Cruise ships use heavy fuel oil (HFO) to power their diesel engines. HFO diesel oil can contain 3,500 times more sulphur than diesel that is used for land traffic vehicles; and cruise ships do not have exhaust abatement technologies like particulate filters that are standard on passenger cars and trucks. The highest readings on the ships were seen at the back, in the area near the smokestack.
Air pollution produced by cruise ships may be hazardous to the passengers and staff, as well as residents of the port communities in which they dock. Their exhaust contains heavy metals and polycyclic aromatic hydrocarbons, released from the processing of the fuel. Concentrations of particulate matter may be extremely high, similar to those found in cities that are known to have poor air quality.
The cruise ship industry is one of the fastest growing sectors in the mass tourism market, with 24 million passengers expected to sail in 2016, compared to 15 million in 2006 and just 1.4 million in 1980. It generated $119.9bn (£83bn) in total output worldwide in 2015, supporting 939,232 full-time equivalent jobs.
The port of Southampton, UK, Britain’s second largest container port and Europe’s busiest cruise terminal, is one of nine UK cities cited by the World Health Organisation as breaching air quality guidelines even though it has little manufacturing. Trends are for more and bigger liners together with very large bulk cargo ships. Up to five large liners a day can be berthed in the docks at the same time, all running engines 24/7. These large liners burn as much fuel as whole towns. They use a lot more power than container ships and even when they burn low sulphur fuel the emissions are 100 times worse than road diesel. Marine pollution analysts say that a giant cruise ship would probably burn at least 150 tonnes of fuel a day, emit over five tonnes of NOX emissions and 450kg of ultra fine particles a day and emit more sulphur than several million cars, more NO2 gas than all the traffic passing through a medium-sized town and more particulate emissions than thousands of London buses. Pollution from the port is linked to asthma and chest diseases.
One cruise ship emits as many air pollutants as five million cars going the same distance because these ships use heavy fuel that on land would have to be disposed of as hazardous waste.