The cruise industry’s environmental record came under scrutiny in a UK TV investigation this week.
A Channel 4 Dispatches programme claimed air pollution on some ships can be twice that in central London.
Exhaust fumes emitted by ships at sea are not covered by regulations which limit emissions on land, and the heavy fuel oil that powers ships’ engines can contain 3,500 times more sulphur than in road fuel.
Undercover investigators on the deck of a cruise ship, standing downwind of a ship’s funnel, reported air pollution of 84,000 ultrafine particles per cubic centimetre.
This is more than double the 38,400 ultrafine particles per cubic centimetre found at London’s Piccadilly Circus and almost 20 times as many as the 4,285 particles found at Camber Sands in East Sussex, the programme reported.
Ultrafine particles are particularly damaging to human health because they are small enough to cross the membranes in lungs.
The programme also drew attention to cruise ships’ practice of flushing out “grey water” from sinks and showers.
Matt Loxham, a respiration biologist at Southampton University, said ultrafine particles are about a thousand times thinner than a strand of human hair.
He told The Times newspaper: “Larger particles that we inhale usually get trapped in the airways by phlegm, or by hairs in the nostrils.
“But ultrafines can get right into the depths of the lung and distribute throughout the body.
“There are some areas of the ship deck that are affected by really quite high levels of particulate matter. These are levels you would expect in some of the most polluted cities in the world.”
Dispatches under cover investigators sailed on P&O Cruises ship Oceana.
They used an infra-red camera to film gases that are not visible to the naked eye, and a P-Trak ultrafine particle counter to measure air pollution.
Carnival Corporation, which owns P&O Cruises, said cruise ships made up less than 1% of the world’s 50,000 commercial maritime vessels.
“Although a tiny fraction of the global maritime industry, cruise lines are leaders in implementing alternative fuels and emission-reduction technology,” the company said.
“The industry has invested more than $10 billion in new ships that can use alternative fuels such as liquefied natural gas.”
The company said it had spent $400 million installing exhaust gas cleaning systems on 60 ships that could reduce particulate matter by up to 80%.
See also:
Cruise lines praised for environmental measures in Clia study
Sustainability ‘key to cruise growth’ says Carnival chief
Investigation finds high levels of pollution on cruise ships