UCSF

Background. Second hand smoke changes physically and chemically after it is released into the environment. Some of the resulting chemicals and particulate matter are toxic and persist in the indoor environment as thirdhand smoke.

Objectives. The aims of this study were to measure the effects of thirdhand smoke on biomarkers inflammation and oxidative stress and biomarkers of tobacco smoke exposure.

Methods. After generation of thirdhand smoke with a smoke generating machine and smoke aging chamber, 17 healthy nonsmokers were given a three-hour respiratory exposure to thirdhand smoke. The systemic effects of respiratory exposure to thirdhand smoke were tested by measuring biomarkers of inflammation, vascular endothelial growth factor and interleukin-6, and a biomarker of oxidative stress, 8-isoprostane, using enzyme-linked immunosorbent assay kits. Biomarkers of cigarette exposure, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and cotinine, were measured with liquid chromatography–atmospheric pressure chemical ionization tandem mass spectrometry.

Results. The results show significant increases in 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and cotinine after three hours of exposure to thirdhand smoke and no significant increases in interleukin-6, vascular endothelial growth factor or 8-isoprostane.

Conclusion. These results have implications for stricter indoor smoking regulations as well as health education around smoking. Additionally, the significant increase in levels of biomarkers, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and cotinine, with thirdhand smoke exposure corroborate the reliability of using these biomarkers for thirdhand smoke exposure screening.