Marine gasoline and diesel engines are among the greatest contributors of hydrocarbons (HC) and oxides of nitrogen (NOx) pollution in the United States. In some regions, fuel from outboard motors in the primary cause of Federal impaired water body designations. Most boaters are aware that engine emissions can produce ground-level ozone and smog. Ozone is a recognized respiratory system irritant that causes lung and heart inflammation. Products of combustion include the greenhouse gases carbon dioxide (CO2) and carbon monoxide (CO). Carbon dioxide is seen as a major contributor to global warming.
Marine engines produce five major classes of emissions caused by the combustion of fossil fuel. Production of each component can be effected by vessel management practices.
Primary Marine Engine Pollutants:
- Hydrocarbons (HC) - Unburned or partially burned fuel and evaporated fuel
- Particulate Matter - Microscopic airborne particles primarily associated with diesel exhaust
- Nitrogen Oxides (NOx) - Byproducts of combining nitrogen and oxygen under high temperature and pressure within an internal-combustion engine
- Carbon Monoxide (CO) - A colorless, odorless, and poisonous gas that is the result of incomplete combustion
- Carbon Dioxide (CO2) - A product of burning hydrocarbon fuels like gasoline and diesel. A major greenhouse gas
Boaters can make a remarkable difference in reducing marine engine pollution. Reducing engine emissions has a positive effect on diminishing respiratory conditions like asthma. The U.S. Environmental Protection Agency (EPA) is phasing in tighter emission standards for marine engines that are now coming on the market. High performance engines burn less fuel and lower pollution levels. The amount of fuel burned determines the carbon footprint of your boat. Reducing CO2 emissions lessens the production of greenhouse gases. Here are some strategies that you can use to reduce marine engine emissions.
Marine Pollution Reduction Strategies:
Engine Maintenance and Considerations
- Keep your engine in good condition and well tuned
- Follow the manufacturer's recommended service schedules
- Properly match engine horsepower to vessel size
- Install electronic engine and fuel monitoring equipment
- Avoid purchasing carburetor equipped engines
Vessel Operations
- Reduce unnecessary engine idling
- Use the right size propeller and keep in good condition. Nicks and dents reduce performance
- Limit full throttle operation of the engine
- Reduce Weight. Carrying extra cargo onboard reduces fuel efficiency and increases fuel consumption
- Drive your boat conservatively. Reduce abrupt starts and excessive cruise speeds
- Learn to trim your boat while underway
- Keep the boat bottom clean and waxed. Marine growth increases drag and fuel consumption
- Consider purchasing a new, cleaner running marine engine
- Store boats properly in the off-season
Fuel Handling
- Avoid spilling gasoline or diesel fuel. Pour oil or fuel slowly and smoothly
- Practice safe fueling procedures
- Close vents on portable tanks when not in use
- Store fuel out of direct sunlight
- Install an overflow warning or cut-off device on your boat
Use of these strategies will reduce engine emissions resulting in better air quality, reduced carbon loads and improved fuel economy.
Alan Sorum - Alan Sorum is the Maritime Operations Project Manager for the Prince William Sound Regional Citizens' Advisory Council (PWSRCAC). Alan is ...
