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Drugs & Health Blog

What the Heck is Third Hand Smoke?

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Winners Jada Nicole Dalley and Sehar Anjum Salman with their poster and NIDA science fair judges.

Sara Bellum

That's what a lot of people were asking at the 2009 Intel International Science and Engineering Fair in Reno a few months ago. Two 16 year olds in San Antonio, Texas, worked together to try and find out.

Keystone High's Sehar Anjum Salman and Jada Nicole Dalley showed that third hand smoke—all the toxic chemicals left behind on furniture, car upholstery or clothing after the cigarette smoke floats away—produces as many mutations in newborn fruit flies as second hand smoke—when someone blows their cigarette smoke near you and you breathe it in.

These photos taken by Jada and Sehar show some of the fruit flies they used for their study. Different genetic mutations can affect the color and shape of the flies' eyes, the color of their bodies, the shape of their wings, the number of bristles they have, and many other features.

Compare the normal fruit fly (left) with the mutant fruit fly (right). Do you see a difference? (Hint: the mutant fruit fly is probably going to have some trouble flying.)

Photo of a fruit fly.       Photo of a fruit fly.

Sehar and Jada won a First Place NIDA Addiction Science Award at the Super Bowl of science fairs for cleverly showing the dangers of third-hand smoke—something scientists don't know a lot about. It makes you think twice about hanging out with smokers, even if they're not lighting up! 

Read more about Sehar and Jada's project.

Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.


The research project conducted by Jada and Sehar was fascinating. These young students are proof that America's youth are capable of making key contributions to our country now and in the future.

This site rocks!

hey this about my sister!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

i went to nida with her and my dad!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hey, this is about my sister!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I went to NIDA with her and my dad!!!!!!!!!!!!!!!!!!

i like the question and this is really helpful for my health project in school!

How do I stop my family from smoking and dieing??????????????????????????????? How do I stay away????????????????????? How do I not smoke????????????????????????? How do I save my family?????????????????????????How do I save me???????????????????????????? HELP ME PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Plaese send me a answer plaese!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

@sonia#1--try going here. You could find some useful info. Best way to not smoke is not to start--and you sound like you're committed to being healthy.

i like when people talk it out or tell what could happen

We had the same studies. We made cigarette smoke as a mutagen to our fruit flies..and the result was that our fruit flies developed vestigial wings a lot shorter and crippled than the picture above..and yes, the fruit has trouble with flying..

My grandmother died from lung cancer. i tell everyone not to smoke and I always feel bad for young children whose parents smoke around them. When I started my business I pledged to donate 2% of all profits to lung cancer and other cancer charities. In my industry many people smoke, and I am trying to change that. Seeing kids do amazing science work like this is inspiring! Keep it up. [commercial link removed, per guidelines]

I work with pregnant women who smoke or are exposed to secondhand smoke. There aren't many materials to educate on thirdhand smoke since its a rather new discovery. I am adding this to my web site 'Favorites' as it will give me a good visual aid to use! Congrats to these young women, keep up your work! You are making an impact on the future!

While I have no doubt smoke and secondhand smoke are bad, I would need to see this study done on animals to even start to be convinced of this happening in humans. The concentrations of the chemicals would be much higher in the flies than they ever would be to a human or large animal. This is true with all toxins and many are deadly to animals and Insects at levels that would not acutely harm a human.
this definitely presents an interesting idea, but how much will it affect humans thousands of times bigger than fruit flies?

It doesn’t look like any significant research has been done in humans, though there has been more research related to the actual chemicals that deposit on surfaces:

what ifa 1 year old visits a home whom they used to smoke in for a week once a year. but after they quit smoke in the home they have repainted got new furniture and have wood floors. Is that child still at risk or is it safe

If you have questions about a child’s safety in a home where drugs were used or are still being used, you should talk to the child’s doctor as soon as possible.