Involuntary inhalation refers to the act of breathing in substances or gases without intentionally doing so. There are several synonyms for this term, including passive smoking, secondhand smoke inhalation, and environmental tobacco smoke exposure. These terms all refer to the uncontrolled intake of smoke and other harmful substances in the environment. They can have serious health consequences for individuals, particularly those who are young, elderly or have pre-existing medical conditions. It is crucial to minimize exposure to these harmful substances by taking preventative measures such as avoiding smoking areas and promoting smoke-free public spaces.