

0.33

0.09

0.18

0.27

5.8

4.2

8.6

4.0

5.1

8.1

10.2

10.8

5.5

9.8

10.8

10.7

7.9

7.7

7.9

11.0

11.9

9.3

12.0

7.7

10.7

9.5

9.3

7.6

7.2

0.9

0.2

1.1

0.2

1.6

0.6

1.2

2.3

1.8

1.8

1.4

1.9

–

0.9

2.9

0.5

–

–

1.5

0.5

–

0.8

–

1.2

0.9

–

–

–

–

–

0.20

0.12

0.22

0.39

0.20

–

0.24

0.12

0.23

0.95

0.10

0.16

0.17

0.18

0.07

0.19

0.13

0.21

0.15

0.15
Projected future emission rates

With the new national emission standards for recreational marine diesel engines, future emission

rates are projected to be lower for HC, NOx, and PM. Because CO levels are already low and

because the CO standard is intended to be a cap, we do not expect reductions in CO to result from

these standards. Table 3 presents the emission standards and implementation dates which vary

depending on engine size. Table 4 presents the projected controlled emission factors used in the

EPA analysis for new engines and for engines deteriorated to the regulatory useful life (10 years).

Table 3 - Recreational Marine Diesel Emission Standards and Implementation Dates

Displacement

[liters/cylinder]

Implementation

Date

HC+NOx

[g/kW-hr]

CO

[g/kW-hr]

PM

[g/kW-hr]

37 kW, disp < 0.9 2007 7.5 5.0 0.4

0.9  disp < 1.2 2006 7.2 5.0 0.3

1.2  disp < 2.5 2006 7.2 5.0 0.2

2.5  disp 2009 7.2 5.0 0.2

Table 4 - Projected Controlled Emission Rates [g/kW-hr]

HC NOx CO PM

Rated power 37 kW, Displacement < 0.9 liters/cylinder

new engine 0.181 6.69 1.27 0.219

after 10 years 0.184 6.72 1.39 0.270

0.9  Displacement < 1.2 liters/cylinder

new engine 0.181 6.41 1.27 0.219

after 10 years 0.184 6.44 1.39 0.270

Displacement 1.2 liters/cylinder

new engine 0.182 6.42 1.27 0.181

after 10 years 0.184 6.44 1.39 0.184
Projected emission inventory 

Total emissions were calculated using Equation 1. Based on data collected in developing the draft

NONROAD model, we use a load factor of 35 percent, an annual usage factor of 200 hours, and an

average operating life of 20 years. The draft NONROAD model also includes population estimates

distributed by rated power. The metric tons estimate can be converted to standard tons (or short

tons) per year by multiplying it by 1.1. EPA’s estimates of the projected annual emissions inventory

with and without the new standards are shown in Tables 5 and 6.

 Equation 1

Table 5 - Estimated Nationwide Recreational Marine Diesel

Baseline Emissions Inventory [short tons per year]

Calendar Year HC NOx CO PM

2000 1,270 38,000 5,850 1,000

2010 1,650 49,400 7,610 1,300

2020 2,030 60,800 9,360 1,600

2030 2,410 72,200 11,100 1,900

Table 6 - Estimated Nationwide Recreational Marine Diesel

Controlled Emissions Inventory [short tons per year]

Calendar Year HC NOx CO PM

2000 1,270 38,000 5,850 1,000

2010 1,490 45,800 7,610 1,230

2020 1,450 48,000 9,360 1,310

2030 1,510 52,200 11,100 1,420