Children are exposed to preventable environmental hazards such as lead, solvents, asbestos, pesticides, air pollution, and environmental tobacco smoke. Children are at greater risk than adults to exposure to and possible illness from environmental hazards due to their decreased ability to detoxify substances, greater sensitivity during development and growth – i.e. behaviors such as crawling and mouthing – greater amount of time spent outdoors near exposures, and greater ingestion of contaminants through different diets than adults.
Exposure to environmental health hazards can have a significant impact on children's health and well-being. All children are at risk of developing learning disabilities, chronic and acute respiratory diseases, cancers, and illnesses caused by damage to the nervous system from hazardous substances. The incidence of chronic childhood diseases such as asthma and bronchitis are increasing. Additionally, cancer rates are increasing, especially childhood cancers such as leukemia.
Levels of many outdoor air pollutants decreased substantially in the USA after the passage of the Clean Air Act of 1970; however, levels of ozone, carbon monoxide, and particulate matter are still high enough to present hazards to children.
US research indicates that acidic aerosols, for which there are no health-based standards, may be associated with adverse respiratory effects in children. Acidic aerosols are traceable mainly to combustion of sulfur-containing fossil fuels and to reactions of photochemical free radicals with nitrogen dioxide.
Ozone causes airway inflammation and hyper-reactivity, bronchial epithelial permeability, decrements in pulmonary function, cough, chest tightness, pain on inspiration, and upper respiratory tract irritation. Non-respiratory effects associated with ozone exposure include nausea, headache, malaise, and decreased ability to perform sustained exercise. Epidemiological studies link increased ozone concentrations with exacerbations of asthmatic symptoms.