'Third-Hand' Smoke -- the Dust Finally Settles

Jan. 6, 2009— -- I wish I had a dollar for every time I have heard a parent who smokes tell me, "But Dr. Spangler, I always smoke in the other room away from my children. Or I go outside."

Safe? Safe enough?

Most of us are aware that exposure to secondhand smoke is bad for you, which is why these parents avoid smoking around their children.

But a study published this week in the medical journal Pediatrics by Dr. Jonathan Winickoff and his colleagues from the Massachusetts General Hospital in Boston underscores the adverse health impact on children of what they call "third-hand smoke."

You can look at cigarette smoke in three ways. Mainstream (firsthand) smoke is the smoke that a smoker inhales. Obviously, it is harmful to the smoker, although the cigarette filter sifts some of the toxins (tar) out.

Secondhand smoke is the combination of the mainstream smoke that a smoker exhales plus the side-stream smoke that comes off the burning end of the cigarette into the environment. Volume for volume, side-stream smoke is more hazardous than mainstream smoke because it is unfiltered.

Winickoff and colleagues have now given us a new name for the toxic particles that settle as dust in rooms and on clothing that have been exposed to cigarette smoke.

They call this third-hand smoke, or "residual tobacco smoke contamination that remains after the cigarette is extinguished."

Studies have shown that these contaminating particles are measurable in rooms, on clothing and on toys long after a person has finished smoking.

These researchers were interested in knowing the characteristics of homes and individuals who believe in third-hand smoke and thus have strict smoking bans within their homes.

They analyzed data from a national random-digit-dial telephone survey from September to November 2005 that asked about attitudes toward smoking in the home and beliefs about secondhand and third-hand smoke.

They found that individuals who believed in the concept of third-hand smoke were two times more likely to have strict no-smoking policies at home than those who did not believe in this notion.