Environmental Engineering Reference
In-Depth Information
Fig. 1
Expressway network in Hungary in 2004
NOx emission from road traffic
120
kilotonnes
80
40
0
1991
1993
1995
1997
1999
2001
2003
Fig. 2
NO
x
emission from road traffic in Hungary, determined by
[1]
increased (Fig.
2
), while the emission of carbon monoxide from the same sources
decreased during the last 20 years (Fig.
3
). The NO
x
emissions from road traffic is
growing (growing rate is 20%) due to the increase in traveled kilometers by cars
and duty vehicles. In the same time NO
x
emissions from the European member
countries decreased by 20% due to the application of three steps catalysts in new
cars and the changes of the compound of the fuel.
Source emissions are a function of both the vehicle emission factors and the
vehicle activity (usually measured in vehicle kilometers traveled). The vehicle
emission factors can differ greatly depending on the type of road, vehicle fleet mix,
and traffic flow encountered. As a result, emission factors were determined specifi-
cally for each roadside location to ensure that the appropriate input was used for the
