ATTACHMENT I 

CONTROLLED AND UNCONTROLLED AVERAGE SUMMER WEEKDAY 

COMMERCIAL MARINE VESSEL INVENTORIES FOR HOUSTON-GALVESTONBRAZORIA AREA FOR SELECT YEARS 2012, 2014, 2017, 2020, 2023, 2026, AND 

2028

CONTROLLED AND 

UNCONTROLLED AVERAGE 

SUMMER WEEKDAY 

COMMERCIAL MARINE 

VESSEL INVENTORIES FOR 

HOUSTON-GALVESTONBRAZORIA AREA FOR SELECT 

YEARS 2012, 2014, 2017,

2020, 2023, 2026, AND 

2028 

FINAL

Prepared for: 

Texas Commission on Environmental Quality 

Air Quality Division 

Prepared by: 

Eastern Research Group, Inc. 

April 24, 2015 
ERG No. 0345.00.001.002 

Controlled and Uncontrolled Average Summer Weekday 

Commercial Marine Vessel Inventories for HoustonGalveston-Brazoria Area for Select Years 2012, 2014, 

2017, 2020, 2023, 2026, and 2028

TCEQ Contract No. 582-15-50416 

Work Order No. 582-15-51493-01 FY: 2015-10

Prepared for: 

Cody McLain 

Texas Commission on Environmental Quality 

Emissions Assessment Section 

Bldg. E, Room 335

Austin, TX 

Prepared by: 

Heather Perez 

Eastern Research Group, Inc. 

1600 Perimeter Park Drive 

Suite 200 

Morrisville, NC 27560 

April 24, 2015 
i 

Table of Contents 

1.0 Introduction ........................................................................................................ 1-1

2.0 Data Collection ................................................................................................... 2-1

2.1 PortVision Automatic Identification System (AIS) Data ....................... 2-1

2.2 Other Vessel Activity Data ...................................................................... 2-1

2.2.1 Government Vessels ..................................................................... 2-1

2.2.2 Dredging Activity .......................................................................... 2-2

2.2.3 Commercial Fishing Activity ........................................................ 2-2

2.3 Vessel Characteristics Data ..................................................................... 2-2

3.0 Local Activity Data Processing ........................................................................... 3-1

3.1 PortVision AIS ......................................................................................... 3-1

3.1.1 Vessel Characteristics ................................................................... 3-2

3.1.2 Load Factors ................................................................................. 3-2

3.1.3 Auxiliary Engines ......................................................................... 3-3

3.1.4 Kilowatt-hour Calculations and Data Quality Checks ................. 3-3

3.2 Government Vessels ................................................................................ 3-4

3.3 Dredging Operations ............................................................................... 3-2

3.4 Commercial Fishing ................................................................................ 3-5

4.0 Emission Factors ................................................................................................ 4-1

5.0 Emissions Calculations ....................................................................................... 5-1

6.0 Projection Factors .............................................................................................. 6-1

7.0 Results ................................................................................................................ 7-2

8.0 References .......................................................................................................... 8-1

Appendix A. CMV 2008 to 2040 Control Programs* ................................................... A-1
ii

List of Tables 

Table 3-1. Coast Guard Vessel Characteristics and Associated Ports .............................. 3-5

Table 3-7. Vessel Operating Characteristics by Fishing Operation Type ........................ 3-5

Table 3-8. 2013 Port Landings for Port Allocations ........................................................ 3-7

Table 3-9. Kilowatt Hours for Texas Fishing Vessel Fleet by Port and Fishing 

Operation ............................................................................................................... 3-7

Table 4-1. CMV Controlled and Uncontrolled Emission Factors (g/kWh) ..................... 4-1

Table 5-1. Emissions Adjustment Factors for Operating Loads Less than 20% ............. 5-2

Table 6-1. 2013-Based Commercial Marine Vessel Activity Growth Factors using 

Uncontrolled CO2 ................................................................................................. 6-2

Table 7-1. Ozone Season Daily Controlled NOX Emissions (tons) by Year for the 

Houston-Galveston-Brazoria Area ....................................................................... 7-2

Table 7-2. Ozone Season Daily Uncontrolled NOX Emissions (tons) by Year for the 

Houston-Galveston-Brazoria Area ....................................................................... 7-3

Table 7-3. Ozone Season Daily Controlled VOC Emissions (tons) by Year for the 

Houston-Galveston-Brazoria Area ....................................................................... 7-3

Table 7-4. Ozone Season Daily Uncontrolled VOC Emissions (tons) by Year for the 

Houston-Galveston-Brazoria Area ....................................................................... 7-3
1-1

1.0 Introduction

The objective of this Texas Commission on Environmental Quality (TCEQ) project was 

to develop volatile organic compound (VOC) and nitrogen oxide (NOX) controlled and 

uncontrolled commercial marine vessel (CMV) emissions estimates for 2012, 2014, 

2017, 2020, 2023, 2026, and 2028 to aid in State Implementation Plan (SIP) 

development for the eight-county Houston-Galveston-Brazoria (HGB) 1997 eight-hour 

ozone nonattainment area. During project development, activity data for 2014 were not 

available. Therefore, Eastern Research Group, Inc. (ERG) obtained activity data from 

2013 as this represented the most recent available data at the time the project began. 

ERG collected activity data for calendar year 2013 and used the data to develop ozone 

season weekday emission inventories for CMVs using updated emissions and activitybased projection factors. 

One improvement of this inventory over previous efforts is its bottom-up approach that 

integrates significant amounts of locally provided data. While previous efforts have 

relied partially on a top-down approach to adjust national inventory data to quantify 

state and county level activity and emissions, recent trends in inventory development 

have emphasized increased spatial resolution that is not well served by modifying 

national-level data. For that reason, the TCEQ sought inventory efforts built on detailed, 

locally based activity and emissions data. 

The Texas CMV SIP Emissions Inventory includes Category I, II, and III vessel activity 

and emissions by waterway for the eight HGB ozone nonattainment counties (Brazoria, 

Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller). The 

Marine categories are based on engine specifications and are divided into three 

categories based on engine cylinder displacement. Category 1 and Category 2 marine 

diesel engines typically range in size from about 500 to 8,000 kilowatt (kW) (700 to 

11,000 horse power (hp)). These engines are used to provide propulsion power on many 

kinds of vessels including tugboats, pushboats, supply vessels, fishing vessels, and other 

commercial vessels in and around ports. They are also used as stand-alone generators 

for auxiliary electrical power on many types of vessels. Category 3 marine diesel engines 

typically range in size from 2,500 to 70,000 kW (3,000 to 100,000 hp). These are very 

large marine diesel engines that run on residual fuel and are used for propulsion power 

on ocean-going vessels such as container ships, oil tankers, bulk carriers, and cruise 

ships. The following sections describe the inventory approach, including initial 

collection of local data, emission calculations, and spatial allocations used to develop the 

SIP CMV emissions inventory. 
2-1

2.0 Data Collection

2.1 PortVision Automatic Identification System (AIS) Data 

As a first step in data collection, ERG obtained Automatic Identification System (AIS) 

activity data for commercial marine vessels from PortVision. PortVision, a service of 

AIRSIS, Inc., is one of the largest international providers of satellite and terrestrial AIS 

data. AIS transponders serve as GPS units that report vessel location, speed, and other 

information every 2 seconds to nearby receivers and are available on most marine 

vessels due to increasing regulations and decreasing cost. AIS signals cover activities 

both in port as well as in state, federal, and international waters, providing a more 

complete picture of each vessel’s activity. While there are a number of vessel activity 

data sources available, many publicly available datasets are highly aggregated and 

include only vessel origins and destinations (or entrances and clearances) with no 

indication of how the distance was traversed. Hours of operation using these datasets 

can only be crudely estimated based on an estimate of vessel speed and the length of the 

shortest route between the origin and destination.

