Environmental Engineering Reference
In-Depth Information
Fig. 1
Daily journeys from vast area toward Naples municipality
Table 4
Estimated total emissions from urban road trafic
in Naples during 2006
Pollutant
Emissions (t)
Pollutant
Emissions (t)
CO
16,849
COV
4,340
NO
x
2,105
PM
10
180
evaporative emissions and that the PM emissions include brakes, tyres and road
pavement wear. The emissions of CO, NOx, COV and PM10 are illustrated for each
vehicle class in Fig.
2
.
Passenger cars contribute more than 57% to the total road traffic emissions of
CO, and about 53% is from gasoline passenger cars (as might be expected, since
the combustion is incomplete due to lack of oxygen in engines powered by
gasoline).
Previously, it has been observed that the gasoline passenger cars fleet in Naples
municipality is relatively old, and old vehicles are generally characterized by higher
emissions compared to the most recent ones. In Fig.
3
the carbon monoxide emis-
sions due to gasoline passenger cars have been split according to the EU Directives:
EURO 0 passenger cars constitute the largest contribution to the CO emissions.
Figure 2
also shows NOx emissions due to different vehicle classes; urban buses
represent the largest contribution in the urban area of Naples (about 26.5%). The
predominant share of these NOx emissions is determined by conventional buses
(Fig.
4
), which are characterized by a high emission factor (about 26 g/km for an
average speed of 12 km/h).
The emissions of VOC are also shown in Fig.
2
for different vehicle classes.
Again a considerable contribution (more than 28%), is due to gasoline passenger
cars, also considering the share of evaporative emissions. About 53% is brought by
