Current Research Projects

Learn about the Thirdhand Smoke Research Consortium’s current projects in Phase 4.

Thirdhand Smoke Chemistry: Exposure Assessment, Quantification Metrics, and Remediation

Hugo Destaillats, Ph.D.
Lawrence Berkley National Laboratory

Chemical processes determine the persistence, partitioning and transformations of tobacco-related contaminants in the indoor environment. Policy and technical decisions are informed by our understanding of how non-smokers are exposed to those toxic compounds. In previous funding cycles, our group has contributed to the Thirdhand Smoke (THS) Consortium by describing the chemical composition and transformations of THS, describing exposure routes, quantifying intake, assessing the efficacy of remediation approaches, and developing sampling and analytical methods. In this new phase of the Consortium, we propose to:
• Characterize emissions, indoor fate and chemical transformations of carcinogens from cannabis and cannabis/tobacco co-use, assessing exposure via inhalation, dermal uptake and ingestion. A bench-scale chamber will be built to smoke cannabis and tobacco cigarettes, sampling and analyzing compounds in air and adsorbed onto model indoor materials. Non-additive interactions between tobacco and cannabis emissions will be investigated.
• This information will enable estimating exposure doses, their contribution to health effects, and evaluating their possible uses as THS environmental tracers.
• Develop, validate and promote the adoption and implementation of a methodology to quantify THS contamination using a scale of reference levels, to better inform prevention, treatment and policy. These metrics will serve as a tool to design middlegame/endgame strategies, e.g., by supporting smoke-free and tobacco-free policies.
• Identify effective remediation strategies targeting deep THS reservoirs in porous indoor materials. We will assess their efficiency in reducing pollutant emissions from THS-contaminated materials. We will also investigate the efficiency of ozonation in the abatement of THS contamination from indoor materials. In addition to quantifying the elimination of THS, we will also follow the formation of oxidized byproducts of potential concern, to fully capture the benefits and limitations of ozonation.

Genetic Susceptibility to Thirdhand Smoke Effects in Collaborative Cross Mice

Antoine Snijders, Ph.D.
Lawrence Berkeley National Laboratory

Thirdhand smoke (THS) refers to tobacco smoke residues in indoor environments that remain, react and/or re-emit form materials and/or re-suspend from surfaces (dust), which clings to hair, skin, clothes, furniture, drapes, walls, carpets, dust, and other surfaces, even long after smoking has stopped. These residues are thought to react with common indoor pollutants to create a toxic mix. Studies have shown that this toxic mix of THS contains cancer-causing substances, posing a potential health hazard to nonsmokers who are exposed to it. Therefore, an emerging human health issue has been raised for exposure to THS. However, there are many unanswered questions in the field of THS as it is still early in the process of characterizing the exposure scenarios as well as potential biological and health effects of THS. Our previous studies have shown that that (1) exposure to THS causes significant DNA damage in human cells and enhances tumorigenic traits; (2) early-life exposure to THS caused persistent immunological alterations in mice; (3) early-life exposure to THS resulted in a mouse strain-dependent increase in cancer incidence, suggesting that genetic backgrounds significantly influence THS-induced cancer development. This proposal aims to address that individual susceptibility across life span impacts cancer risk from THS exposure using a population-based animal model system. It furthermore aims to investigate the toxic and inflammatory effects of exposure to mixed tobacco and cannabis thirdhand smoke. At the completion of this 3-year project, we will identify biomarkers and mechanisms associated with THS health effects and develop a THS risk prediction model based on an individual’s risk profile to THS-induced cancer development and provide guidance to protect the most vulnerable subpopulations. Our research may shed light on whether THS exposures can contribute to cancer development and will delineate molecular mechanisms underlying THS-induced cancer. This understanding is critical to formulate novel cancer preventive strategies including educating health practitioners, families, and public health providers and organizations regarding the potential risks of THS exposures, and to help framing and enforcing new policies against THS in the U.S. and the world.

Melanin and Dermal Uptake of Thirdhand Smoke in Human Exposures

Suzaynn Schick, Ph.D.
University of California San Francisco

This study will explore the role of dermal melanin in the uptake of tobacco smoke chemicals from clothing, in human subjects.  Melanin is the pigment that gives color to our skin, hair and eyes.  Many different drugs, including nicotine, bind to melanin. Although African-Americans start smoking later than whites and smoke fewer cigarettes per day, they are more likely to die of smoking-related disease than whites.  More African-American smokers want to quit, more attempt to quit and fewer succeed in quitting smoking, compared to whites and Hispanics.  National surveys also consistently show that African-American children have higher urinary cotinine levels than non-Hispanic white or Mexican-American children.  Understanding whether these disparities are due strictly to racism and lack of access to healthcare or whether there are biological factors that also contribute is essential to reducing and eliminating the disparities. 