In contrast, AIS data provide individual vessel identification information along with 

both geographic location and time stamps, allowing for spatially and temporally 

accurate vessel routes. Using these data enables one to map individual trips for each 

vessel to calculate actual hours of operation resulting in a more refined estimate of CMV 

activity. 

As AIS data is primarily geared toward traffic control and accident avoidance, it is not 

ideally formatted for use in inventory efforts. The dataset ERG obtained from PortVision 

for this effort includes observations every 15 minutes for every vessel in the area of 

interest during 2013 (31,841,919 unique observations associated with 9,584 vessels) to 

provide a clearer picture of vessel movement and to avoid data gaps. 

2.2 Other Vessel Activity Data 

AIS data, while far more comprehensive than in the past, may not capture all CMVs 

within the study area. In particular, smaller vessels that are not required to carry AIS 

transponders may not be well represented in the dataset. ERG identified three 

categories of vessels with insufficient data in AIS: military, dredging, and commercial 

fishing vessels. The following sections describe the additional data sources that ERG 

used to complement, gap-fill, or replace AIS data where needed. 

2.2.1 Government Vessels 

The Department of Homeland Security limits the ability to collect activity data and 

estimate emissions. In the Gulf of Mexico, military vessel activity is implemented by the 
2-2 

U.S. Navy and the U.S. Coast Guard. ERG assumed that Navy vessel activities in Texas 

state waters were relatively few, since the last Navy base located in Texas was closed in 

2006 and most military vessel exercises occur in federal waters. 

ERG obtained information about Coast Guard vessels operating in Texas waters using 

fleet profiles obtained from their websites (USCG, 2014).

2.2.2 Dredging Activity 

ERG obtained information concerning dredging operations occurring in Texas state

waters from the U.S. Army Corps of Engineers Dredging Activity Database (USACE,

2014). 

2.2.3 Commercial Fishing Activity 

Commercial fishing activities can be difficult to estimate since fishing vessels tend to 

consider the locations of their fishing spots confidential business information. ERG 

estimated commercial fishing activity based on the following data sources. ERG 

obtained fish landings from the National Marine Fisheries Service (NMFS, 2015),

obtained fishing vessel counts from the National Transportation Safety Board (NTSB,

2010), obtained fishing vessel activity assumptions (Wells 2012) and obtained values of 

fish landing from the Texas Parks and Wildlife (TPW, 2014). Using these four datasets, 

ERG estimated and spatially allocated commercial fishing activity.

2.3 Vessel Characteristics Data 

In addition to activity data, emission calculations require information about the vessels 

themselves, particularly the engine category (derived from the cylinder displacement) 

and its kilowatt (kW) rating to determine which subset of emission factors to use. The 

kilowatt rating is multiplied by the hours of operation to estimate the kilowatt-hours 

(kWh), which can then be multiplied by the kWh-based emission factors. These data 

elements are available in the Information Handling Services (IHS) Vessel Database, 

which ERG purchased for use in this project. 
3-1 

3.0 Local Activity Data Processing

3.1 PortVision AIS 

The AIS data file received from PortVision included 31,841,919 unique observations, in 

15 minute intervals, associated with 9,584 vessels, provided in monthly files. Data were 

examined in their raw monthly format as both a QA check as well as to determine if 

there was significant seasonality between months. In terms of vessel observations, each 

month represented between 7.7 % and 8.8% of the total annual observations. The 

average was 8.3% with a standard deviation of 0.36%. The average summer month 

observations was 8.6%. This analysis indicated that the data files were complete and 

that commercial marine vessel traffic within the Gulf does not have a significant 

seasonal variation. 

To obtain activity data that could be used for annual and daily estimates, data 

processing steps included consolidating monthly data files into a single dataset in 

Structured Query Language (SQL) Server and organizing the dataset by vessel and time 

stamp. ERG performed a quality assurance review of the records and removed records 

that could not be used, including the following: 

 12 records with no date; 

 11 records with an invalid Maritime Mobile Service Identity (MMSI); and 

 2,564 vessels that each had a single observation in the year, which is insufficient 

for routing.

ERG mapped the points in a geographic information system (GIS) and removed 

2,523,130 records that plotted more than one nautical mile outside of Texas state 

waters. ERG selected a buffer distance of one nautical mile to ensure vessel movements 

near the edge of the nine-mile state waters area were included. This method aimed to 

capture data points just outside of the area of interest in order to represent the 

movements as vessels enter and exit state waters. 

Summary statistics performed on the AIS data in SQL server indicated that 72.8 percent 

of the records indicated speeds of less than 0.2 knots. Discussions with PortVision 

clarified that speeds of 0.2 knots or less could indicate vessels maintaining position or 

otherwise not moving. As a result, ERG consolidated consecutive records with vessel 

speeds of less than or equal to 0.2 knots by averaging the coordinates and speeds to 

reduce the record count. These processing steps further reduced the size of the dataset 

to 5,667,338 records. 
3-2 

3.1.1 Vessel Characteristics 

The AIS data contain identifying information including International Maritime 

Organization (IMO) number, Maritime Mobile Service Identity (MMSI), vessel name,

and vessel type. ERG used these identifiers to match individual vessels to their 

characteristics in the IHS Vessel Database (IHS 2014). The best method to match 

vessels is by matching IMO numbers between the two datasets; however, the IMO 

number is not fully populated in AIS data. As a result, ERG conducted additional rounds 

of matching using vessel names, call signs, and vessel type to match as many vessels as 

possible to their detailed vessel characteristics and to validate matches made by IMO 

number. 

Ultimately, ERG successfully matched 4,152 vessels to the IHS database to obtain kW 

ratings and maximum speeds. IHS data, while comprehensive, may not have fully 

populated engine characteristics. For vessels that matched to IHS but did not have 

kilowatt rating or maximum speed data, ERG calculated average values (excluding 

zeros) by vessel type and category. For vessels that lacked a category, ERG used the 

vessel type to assign a category, and average kW rating and maximum speeds were gapfilled based on the type and category. 

Vessels that could still not be matched, for example, because they were lacking IMO 

number, vessel type, and vessel category, were considered most likely to be Category 2 

vessels that do not meet the IMO requirements but have invested in AIS technology. 

