On the list of underreported environmental issues, the air pollution caused by cargo ships should rank pretty high. We've been covering it for a while, writing in 2009: "Just 15 of the world's biggest ships may now emit as much pollution as all the world's 760m cars."
This is mostly because cargo ships spend most of their time in international water in a kind of regulatory blind spot. The low-grade ship bunker fuel that powers these ships has up to 2,000 times (!) the sulphur content of diesel fuel used in US, and European automobiles and emission control is practically non-existent.
Thankfully, there's been some good news on that front in recent times. While it's still very hard to truly monitor and control what is happening at high sea, territorial waters near land are a different story. Some international regulations requiring ships sailing in the North and Baltic seas to cut sulfur content in fuel are already having a huge impact.
The first air measurements performed by the sniffer show that 98% of ships comply with the sulfur standards and, according to a new report by the Danish Center for Environment and Energy at Aarhus University (DCE), the total content of airborne sulfur has been reduced by up to 60% since the new year. (source)
“Sulfur and particles are harmful to people, so it is good news that the new environmental requirements are having an effect. As the first country in the world, Denmark has implemented new technology to monitor ships’ emissions and ensure full compliance with the requirements. Significant economic savings are possible by circumventing the law, so monitoring and enforcement are important to avoid harmful pollution from the ships and an unfair competitive situation for the law-abiding shipowners,” says Minister for Environment and Food Eva Kjer Hansen.