60 people will participate in this study: 30 with low-melanin, light colored skin and 30 with high-melanin, dark colored skin.  Everyone will wear clothing that has been exposed to cigarette smoke (pants and long-sleeved shirt) for three hours.  We will collect blood samples for 6 hours to track how fast nicotine moves through their skin and we will collect urine samples for 10 days to measure how much nicotine they take in and how long it stays in their skin.  We will test the samples for nicotine, NNK (a tobacco carcinogen) and their metabolites and compare them to skin color and melanin content.  This is the first study to test both skin color and skin uptake of smoke chemicals. 

If people with more melanin in their skin absorb less nicotine uptake and we see the metabolites in the urine for a shorter period of time, then melanin is probably protective and the health disparities are caused by other factors.  If people with more melanin absorb less nicotine, and we see the metabolites for a longer time or they absorb more nicotine and we see the metabolites or longer, then melanin may be part of the cause of the health disparities.  No matter what we find, this study will improve our understanding of the health effects of tobacco in people with darker skin.  

Thirdhand Smoke in Homes: Fate, Characterization, and Remediation

Nathan Dodder, Ph.D.
San Diego State University

There is growing evidence that toxic thirdhand smoke (THS) persists in indoor environments long after smoking ends. THS is expensive to remediate, lowers the value of real estate and used cars, and contains numerous chemicals known to cause cancer and harm reproductive health. Research from laboratory and field studies has demonstrated that chemicals in THS sorb (reversibly bind) to surfaces during smoking and become embedded in materials. THS can then desorb (emit) from the materials after smoking has stopped. To develop effective remediation approaches, the role of various household materials in the storage and release of THS must be understood. Prior research investigated the short-term sorption (e.g., hours) and desorption of THS using different materials in test chambers or model rooms. Although an important first step, these studies did not test realistically long exposure periods, patterns, or amounts (e.g., months) that may lead to different outcomes under real-world conditions. This proposal aims to quantify the sorption capacities of common household materials that are suspected major reservoirs of THS (carpet, drywall, cushioned furniture) the effectiveness of common remediation methods, and the long-term persistence of THS in remediated materials. 

In this proposal, samples of THS-contaminated household materials of carpet, drywall, and cushioned furniture (e.g., couches) will be collected from participants’ homes. First THS in these household materials will be characterized in detail, in particular the depth to which THS penetrates the different items. Remediation experiments will then determine the effectiveness of commonly used clean methods that attempt to remove THS: painting drywall, shampooing carpet, and shampooing cushioned furniture. THS measurements over time after remediation will determine the effectiveness of each method. Results will guide advice on how to best remediate THS by cleaning or replacing items in contaminated homes and will also help inform occupants what they can expect in terms of the longevity of the existing contamination. Knowledge of how much THS accumulates in these materials and which materials release the most THS will be crucial for THS remediation, prevention, and education about THS risks. This proposal collaborates with three THS Consortium Cores and three subsidiary projects.

Thirdhand Smoke Disparities, Harm, and Risk in Children

Penelope JE (Jenny) Quintana, Ph.D., MPH
San Diego State University

In this Subsidiary Award in the Thirdhand Smoke Consortium, we study whether smoking in indoor environments results in house dust contaminated with toxic metals such as lead, cadmium, and arsenic. The toxic residue of smoking indoors, called thirdhand smoke (THS), has been shown to contain numerous toxic compounds, but toxic metals have not been studied hardly at all. We will also examine markers of exposure and harm in urine from children living in the homes. Our study will use samples already collected as part of clinical study directed by Dr. Mahabee-Gittens, a pediatrician at Cincinnati Children’s Medical Center (NIH R01ES030743). Because clinical studies in children are very expensive, using already collected samples is a very cost-effective way to investigate our question about harms from metals in house dust. We have previously found that lead and cadmium in dust samples from low-income homes were related to nicotine in the same sample, which suggests that tobacco smoking can be a source of these toxic metals. We are also investigating disparities in exposures to and risks of thirdhand smoke related to income, housing type and race/ethnicity.  We will bring together data on house dust from our previous funded projects and obtain new data on these archived samples to get data on the same set of toxic chemicals. We will measure novel toxic compounds we have previously identified in house dust contaminated with THS through non-targeted chemical analysis, which is a method of finding unknown chemicals in environmental samples. We want to find out if a disproportionate burden of involuntary THS exposure and risk is borne by low-income and minority communities. This may help to leverage resources for prevention. We will also continue to develop direct-reading and simple tests for finding out thirdhand smoke contamination of homes. Our proposal will also collaborate with the Lead Award of the Thirdhand Smoke Consortium to come up with suggested Voluntary Reference Levels, (meaning the amount of nicotine or other chemicals inside your homes would be expected when no-one has smoked inside). This could help renters and homebuyers decide if the home is contaminated or not with THS. Our THS research will inform and contribute to the California Tobacco Endgame Initiative which seeks to end the sale and use of all tobacco products in the state by the year 2035.

