There is increasing recognition of the importance of early environmental exposures in the development of childhood asthma. Outdoor air pollution is a recognized asthma trigger, but it is unclear whether exposure influences incident disease. An investigation into the effect of exposure to ambient air pollution in utero and during the first year of life on risk of subsequent asthma diagnosis yielded the following results. A total of 3,482 children (9%) were classified as asthma cases. Researchers observed a statistically significantly increased risk of asthma diagnosis with increased early life exposure to air pollution and black carbon and proximity to point sources. Traffic-related pollutants were associated with the highest risks. These data, recently published in the journal of Environmental Health Perspectives, support the hypothesis that early childhood exposure to air pollutants plays a role in development of asthma. Click here for access to the complete article.