The type of fuel used by ships has a substantial effect on cloud formation. Exhausts from dirty heavy oils leave a telltale trail of such dense cloud that they can be tracked from space. While ship emissions contain many chemicals including black carbon, researchers have discovered that it is the sulphate aerosols formed from the sulphur in the oil that is responsible for the clouds that sometimes trail behind ships for hundreds of miles.

The tracking technology was developed because researchers are trying to discover what effect this pollution is having on climate change and rainfall but also it will help enforce new regulations to curb these emissions.

Already there are prohibitions on using these sulphur-laden fuels in the North Sea, Baltic, English Channel and North America because of the damaging air pollution that drifts on land. Where these regulations are enforced the clouds associated with ship exhausts disappear.

From January 2020 new regulations to clean up the shipping trade apply worldwide but some unscrupulous companies are expected to try and ignore them and continue to use the cheaper and dirtier heavy fuel oils. However, having tracked 17,000 ships, the researchers are confident they will be able to identify individual miscreants from space simply by monitoring the dense clouds behind the ships as they cross the oceans.