Thirdhand Smoke Messaging Among Priority Populations

Rachael Record, Ph.D.
San Diego State University

Thirdhand smoke (THS) is the toxic residue left behind in spaces where tobacco products were previously used. While people can recognize the unpleasant odor and unsightly stains from THS, few are aware that THS exposure is bad for human health and can be an expensive problem. Understanding how people experience and perceive the risks of THS is central to the Tobacco Endgame, which seeks to ensure that everyone is protected from tobacco-related health risks. This is particularly true for minority, low-income, and underserved communities who are the most likely to be exposed to THS. To effectively counter tobacco industry efforts in communities that have received the most tobacco marketing, the purpose of this project is to develop and test messages to educate priority populations about THS and build support for THS prevention and Tobacco Endgame policies. This goal will be accomplished in three steps and will focus on the priority populations of low-income adults from Hispanic/Latino, Black/African, Asian/Pacific Islander, and LGBTQ+ communities. First, the identified priority populations will be asked to share their experiences with, and perceptions of, THS. This will be done through focus groups with California members of the priority populations and through a national survey of members of the priority populations. Second, the findings from the first step will be used to develop messages. Following the guidance of a theoretical framework that emphasizes cultural aspects of populations, messages will be designed to leverage unique THS experiences within each priority population. The developed messages will be pre-tested in a national online survey with members of the priority populations. Finally, in step three, messages that were found to be persuasive in phase two will be used in a social media-based campaign targeting California priority populations. User engagement data will be collected and analyzed to determine which messages were the most effective at reaching and persuading priority populations. Through population targeted messaging, THS awareness and knowledge is expected to increase, resulting in greater intentions to prevent THS exposure. Findings from this project will provide suggestions for tobacco control efforts, including Tobacco Endgame policy plans, for reaching and persuading members of these priority populations.

Thirdhand Smoke Consortium Core Research Facilities

The Consortium will provide four core facilities that will support hypothesis-driven research conducted by the subsidiary projects.

Thirdhand Smoke Biomarkers Analytical Chemistry Core

The Thirdhand Smoke Biomarkers Analytical Chemistry Core, led by Dr. Peyton Jacob III at UCSF, will conduct targeted analyses of tobacco-specific nitrosamines, minor tobacco alkaloids, and human exposure biomarkers.

The following biomarkers will be used in Consortium studies. Others may be added as research progresses: cotinine and trans-3’-hydroxycotinine in urine of humans and mice; NNAL, the metabolite biomarker of the tobacco-specific carcinogen, NNK, in human urine;  nicotine in hair from mice; nicotine and cotinine in human saliva; tobacco alkaloids and TSNAs in various sample types.

Thirdhand Smoke Analytical Chemistry Core for Environmental Markers

The Thirdhand Smoke Analytical Chemistry Core for Environmental Markers, led by Dr. Eunha Hoh at SDSU, will conduct targeted and nontargeted analyses of environmental samples for various THS markers for Consortium projects.

The following chemical analyses will be used in Consortium studies: nicotine in surface wipes and silicone wristbands; nicotine, TSNAs, and heavy metals in dust; nicotine, nicotelline, and TSNAs in various non-routine house materials (e.g., drywall, carpets, couch cushions). We will also provide cotinine measurements in surface wipes, silicone wristbands, and dust for studying cotinine as alternate THS markers. We will provide rapid chemical analyses (within 3 weeks), which is critical for selecting highly polluted homes with THS. In addition, GC×GC/TOF-MS based nontargeted analysis will be conducted in a subset of samples generated by the THS generation core or subsets of samples to examine non-routine THS chemical markers.

Thirdhand Smoke-Exposed Material Generation Core

The Thirdhand Smoke-Exposed Material Generation Core, led by Dr. Suzaynn Schick at UCSF, will prepare THS-exposed fabrics and other materials for use by Consortium projects.

This core laboratory is one of the few laboratories in the world equipped to generate SHS and THS under controlled conditions and to perform controlled inhalational and dermal human exposures to SHS and THS.  As requested by Consortium scientists, substrate materials are labeled, logged, and placed in the smoke aging chamber. SHS is generated and passed through the smoke aging chamber 2-4 days a week. Each SHS or THS sample returned to a collaborating laboratory comes with an exact quantification of exposure: total particles, hours of smoke exposure, hours of clean air ventilation, and the total time of exposure in the smoke aging chamber. 

Thirdhand Smoke Outreach, Dissemination, and Resource Center Core

The Thirdhand Smoke Outreach, Dissemination, and Resource Center Core, led by Dr. Georg Matt at SDSU, will disseminate findings from Consortium projects, engage with the general public, priority populations, tobacco control, business, and health care stakeholders, support the development and implementation of policies aimed at reducing THS exposure, and contribute to Tobacco Endgame initiatives.

The overall mission of the THSRC is to disseminate research findings generated by Consortium investigators to California’s diverse communities to achieve indoor environments that are 100% free of tobacco smoke toxicants. The proposed activities include (1) raising awareness about THS; (2) translating and disseminating research findings to the general public and stakeholders in health care, education, business, tobacco control, and government; (3) offering resources to consumers and stakeholders to examine THS pollution; and (4) collaborating with stakeholders to develop and implement effective policies to eliminate human exposure.

Stay Informed

Get the latest thirdhand smoke news and research delivered straight to your inbox, or follow us on social media: