Berkeley Lab scientist Hugo Destaillats, who has studied thirdhand smoke for a decade, reports that the most common inquiry he receives from the public pertains to how to clean up a property where a smoker previously resided. Thirdhand smoke is the hazardous residue from cigarettes that can adhere to indoor surfaces for several months or years.

Ozone generators are often employed by remediation companies to eradicate mold, tobacco, and fire damage odors by subjecting homes to elevated levels of ozone. However, there is limited research examining its efficacy in eliminating harmful residues or identifying potential hazards. As a result, Hugo Destaillats and his colleagues from Berkeley Lab’s Indoor Environment Group conducted a study in a room-sized chamber to investigate the impact of ozonation on the levels of chemical compounds commonly present in thirdhand smoke.

Recently published in the journal Environmental Research, and supported by funding from the University of California’s Tobacco Related Diseases Research Program, the study discovered that ozonation can eliminate tobacco residues that have been absorbed by materials. However, the process also triggered a surge of contaminants while the generator was in operation, with particles lingering in the air for a certain period of time. The study emphasized the importance of designating a safe re-entry time following ozonation, which should be conducted in unoccupied areas.

According to the researcher, “Ozone has the potential to eliminate nicotine and polycyclic aromatic hydrocarbons (PAHs) that have adhered to fabrics due to smoking. However, our study indicates that individuals should wait for even over 1 hour following the generator’s operation and ensure adequate ventilation before re-entering the area.”

The researchers conducted this study on thirdhand smoke that was recently produced. In the future, they plan to investigate materials that have been contaminated for longer periods, potentially lasting years. According to Destaillats, “Homes harbor numerous hidden reservoirs of tobacco pollutants. Drywall, which is primarily composed of gypsum, is highly permeable and can accumulate substantial amounts of indoor pollutants. Nicotine and other contaminants can persist in drywall and carpets for extended periods.”