In this book excerpt, the author of "An Empowering Guide to Lung Cancer: Six Steps to Taking Charge of Your Care and Your Life" explains a little-known health risk of tobacco.

Eric Presser, MD
November 28, 2017

It took decades for the public to wake up to the dangers associated with secondhand smoke. Now, another cigarette-related phenomenon is raising concern: third-hand smoke. Before you start laughing, know this: It's real, and it's ubiquitous.

Have you ever taken a whiff of a smoker’s hair? Did you ever enter a room and wonder why it smelled like a dirty ashtray when there wasn't a cigarette in sight? This is third-hand smoke.

Third-hand smoke is the fallout from smoking. Toxic airborne elements build up over time. It's the stuff that lingers long after secondhand smoke has disappeared to the eye. It’s in the smell, grunge, and yellowing on the environment where a smoker spends time. It’s more noticeable in smaller spaces, such as a car. But third-hand smoke settles on and seeps into carpet and porous surfaces such as paneling or drywall, in addition to lingering on hair, skin, clothes, and fingernails. Even going outside to smoke and then entering the home can expose a person's surroundings to third-hand smoke.

RELATED: 7 Causes of Lung Cancer in Non-Smokers

Research has not been done to determine just how long toxins from third-hand smoke stay in the home, automobile, and other environments. However, we do know that the compounds in third-hand smoke are dangerous to human health. Lead, for example, can damage the frontal lobes of children's brains, and cyanide can interfere with the release of oxygen to tissues.

Of greatest concern is the effect of third-hand smoke on the most vulnerable, including babies, toddlers, children, the sick, and the elderly. Babies crawl on carpets, sleep on couches, and teethe on household and other porous objects, all of which may be invisibly dirtied with third-hand smoke toxins. The sick and elderly, both with compromised immune systems, spend a lot of time indoors and are especially at risk in places exposed to third-hand smoke.

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Although any number of environmental toxins can contribute to lung cancer, cigarette smoke is far more lethal than toxins found in automobile exhaust and asbestos. The bottom line is that there’s no such thing as a risk-free level of tobacco exposure.

Excerpted from An Empowering Guide to Lung Cancer: Six Steps to Taking Charge of Your Care and Your Life by Eric Presser, MD. Reprinted by permission of the publisher, Praeger.

Eric Presser, MD, is a thoracic surgeon, a member of First California Physician Partners (FCPP), and an associate professor with University of California, Riverside School of Medicine.