Particulate Matter Emissions Reductions Due to Adoption of Clean Diesel Technology at a Major Shipping Port

摘要

Air pollution emissions from major ports around the world contribute to airborne particulate matter (PM) exposure in surrounding communities. The Port of Oakland is one of three major shipping ports in California that collectively account for 39 of all the goods movement in the United States. The current study is the first to perform relatively complete chemical speciation on the real-world reduction in primary PM emissions from heavy-duty trucks at a major shipping port during the implementation of a retrofit and replacement program. Measurements of fine PM composition at the Port were analyzed by using positive matrix factorization (PMF) to identify five dominant PM sources: shipping, port truck traffic, distant on-road traffic, background sea spray, and road dust. Changes to port truck traffic-related PM concentration on days with similar meteorological conditions during and after implementation of the controls were used as a direct indication of emissions reductions. Primary PM mass emissions from port trucks decreased by 75 due to the control program, which meets the targets inherent in the Emission Reduction Plan for Ports and Goods Movement in California. Contributions of PM components attributed to port truck activities decreased by amounts ranging from 66 to 87 (elemental carbon (EC) = 66, organic carbon (OC) = 78, Na = 82, Ba = 84, Fe = 87). These reductions include contributions from both tailpipe emissions and brake/tire wear. Prior to implementation of the control program, port trucks accounted for approximately 56 of the ambient EC concentrations in the vicinity of the Port while ships accounted for approximately 12 of the EC concentrations. After implementation of the control program, port trucks and ships accounted for approximately 23 and 29 of the ambient EC concentrations at the Port, respectively. The current study provides an example of how emissions control programs at other major shipping ports in the United States could lower overall emissions.