Thirdhand smoke lingers in casinos months after smoking ban

Thirdhand smoke, the poisonous residue from smoking, can linger in casinos on walls, furniture, and in carpets months after smoking is eliminated, say scientists at San Diego State University.

Researchers studied the results of a smoking ban in a Northern California casino. They found that even though thirdhand smoke declined significantly after the ban, toxic tobacco smoke residue remained at levels higher than found in hotels or private homes with smoking bans.

"Casinos are unusual environments because of the amount of smoking that takes place 24/7 over long periods of time," said lead author Georg Matt. "Over years of smoking, layers of smoke residue stick to surfaces and penetrate deep into materials.

These chemical residues, such as nicotine, cotinine and the potent lung carcinogen known as NNK, can harm people's health when they're exposed to them, even if they aren't smokers themselves.

"If you work at a casino that allows smoking or are a guest, you already know you inhale secondhand smoke every time you breathe," he continued. "Because the tobacco smoke residue remains long after a smoking ban, you will continue to get exposed even after the secondhand smoke has disappeared."

Only by intensive surface cleaning — and in some cases replacing surfaces entirely — can casinos hope to make their environment significantly safer for its guests after imposing a smoking ban, Matt said.

Replacing carpets, furniture, equipment, wallpaper and drywall, and drapery and curtains, and washing/vacuuming the walls, floors and ceilings are necessary to reduce health risks associated with thirdhand smoke, Matt said, and the longer tobacco is smoked indoors, the more difficult and costly it will become to clean up that indoor environment.

"Tobacco should never be smoked indoors unless you are prepared to pay the price for extensive clean up," he said. "The sooner you stop smoking indoors, the sooner you will benefit from clean air and the less it will cost to clean up the toxic legacy."

According to Mayo Clinic, children and adults could be at risk of tobacco-related health problems when they touch, inhale, or swallow substances containing thirdhand smoke.

A study published in Mutagenesis found that thirdhand smoke might cause damage to human DNA, which increases the risk of disease. Another study, which was published in the journal Proceedings of the National Academy of Sciences, found that the toxic chemicals from smoke react with nitrous acid in the air to form carcinogens.

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