The best way to explain it when you get into someone's car or go to their house, and you know immediately they're a smoker.
You can smell it.
That smell, that residue is third hand smoke, and it's thought to be dangerous, especially for children.
We know smoking can harm us. And if we live with a smoker, that second hand smoke we inhale can affect us as well.
"That causes all kinds of problems such as lung cancer, such as c-o-p-d, such as asthma and respiratory infections in children," said Dr. Normal Edelman, Director of the American Lung Association.
Now scientists are finding that third hand smoke may be just as harmful. Third hand smoke is the residue that's created by the cigarette smoke. It's thought to contain cancer-causing substances and it clings to bedding, curtains, furniture, and carpet.
It may put children and adults at risk when they inhale it or touch it and ingest it.
"There's evidence now that third-hand smoke is a risk factor in children like chronic ear infections and chronic respiratory infections. And if your clothes reek of smoke, your hair reeks of smoke...your little child is going to get an asthma attack, more than likely," adds Dr. Edelman.
How to avoid passing on your smoke to others? Try to quit. If that's not possible take the smoking outside, where the air is less concentrated and the smoke fumes are not as heavy and won't be left on clothing.
"Smokers should know that they're not only doing damage to their own hearts and lungs and other organs but they're doing damage to the people around them," Dr. Edleman adds.
If you do smoke inside your home and have small kids, it's worth it to pay for a professional cleaning if you can.
Have your carpets, drapes and furniture professionally cleaned. Especially if they kids are crawling on the carpet.
Third hand smoke is a relatively new concept.
But there have been several studies looking at what chemicals are in it, and showing that the residue can become airborne again.
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