Secondhand smoke is the smoke you are exposed to when someone nearby is smoking. It includes the smoke exhaled by the smoker, and the smoke given off directly by the burning tobacco.
Secondhand smoke is the smoke you're exposed to when someone nearby is smoking. It includes the smoke breathed out by the smoker. And it includes the smoke given off by the burning tobacco.
Environmental tobacco smoke can be exhaled by smokers, or come directly from burning cigarettes, cigars, and pipes. When children breathe in tobacco smoke, they are at higher risk for health problems.