Ever walked into a hotel room and smelled old cigarette smoke? While the last smoker may have left the room hours or even days ago, the lingering odors -- resulting from noxious residue that clings to walls, carpets, furniture, or dust particles -- are thanks to thirdhand smoke. Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), who have made important findings on the dangers of thirdhand smoke and how it adsorbs strongly onto indoor surfaces, have published a new study assessing the health effects of thirdhand smoke constituents present in indoor air. Looking at levels of more than 50 volatile organic compounds (VOCs) and airborne particles for 18 hours after smoking had taken place, they found that thirdhand smoke continues to have harmful health impacts for many hours after a cigarette has been extinguished.

"In the U.S., the home is now where nonsmokers are most exposed to second- and thirdhand smoke. The goal of our study is to provide information supporting effective protective measures in the home. The amount of harm is measurable even several hours after smoking ends," said chemist Hugo Destaillats, lead author of the study. "Many smokers know secondhand smoke is harmful, so they don't smoke when their kids are present. But if, for example, they stop smoking at 2 p.m. and the kids come home at 4 p.m., our work shows that up to 60 percent of the harm from inhaling thirdhand smoke remains."

Their study, "Inhalable Constituents of Thirdhand Tobacco Smoke: Chemical Characterization and Health Impact Considerations," has been published online in the journal Environmental Science & Technology. Other co-authors were Berkeley Lab scientists Mohamad Sleiman, Jennifer Logue, and Lara Gundel, and Portland State University professor James F. Pankow and researcher Wentai Luo.