Avoiding Tobacco Smoke and E Cigarette Aerosol Is a Key Part of Asthma Management Asthma and Allergy Foundation of America Health Problems Caused by Secondhand Smoke Smoking and Tobacco Use CDC Is passive vaping a hidden risk to the public? Here's what the experts know so far ABC News Secondhand e cigarette aerosols expose kids to less nicotine than cigarettes, study finds, but can still be risky CNN