title: Characterization of particulate matter emissions from a current technology natural gas engine.
abstract: Experiments were conducted to characterize the particulate matter (PM)-size distribution, number concentration, and chemical composition emitted from transit buses powered by a USEPA 2010 compliant, stoichiometric heavy-duty natural gas engine equipped with a three-way catalyst (TWC). Results of the particle-size distribution showed a predominant nucleation mode centered close to 10 nm. PM mass in the size range of 6.04 to 25.5 nm correlated strongly with mass of lubrication-oil-derived elemental species detected in the gravimetric PM sample. Results from oil analysis indicated an elemental composition that was similar to that detected in the PM samples. The source of elemental species in the oil sample can be attributed to additives and engine wear. Chemical speciation of particulate matter (PM) showed that lubrication-oil-based additives and wear metals were a major fraction of the PM mass emitted from the buses. The results of the study indicate the possible existence of nanoparticles below 25 nm formed as a result of lubrication oil passage through the combustion chamber. Furthermore, the results of oxidative stress (OS) analysis on the PM samples indicated strong correlations with both the PM mass calculated in the nanoparticle-size bin and the mass of elemental species that can be linked to lubrication oil as the source.
authors: Mechanical and Aerospace Department, West Virginia University , Morgantown, 395 Evansdale Drive, P.O. Box 6106, West Virginia 26505, United States.
authors: Arvind
authors: A
authors: Thiruvengadam
authors: Marc C
authors: MC
authors: Besch
authors: Seungju
authors: S
authors: Yoon
authors: John
authors: J
authors: Collins
authors: Hemanth
authors: H
authors: Kappanna
authors: Daniel K
authors: DK
authors: Carder
authors: Alberto
authors: A
authors: Ayala
authors: Jorn
authors: J
authors: Herner
authors: Mridul
authors: M
authors: Gautam
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D002244:Carbon / Q000032:analysis; D005591:Chemical Fractionation; D016676:Macrophages, Alveolar / Q000378:metabolism; D018986:Motor Vehicles; D059206:Natural Gas; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014481:United States; D014484:United States Environmental Protection Agency; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D059206:Natural Gas; D052638:Particulate Matter; D017382:Reactive Oxygen Species; D001335:Vehicle Emissions; D002244:Carbon