Note that vessels equipped with Category 3 engines have a very high match rate as they 

tend to include IMO or MMSI codes. Smaller Category 1 vessels are less likely to 

participate in the AIS. Therefore, vessels that could not be matched, because they were 

lacking both vessel type and category were considered to be Category 2 vessels. This 

assumption may potentially result in an over estimation of emissions as there are a few 

Category 1 vessels in the AIS dataset. Therefore, ERG developed average values for 

Category 2 vessels to gap-fill engine data for vessels that could not be matched to 

detailed vessel characteristics. For the 2,155 vessels that could not be matched to 

detailed vessel characteristics, ERG averaged the kW and maximum speed data values 

for the 253 Category 2 vessels present in the Texas IHS data to gap-fill engine data. 

Outliers were accounted for and removed before averaging. The averages were 3,201 for 

engine kW rating and 12.68478 for maximum speed 

3.1.2 Load Factors 

Previous inventories used default load factors in estimating emissions. This is a 

common practice and has been the established practice for the TCEQ and the United 

States Environmental Protection Agency (EPA) for previous CMV emissions inventories. 
3-3 

Vessels tend to operate at an optimal and consistent load while cruising, but their 

engine loads can vary significantly while they are transiting reduced speed zones or 

shifting in a port area. AIS data include actual vessel speed, which ERG used in 

conjunction with the maximum vessel speed as provided by IHS data to accurately 

calculate engine load using the Propeller law: 

LF = (AS/MS)3

Where: 

LF = load factor 

AS = actual vessel speed 

MS = maximum vessel speed 

After linking the vessels to the IHS database, ERG calculated load factors using the 

maximum vessel speed and the observed (actual) vessel speed for individual route 

segments. In some cases, however, the actual speed reported in AIS data exceeded the 

maximum speed reported in IHS data. In these cases, the actual speed was set equal to 

the maximum speed and their load factors, which exceeded 1.0, were replaced by 

averages derived from IHS data by vessel type. Load factors under 20% were rounded to 

the nearest percent for later processing as described in Section 5. 

3.1.3 Auxiliary Engines 

Data on auxiliary engines were obtained for all Category 3 vessels from the IHS data. 

Category 1 and 2 vessels are smaller and as such tend not to have auxiliary engines or 

turn their engines off while dockside, so no gap-filling of Category 2 and 3 auxiliary 

engines was necessary. 

3.1.4 Kilowatt-hour Calculations and Data Quality Checks 

With kW ratings, maximum speeds, and loading factors fully populated, the kilowatt 

hours (kWh) were calculated as follows: 

A = MCR x LF x H 

Where: 

A = vessel activity in kWh 

MCR = maximum continuous rated engine power, kW 

LF = load factor 

H = hours of operation 
3-4 

Activity for propulsion engines were calculated using the kW rating of the main engines 

for all records with an AIS-reported speed over ground greater than 0.2 knots. For 

Category 3 vessels, all records indicating movement were considered underway 

activities. For Category 1 and 2 vessels, the activity associated with speeds over 0.2 knots 

was split between port and underway Source Category Codes (SCCs) to account for 

hoteling (operations while stationary at dock). 11.75% of the activity was considered 

hoteling while the remaining 88.25% was considered underway as identified in a 

previous Category 2 Census Report from the EPA (U.S. EPA, 2007). Activity in the 

reduced speed zone (RSZ) was calculated using the kW rating of the auxiliary engines 

for all Category 3 vessels with a recorded speed greater than 0.2 knots. Hoteling activity 

was calculated using the kW rating of the auxiliary engines for all Category 3 AIS 

observations where the speed was less than or equal to 0.2 knots. 

3.2 Government Vessels 

Table 3-1 shows information ERG obtained about Coast Guard vessels operating in 

Texas waters using fleet profiles obtained from their websites and from direct 

communication with Coast Guard staff in 2011 (USCG, 2014). ERG obtained the list of 

vessels in 2015 from the Coast Guard, but was not able to contact anyone at the Coast 

Guard to obtain or confirm activity information at this time. Therefore, ERG used the 

original assumptions which are listed in Table 3-1 from the 2011 inventory as surrogates. 

For three new vessels that were not included in the 2011 inventory, ERG assigned 

activity hours to these vessels to be consistent with other similar Coast Guard Classes. 

For example navigational aid boats were assumed to have annual operating hours less 

than larger vessels involved in inland construction and lighter faster medium response 

boats were assumed to be used slightly more often than larger coastal patrol boats. 

The Coast Guard’s Eighth District is responsible for safety and security of the full length 

of the Mississippi River, as well as the Gulf of Mexico (Peschke, 2015). In the HGA area, 

the District operates 10 vessels from the Freeport and Galveston ports, as listed in Table 

3.1. 
3-5 

Table 3-1. Coast Guard Vessel Characteristics and Associated Ports 

Port

Vessel 

ID Class Vessel Name Vessel Type

Horsepower 

(hp)

State Water 

Hours

Source of 

Hours

Freeport

WPB 

87320 WPB-87 Manta

Coastal Patrol Boat -

Marine Protector Class 3000 360

2011 TX 

Inventory

Galveston

WPB 

87330 WPB-87 Man-O-War

Coastal Patrol Boat -

Marine Protector Class 3000 360

2011 TX 

Inventory

Galveston 45630 RB-M

Response BoatMedium Response Boat-Medium 825 640Engineering 

Judgment

Galveston

ANB 

55103 ANB-55

55-foot Aids to 

Navigation Boat Aids to Navigation Boat 1080 500

Engineering 

Judgment

Galveston

WMEC 

624

WMEC 

210 Dauntless Medium Endurance Cutter 5000 240

2011 TX 

Inventory

Galveston

WLIC 

75309 WLIC-75 Hatchet

Inland Construction 

Tenders 1320 1700

2011 TX 

Inventory

Galveston

WLIC 

75306 WLIC-75 Clamp

Inland Construction 

Tenders 1320 1700

2011 TX 

Inventory

Galveston

WLM 

561

WLM175 Harry ClaiborneCoastal Buoy Tender -

Keeper Class 3400 240

2011 TX 

Inventory

Galveston 45618 RB-M

Response BoatMedium Response Boat - Medium 825 640Engineering 

Judgment

Galveston

WPB 

87353 WPB-87 Skipjack

Coastal Patrol Boat -

Marine Protector Class 3000 360

2011 TX 

Inventory
3-1 

Table 3-1 notes for each Coast Guard vessel the home port, vessel ID number, name, 

type, horsepower rating of the propulsion engines, and an estimate of the number of 

hours these vessels operate in state waters. The Coast Guard provided a past estimate of 

the annual hours of operation and the percentage of time the vessels operated within 

state waters for 2011. ERG was not able to obtain 2013 data. ERG used these 2011 data 

to estimate the horsepower hours (hp hr) of operation within state waters using the 

following equation: 

hp hr = Vn × hp × Ao 

Where: 

hp hr = kilowatt hours 

Vn = number of vessels 

hp = total horsepower rating of the Coast Guard vessel's propulsion 

 engines 

Ao = annual operating hours in Texas state waters

Example: Military Vessel Activity Calculation 

The 87-foot coastal patrol boat, Steelhead, operates out of Corpus Christi; it is equipped 

with two 1,475 horsepower (hp) engines. The vessel operates 1,800 hours per year; 20 

percent of operations are in Texas state waters. Using the equation above, ERG 

calculated the horsepower hours for this vessel: 

hp hr = Vn × hp × Ao 

hp hr = 1 × 2950 hp × 360 hrs 

hp hr = 1,062,000 

ERG developed emission estimates for NOx and non-methane volatile organic 

compounds (NMVOC) using the following equation: 

DE = AH × CF1 × LF × EF × CF2 × D 

Where: 

DE = daily emissions (tons per day) 

AH = annual activity (hp hr) 

CF1 = conversion factor (0.7455 kW/hp) 

LF = engine load factor 

EF = emission factor (g/kWh) 
3-2 

CF2 = conversion factor (1.10231 E-6 ton/g) 

D = conversion of Annual hours to summer season daily hours 

 (1 year / 365 days) 

Example: Military Vessel Emission Calculation 

The Steelhead has annual hp hrs of 1,062,000, which it operates at a load factor of 0.80. 

