Abstract
Emission characteristics of ultrafine particles emitted from a diesel vehicle were measured on the chassis dynamometer using dilution tunnel and high speed particle sizer in transient test cycle. Averaged size distribution for whole test cycle showed a single mode size distribution with a peak of around 50 ∼ 60 nm diameter. Nanoparticles which have a peak diameter about 20 nm were observed only under deceleration condition in case of the tested vehicle.
Long term measurement of size distribution and number concentration of ultrafine particles have been performed using Scanning Mobility Particle Sizer to understand the impact of vehicle emission and behavior of the ultrafine particles in the atmosphere at three roadside sites. At roadside, bimodal size distribution with peak diameters of 20 ∼ 30 and 60 ∼ 90 nm was observed in winter. On the other hand unimodal size distribution with peak diameters of 30 ∼ 40 nm was observed in summer. Number concentration is influenced by traffic of heavy duty vehicles, meteorological condition and background atmosphere. The correlation analysis result shows a good correlation between number and NO concentration in the roadside atmosphere.
