title: Physical and Chemical Characterization of Real-World Particle Number and Mass Emissions from City Buses in Finland.
abstract: Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10(14) # (kg fuel)(-1), 6-40 g (kg fuel)(-1), 0.004-0.88 g (kg fuel)(-1), 0.004-0.56 g (kg fuel)(-1), 0.01-1.2 g (kg fuel)(-1), for particle number (EFN), nitrogen oxides (EFNOx), black carbon (EFBC), organics (EFOrg), and particle mass (EFPM1), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions.
authors.affiliation: Department of Technology, Metropolia University of Applied Sciences , P.O. Box 4021, 00180 Helsinki, Finland.|Department of Physics, University of Helsinki , P.O. Box 64, 00014 Helsinki, Finland.
authors.forename: Liisa
authors.initials: L
authors.lastname: Pirjola
authors.affiliation: KVM - Katedra vozidel a motorů, Fakulta strojní Technická univerzita v Liberci , 461 17 Liberec 1, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Dittrich
authors.affiliation: Helsinki Region Environmental Services Authority HSY, P.O. Box 100, 00066 HSY Helsinki, Finland.|Department of Environmental Sciences, University of Helsinki , P.O. Box 65, FI-00014 Helsinki Finland.
authors.forename: Jarkko V
authors.initials: JV
authors.lastname: Niemi
authors.affiliation: Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Saarikoski
authors.affiliation: Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland.
authors.forename: Hilkka
authors.initials: H
authors.lastname: Timonen
authors.affiliation: Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland.
authors.forename: Heino
authors.initials: H
authors.lastname: Kuuluvainen
authors.affiliation: Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland.
authors.forename: Anssi
authors.initials: A
authors.lastname: Järvinen
authors.affiliation: Helsinki Region Environmental Services Authority HSY, P.O. Box 100, 00066 HSY Helsinki, Finland.
authors.forename: Anu
authors.initials: A
authors.lastname: Kousa
authors.affiliation: Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland.
authors.forename: Topi
authors.initials: T
authors.lastname: Rönkkö
authors.affiliation: Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland.
authors.forename: Risto
authors.initials: R
authors.lastname: Hillamo
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry*; D002947:Cities; D005387:Finland; D008970:Molecular Weight; D018986:Motor Vehicles; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions