Outdoor air pollution is a significant public health hazard in population centers throughout the world. Recognition of air pollution as a nuisance dates back many centuries. Decades of research have established a strong link between air pollution and a spectrum of adverse health effects. Health care practitioners rarely consider the health risk of air pollution in the course of patient care and generally do not provide risk modification strategies as part of patient management. The purpose of this article is to provide front line clinicians with: 1) an overview of the evolution in scientific understanding about air pollution and its health effects, 2) an introduction to the hazards contemporary air pollution presents to patients, and 3) an introduction to the contributions of specific pollutants to outdoor air quality.