Using the equation directly above, ERG estimated the NOx emissions using a NOx 

emission factor of 13.2 g/kWh: 

DE = AH × CF1 × LF × EF × CF2 × D 

DE = 1,062,000 hp hrs per year × 0.745 kW/hp × 0.80 × 13.2 g/kWh × 1.10231 E-6 

ton/g × 1/365 

DE = 0.025 tons per day 

ERG assumed that the underway load factor for propulsion engines of Coast Guard 

vessels was 80 percent. To estimate emissions, ERG used emission factors that the EPA 

developed in support of recent marine vessel rule making (EPA 2010). ERG spatially 

allocated Coast Guard activity and emissions based on the district associated with each 

base and assigned them to appropriate counties based on the geographic information 

system (GIS) shapefiles. Similar to the data processing for the AIS Category 1 and 2 

vessels, total activity was split between port and underway SCCs to account for hoteling. 

11.75% of the activity was considered hoteling while the remaining 88.25% was 

considered underway as identified in a previous Category 2 Census Report from the EPA 

(U.S. EPA, 2007). 

3.3 Dredging Operations 

ERG obtained information concerning dredging operations occurring in Texas state

waters for 2012 through 2014 from the U.S. Army Corps of Engineers Dredging Activity 

Database (USACE, 2015). The 14 dredging projects that ERG identified were 

implemented by both the Army Corps as well as private contractors. The Army Corps of 

Engineers private company data set included the following information:

 the name of the dredging site; 

 the type of dredging equipment used; 

 the dates on which dredging was planned to be initiated and completed; 

 the dates when dredging was actually initiated and completed; 

 the amount of material dredged and the disposal method; and 

 information about the private company (including address) that was awarded the 

work. 
3-3 

ERG used the actual dredging start and completion dates to estimate the total hours of 

operation for the dredging equipment. In some cases, the completion dates were not 

documented in the database, in which case ERG assumed the project was ongoing and 

would continue until December 31, 2014. 

Though this equipment operates 24 hours per day seven days per week, ERG assumed 

that dredging engines operate 90 percent of the time to account for vessel positioning, 

minor maintenance, and refueling activities. 

Three different dredging types are used in state waters: cutter suction (pipeline), 

hopper, and cutter and hopper combination vessels. Cutter suction dredges use a 

rotating drill to bring sediment up. Hopper vessels use a vacuum device that transports 

sediments from the ocean floor into the vessel’s hold. ERG assumed that cutter suction 

dredges are equipped with engines rated from 5,000 to 15,000 horsepower (for this 

project ERG used a value of 9,600 horsepower (7,161 kW) based on data provided by 

dredging services that implemented similar dredging activities). Hopper dredges with a 

horsepower rating of 7,500 to 12,000 horsepower (5,593 to 8,951 kW), based on data 

provided by dredging companies that implemented identified dredging activities, with

an average value of 9,814 horsepower (7,272 kW). This value was used for hopper 

dredges (TCEQ 2011). ERG found only one example of a combination dredger at Marine 

Aggregate Levy Sustainability Fund (MALSF) website, which had an assumed 

horsepower of 5,476 horsepower (4,080 kW) (MALSF, 2015). 

ERG obtained limited information concerning the dredging vessels from websites of the 

companies implementing the dredging contracts. Ideally engine kW ratings would be 

available for each of the dredging vessels used in the dredging projects. However, very 

few websites did included this data. Therefore, the average kW ratings of 7,272 kW were 

used. ERG compiled the information that was available in the project database. To 

clarify, the U.S. Army Corps of Engineers’ Dredging Activity Database included the 

estimated project arrival and departure dates (based on the proposal for the dredging 

project) and actual project arrival and departure dates. For this inventory, ERG 

estimated hours of operation based on the actual arrival and departure dates. 

ERG estimated total kilowatt hours using the following equation: 

TKW = THP × 0.745 KW/hp × (DP-AR) × 24 hrs/day × 0.90 

Where: 

TKW = total kilowatt hours (kWh) 

THP = total maximum horsepower rating of the engine (hp) 

0.745 = conversion of hp to kW 

DP = departure date 
3-4 

AR = arrival date 

24 = hours per day 

0.90 = total fraction of time operating (considering ongoing 

 maintenance activities and refueling) 

Example: Dredging Activity Calculation 

A hopper vessel equipped with a 9814 hp engine arrived at the site on January 1, 2014, 

and departed on January 11, 2014. Using the equation above, ERG calculated the 

operating kilowatt hours for this vessel: 

kWh = THP × 0.745KW/hp × (DP-AR) × 24 hrs/day × 0.90 

kWh = 9,814 hp × 0.745 KW/hp× (1/1/14 – 1/11/14) × 24 × 0.90 

kWh = 1,570,790 kWh

ERG calculated the total operating kilowatt hours based on the hours of operation 

applied to the vessel and horse power rating. For future SIP years, ERG used the 2013 

data as the base year for the growth factors. Similar to the data processing for the AIS 

Category 1 and 2 vessels, total activity was split between port and underway SCCs to 

account for hoteling. 11.75% of the activity was considered hoteling while the remaining 

88.25% was considered underway as identified in a previous Category 2 Census Report 

from the EPA (U.S. EPA, 2007). 

ERG developed emissions estimates for NOx and VOC using the following equation: 

DE = AH × EF × CF × D 

Where: 

DE = daily emissions (tons per day) 

AH = annual activity (kWh) 

EF = emission factor (g/kWh) 

CF = conversion factor (1.10231 E-6 ton/g) 

D = conversion of annual emissions to summer season daily 

 emissions (1 year / 365 days) 

Example: Dredging Emission Calculation 

Using the equation directly above, ERG estimated the NOx emissions of a dredging 

vessel with annual operations of 829,487 kWh. The NOx emission factor is 19.54 g/kWh.

DE = AH × LF × EF × CF × D 
3-5 

DE = 829,487 kWhs × 19.54 g/kWh × 1.10231 x 10-6 ton/g × 1/365 

DE = 0.049 tons of NOx per day

There is little data currently available to quantify engine operating loads for dredging 

propulsion engines. ERG assumed that vessel operators would attempt to optimize fuel 

consumption rates which, for diesel engines, would be associated with operating loads 

around 80 percent based off the EPA’s Current Methodologies in Preparing Mobile 

Source Port-Related Emission Inventories (April 2009). 

