Research Projects

Project at a Glance

Project Status: complete

Report Published June 1995:

Title: Development of an improved inventory of emissions from pleasure craft in California.

Principal Investigator / Author(s): Causley, Marianne

Contractor: Systems Applications International

Contract Number: A132-184

Research Program Area: Emissions Monitoring & Control

Topic Areas: Mobile Sources & Fuels


In order to improve estimates of emissions from pleasure craft in California, the California Air Resources Board (CARB) retained the services of Systems Applications International (SAI) and Freeman, Sullivan & Company (FSC) to develop a bottom-up emissions inventory for these vessels. The objective of this study is to update the current emission inventory of total organic gases (TOG), nitrogen oxides (Nx)' carbon monoxide (CO), sulfur oxides (SOx), and particulate matter (PM). The inventory developed during this study is based on a statewide survey of pleasure craft vessel owners that was conducted during a one-year period from June 1993 to May 1994. The survey was designed to ascertain the spatial and temporal distribution of utilization of pleasure craft in California, as well as to collect updated consumption rates for vessels.

Over 10,000 surveys were sent to randomly selected owners of motorized pleasure craft registered with the California Department of Motor Vehicles (DMV). The overall response rate from the survey was close to 50 percent. Of the surveys returned, approximately 40 percent of the vessels were used in the Peak (June-August) and Ozone (April-September) seasons and 11 percent in the Winter season (October-March). During the wintertime, owners of vessels were contacted in the Southern region only.

To generate the updated pleasure craft emissions inventory, the survey results were used to estimate the annual fuel consumption for vessels by propulsion-engine combinations on a regional basis (Northern, Central, and Southern). The annual fuel consumption per region is then used to estimate the regional and county-level emissions using an emissions model developed for this study, PCEM (Pleasure craft Emissions Model). This model includes emission estimates from vessels registered with the DMV, vessels documented with the Coast Guard, and rental vessels. The fuel consumption is then multiplied by the appropriate emission factor for each propulsion-engine type and allocated to the county level with spatial allocation factors developed from the survey data. Temporal (seasonal, weekly, and diurnal) profiles associated with pleasure craft are provided in this report based on the survey data.

The estimates in this study suggest that 1993-1994 NOx TOG, and sax emissions inventories for this category be decreased from the values included in the 1990 CARE inventory by about 45, 18 and 85 percent, respectively, while CO and PM inventories should be increased by 3 and 100 percent respectively. These differences occur because of the use of updated emission factors and fuel consumption. An average annual fuel consumption rate of 77.5 gallons per vessel is estimated in this study.


For questions regarding research reports, contact: Heather Choi at (916) 322-3893

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