How can secondhand smoke affect children’s lungs and asthma risk?

Children are particularly vulnerable to the harmful effects of secondhand smoke, also known as environmental tobacco smoke (ETS). When children are regularly exposed to this smoke in their households, they face a significantly increased risk of developing asthma and chronic cough.12

The chemicals in secondhand smoke irritate the respiratory tract, which can trigger allergy-like symptoms such as wheezing and shortness of breath. This irritation is often linked to bronchial hyperreactivity, where the airways become overly sensitive to irritants and constrict, a condition that is especially pronounced in children who already have asthma. Furthermore, regular exposure to secondhand smoke is associated with reduced lung growth and impaired lung function in children.31

Beyond these respiratory impacts, secondhand smoke contains thousands of chemicals—including dozens of known carcinogens—that can cause a wide range of illnesses, including respiratory infections. Protecting children from involuntary inhalation of tobacco smoke is essential for their long-term respiratory health.231