Thirdhand smoke is real and insignificant

This blog has previously chronicled attempts to scare people into persecuting smokers based on trumped up fears of “thirdhand smoke,” residue left on clothes and furniture after a smoker lights up. New research attempts to measure levels of this residue directly by artificially re-suspending particles left behind by a smoking device:

These quantitative data support the hypothesis of a resuspension from the cigarette smoke surface contamination. However, this airborne contamination through resuspension remains much lower (100 times) than that of secondhand smoke.

In other words, there’s nothing to worry about.


Why debunking junk tobacco science matters

In the past year alarmist studies about “thirdhand smoke,” the particles left behind from tobacco combustion, have proliferated. There’s no evidence such residuals are actually causing cancer but that hasn’t stopped anti-smoking activists and journalists from running with the story. Michael Siegel has recently spotted a couple ways this research has been abused to discriminate against smokers. First there’s the “sniff test” policy now in place at Kimball Physics, a technology company in New Hampshire:

No tobacco-residuals emitting person, article of clothing, or other object is allowed inside any Kimball Physics building. This restriction also applies to anyone or anything emitting characteristic tobacco odors. Anyone who has used a tobacco product within the previous two hours is automatically to be turned away, unless measures have been taken such that residuals-sensitive persons are not exposed. The determining factor, regarding allowable residuals levels and/or exposure durations, is whether anyone is either significantly bothered, or even worse, made ill.

This is an absurd policy and it should come as no surprise that the person who created it is a board member of the extremist anti-tobacco group Action on Smoking and Health. Nonetheless it creates a precedent that less fanatical employers might decide to follow.

Speaking of ASH, Siegel also catches them advocating bans on smokers adopting or fostering children. From ASH’s press release:

Midlothian Council in the U.K. is just the latest entity to prohibit smokers from adopting or providing foster care for children, a step Portsmouth, Hants, in England and other jurisdictions took several years ago, says public interest law professor John Banzhaf, Executive Director of Action on Smoking and Health (ASH). Anyone wanting to care for a child under the age of five will be required not to have smoked for at least six months, even if they only smoke outdoors. […]

… thirdhand tobacco smoke, what the New York Times called “the invisible yet toxic brew of gases and particles clinging to smokers’ hair and clothing,” has just been reported by researchers at Lawrence Berkeley Laboratory to combine with a common indoor air pollutant to form very potent cancer causing substances. This, the researchers say, places children at serious risk, even if parents smoke only outside the home, because they carry the residues inside with them.

I criticized that Times article when it came out last year for taking such a credulous approach to the “thirdhand smoke” study it covered, buying into the researchers’ hype despite the fact that the study consisted of nothing but a phone survey. At the time the author couldn’t have known that her words and the reputation of the paper would be used to deny children foster care, but that’s how low the anti-smoking movement has sunk. Reporters need to realize that today’s anti-tobacco researchers should be treated with just as much skepticism as the Big Tobacco-funded scientists of the pre-Master Settlement days.


Reuters hypes thirdhand smoke fears

Reuters reporter Maggie Fox buys into the thirdhand smoke scare:

Old tobacco smoke does more than simply make a room smell stale — it can leave cancer-causing toxins behind, U.S. researchers reported on Monday.

They found cancer-causing agents called tobacco-specific nitrosamines stick to a variety of surfaces, where they can get into dust or be picked up on the fingers. Children and infants are the most likely to pick them up, the team at Lawrence Berkeley National Laboratory in California reported.

“These findings raise concerns about exposures to the tobacco smoke residue that has been recently dubbed ‘third-hand smoke’,” the researchers wrote in the Proceedings of the National Academy of Sciences, available here.

Of course there are policy implications:

James Pankow, who also worked on the study, said it may raise questions about the safety of electronic cigarettes, or “e-cigarettes.” which produce a nicotine vapor but not smoke.

The researchers said regulators who have cracked down on second-hand smoke with smoking bans may decide to consider policies on third-hand smoke.

That nicotine works on surfaces in this way is interesting from an abstract, scientific point of view. What the article fails to mention is that there is essentially no evidence that anyone, anywhere, has ever suffered from exposure to so-called “thirdhand smoke.” The reason these carcinogens are so deadly to cigarette smokers is that smokers inhale them deeply through their mouths directly into sensitive lung tissues dozens of times per day. Exposure from surfaces or from dust inhalation through the nose is going to be far less substantial.

Nonetheless, you probably shouldn’t wrap your infant in smoky blankets. Fair enough. But spreading paranoia about thirdhand smoke has significant negative consequences. We’ve already seen employers discriminate against smokers using these fears as justification. And if this research is used to back legislation against e-cigarettes — devices that are unequivocally safer to smoke than actual tobacco — that will be a blow to public health.

Unfortunately journalists tend to be extremely credulous of any research that condemns tobacco and its related products. Last year The New York Times gave significant coverage to a thirdhand smoke study that consisted entirely of conducting a telephone poll of random people. Soon after Scientific American published an uncritical interview with the study’s author, Jonathan Winickoff, who said in an unmeasured words, “Smokers themselves are also contaminated…smokers actually emit toxins.”

If reporters are going to cover these sorts of stories, they owe it to readers to put the actual risks in proper perspective.

[Via Lene Johansen’s Twitter feed.]

Update: Since writing this some debate has gone back and forth on Twitter among science writer Lene Johansen, Jeff Stier at the American Counsel on Science and Health, and Reuters health editor Ivan Oransky. Since Twitter isn’t the most conducive format for extended comments I thought I’d clarify here why I object to the article.

The problem is not that this is junk science or that it shouldn’t be covered. The problem is that people reading the article aren’t interested in the abstract question of how nicotine reacts with other chemicals on a household surface. What they want to know is whether tobacco residue presents a real health hazard to them and whether there are policy implications stemming from the research.

A layman reading about all the carcinogens mentioned in the article would conclude that the health hazard is real. Given the dosages involved this belief is likely false and is certainly unproven. As science journalism, the article fails to give readers the context they need to make sense of the research.

As for policy, the article itself notes that the research is bound up with political goals. The findings may be used to justify such measures as employment discrimination, bans on e-cigarettes, and further restrictions on smokers. This makes providing the proper context doubly important. There are plenty of reputable skeptics of these measures and at the very least the article could have quoted one.

Update 2/9/10: Chris Snowdon’s lengthy debunking of thirdhand smoke fears from last year is worth rereading.