3.4 Commercial Fishing 

ERG based commercial fishing activity on a variety of data sources for commercial 

fishing in Texas. More information on the data will be discussed in this section. ERG 

estimated fishing vessel ship calls as a function of vessel purpose and its type of fishery. 

Table 3-7 summarizes vessel operating characteristics for the four main types of fishing 

operations, specifically the number of vessel port calls per year, distance traveled in 

state waters per call, vessel speed, kilowatt rating of the engine, calculated hours of 

operation in state waters, and calculated kilowatt hours. These data in table 3-7 were 

provided by an expert consultant on marine vessel activity (Wells 2012) 

ERG obtained the number of vessels from information from the Texas Parks and 

Wildlife Commercial Fishing License Buyback Programs (TPWD, 2015). To estimate 

annual kilowatt-hours of operation per vessel, ERG multiplied the number of calls by 

the vessel’s kilowatt rating, the hours per call, and a load factor of 68 percent. Most 

fishing vessels have a governor and “trolling gear” to lower engine loads to 68 percent 

optimizing diesel fuel consumption. For this component of the TCEQ emission 

inventory, ERG assumed the load factor to be 68 percent. ERG calculated fishing vessel 

kilowatt hours using the following equation: 

Table 3-2. Vessel Operating Characteristics by Fishing Operation Type 

Fishery

Operation Vessels Calls/Yr Distance Speed Hours kW kW/ Vessel - Yr

Snapper 84 40 20 7.5 2.7 224 16,247

Shrimp 1,086 20 20 7.5 2.7 522 18,931

Oyster 252 100 40 7.5 5.3 224 81,133

Other 195 50 30 7.5 4.0 186 25,354

Total 1,617 141,646
3-6 

Actf = Kw × Dt / Sp × Cf × Lf

Where: 

Actf = annual activity per vessel in terms of adjusted kilowatt hours 

Kw = typical kilowatt rating of fishing boats’ propulsion engines 

by type of fishing vessel operation 

Dt = distance traveled in state waters per trip (nautical miles) 

Sp = vessel speed (nautical miles per hour) 

Cf = number of calls per year 

Lf = load factor (percent) 

Example: Fishing Vessel Activity Calculation 

A vessel involved in fishing operations for snappers is equipped with a 224 kW 

propulsion engine, has 40 calls per year where they transit 20 nautical miles per call and 

operate at a speed of 7.5 nautical miles per hour. ERG used the equation directly above 

to calculate the total horsepower hours of operation: 

Actf = Kw × Dt / Sp × Cf × Lf

Actf = 224 kw × 20 NM/7.5 NM/hr × 40 × 68/100 

hp hr = 16,247 

The fleet of Gulf of Mexico fishing vessels involved in pelagic fishing (e.g., red snapper 

and other ground fish), long-line tuna and swordfish, and shrimping operations actually 

operate most of the time in federal waters. Many of these fishing boats go out into the 

Gulf and stay out for a week to 3 months. When returning to Texas ports, each vessel 

operates for only 2 to 3 hours within Texas waters (Wells 2012). 

Fishing operations within state waters are dominated by the oyster fishery in the upper 

Texas Coast with most vessels operating in the Galveston area. These vessels rarely leave 

the bays or Texas waters and can include bait shrimping, black drum, blue crabs, 

flounder, and other inshore fisheries (Wells 2012). These boats spend 100 percent of the 

time within Texas waters and are basically regulated by the fishing season, fishing 

permits, and the TPWD. ERG obtained the number of vessels associated with each type 

of fishing operations using the TPWD buyback program in Table 3-7.

The main fishery ports in the Houston-Galveston-Brazoria area are Freeport, Galveston, 

and Houston. ERG obtained 2013 fish landings for each port from the National Marine 

Fisheries Service (NMFS, 2015); these numbers are presented in Table 3-8. Table 3-8 

presents each port’s percentage of the total, both as total catch and by fishery operations 

(e.g., snapper, shrimp, oyster, and other). 
3-7 

Table 3-3. 2013 Port Landings for Port Allocations

Port County

Millions 

of Pounds

Percent 

by 

Poundage

Snapper 

Vessels

Shrimp 

Vessels

Oyster 

Vessels

Other 

Vessel

Freeport Brazoria 2.7 10.5% 3 39 9 7

Galveston Galveston 22.6 88.3% 25 329 76 59

Houston Harris 0.3 1.2% 1 5 1 1

Total 25.6 100.0% 29 373 86 67

NMFS, 2015. 

ERG used the fractions and number of vessels in Table 3-8 to estimate the portion of the 

Texas fleet for each of the fisheries operations. Also, ERG applied the vessel count data 

presented in Table 3-8 to the per vessel annual kWhs data presented in Table 3-7 to 

estimate the kWhs associated with the different fishing operations and port which are 

presented in Table 3-9. 

Table 3-4. Kilowatt Hours for Texas Fishing Vessel Fleet by Port and Fishing 

Operation

Port County Snapper 

kWh

Shrimp

kWh

Oyster

kWh

Other Vessel 

kWh

2014 Total 

kWh

Freeport Brazoria 48,680 738,315 730,201 177,479 1,694,676

Galveston Galveston 405,667 6,228,347 6,166,145 1,495,899 14,296,058

Houston Harris 16,227 94,656 81,133 25,354 217,370

Total 470,574 7,061,318 6,977,479 1,698,732 16,208,104

ERG applied these kilowatt hours to the EPA’s emission factors to estimate VOC and 

NOX emissions using the following equation: 

DEf = Actf × EF × CF × D 

Where: 

DEf = daily emissions associated with fishing vessels (tons per day) 

Actf = annual activity (kWh) 

EF = emission factor (g/kWh) 

CF = conversion factor (1.10231 E-6 ton/g) 

D = conversion of annual emissions to summer season daily 

 emissions (1 year / 365 days) 

Example: Fishing Vessel Emission Calculation 

Snapper fishing vessels in 2013 account for 1,363,043 kWhs. Using the equation directly 

above, ERG calculated fishing vessel emissions: 
3-8 

DEf = Actf × EF × CF × D

DEf = 1,363,043 kWh × 14.30 g/kWh × 1.10231E-6 ton/gr × 1/365 

= 0.059 tons of NOx per day

ERG used 2013 as the base year for all the SIP inventory years. ERG used fish landings 

to allocate the activity data spatially to the ports and their surrounding areas. Similar to 

the data processing for the AIS Category 1 and 2 vessels, total activity was split between 

port and underway SCCs to account for hoteling. 11.75% of the activity was considered 

hoteling while the remaining 88.25% was considered underway as identified in a 

previous Category 2 Census Report from the EPA (U.S. EPA, 2007). 
4-1 

4.0 Emission Factors

EPA reviewed CMV emission factors (USEPA 2010) for planned use with the 2014 

National Emission Inventory (NEI) as shown below in Table 4-1. ERG developed 

controlled emission factors (EF) from EPA data which took into account fleet turnover 

and the implementation of regulatory programs. 

