Corresponding author Dr. Virender Rehan -- a principal investigator at Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles, Medical Center -- says thirdhand smoke is aged secondhand smoke, and it attaches to the surfaces in homes and cars on furniture, curtains, clothing and other surfaces.
Because the ultrafine particles have a greater molecular weight they pose a greater asthma hazard than firsthand or secondhand smoke, and can have at least as serious an impact as postnatal or childhood exposure to smoke on infants' lung development.
"Thirdhand smoke is a stealth toxin because it lingers on the surfaces in the homes, hotel rooms, casinos and cars used by smokers where children, the elderly and other vulnerable people may be exposed to the toxicants without realizing the dangers," Rehan says in a statement. "Pregnant women should avoid homes and other places where thirdhand smoke is likely to be found to protect their unborn children against the potential damage these toxins can cause to the developing infants' lungs."
Rehan says touching surfaces contaminated with thirdhand smoke, as well as ingesting dust containing the superfine particles of thirdhand smoke, are the most likely major pathways for exposure to these toxins.
The fidings are published in the American Journal of Physiology.