AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Measurement of In-Use Freight and Passenger Locomotive Black Carbon Emissions in California
Trevor Krasowsky, Nicholas Tang, Nancy Daher, Joshua Apte, Constantinos Sioutas, Philip Martien, George Ban-Weiss, THOMAS KIRCHSTETTER, University of California, Berkeley
Abstract Number: 712 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Black carbon (BC) emission factors were measured for diesel-electric passenger and line-haul freight locomotives along the San Francisco peninsula and near the Ports of Long Beach/Los Angeles, respectively. The emission factors are based on 1 Hz measurements of BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian and roadway overpasses using portable analyzers. Average emission factors, expressed as g BC emitted per kg diesel consumed, were nearly the same for both fleets (0.9 ± 0.7 g/kg for passenger locomotives (n= 362 samples) and 0.9 ± 0.5 g/kg for freight locomotives (n = 88 samples)).
These values were compared to BC emission factors previously measured for on-road light-duty vehicles (i.e., cars) and heavy-duty trucks. In most cases freight locomotives emit less BC pulling an intermodal freight container over a given distance than diesel trucks. However, continual decreases in diesel truck BC means that unless emissions from locomotives are decreased in the near future, emissions associated with hauling a container could become lower for diesel trucks than locomotives. Per passenger mile, diesel-electric locomotives emit only 20% of the CO2 but ten times more BC than emitted by typical gasoline powered cars. Therefore, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.