Environmental Engineering Reference
In-Depth Information
CO emission from road traffic
kilotonnes
600
400
200
0
1991
1993
1995
1997
1999
2001
2003
Fig. 3
CO emission from road traffic in Hungary, calculated by
[1]
Fig. 4
Diffusion processes in road traffic modeling.
Arrows
represent interactions
modeling of subsequent roadway emissions. These site-specific emission factors
were then combined with the vehicle kilometers traveled data to give a total emission
rate for the road.
Diffusion Processes in Road Modeling
The total diffusion is divided into primary diffusion affected by the traffic and dif-
fusion caused by ambient meteorological conditions (see Fig.
4
). Contaminants
outcome from the tailpipe take part in the primary process, on one hand by the
thermal turbulence caused by differential surface heating and by eddy movements
created by the buoyant exhaust plume, on the other hand by mechanical turbulence
from wind flow and the traffic wake induce turbulence. Thermal influences interact
with mechanical effects. There are interactions between the ambient wind speed,