Table 4-1. CMV Controlled and Uncontrolled Emission Factors (g/kWh) 

Vessel 

Category Year

VOC VOC NOx NOx

EF(g/kwh)-

Controlled

EF(g/kwh)-

Uncontrolled

EF(g/kwh)-

Controlled

EF(g/kwh)-

Uncontrolled

1 2012 0.37752221 0.414246439 11.87915089 13.67405715

1 2014 0.344530113 0.414246439 10.91841802 13.67405715

1 2017 0.286655015 0.414246439 9.283438348 13.67405715

1 2020 0.22981902 0.414246439 7.578271349 13.67405715

1 2023 0.183826734 0.414246439 6.272283478 13.67405715

1 2026 0.147721047 0.414246439 5.23155296 13.67405715

1 2028 0.132037217 0.414246439 4.708707722 13.67405715

2 2012 0.216885092 0.216885092 15.71832872 18.13310412

2 2014 0.210026583 0.216885092 14.30384093 18.13310412

2 2017 0.188774682 0.216885092 12.43740304 18.13310412

2 2020 0.164228307 0.216885092 10.63451944 18.13310412

2 2023 0.14112125 0.216885092 8.989550799 18.13310412

2 2026 0.119410144 0.216885092 7.577245665 18.13310412

2 2028 0.105671573 0.216885092 6.703434571 18.13310412

3 2012 0.623530845 0.623530845 15.33941522 16.05531595

3 2014 0.623530845 0.623530845 14.79396063 16.05531595

3 2017 0.623530845 0.623530845 13.50968287 16.05531595

3 2020 0.623530845 0.623530845 11.23791401 16.05531595

3 2023 0.621711121 0.623530845 9.551909679 16.05531595

3 2026 0.620200071 0.623530845 8.114494301 16.05531595

3 2028 0.619070859 0.623530845 7.425013114 16.05531595

Appendix A includes a summary table of the various control programs associated with 

CMV. These control programs and their reductions are already taken into account by the 

emission factors in Table 4-1. 
5-1

5.0 Emissions Calculations

ERG estimated emissions as a function of vessel power demand multiplied by an 

emission factor, where the emission factor is expressed in terms of grams per kilowatt 

hour (g/kWh). ERG then applied emission factors and propulsion engine load to the 

activity data to estimate emissions. Below is the basic equation used to estimate port 

emissions: 

DE = MCR x LF x A x EF x D 

Where: 

DE = emissions from the engine(s), usually calculated as grams of 

 emissions per day

MCR = maximum continuous rated engine power, kW 

LF = load factor 

A = activity, hours 

EF = emission factor (g/kWh) 

D = conversion of annual emissions to summer season daily 

 emissions (1 year / 365 days) 

Both controlled and uncontrolled emissions estimates were calculated using the 

emission factors in Section 4.0. Because the AIS data note the actual vessel speed and 

the IHS data provide maximum design speed, the engine load can be calculated directly. 

Where the engine load is below 20 percent, the emission factors in Table 4-1 were 

adjusted for low load using the adjustment factors presented in Table 5-1, obtained from 

2009 EPA port emissions inventory guidance (EPA 2009). The emissions estimates 

were multiplied by the adjustment factors to estimate the increase in emissions 

associated with low operating loads. Since data review indicated no significant 

seasonality in the AIS data, the annual values were divided by 365 to obtain ozone 

season daily emissions values.
5-2 

Table 5-1. Emissions

Adjustment Factors for 

Operating Loads Less than 

20%

Load NOx VOC

1% 11.47 62.32

2% 4.63 22.27

3% 2.92 12.28

4% 2.21 8.11

5% 1.83 5.90

6% 1.60 4.57

7% 1.45 3.70

8% 1.35 3.10

9% 1.27 2.65

10% 1.22 2.31

11% 1.17 2.06

12% 1.14 1.85

13% 1.11 1.68

14% 1.08 1.55

15% 1.06 1.43

16% 1.05 1.32

17% 1.03 1.24

18% 1.02 1.17

19% 1.01 1.10

20% 1.00 62.32
6-1

6.0 Projection Factors

ERG based projected commercial marine vessel activities for Texas ports on the carbon 

dioxide (CO2) emission estimates from the business as usual (BAU) Global Scenario 13 

developed in the International Maritime Organization’s (IMO) Third Green House Gas 

Study (2014). CO2 tends to be strongly correlated to fuel combustion as it is based on 

the carbon content of the fuel which tends to be relatively constant over time. It should 

be noted that the projection profiles in the IMO study represent the most current 

economic information on the marine vessel activities developed by an international 

consortium of leading experts. Studies that have been implemented prior to the global 

economic decline in 2008 and the uncertain period of recovery (2009-12) tend to 

overestimate projected growth in the sector. The IMO team addressed the still lingering 

uncertainties about future trends by providing four different BAU scenarios (13, 14, 15, 

and 16). All four of the BAU scenarios assumed modest engine efficiency improvement 

(no control options), no further expansion of global Emission Control Areas (ECA) and 

limited use of liquefied natural gas (LNG). To insure that projected activities were not 

underestimated, BAU Scenario 13 was used as it assumed the highest level of projected 

growth. 

A wide range of control studies were also included in the projection scenarios 1-12. It 

should be noted that none of these control scenarios were used in projecting marine 

vessel activities for this TCEQ project. Additional research supported this assessment, 

including the assessment developed by the Center for Transportation Research and 

Texas Transportation Institute for the “Trade Flows and Texas Gulf Ports: Panama 

Canal Expansion and South American Markets” (August 2013) report. This assessment 

suggests that international cargo volume will gradually increase as noted in the IMO 

BAU projections concurrent with an increase in vessel size due to the Panama Canal 

expansion, providing less vessel traffic with fewer emissions per cargo ton-mile. ERG 

reviewed other references such as the U.S. Department of Transportation Bureau of 

Transportation Statistics 2014 (TranStat 2014), the U.S. Department of Energy’s Annual 

Energy Outlook (EIA 2014), and the Organisation for Economic Co-operation and 

Development (OECD) Economic Outlook (2014) to ensure that projected vessel traffic 

estimates are reasonable. 

Note the projections provided in the IMO report did not account for recent changes in 

fuel costs. ERG anticipates that these changes may have limited impact on marine vessel 

activities as projected fuel usage in Texas ports will require fuels that comply with 

emissions control area standards. Conversely, if vessels use high sulfur content fuels,

they will need to install scrubbers to ensure that emissions are comparable with those 

from the use of low sulfur fuels. Table 6-1 lists forecasting and backcasting factors. 
7-2 

Table 6-1. 2013-Based Commercial Marine 

Vessel Activity Growth Factors using 

Uncontrolled CO2

Year

CO2 Emissions

(million tonnes)

Growth ratio from

2013 base year

2012 816 1.01

2014 816 1.00

2017 850 1.04

2020 910 1.12

2023 1024 1.25

2026 1120 1.37

2028 1160 1.42

ERG matched projected activity to the appropriate future year emission factors in Table 

6-1 to account for federal rules that are implemented relative to the year that the marine 

engine was originally manufactured, such that full benefit of the rule would occur in the 

future once fleet turnover was completed. ERG made additional adjustments to future 

year emissions estimates to account for compliance with emissions control area fuel 

sulfur standards and Texas Emissions Reduction Plan (TERP) investments. Appendix A 

includes a complete list of control programs addressed in this inventory. 

