Pollution from cargo ships drops in wake of new California rules
At some point in the journey from factory to store shelves, as much as 90% of the world's shipped goods spends time on board a ship. For places like Los Angeles and Long Beach, the good news about this supply chain reality is that the biggest seaports handle the most cargo and get the greatest number of generally well paying jobs.
The bad news is also sizeable. Cargo ships at sea burn what can only be described as the -- in the words of one research chemist -- "bottom of the barrel" grade of fuel, also known as bunker.
"Bottom of the barrel is literally what bunker fuel is. It's what the refineries have left after all of the cleaner burning fuels -- aviation, gasoline, diesel -- has been produced. It's the sludge at the bottom where all of the bad stuff concentrates, all of the sulfur and the heavy-metal compounds," said chemist Dan Lack, who works with with the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory and the Cooperative Institute for Research in Environmental Sciences.
But Lack and his associates have some data that might literally help those who live near California's major seaports breathe a little easier: When cargo ships slow down and switch to a cleaner-burning fuel as they approach shore, the reduction in pollution levels is startling.
Their study of a Maersk cargo container ship operating under California's 2009 near-shore, low-sulfur fuels regulation and the state's voluntary slowdown policy found that emissions of several health-damaging pollutants, including sulfur dioxide and particulate matter, fell dramatically. The ship was the Margrethe Maersk.
Sulfur dioxide levels fell 91%. Sulfur dioxide emissions can lead to the formation of particulate matter in the atmosphere that poses serious public health concerns. Particulate matter pollution, which can damage people’s lungs and hearts, dropped 90%.
Lack said the study was important because it involved a case in which a regulation wasn't ignored after it was enacted.
"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,” Lack said.
-- Ronald D. White
Photo: The container ship Margrethe Maersk steams toward California in May 2010. Credit: National Oceanic and Atmospheric Administration and Cooperative Institute for Research in Environmental Sciences