Chemistry Reference
In-Depth Information
Locations of the airbase stations
Power Generation
Other Combustion
Industrial Comb.
Industrial Processes.
Extr. dist. of fossil fuels
Solvent use
Road Transport
Other transport
Waste
Agriculture
Natural
Bound+Initial
1.0
1.0
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0.0
0.0
-0.2
-0.2
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
g/m
3
]
g/m
3
]
Observed PM10 Concentration [
µ
Observed PM25 Concentration [
µ
Fig. 1 AIRBASE monitoring sites (
top
) used to calculate average regional contributions to PM
10
and PM
2.5
(
bottom
) by means of the LOTOS-EUROS source apportionment tool
Road transport is an important contributor to primary emissions of PM (soot,
wear particles and road dust) and also a source of secondary particles formed by
condensation of gaseous species (mainly S- and N-compounds and organics)
emitted by the tailpipe and partly also by the wear of brakes and tyres. Thus, PM
emissions from road traffic are responsible for an important proportion of the
exceedances of the PM
10
and PM
2.5
Air Quality Limit Values established by the
European legislation for the protection of the human health (2008/50/EC; [
17
]).
The daily (50
gm
3
) limit values for PM
10
(atmospheric
particles with mean aerodynamic diameter
gm
3
) and annual (40
m
m
<
10
m) and the annual limit value for
m
gm
3
) (in force from 2015) concentrations in ambient air are indeed
exceeded mostly in the urban areas (Fig.
1
;[
17
]).
In spite of the new vehicle emission EUROx regulations, 20% of Europe's urban
population is also living in areas where the atmospheric concentrations of nitrogen
dioxide (NO
2
) exceed established air quality standards [
18
]. This is due to several
factors related to the diesel-powered cars [
19
]: (1) their increasing market penetra-
tion across Europe [
20
]; (2) the NO
x
emission factors of diesel cars exceed the
emission levels as established during the type approval of these vehicles in the
laboratory [
19
,
21
-
25
] and (3) the fraction of NO
2
in the NO
x
emissions of diesel
PM
2.5
(25
m
