Secondhand Smoke and Electronic Cigarette Aerosol Resources US EPA What Is Secondhand Smoke and Why Is It Dangerous? Secondhand smoke and vape can trigger your child's asthma attacks. Smoking and vaping are unhealthy for everyone but especially harmful for people with asthma. Whether at home, in the car, or Do electronic cigarettes create thirdhand chemical residue? Thirdhand Smoke Resource Center Avoiding Tobacco Smoke and E Cigarette Aerosol Is a Key Part of Asthma Management Asthma and Allergy Foundation of America