Mobile-source diesel exhaust particulate has been estimated to be responsible for more than 70% of the air toxic carcinogenic risk in the Los Angeles region. Diesel particulate emissions vary by engine operating characteristics (e.g., engine load, RPM), and operational characteristics will vary by facility type and congestion levels, thus producing different particulate emission levels. Existing emission factor models capture this effect through a functional relationship where the emissions vary with respect to vehicle speed. Second by second measurements on the US federal test procedure dynamometer driving cycle show PM10 spikes at the hard acceleration points. Transportation plans attempt to reduce congestion and smooth traffic flow. This paper combines available data on variations in diesel particulate emissions with engine operations to provide guidance on how transportation plans can indirectly affect the carcinogenic risk associated with diesel particulate matter from mobile sources. For the covering abstract see ITRD E128680.
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