Secondhand tobacco smoke contains more than 7,000 substances. It can cause lung cancer, heart disease and stroke.

Secondhand tobacco smoke exposure can result in premature deaths among non-smokers.

Secondhand tobacco smoke can also cause health problems in infants and children, including sudden infant death syndrome, respiratory and ear infections, and it can trigger more frequent and severe asthma attacks in children.

Secondhand marijuana smoke is a mixture of the smoke given off by a burning marijuana product and the smoke exhaled by a smoker.

Secondhand marijuana smoke contains many of the same toxic and cancer-causing chemicals found in tobacco smoke and contains some of those chemicals in higher amounts.

Electronic cigarettes produce aerosols by heating a liquid that usually contains nicotine, flavorings, and other chemicals. Aerosols are a mix of tiny particles and/or droplets in the air.

Aerosols from electronic smoking products can contain potentially harmful substances — including nicotine, formaldehyde, and metals — some of which cause cancer and other harmful health effects.

Some of the harmful substances emitted in secondhand e-cigarette aerosols are similar to those in secondhand tobacco smoke.

Prohibiting the smoking of tobacco inside or near homes, buildings, vehicles, and other enclosed spaces is the only way to eliminate indoor exposure to secondhand smoke and the health risks that may come with it.

Secondhand tobacco smoke can move between rooms of a building, including between apartment units. Several studies indicate that ventilation, filtration and air cleaning techniques can reduce secondhand smoke indoors, but they do not eliminate it.