Children spend almost 90% of their time indoors, though outside air can be a significant source of potential and actual exposure to outdoor air pollutants. Children are vulnerable to pollutants and toxins because of their size and developing organ systems. Young children have increased respiratory rates and inhale more toxins, and young children often ignore respiratory symptoms and continue play. Outdoor play and recreational activities expose children to outdoor air pollution from sources such as automobiles, power plants, industry, and other combustion sources, which can impact children. Outdoor air pollution has been linked to respiratory illness exacerbations, infant mortality, the development of asthma, and atopy and reduction in lung development in children. This article will examine outdoor air pollution and its impact on children's health, as well as implications for pediatric nursing clinical practice.