Secondhand smoke is a term used to describe the smoke that a non-smoker inhales from a nearby smoker. It can also be referred to as passive smoking or environmental tobacco smoke. Other synonyms for secondhand smoke include side-stream smoke and passive smoking. This type of smoke is particularly harmful to young children, pregnant women and people with existing respiratory conditions. Therefore, it is important to avoid exposure to secondhand smoke whenever possible. There are several ways to minimize exposure, such as avoiding smoking areas, opening windows for ventilation and encouraging smokers to smoke outside.