Thirdhand smoke is the chemical residue from tobacco smoke. It is also called “tobacco smoke
residue” or “stale tobacco smoke.” The chemicals in thirdhand smoke are toxic to humans,
especially children. It can linger for years in dust and on household surfaces. It can also become
embedded in carpets, furniture, clothes, and building materials. It is difficult and expensive to
Many researchers are studying thirdhand smoke. New findings are published regularly. We invite you to learn more about this study:
Respiratory Exposure to Thirdhand Cigarette Smoke Increases Concentrations of Urinary Metabolites of Nicotine
Kelly Pratt, Lawrence Berkeley National Laboratories, Berkley, CA; Andrew Hilty, Community Clinical Services Inc., Lewiston, ME; and Peyton Jacob III, PhD and Suzaynn F Schick, PhD, University of California, San Francisco, CA
Why was the study conducted?
Thirdhand smoke is the chemical residue that sticks to surfaces in rooms where people smoked. Researchers wanted to find out if people are exposed to tobacco smoke pollutants when they breathe the air from a chamber with tobacco smoke residue 22 hours after smoking stopped. They also wanted to understand how airborne thirdhand smoke particles change over time.
Who or what was studied?
Study participants were adult nonsmokers who breathed air from a chamber that contained tobacco smoke residue.
Where were the data collected?
Data were collected in a laboratory. Participants gave urine samples before and after breathing contaminated air for three hours. Researchers analyzed the air from the thirdhand smoke polluted chamber. Researchers examined the participants’ urine for chemical markers of tobacco smoke and its residue.
What did the researchers find?
The air measures showed that 22 hours after smoking stopped, the thirdhand residue in the chamber generated a substantial amount of pollutants in the air. The chemical markers in the urine samples showed that the participants had inhaled these pollutants. The researchers also found that the average airborne particle size of these pollutants increased with time.
When should I care?
If you spend time in spaces where people smoked before (for example, a friend’s apartment, a car, a hotel room), you are breathing in tobacco chemicals that can harm your health.
How does this finding help me?
Before traveling or making purchases, find out if a house, apartment, car, or hotel room has been smoked in. Stay away from indoor locations where people have smoked before. Advocate for 100% smokefree spaces.