Quantification of Particle Number Emission Factors for Motor Vehicles from On-Road Measurements

Morawska, Lidia, Jamriska, Milan, Thomas, Stephen, Ferreira, Luis, Wraith, Darren E., & McGregor, Fraser A. (2005) Quantification of Particle Number Emission Factors for Motor Vehicles from On-Road Measurements. Environmental Science and Technology, 39(23), pp. 9130-9139.

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The database on particle number emission factors has been very limited to date despite the increasing interest in the effects of human exposure to particles in the submicrometer range. There are also major questions on the comparability of emission factors derived through dynamometer versus on-road studies. Thus, the aims of this study were (1) to quantify vehicle number emission factors in the submicrometer (and also supermicrometer) range for stop-start and free-flowing traffic at about 100 km h-1 driving conditions through extensive road measurements and (2) to compare the emission factors from the road measurements with those obtained previously from dynamometer studies conducted in Brisbane. For submicrometer particles the average emission factors for Tora Street were estimated at (1.89 ( 3.40) 1013 particles km-1 (mean ( standard error; n ) 386) for petrol and (7.17 ( 2.80) 1014 particles km-1 (diesel; n ) 196) and for supermicrometer particles at 2.59 109 particles km-1 and 1.53 1012 particles km-1, respectively. The average number emission factors for submicrometer particles estimated for Ipswich Road (stop-start traffic mode) were (2.18 ( 0.57) 1013 particles km-1 (petrol) and (2.04 ( 0.24) 1014 particles km-1 (diesel). One implication of the conclusion that emission factors of heavy duty diesel vehicles are over 1 order of magnitude higher than emission factors of petrol-fueled passenger cars is that future control and management strategies should in particular target heavy duty vehicles, as even a moderate decrease in emissions of these vehicles would have a significant impact on lowering atmospheric concentrations of particles. The finding that particle number emissions per vehiclekm are significantly larger for higher speed vehicle operation has an important implication on urban traffic planning and optimization of vehicle speed to lower their impact on airborne pollution. Additionally, statistical analysis showed that neither the measuring method (dynamometer or onroad), nor data origin (Brisbane or elsewhere in the world), is associated with a statistically significant difference between the average values of emission factors for diesel, petrol, and vehicle fleet mix. However, statistical analyses of the effect of fuel showed that the mean values of emission factors for petrol and diesel are different at a 5% significance level.

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ID Code: 5783
Item Type: Journal Article
Refereed: Yes
Additional Information: This article is freely available from the American Chemical Society website 12 months after the publication date. See links to publisher website in this record.
DOI: 10.1021/es050069c
ISSN: 0013-936X
Subjects: Australian and New Zealand Standard Research Classification > EARTH SCIENCES (040000) > ATMOSPHERIC SCIENCES (040100) > Atmospheric Sciences not elsewhere classified (040199)
Divisions: Past > QUT Faculties & Divisions > Faculty of Science and Technology
Copyright Owner: Copyright 2005 American Chemical Society
Copyright Statement: The contents of this journal can be freely accessed online via the ACS web page 12 months after publication. See hypertext link.
Deposited On: 11 Dec 2006 00:00
Last Modified: 29 Feb 2012 13:17

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