7.0 Results

Table 7-1 through 7-4 presents the total daily CMV emissions (tons per day) for each 

pollutant by county. Table 7-1 and 7-2 present the controlled and uncontrolled daily 

emissions for NOX and Tables 7-3 and 7-4 presents the controlled and uncontrolled 

daily emissions for VOC. It should be noted that the emissions for 2012 were 

significantly higher than the other years due to the higher level of dredging activity that 

occurred in 2012. It should also be noted that only the emissions from the eight counties 

in the HGB nonattainment areas are included. 

Table 7-1. Ozone Season Daily Controlled NOX Emissions (tons) by Year for 

the Houston-Galveston-Brazoria Area

County 

Name

Ozone Season Daily NOX Emissions (tons/day)

2012 2014 2017 2020 2023 2026 2028

Brazoria 14.684 2.125 1.934 1.771 1.673 1.547 1.425

Chambers 0.276 0.249 0.225 0.207 0.196 0.181 0.166

Galveston 28.663 20.648 19.203 17.379 16.457 15.266 14.280

Harris 12.375 8.006 7.404 6.722 6.356 5.892 5.492

Total 55.998 31.028 28.766 26.079 24.682 22.886 21.363
7-3 

Table 7-2. Ozone Season Daily Uncontrolled NOX Emissions (tons) by Year 

for the Houston-Galveston-Brazoria Area 

County 

Name

Ozone Season Daily NOX Emissions (tons/day)

2012 2014 2017 2020 2023 2026 2028

Brazoria 17.302 2.918 2.864 2.974 3.305 3.621 3.753

Chambers 0.326 0.321 0.331 0.354 0.395 0.433 0.448

Galveston 32.485 24.539 25.204 26.921 30.043 32.918 34.116

Harris 14.182 9.694 9.942 10.617 11.836 12.972 13.445

Total 64.295 37.472 38.341 40.866 45.579 49.944 51.762

Table 7-3. Ozone Season Daily Controlled VOC Emissions (tons) by Year for 

the Houston-Galveston-Brazoria Area 

County 

Name

Ozone Season Daily VOC Emissions (tons/day)

2012 2014 2017 2020 2023 2026 2028

Brazoria 0.252 0.079 0.075 0.073 0.072 0.070 0.067

Chambers 0.010 0.010 0.009 0.009 0.008 0.008 0.007

Galveston 0.836 0.731 0.738 0.767 0.826 0.875 0.887

Harris 0.390 0.331 0.331 0.340 0.362 0.379 0.381

Total 1.488 1.151 1.153 1.189 1.268 1.332 1.342

Table 7-4. Ozone Season Daily Uncontrolled VOC Emissions (tons) by Year 

for the Houston-Galveston-Brazoria Area 

County 

Name

Ozone Season Daily VOC Emissions (tons/day)

2012 2014 2017 2020 2023 2026 2028

Brazoria 0.252 0.081 0.084 0.091 0.102 0.111 0.115

Chambers 0.010 0.010 0.010 0.011 0.013 0.014 0.014

Galveston 0.837 0.740 0.770 0.829 0.925 1.014 1.051

Harris 0.391 0.336 0.349 0.376 0.420 0.460 0.477

Total 1.49 1.167 1.213 1.307 1.46 1.599 1.657
8-1

8.0 References

1. Center for Transportation Research, The University of Texas at Austin. Texas 

A&M Transportation Institute, Texas A&M University. Trade Flows and Texas 

Gulf Ports: Panama Canal Expansion and South American Markets, August 2013. 

http://library.ctr.utexas.edu/ctr-publications/0-6690-CTR-2.pdfsdf. 

2. IHS Inc. Vessel Database 2014 http://www.ihs.com. 

3. International Maritime Organization. Third IMO GHG Study 2014, June 2014. 

http://www.iadc.org/wp-content/uploads/2014/02/MEPC-67-6-INF3-2014-

Final-Report-complete.pdf. 

4. Marine Aggregate Levy Sustainability Fund (MALSF). Measurement of 

underwater noise arising from marine aggregate dredging operations – Final 

Report, February 2011 

http://www.cefas.defra.gov.uk/media/462859/mepf%20p108%20final%20repor

t.pdf.

5. National Marine Fisheries Service (NMFS). Total Commercial Fishery Landings 

at an individual U.S. Port, 2015 

(http://www.st.nmfs.noaa.gov/st1/commercial/landings/lport_hist.html). 

6. OECD. OECD Economic Outlook: Volume 2014/2, OECD Publishing. 

http://dx.doi.org/10.1787/eco_outlook-v2014-2-en 2, November 2014. 

7. Peschke, John. Quarter Master - Eighth Coast Guard District, New Orleans, LA, 

Last modified: August 20, 2014. The 8th District Website was reviewed in 2015 to 

identify any new vessels (http://www.uscg.mil/d8/d8units.asp). 

8. Texas Parks and Wildlife 

http://tpwd.texas.gov/publications/pwdpubs/media/pwd_bk_v3400_0074.pdf, 

November 2014. 

9. Texas Parks and Wildlife 

http://tpwd.texas.gov/fishboat/fish/commercial/buyback.phtml, January 2015.

10. United States Army Corp of Engineers, “U.S. Waterway Data Vessel Entrances 

and Clearances” November 28, 2014 

http://www.navigationdatacenter.us/data/dataclen.htm. 

11. United States Army Corps of Engineers. Waterway Data, Dredging Information 

System. (http://www.navigationdatacenter.us/data/datadrgsel.htm), Last 

revised: November 28, 2015, U.S.

12. United States Bureau of Transportation Statistics. TranStats, 2014. 

http://www.transtats.bts.gov/homepage.asp. 
8-2 

13. U.S. Environmental Protection Agency, Category 2 Vessel Census, Activity and 

Spatial Allocation Assessment and Category 1 and 2 In-Port / At- Sea Splits, 

February 16, 2007. 

14. U.S. Environmental Protection Agency, Current Methodologies in Preparing 

Mobile Source Port-Related Emission Inventories, Section 2.5 Load Factors, Page 

2-11. April 2009 

15. U.S. Environmental Protection Agency, Office of Transportation and Air Quality 

(USEPA 2010), E-mail entitled: Re: MY CMV Emission Factors from P. Carey 

(USEPA) to R. Billings (ERG). 

16. United States Environmental Protection Agency. Current Methodologies in 

Preparing Mobile Source Port-Related Emission Inventories, Final Report, April 

2009. 

17. United States Environmental Protection Agency, 2011 National Emission 

Inventory. ftp://ftp.epa.gov/EmisInventory/2011/doc. 

