Tests were carried out earlier this week on Santorini looking at the concentrations of dangerous ultrafine particles in the atmosphere, and the results are staggering.

Conducted by the Hellenic Ornithological Society (HOS) with air pollution experts from Germany’s Nature and Biodiversity Union (Nabu), they found the particles near cruise ships entering the island’s waters were 100 times higher in comparison to surrounding areas, reports Independent.

Experts say the pollution has been linked to heart attacks and strokes, especially dangerous for the elderly. While figures released by the European Commission estimate at least 50,000 people die prematurely each year in Europe due to air pollution from shipping.

“People living on the Greek islands as well as tourists visiting them are suffering from shipping emissions,” said Nobu’s transport policy officer Sonke Diesener.

“We have seen these high concentrations of air pollutants in many different port cities in the Mediterranean region and all over the world. However, this is no excuse for ship operators to go on with their reckless pollution.”

Unlike road vehicles, cruise ships are subject to weaker standards and use heavy fuel oil without exhaust cleaning systems, resulting in the ultrafine particles, carcinogenic compounds and soot being emitted into the atmosphere.

“We found concentrations of over 340 particles per cubic centimetre,” said Dr Axel Friedrich who conducted the tests.

“In a very busy street, you will find 20 to 30. The load of air pollutants that the ships cause was enormous.”

Senior cardiac nurse at the British Heart Foundation, Philippa Hobson said the research reveals that even short-term exposure to such air pollution over one or two hours can have a lasting impact and urged tourists travelling on cruise ships to be cautious, especially if they already suffer from heart and circulatory diseases.

“If you are worried about your health and are travelling on a cruise ship, it is best to try and minimise your exposure to air pollution by avoiding the areas near or downwind of the engine funnels – try to seek out the sea breeze on the decks,” Ms Hobson said.

Nabu has called on the shipping industry to switch to low sulphur fuels, which are safer, and to install systems that remove harmful pollutants from exhausts.

Until the owners of the ships take responsibility, the union called for coastal communities to ban high-polluting ships.

Moreover, it urged Greece to support the designation of the Mediterranean as a sulphur emission control area, a status given to the North and Baltic seas with positive results.