California Thirdhand Smoke Research Consortium



What is thirdhand smoke?

Thirdhand smoke (THS) refers to tobacco smoke residues that remain in indoor environments, react to make additional pollutants, and/or re-emit back into the air. THS includes settled dust and particles containing tobacco residues that can re-suspend into the surrounding air.

Over the last decade the concept of thirdhand smoke has emerged as a distinct entity that poses health risks because hazardous compounds in THS include many that are toxic or cancer-causing agents. While the public health impacts of smoking and secondhand smoke exposure are well documented, recent recognition of the potential hazards of THS has spurred fundamental research into its mechanisms of harm to vulnerable groups and development of policy to reduce exposure, as well as evaluation of ways to remove THS from buildings and materials.

Early laboratory and field studies funded by the Tobacco-Related Disease Research Program (TRDRP) showed that nicotine from secondhand cigarette smoke (SHS) adsorbs rapidly onto furniture, walls, textiles, dust and other surfaces in buildings and vehicles. Other compounds with low volatility in THS also remain on indoor surfaces long after smoking has stopped and secondhand smoke levels have dropped through ventilation. Later research showed that THS also adsorbs onto skin and clothes, as indicated by finding that homes of parents who only smoked outdoors still had higher levels of nicotine in the dust and on surfaces than homes of non-smokers. Even more importantly, children of parents who never smoked in the home had higher levels of the main biomarker of exposure to nicotine, urinary cotinine, than children of non-smokers.

For more information, visit the Thirdhand Smoke Resource Center at


Who can be exposed to thirdhand smoke?

The findings described above and other studies suggest that THS can create long-term, low-level exposure to smoke chemicals that may constitute significant risks to human health, especially to children and other vulnerable people. Adults are primarily exposed to THS by inhaling air in tobacco-contaminated spaces. For young children, a very significant route of exposure to THS constituents is transfer of contaminants through skin contact with contaminated material like carpet and also from contact with their parents if they have been smoking. THS exposure can also occur by ingestion when young children mouth toys and other objects.


The Thirdhand Smoke Research Consortium

In response to the mounting evidence, TRDRP formed and funded the California Consortium on Thirdhand Smoke and Human Health Effects in 2011. The consortium is a multi-institutional and interdisciplinary effort, involving research groups from Lawrence Berkeley National Laboratory, San Diego State University, University of California Riverside, University of California San Francisco, and University of Southern California. Their main goal is to determine how much harm THS causes to human health and carry out robust risk assessments so the policy implications of THS become clear and compelling.

In the Thirdhand Smoke Research Consortium, innovative chemistry complements incisive state-of-the-art biological research and field work. This multi-disciplinary collaborative approach ensures that the specific aims of every sub-project are coordinated and integrated with those of all the others. Resources such as samples from lab and field work are shared, as well as methods and analytical services.



Printed with permission from "Thirdhand Smoke: New Evidence, Challenges, and Future Directions. Jacob III P, Benowitz NL, Destaillats H, Gundel L, Hang B, Martins-Green M, Matt GE, Quintana PJ, Samet JM, Schick SF, Talbot P, Aquilina NJ, Hovell MF, Mao JH, Whitehead TP. Chem Res Toxicol. 2017. Jan 17; 30(1): 270-294." Copyright 2016 American Chemical Society