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Cleaner Fuel on Ships Produces Fewer Emissions, NOAA Finds

Cleaner Fuel on Ships Produces Fewer Emissions, NOAA Finds

15 September 2011
NOAA researchers and collaborators studied the emissions produced by this container ship, operated by the Maersk Line. This photo was taken from the research aircraft.

NOAA researchers and collaborators studied the emissions produced by this container ship, operated by the Maersk Line. This photo was taken from the research aircraft.

Air pollution emitted by a seagoing vessel drops sharply when the ship switches to a cleaner, low-sulfur fuel, according to a study conducted by the National Oceanic and Atmospheric Administration (NOAA) and the Woods Hole Oceanographic Institute.

Pollution emission laws in the state of California require ships to make a switch to clean fuel as they approach shore, so researchers conducted their study in the ocean waters off the state’s Pacific coast. California regulations also require that ships slow down as they near shore, and these two actions together resulted in emissions declines of as much as 90 percent in some cases.

Study sponsors say the findings have broader implications because regulations similar to the California rules are set to take effect across North American waters in the next few years.

NOAA worked with Maersk Line shipping to conduct the emissions surveillance. A NOAA aircraft flew over a Maersk commercial container ship when it was still about 65 kilometers out at sea and burning higher-sulfur fuels. When the ship was within the low-emissions zone required by California law and traveling at a slower speed, a NOAA-sponsored research ship took more emissions samples.

The study found that both sulfur dioxide and particulate matter declined dramatically after the ship powered down with the cleaner fuel. Sulfur dioxide went down from 49 grams of emissions per kilogram of fuel to 4.3 grams.

“This study gives us a sense of what to expect in the future, for the people of California, the nation and even the globe,” said Daniel Lack, a chemist with NOAA’s Earth System Research Laboratory and the Cooperative Institute for Research in Environmental Sciences. “It’s important to know that the imposed regulations have the expected impacts. The regulators want to know, the shipping companies want to know and so do the people.”

The regulations that reduced the emissions from the Maersk ship are only in force off the coast of California now, but a similar, broader regulatory regimen will be in place in less than a year. In August of 2012, ships sailing into the waters surrounding North America will be subject to stronger controls than those in force globally for sulfur oxides, nitrogen oxides and particulate matter.

The stricter standard will take effect as an amendment to MARPOL, the International Convention for the Prevention of Pollution from Ships. MARPOL is a marine environmental agreement designed to minimize pollution of the seas, whether through dumping, oil discharge or emissions. The agreement took effect in October 1983 and is administered by the International Maritime Organization. One hundred fifty nations are party to the original provisions of the agreement, though fewer nations have signed on to amendments that have passed in the ensuing years.

The various annexes to the agreement set standards for prevention of pollution by various commodities: oil; noxious liquid substances; harmful substances in packaged form; garbage; and air pollution.