A new study led by Dr. Myung-Bae Park from Pai Chai University in Korea found that visitors can be exposed to thirdhand smoke even on short visits to places where people are not smoking but may have smoked in the past. The researchers sent participants to Internet cafes or Noraebang (Korean-style karaoke), where no one was currently smoking, for two separate 2-hour visits. They measured the amount of cotinine in participants’ urine three times: before their first visit, after their first visit, and after their second visit. Cotinine is a marker of tobacco exposure, and the level is higher when someone is exposed to tobacco smoke. The researchers also collected dust samples at each location to find out how much nicotine-derived nitrosamine ketone (NNK) was present. NNK is a cancer-causing chemical in tobacco products and a marker of thirdhand smoke residue in dust.

The researchers found that participants’ cotinine levels were significantly higher after the second visit than before and after the first visit. NNK levels also increased alongside the cotinine levels after the second visit. These results suggest that even short visits to places with tobacco residue can expose people to thirdhand smoke. These findings suggest that individuals should avoid frequenting places where known smoking occurs in order to protect themselves from toxic thirdhand smoke exposure.

Click here to read the research study.