Children who are exposed to diesel exhaust from idling school buses are at increased risk of asthma exacerbation, decreased lung function, immunologic reactions, leukemia, and increased susceptibility to infections. Policies and initiatives that aim to protect school children from the harmful effects of exposure to diesel exhaust range from general environmental air quality standards to more specific legislation that targets diesel exhaust near school children. School nurse standards of practice specify that school nurses should attain current knowledge of environmental health concepts, implement environmental health strategies, and advocate for environmental health principles. This article provides a description of the professional responsibilities of school nurses in protecting children from harmful environmental exposures, provides an overview of legislative initiatives intended to protect school children from diesel exhaust exposure, and summarizes one school district's effort to reduce diesel exhaust exposure among school children.