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Pirjola L, Dittrich A, Niemi JV, Saarikoski S, Timonen H, Kuuluvainen H, Järvinen A, Kousa A, Rönkkö T, Hillamo R. Physical and Chemical Characterization of Real-World Particle Number and Mass Emissions from City Buses in Finland. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:294-304. [PMID: 26682775 DOI: 10.1021/acs.est.5b04105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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.
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Affiliation(s)
- Liisa Pirjola
- 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
| | - Aleš Dittrich
- KVM - Katedra vozidel a motorů, Fakulta strojní Technická univerzita v Liberci , 461 17 Liberec 1, Czech Republic
| | - Jarkko V Niemi
- 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
| | - Sanna Saarikoski
- Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Hilkka Timonen
- Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
| | - Heino Kuuluvainen
- Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland
| | - Anssi Järvinen
- Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland
| | - Anu Kousa
- Helsinki Region Environmental Services Authority HSY, P.O. Box 100, 00066 HSY Helsinki, Finland
| | - Topi Rönkkö
- Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 692, 33101 Tampere, Finland
| | - Risto Hillamo
- Atmospheric Composition Research, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland
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Kamarianakis Y, Gao HO. Accounting for exhaust gas transport dynamics in instantaneous emission models via smooth transition regression. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1320-1326. [PMID: 20070072 DOI: 10.1021/es901913k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Collecting and analyzing high frequency emission measurements has become very usual during the past decade as significantly more information with respect to formation conditions can be collected than from regulated bag measurements. A challenging issue for researchers is the accurate time-alignment between tailpipe measurements and engine operating variables. An alignment procedure should take into account both the reaction time of the analyzers and the dynamics of gas transport in the exhaust and measurement systems. This paper discusses a statistical modeling framework that compensates for variable exhaust transport delay while relating tailpipe measurements with engine operating covariates. Specifically it is shown that some variants of the smooth transition regression model allow for transport delays that vary smoothly as functions of the exhaust flow rate. These functions are characterized by a pair of coefficients that can be estimated via a least-squares procedure. The proposed models can be adapted to encompass inherent nonlinearities that were implicit in previous instantaneous emissions modeling efforts. This article describes the methodology and presents an illustrative application which uses data collected from a diesel bus under real-world driving conditions.
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Affiliation(s)
- Yiannis Kamarianakis
- School of Civil and Environmental Engineering, Cornell University, Ithaca, New York 14853.
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