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The dangers of

While we inhale less secondhand smoke these days (because fewer people smoke in public), research has revealed a more insidious danger - thirdhand smoke.

So what exactly is thirdhand smoke?


Thirdhand smoke penetrates and clings to surfaces, leaving a nasty residue on furniture, carpets, walls, clothing; even in dust!  It's that lingering unpleasant odour you notice in the homes of smokers or in hotel rooms where people have smoked hours or even days earlier. It is hard to get rid of, and it's more than just an unpleasant smell; contained within this odour are tobacco-related compounds that are dangerous to our health.  


Scientists first coined the term "thirdhand smoke" almost a decade ago when initial research showed that tobacco substances (carcinogens and other toxic chemicals) absorbed by surfaces can react with ozone and other household air pollutants to form additional dangerous compounds (such as nitrosamines) and be discharged into the air as vapor or ultrafine particles or else "hitch a ride" on dust particles.

Additional research has only further confirmed the idea that thirdhand smoke exists and is dangerous to our health. The latest research, which was conducted in a room-sized chamber (by a machine) and in a smoker's home, released estimates that health harms would be greatest during the first 10 hours after the last cigarette was smoked and then would start to level off (though not disappear even after 18 hours). The most significant damage would come from ultrafine particles, which - like vapor - can be inhaled deep into the lungs.


It can be difficult to determine when exactly secondhand smoke becomes thirdhand smoke - there is a gradual transition as the smoke dissipates. Researchers have found that much of the harm attributed to secondhand smoke is actually caused by thirdhand smoke. As growing public knowledge of the dangers of thirdhand smoke grows, it should certainly encourage even more places to go smoke-free and more smokers to quit.




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