Today ship cruises are increasingly popular among tourists. They provide relaxation and 24-hour service for stressed out workers.
Forget about searching for the perfect, pristine beach - which most people will never find, anyhow. Instead, just go to the pool on the upper deck, enjoy some tasty drinks and take in breathtaking views of the ocean from high above.
But you better think twice about taking a deep breath. The German Environmental Association "Naturschutzbund Deutschland"(NABU) now warns that it is more likely you inhale polluted air than a fresh breeze. NABU says that it cannot recommend any of the large European cruise ships.
Measuring results are worse than expected.
Recent measurements of actual air quality onboard a cruise ship seem to support NABU's view. French TV journalists from broadcaster France 3 conducted covert measurements while on a cruise. They boarded a ship in Marseille for a cruise of the Mediterranean.
Results show that "the shipping companies are exposing their travelers to high concentrations of harmful substances," NABU managing director Leif Miller concluded.
Even environmentalists were surprised by the high concentrations that the journalists detected. Right after leaving Marseille, air pollution was roughly 200 times that of a heavily trafficked urban street.
Besides fine dust and soot, the combustion of marine diesel fuel and heavy oil also set free other harmful substances such as nitrogen oxides and heavy metals.
Former captain and ship broker Helge Grammerstorf, who is the German national director of the Cruise Lines International Association CLIA, defends his industry.
Grammerstorf argues that the measurements were taken only selectively and that one would need to run a more systematic test to collect data over a longer time period.
Some cruise lines have pledged to install particle filters, but so far, there are none in use.
Previously, NABU has only had the opportunity to measure harmful ultra fine dust particles in the air around cruise ships in harbors. They have done so in Hamburg, Venice and the north-eastern German city of Rostock-Warnemünde. The ship owners did not allow the environment agency to take measurements on board, Daniel Rieger said.
In all cases the ships were burning off heavy oil. Four of five vessels were not equipped with any exhaust gas cleaning or they were only fulfilling the lowest legal standard for northern Europe - a system that only reduces sulfur oxide emissions.
Technical solutions to reduce particle and nitrogen oxide emissions have long been on the market, though. Therefore, NABU argues, not implementing them is largely due to greed. It would cost money to install the system and furthermore require the companies to use more expensive types of fuel.
The German Lung Foundation already recommended several years ago that people with chronic respiratory diseases only stay on certain parts of the deck when on a cruise ship and thus avoide breathing in the ship's exhaust.
The World Health Organization (WHO) has concluded that diesel exhaust is just as carcinogenic as asbestos. The ultrafine particles, which are smaller than 0.1 micrometer can get into the smallest pulmonary alveoli and from there into the blood stream and other organs.