Around the world, students are gathering this month to celebrate their academic achievements. Two such students from San Diego State University are celebrating after completing a master’s thesis about thirdhand smoke. Both students were mentored by Thirdhand Smoke Research Consortium investigator Dr. Penelope J.E. Quintana, a Professor of Environmental Health in the School of Public Health at San Diego State University. Below you will find a summary of their important contributions to thirdhand smoke science and links to their full theses.
Madison Toyama’s master’s thesis is entitled Thirdhand Smoke Chemicals Present After Dry/Damp and Wet Cleaning in Contaminated Multi-Unit Housing. Toyama wanted to see which cleaning method(s) best remove thirdhand smoke pollutants from homes.
To do this, Toyama and fellow researchers identified four thirdhand smoke-polluted homes and assigned them to one of two groups. In the first group, they dry-cleaned by vacuuming carpets and dusting. A month later, they wet-cleaned by steam-cleaning carpets and other fabric surfaces. In the second group of homes, they wet-cleaned the homes first and dry-cleaned them a month later. They used a cleaning solution on hard surfaces in all homes. The researchers collected dust from all the homes on the day before and the day after each cleaning; they then measured the compounds in the dust, noting those found in tobacco or tobacco smoke.
Before cleaning, the researchers identified 371 compounds in the homes. After cleaning, 366 of these compounds remained, and 127 compounds were tobacco-related. Dry-cleaning completely removed only 2 tobacco-related compounds, and wet-cleaning did not remove any tobacco-related compounds. Based on these results, the researchers found the type of cleaning on surfaces did not significantly reduce the number of compounds. While cleaning did not completely remove any compounds present in house dust, reducing the amount of dust in a home (e.g., vacuuming) is an effective strategy to lower the amount of thirdhand smoke pollutants.
Paulina Vanessa Michel’s master’s thesis is entitled Spatial Analysis of Thirdhand Smoke Residue in Homes and Determination of Effective Sampling Strategies. Michel wanted to determine which surface is the most reliable for taking wipe samples to detect thirdhand smoke contamination in a home.
To do this, Michel and fellow researchers took surface wipe samples to measure for nicotine in the homes of people who don’t smoke and vacant homes that were highly polluted with thirdhand smoke. The polluted homes were then professionally cleaned, and the researchers took more surface wipes. They compared which surfaces, such as cabinets, doors, and walls, most frequently had nicotine on them.
They found that surface wipe samples taken from cabinets (usually the undersides of kitchen cabinets) most frequently had medium to very high levels of nicotine compared to doors and walls. In very thirdhand smoke-polluted homes, 83% of surface wipe samples from cabinets still had at least 2 µg/m2 nicotine after cleaning.
The findings from this thesis suggest that cabinets, particularly the undersides of kitchen cabinets, are a reliable surface for testing thirdhand smoke pollution in a home, even after cleaning. Michel suggests that this knowledge can be helpful for home inspectors and buyers to learn the smoking history of a home.
This thesis highlights how difficult it is to remove tobacco-related compounds from indoor environments and emphasizes the need for additional research on how to effectively remove thirdhand smoke. The best way to avoid thirdhand smoke pollutants is to not allow smoking in or around your home.
Click here to read Toyama’s thesis.
Click here to read Michel’s thesis.
