AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Black Carbon, Particle Number Concentration and Nitrogen Oxide Emission Factors of Random In-Use Vehicles Measured with the On-Road Chasing Method
Irena Jezek, Tomaz Katrasnik, Dane Westerdahl, GRISA MOCNIK, Aerosol d.o.o., Slovenia
Abstract Number: 640 Working Group: Urban Aerosols
Abstract The chasing method was used in an on-road measurement campaign, and emission factors (EF) of black carbon (BC), particle number (PN) and nitrogen oxides (NOx) were determined for 139 individual vehicles of different types encountered on the roads. We report EFs for BC, NOx and PN for three vehicle categories: goods vehicles, gasoline and diesel cars. This is the first on-road measurement study where BC EFs of numerous individual diesel cars were determined in real-world driving conditions. We found good agreement between EFs of goods vehicles determined in this campaign and the results of previous studies (chasing, remote sensing). The composition of the sampled car fleet determined from the national vehicle registry information is reflective the Slovenian and European vehicle fleets. The median BC EF of diesel and gasoline cars that were in use for less than 5 years, decreased by 60% and 47% from those in use for 5 – 10 years, respectively, the median NOx and PN EFs, of goods vehicles that were in use for less than five years, decreased from those in use for 5 – 10 years by 52% and 67%, respectively. Surprisingly, we found and increase of BC EFs in newer goods vehicle fleet compared to 5 – 10 year old one. The influence of engine maximum power on the measured EFs showed an increase in NOx EF from least to more powerful vehicles with diesel engines. A disproportionate contribution of high emitters to the total emissions of the measured fleet was found; the top 25% of emitting diesel cars contributed 63%, 47% and 61% of BC, NOx and PN emissions respectively. With the combination of relatively simple on-road measurements with sophisticated post processing individual vehicles EF can be determined and useful information about the fleet emissions can be obtained by exactly representing vehicles which contribute disproportionally to vehicle fleet emissions; and monitor how the numerous emission reduction approaches are reflected in on-road driving conditions.