It is well known and accepted that tiny particles breathed into human lungs can cause a number of different health effects including asthma, heart attacks, lung cancer and other respiratory illnesses. The dangerous size is particles that are 2.5 microns or less because there are few natural defenses against these becoming deeply embedded into lung tissue. Fossil fuel combustion is a major source of these particles with high sulfur and high ash content fuel being worse than fuels that are low in these two components.
For many people, ocean shipping is invisible and not considered when thinking about sources of air pollution that need to be addressed. Because they operate out of sight in international waters, ships have been allowed to burn lower quality “bunker” fuels that can have sulfur and ash content that is 10s to thousands of times higher than the fuels burned on land.
A recent study was conducted to take a hard look at the effects of that policy and the increasing number of ocean going ships with ever larger engines and air polluting emissions. I learned about the study from an article on the Australian Broadcasting Corporation Science Web site written by Lindsay Beck titled Ship emissions kill 60,000 a year.
The study was conducted by a large team – here is the list of participants and their affiliations as given in the paper abstract.
James J. Corbett,* James J. Winebrake, Erin H. Green, Prasad Kasibhatla, Veronika Eyring, and Axel Lauer
College of Marine and Earth Studies, University of Delaware, 305 Robinson Hall, Newark, Delaware 19716,
Department of STS/Public Policy, Rochester Institute of Technology, 1356 Eastman, Rochester, New York 14623,
Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 22708,
Deutches Zentrum fuer Luft- und Raumfahrt (DLR) DLR-Institute fuer Physik der Atmosphaere, Oberpfaffenhofen, Wessling, Germany
You can find the paper at Mortality from Ship Emissions: A Global Assessment. It is pretty dense academic reading, but it is sobering to think about how these emissions might be harming human health.
On a brighter, more optimistic note – there is a better way as hinted by this visionary ship that was slightly before its time:
The NS Savannah produced no emissions at all, just like those submarines that I used to ride. Unfortunately, there was no follow through with the Savannah and she was laid up more than 35 years ago. Here is a picture taken by a friend of mine this summer when he visited her during a short dockyard visit for watertight integrity repairs. Kind of sad isn’t it?
Maybe it is past time to think harder about commercial nuclear ship propulsion. As you might imagine, I have been thinking about that topic myself more and more, but it is not the first time. Take a look at a paper I wrote more than a decade ago; I think it still holds true. Nuclear Power for Commercial Ships