From the article:

The regulation of auto emissions appears to be getting more stringent by the day. For example, California is mandating more plug-in hybrids for its roads, and the Feds are bringing tougher fuel economy standards for big rigs. At the same time, European governments are rapidly turning their backs on diesel fuel because of the allegedly serious health implications. There might be bigger fish to fry in cleaning up the world, though. According to a confidential study by maritime industry insiders obtained by The Guardian, a single container ship might produce the same amount sulfur oxide gases a year as about 50 million cars. With air pollution’s links to cancer and heart disease, the next major emissions battleground might move from the highways to the sea.

These ships are behemoths and carry a significant portion of the world’s goods. However, they also aren’t subject to the stringent standards as vehicles on land. Running on bunker fuel, the largest diesel engines in these vessels can produce up to 5,732 tons of sulfur oxide gases a year, according to The Guardian. For the whole shipping industry, that equates to about nine percent of the global annual emissions of that pollutant and a further 18-30 percent of the nitrogen oxide each year. To put things in perspective, 15 of the world’s biggest ships emit as much as 760 million cars, The Guardian reports.

The result of all of this pollution is seriously detrimental health effects, including asthma and even heart attacks. The Guardian references a study in the US that estimates 60,000 deaths a year in the country and $330 billion in annual health costs from things like lung disease can be attributed cargo-ship emissions. Research from Denmark provides further support with projections of 1,000 fatalities yearly and $7.8 billion in health effects.

The issue of container-ship emissions isn’t a new one, but the US is reacting by setting up a 230-mile buffer for the biggest polluters along the East Coast, according to The Guardian. The International Maritime Organisation and the European Union are considering tightening cargo ship emissions, as well.