Does the Smoke Ever Really Clear? Thirdhand Smoke Exposure Raises New Concerns

You may never have heard of thirdhand smoke, or THS, but chances are you’ve smelled it. THS is, in the words of The New York Times, “the invisible yet toxic brew of gases and particles clinging to smokers’ hair and clothing, not to mention cushions and carpeting, that lingers long after secondhand smoke [SHS] has cleared from a room.”1 Recent research exploring potential dangers of THS has received a flurry of coverage in the international media2,3,4 and the scientific press.5,6,7 And in the United States, court cases are beginning to appear in which plaintiffs are citing these alleged dangers,8,9 despite a lack of human health studies on the long-term health effects of THS exposure. So how dangerous might THS really be? The answer, still to be pronounced, will depend on many factors.