Determination of average emission factors for vehicles on a busy road

In this paper, the CALINE4 software package, designed for calculation of concentrations of carbon monoxide near a busy road, is adapted for the analysis of aerosols of fine and ultra-fine particles, generated by vehicles on the road. A scaling procedure of the CALINE4 package is developed and justified. A new efficient method of determination of the average emission factor for fine particle emission from the average fleet (one average vehicle) on a given road is also developed. This method is based on measurements of the average particle number concentration at just one point near the road. An example of a specific road in the Brisbane area, Australia, is considered. The average emission factor for vehicles on this road is calculated to be similar to4.5 x 10(14) particle/vehicle/mile. The obtained scaling coefficient is shown to be correct, and the procedure is directly applicable for the analysis of an arbitrary road with different types of vehicles and their average speed. Good agreement between the experimental results and the predicted theoretical dependencies of concentration on distance from the road clearly confirms the applicability of the CALINE4 package for the analysis of propagation of fine particle aerosols from a busy road. Statistical analysis of the experimental and theoretical results demonstrates that the concentration of fine and ultra-fine particles approximately reduces as a power law in distance from the road. (C) 2002 Elsevier Science Ltd. All rights reserved.