Detailed Characterization and Profiles of Crankcase and Diesel Particulate Matter Exhaust Emissions Using Speciated Organics

• Published in: Environmental science & technology Vol. 42; no. 15; pp. 5661 - 5666
• Main Authors: Zielinska, Barbara, Campbell, David, Lawson, Douglas R, Ireson, Robert G, Weaver, Christopher S, Hesterberg, Thomas W, Larson, Timothy, Davey, Mark, Liu, L.-J. Sally
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.2008
• Subjects: 02 PETROLEUM; Air Pollutants - analysis; Air Pollutants - chemistry; Air Pollutants - toxicity; Applied sciences; Automotive parts; BUSES; CARBON; Comparative analysis; Deuterium - chemistry; DIESEL ENGINES; Emissions; ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ENGINES; Environmental Measurements Methods; Environmental Monitoring; ENVIRONMENTAL SCIENCES; Exact sciences and technology; Hydrocarbons - chemistry; LUBRICATING OILS; MONITORING; Motor Vehicles; Particle Size; Particulate Matter - analysis; Particulate Matter - chemistry; PARTICULATES; Pollution; Polycyclic Aromatic Hydrocarbons - chemistry; Risk Assessment; School buses; Studies; Time Factors; Transportation; Vehicle Emissions - analysis; Vehicle Emissions - toxicity; Lubricating oil; Bus; Hydrocarbon; Pollutant behavior; Emission content; Diesel engine; Motor vehicle; Polycyclic aromatic compound; Pollutant emission; Persistent organic pollutant; Cabin; Surveillance; Particle emission; Alkane; Aerosols; Air pollution; Exhaust gas; Road traffic; Speciation; Organic compounds; Tracers
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es703065h

A monitoring campaign was conducted in August−September 2005 to compare different experimental approaches quantifying school bus self-pollution. As part of this monitoring campaign, a detailed characterization of PM2.5 diesel engine emissions from the tailpipe and crankcase emissions from the road draft tubes was performed. To distinguish between tailpipe and crankcase vent emissions, a deuterated alkane, n-hexatriacontane-d74 (n-C36D74) was added to the engine oil to serve as an intentional quantitative tracer for lubricating oil PM emissions. This paper focuses on the detailed chemical speciation of crankcase and tailpipe PM emissions from two school buses used in this study. We found that organic carbon emission rates were generally higher from the crankcase than from the tailpipe for these two school buses, while elemental carbon contributed significantly only in the tailpipe emissions. The n-C36D74 that was added to the engine oil was emitted at higher rates from the crankcase than the tailpipe. Tracers of engine oil (hopanes and steranes) were present in much higher proportion in crankcase emissions. Particle-associated PAH emission rates were generally very low (<1 μg/km), but more PAH species were present in crankcase than in tailpipe emissions. The speciation of samples collected in the bus cabins was consistent with most of the bus self-pollution originating from crankcase emissions.