Martinez-Morett, DavidHesketh, Robert P.Marchese, AnthonyBhatia, Krishan2021-02-252021-02-252009-05-25https://hdl.handle.net/10929/69824This study evaluated the actual contributions from both the crankcase and the tailpipe emissions to in-cabin levels of fine and ultrafine particulate matter, and determined the effectiveness of commercially available retrofit technologies towards reducing levels of particulate matter inside the school bus passenger compartment. Previous studies have reported elevated concentrations of diesel particulate matter inside the cabin of the school bus. The elevated particulate concentrations have been attributed to the self-pollution from the school bus tailpipe and/or crankcase vent. Although there are uncertainties in the source of the particulate matter, the issue has gained national attention because children are a particularly sensitive subpopulation to the adverse health effects from diesel particulate matter. The objectives of this study are to measure the concentrations of fine and ultrafine particles within the cabin of a school bus with and without retrofit technologies.en-USSchool buses - Environmental aspectsSchool buses - Health aspectsMotor vehicles - Pollution control devicesTechnical Report