According to the undercover report, cruise ships generate high levels of air pollution that could be damaging to your health.

By Marisa Spyker
Michael H/Getty Images

If you’ve ever blissed out on a cruise ship deck with views for days and a margarita in hand, you might liken the feeling to a big breath of fresh air.

But—bad news for cruise fans—a new study is calling the actual freshness of that on-deck air into question.

A published by environmental organization Stand.earth is claiming that air samples taken on four separate cruises in the Caribbean and on the West coast reveal startlingly high levels of pollution. The samples, taken over a two-year period, contained concentrations of particulate matter that are “comparable to concentrations measured in polluted cities, including Beijing and Santiago,” said Ryan Kennedy, author of the study and an assistant professor at Johns Hopkins University.

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According to the report, particulate matter refers to tiny droplets suspended in the air that are susceptible to being inhaled into the lungs and absorbed into the bloodstream. Cruise ship exhaust is known to contain harmful particles, including metal and polycyclic aromatic hydrocarbons that, when absorbed by the body, can have toxic, mutagenic or carcinogenic properties. But the exact concentration of those particles out in the open ocean, where air should be the freshest, was previously unknown.

To determine pollution levels, researchers took measurements from both the bow and stern of cruise ships while at sea. Unsurprisingly, pollution levels were found to be up to eight times greater behind the smoke stacks, which the study notes is often where designated lounge and exercise areas—including running tracks—are located.

Carnival, which operated two of the four cruises tested in the study, said in a statement that it regularly coordinates with national and international regulatory bodies like the Environmental Protection Agency to ensure A Carnival spokesperson also told the Miami Herald that smoke stacks are purposefully tall so exhaust is diverted away from passengers and crew.

“It really hasn’t been an issue since the ship is moving, the air is flowing,”

Take that reassurance and breathe a little easier, cruise devotees—and maybe, just in case, spend a tad more time on your next getaway at sea under cover. (Your skin will thank you, too.)