Black cloud over estimates of tugboat, cargo ship soot

Tugboats and cargo ships alike are pumping out far more soot than previously thought, according to new findings released today by federal and private scientists.

Stubby tugboats plying busy harbors puff out more sooty black carbon than any other commercial vessels, and large cargo ships emit more than twice as much soot as previously estimated, according to the first broad study of commercial vessel emissions, say researchers from the National Oceanic and Atmospheric Administration and the University of Colorado. The findings are laid out in the July 11 issue of the journal Geophysical Research Letters.

"Commercial shipping emissions have been one of the least studied areas of all combustion emissions," said lead author Daniel Lack, of NOAA's Earth System Research Laboratory. "The two previous studies of soot emissions examined a total of three ships. We reviewed plumes from 96 different vessels."

Lack and his colleagues observed and measured black carbon plumes emitted by tankers, cargo and container ships, large fishing boats, tug boats and ferries in open ocean waters, channels and ports along the southeast United States and Texas during the summer of 2006.

The ports of Los Angeles and Long Beach, the nation's busiest, along with nearby Santa Barbara Channel, are regularly used by hundreds of polluting vessels, and local and state air regulators say marine vessel emissions are a major piece of Southern California's continuing air pollution woes.

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A major culprit is the dirty "bunker" fuel used by such vessels, literally the dregs of other, cleaner fuels, which can contain levels of harmful pollutants thousands of times higher than legal limits inside the U.S. Major cargo shipping companies say they want to clean up their act, but have fought efforts at domestic regulation, saying they are only subject to international standards. The U.N.'s International Maritime organization is inching toward tightening up allowable amounts but has yet to do so.

A separate 2007 study by American and German scientists linked particle pollution from shipping to tens of thousands of premature deaths each year. Soot makes up a quarter of that pollution, said Lack.

Tugboats have a disproportionate impact on air quality because they travel within ports, emitting potentially harmful particles near populous urban areas, according to the authors.

"Tugboats are a huge source of black carbon that may be under-reported or not reported at all in emissions inventories compiled by ports," said Lack.

On a global scale, soot's small, dark particles absorb sunlight, create haze and affect how clouds form and make rain, further altering a region's heat balance, according to the new study.  In the Arctic, an increase in soot may contribute to climate change if shipping routes expand through waters there, according to the study.

-- Janet Wilson

Photo: Tugboat emitting sooty smoke in San Francisco Bay. Credit: Michael Macor, AP Photo/San Francisco Chronicle

Comments

[Louis Vest]

It would seem like a study of the long term health of sailors would be the most logical step. Here we are making general assumptions about the health effects on the general population while, as far as I know, no one has looked at the sailors, longshoremen, or tugboat sailors to find out if anything unusual is going on with their health. Wouldn't it make sense to look at the effects on people who live and work on these vessels 24 hours a day for months at a time before making wider speculations?

[Alisdair Pettigrew]

A newly-approved emissions control system, designed to fit onboard ocean-going ships, could prevent thousands of premature deaths by significantly reducing some of the most deadly pollutants affecting regions along North American coastlines.

Approval of the system, known as seawater scrubbing, by United Nations' body the International Maritime Organization has opened the way for the first North American ECA – an Emissions Control Area for ships potentially stretching up to 200 miles offshore - to incorporate the technology.

The success of the 'seawater scrubbing system' in removing harmful emissions allows shipping lines a cost-effective means of 'future proofing' vessels from tougher international and federal emissions restrictions introduced throughout a vessel's lifetime.

Significantly, while both scrubbing and distillates – or ultra low sulphur marine fuel – reduce harmful sulfur emissions by over 97%, only scrubbing technology' is able to significantly reduce Particulate Matter (PM) emissions. Moreover, distillates release over 60% more CO2 than the same engine with a scrubber burning heavy fuel oil.

Health experts say the particulates also worsen respiratory illnesses, cardiopulmonary disorders and lung cancers, particularly among people who live near heavy ship traffic. Clean air agencies throughout North America have sought ways to reduce PM emissions from marine engines for many years. Recent studies estimate that more than 8,000 premature deaths in North America are as a result of particulates from ships.

If applied to the North American west coast shipping fleet, the scrubbing system - which can be retro-fitted within three days - it is estimated to be capable of removing particulates in the entire Los Angeles region (South Coast Air Basin) by more than 15%, according to Air Resources Board figures*.

[Alisdair Pettigrew]

A newly-approved emissions control system, designed to fit onboard ocean-going ships, could prevent thousands of premature deaths by significantly reducing some of the most deadly pollutants affecting regions along North American coastlines.

Approval of the system, known as seawater scrubbing, by United Nations' body the International Maritime Organization has opened the way for the first North American ECA – an Emissions Control Area for ships potentially stretching up to 200 miles offshore - to incorporate the technology.

The success of Krystallon's 'seawater scrubbing system' in removing harmful emissions allows shipping lines a cost-effective means of 'future proofing' vessels from tougher international and federal emissions restrictions introduced throughout a vessel's lifetime.

Significantly, while both scrubbing and distillates – or ultra low sulphur marine fuel – reduce harmful sulfur emissions by over 97%, only scrubbing technology' is able to significantly reduce Particulate Matter (PM) emissions. Moreover, distillates release over 60% more CO2 than the same engine with a scrubber burning heavy fuel oil.

Health experts say the particulates also worsen respiratory illnesses, cardiopulmonary disorders and lung cancers, particularly among people who live near heavy ship traffic. Clean air agencies throughout North America have sought ways to reduce PM emissions from marine engines for many years. Recent studies estimate that more than 8,000 premature deaths in North America are as a result of particulates from ships.

If applied to the North American west coast shipping fleet, the scrubbing system - which can be retro-fitted within three days - it is estimated to be capable of removing particulates in the entire Los Angeles region (South Coast Air Basin) by more than 15%, according to Air Resources Board figures*.

[Eric Tomasi]

The regulation of International shipping emissions are governed by the International Convention for the Prevention of Pollution From Ships, 1973 as modified by the Protocol of 1978, usualy referenced as MARPOL (short for marine pollution). The current regs are MARPOL annex six which limit oxides of nitrogen and Sulfur dioxide emissions from ships, one of the primary reasons that you see the black clould is the high level of sulfur in the fuel (sulfur forms particulates). The international limit for sulfur in marine fuels is 4.5%, although the current worldwide fleet average is 2.7%. In, several areas around the world, The Baltic Sea, as an example, countries agree to enforce a lower sulfur fuel percentage of 1.5%, which is not terribly expensive and significantly decreases sulfur dioxide and soot emissions. I would hope that after a more environmentally friendly administration, we would look at enforcing this at the big american ports in Southern California, along the gulf of mexico and in the Northeast.

[David Pettit]

This new data will not come as a surprise to the millions of people in the U.S. who live downwind of busy ports. Dirty exhaust from diesel engines is a known carcinogen and contributes to asthma, other cardio-respiratory diseases and 24,000 deaths annually, as California’s Air Resource Board found in May. The huge diesel engines in oceangoing ships are the dirtiest of all because of the high-sulfur bunker fuel that they burn. California is leading the nation in its attempts to clean up ocean shipping, but there needs to be a tough, enforceable international solution to this deadly worldwide problem.

[Wilbur Varela]

Will the last human standing please turn out the lights. The technology exists today to clean up their act, at a moderate cost. The cowardice and poor global leadership to stand up to international shipping is a harbinger of more missed chances to come. In the future, clean air will be sold to the rich, their homes will have breathing rooms, and the poor will gasp their last dying breaths in squalor. Welcome to earth, 2038, thirty years from now.