"Says James Corbett, professor of marine policy at the University of Delaware: “Ship pollution affects the health of communities in coastal and inland regions around the world, yet pollution from ships remains one of the least regulated parts of our global transportation system.” It sounds serious, but how bad could it be? Staggeringly, if a report by the UK’s Guardian newspaper is to be believed. According to their story, just one of the world’s largest container ships can emit about as much pollution as 50 million cars. Further, the 15 largest ships in the world emit as much nitrogen oxide and sulphur oxide as the world’s 760 million cars.
The problem isn’t necessarily with the ships’ 109,000-horsepower engines that endlessly spin away 24 hours a day, 280 days a year. In fact, these powerplants are some of the most fuel efficient units in the world. The real issue lies with the heavy fuel oil the ships run on and the almost complete lack of regulations applied to the giant exhaust stacks of these container ships.
The good news is that pressure is building from various governments around the world, including the United States, which just recently introduced legislation to keep these ships at least 230 miles away from U.S. coastlines. Similar measures are likely to follow in other countries like the United Kingdom."[via]