Poisons in the air: a cause of chronic disease in children.

Children represent the largest subpopulation of those susceptible to the adverse effects of air pollution. Compared to adults, children express a greater vulnerability, which can be explained by differences in: the circumstances of exposure related to age, their activities, their child status, differences in lung anatomy and physiology, differences in the clinical expression of disease, and their organ maturity. Many factors have to be assessed in order to evaluate the severity of toxic exposures: pollutant solubility, particle size, concentration, reactivity of pollutants, and pattern of ventilation. Within the numerous air pollutants, some are of special concern for children. For example, ozone has been shown to affect the lungs of healthy school children, especially asthmatics. Airborne particles, nitrogen oxides, sulfur oxides, and acid aerosols have also been shown to induce acute respiratory symptoms, asthma, and bronchitis. Of particular importance is carbon monoxide, which, under certain circumstances, may be found in highly toxic concentrations indoors where children spend most of their time. Special attention has to be given to children's unique differences in order to evaluate the clinical consequences of their toxic exposures. This circumstance emphasizes the key roles of poison centers, clinical toxicologists, and pediatricians, all of whom can collaborate on the identification, assessment, and surveillance of toxic risk for child health and development.