The beautiful salty breeze on the deck of a cruise ship might not be as fresh or clean as you think it is and a new study has revealed it might be less clean than beach air.

Research conducted on four Carnival Corporation ships over the last two years found particulate matter (PM) – pollution comprising of small solids or liquid droplets in the air – had amounts comparable to places with high levels of pollution like Beijing and Taipei, Taiwan.

The worst readings taken in the cruise ships were in areas designated for exercise or children’s activities.

When cruise ship air is inhaled, it can “damage the heart and lungs,” according to the study completed by associate professor at the John Hopkins Bloomberg School of Public Health, Ryan Kennedy.

”It’s dangerous, it’s not a healthy thing for us to be exposed to,“ he told CNN.

The report explains the ship may exhaust harmful toxins into the air including metals and polycyclic aromatic hydrocarbons (PAHs) – of these which can have damaging impacts on vacationers and ship employees.

The cruise ships tested were: Carnival Liberty in 2017, Carnival Freedom in April-May 2018 in the Caribbean, Holland America Amsterdam in October 2018 and Princess Emerald in November 2018.

Holland America and Princess Cruises are both under the ownership of Carnival Corporation.

Carnival Corporation has rebuffed the tests saying they were “completely ridiculous, inaccurate and in no way represent reality”.

“We test the air quality of our ships and they meet or exceed every requirement.”

This is not the first time that cruise lines have been subject to criticism for their contribution to pollution. 

In 2018 the Cruise Lines International Association (CLIA) committed to reduce the rate of carbon emissions across the industry fleet by 40 per cent by 2030 globally.