PDF) The New Danger of Thirdhand Smoke: Why Passive Smoking Does Not Stop at Secondhand Smoke Knowledge, perceptions, and experiences of e cigarettes among young adults in Cape Town, South Africa: Insights from focus groups to inform regulations and prevention strategies Passive smoking as an air quality problem How It Works Smoke Free Frontiers Aerosolized nicotine from e cigarettes alters gene expression, increases lung protein permeability, and impairs viral clearance in murine influenza infection