18. Wells, Sam, Memo entitled: Re: Texas Commercial Fishing Emissions Inventory 

to R. Billings (ERG) July 25, 2012 
A-1

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

2008 TERP Statewide Reduction by 1,632 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/co

mm_exec/pubs/sfr/079_08.pdf

2009 TERP Statewide Reduction by 1,688 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/co

mm_exec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 3 tons this year, 

VOC reduced by 7 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2010 TERP Statewide Reduction by 1,190 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/co

mm_exec/pubs/sfr/079_08.pdf

MARPOL Annex VI - SOx 

reduction

North America 

(excluding Mexico)

1.50% mass/mass (m/m) prior to 1 July 

2010

http://www.imo.org/OurWork/Environment/

PollutionPrevention/AirPollution/Pages/Sulp

hur-oxides-(SOx)-%E2%80%93-Regulation14.aspx

MARPOL Annex VI - SOx 

reduction

North America 

(excluding Mexico)

1.00% m/m on and after 1 July 2010 http://www.imo.org/OurWork/Environment/

PollutionPrevention/AirPollution/Pages/Sulp

hur-oxides-(SOx)-%E2%80%93-Regulation14.aspx

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 6 tons this year, 

VOC reduced by 14 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2011 TERP Statewide Reduction by 1,140 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/co

mm_exec/pubs/sfr/079_08.pdf

MARPOL Annex VI - NOx 

reduction

North America 

(excluding Mexico)

Tier II NOx reductions, ships 

constructed on or after Jan 1, 2011; n <

130: 14.4, n = 130-1999: 44·n(-0.23), n 

≥ 2000: 7.7; n = engine's rated speed 

(rpm), units are g/kWh

http://www.imo.org/OurWork/Environment/

PollutionPrevention/AirPollution/Pages/Nitro

gen-oxides-(NOx)-%E2%80%93-Regulation13.aspx
A-2 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 8 tons this year, 

VOC reduced by 22 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2012 TERP Statewide Reduction by 850 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/co

mm_exec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 76 tons this year, 

NOx reduced by 1,463 tons this year, 

VOC reduced by 152 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2013 TERP Statewide Reduction by 767 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 321 tons this year, 

NOx reduced by 4,935 tons this year, 

VOC reduced by 383 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2014 TERP Statewide Reduction by 595 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 776 tons this year, 

NOx reduced by 17,326 tons this year, 

VOC reduced by 837 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2015 TERP Statewide Reduction by 428 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf
A-3 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

MARPOL Annex VI - SOx 

reduction

North America 

(excluding Mexico)

0.10% m/m on and after 1 January 

2015

http://www.imo.org/OurWork/Environment/Pollu

tionPrevention/AirPollution/Pages/Sulphuroxides-(SOx)-%E2%80%93-Regulation-14.aspx

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 1,149 tons this year, 

NOx reduced by 29,723 tons this year, 

VOC reduced by 1,290 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2016 TERP Statewide Reduction by 296 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

MARPOL Annex VI - NOx 

reduction

In ECA only (North 

America excluding 

Mexico)

Tier III NOx reductions, ships 

constructed on or after Jan 1, 2016; n < 

130: 3.4, n = 130-1999: 9·n(-0.2), n ≥ 

2000: 2.0; n = engine's rated speed 

(rpm), units are g/kWh

http://www.imo.org/OurWork/Environment/Pollu

tionPrevention/AirPollution/Pages/Nitrogenoxides-(NOx)-%E2%80%93-Regulation-13.aspx

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 1,740 tons this year, 

NOx reduced by 49,151 tons this year, 

VOC reduced by 1,848 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2017 TERP Statewide Reduction by 249 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 2,469 tons this year, 

NOx reduced by 71,006 tons this year, 

VOC reduced by 2,497 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2018 TERP Statewide Reduction by 217 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf
A-4 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 3,245 tons this year, 

NOx reduced by 94,975 tons this year, 

VOC reduced by 3,183 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2019 TERP Statewide Reduction by 217 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 4,019 tons this year, 

NOx reduced by 118,882 tons this year, 

VOC reduced by 3,867 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2020 TERP Statewide Reduction by 33 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 4,808 tons this year, 

NOx reduced by 142,666 tons this year, 

VOC reduced by 4,545 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2021 TERP Statewide Reduction by 33 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 5,644 tons this year, 

NOx reduced by 166,339 tons this year, 

VOC reduced by 5,218 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2022 TERP Statewide Reduction by 23 tons this year to 

various counties (listed in detail in the 

TERP table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf
A-5 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 6,491 tons this year, 

NOx reduced by 189,855 tons this year, 

VOC reduced by 5,883 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2023 TERP Statewide Reduction by 1 ton this year to various 

counties (listed in detail in the TERP 

table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 7,347 tons this year, 

NOx reduced by 213,181 tons this year, 

VOC reduced by 6,539 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2024 TERP Statewide Reduction by 1 ton this year to various 

counties (listed in detail in the TERP 

table)

https://www.tceq.texas.gov/assets/public/comm_e

xec/pubs/sfr/079_08.pdf

Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 8,210 tons this year, 

NOx reduced by 236,257 tons this year, 

VOC reduced by 7,183 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2025 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 9,064 tons this year, 

NOx reduced by 258,828 tons this year, 

VOC reduced by 7,794 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2026 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 9,899 tons this year, 

NOx reduced by 280,771 tons this year, 

VOC reduced by 8,360 tons this year

http://www.epa.gov/nonroad/420d07001.pdf
A-6 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

2027 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 10,711 tons this year, 

NOx reduced by 301,951 tons this year, 

VOC reduced by 8,880 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2028 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 11,503 tons this 

year, NOx reduced by 322,410 tons this 

year, VOC reduced by 9,360 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2029 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 12,277 tons this 

year, NOx reduced by 341,797 tons this 

year, VOC reduced by 9,811 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2030 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 13,027 tons this 

year, NOx reduced by 359,780 tons this 

year, VOC reduced by 10,225 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2031 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 13,752 tons this 

year, NOx reduced by 376,481 tons this 

year, VOC reduced by 10,605 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2032 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 14,458 tons this 

year, NOx reduced by 392,324 tons this 

year, VOC reduced by 10,960 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf
A-7 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

2033 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 15,151 tons this year, 

NOx reduced by 407,598 tons this year, 

VOC reduced by 11,300 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2034 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 15,834 tons this 

year, NOx reduced by 422,367 tons this 

year, VOC reduced by 11,625 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2035 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 16,500 tons this 

year, NOx reduced by 436,542 tons this 

year, VOC reduced by 11,936 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2036 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 17,126 tons this year, 

NOx reduced by 449,899 tons this year, 

VOC reduced by 12,228 tons this year

http://www.epa.gov/nonroad/420d07001.pdf

2037 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 17,686 tons this 

year, NOx reduced by 461,578 tons this 

year, VOC reduced by 12,490 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2038 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 18,198 tons this 

year, NOx reduced by 471,739 tons this 

year, VOC reduced by 12,728 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf
A-8 

Appendix A. CMV 2008 to 2040 Control Programs*

Year Programs Application Notes Source

2039 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 18,664 tons this 

year, NOx reduced by 480,787 tons this 

year, VOC reduced by 12,947 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

2040 Control of Emissions of 

Air Pollution for 

Locomotive Engines and 

Marine CompressionIgnition Engines Less than 

30 Liters per Cylinder

Nationwide PM2.5 reduced by 19,063 tons this 

year, NOx reduced by 488,838 tons this 

year, VOC reduced by 13,143 tons this 

year

http://www.epa.gov/nonroad/420d07001.pdf

*Note: only the NOx and VOC reductions were used in the development of future emissions estimates for this report.