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.
Households with children in the home, and households without smokers in the home, were each three times more likely to enforce a strict no-smoking ban.
As might be expected, nonsmokers who responded to the survey strongly supported such proscription -- these individuals were 13 times more likely to fight for a tobacco-free household.
White individuals and college-educated individuals were two times and four times more likely to favor such bans, respectively.
The researchers were surprised, however, that individuals who believed in the harm of secondhand smoke were not necessarily behind banning smoking from their households.
In addition, having community policies prohibiting smoking in bars and restaurants had no impact on household bans among individuals in those communities.
The authors point out that exposure to low levels of tobacco smoke affects the neurological development of children, leading in some cases to reduced reading and thinking skills.
Additionally, children are the most vulnerable to ingesting poisonous tobacco dust, taking in two times the amount of this dust compared with adults. Think about what children do -- they crawl on the floor, suck their fingers, mouth toys.
And they breathe in the particles that have settled on their parents' clothes. This certainly puts snuggling up close to your children in a new light.
So what can be done?
Intrusive as it might sound, many experts are arguing for laws that would ban smoking in homes, just as laws have banned the use of lead paint indoors. Such laws can have an effect in protecting children.
But the effect is going to be largest when more and more people become aware of the hidden danger of third-hand smoke.
I have always told parents who smoke that tobacco smoke clings to their clothing and home furnishings -- and have usually received a blank stare back, like, "Are you from Mars, Dr. Spangler?"
Maybe now the stare will be one of recognition of the harm to which they are exposing their children.
At least, that's my hope.
We can thank these researchers for introducing this topic into the public discourse and for giving us a new name to think about -- third-hand smoke dust that is smokeless but not harmless.
Dr. John Spangler is director of tobacco intervention programs and a professor of family medicine at Wake Forest University School of Medicine in North Carolina.