Chemistry Reference
In-Depth Information
Table 1 Annual emission
of ammonia (Gg NH
3
) from
different sectors in Europe
during the period 1985-2009.
Emissions are distributed
according to the SNAP
categories developed within
the EMEP inventories
(Webdab extraction,
12th May 2012)
1985
1990
1995
2000
2005
2009
S1
6
5
4
5
5
6
S2
9
10
9
9
8
7
S3
3
7
6
5
8
6
S4
155
125
91
89
87
37
S5
0
6
5
10
12
11
S6
6
5
5
5
6
6
S7, road
45
16
47
98
83
69
S8
1
1
1
1
1
1
S9
138
136
117
90
85
84
S10
5,068
4,738
4,028
3,840
3,668
3,546
[
90
,
91
,
92
,
93
]. Bidirectional fluxes over forests have recently been observed
during senescence and leaf fall [
70
], suggesting that a large fraction of N that has
been taken up during the growing season is released again in the autumn when litter
is decomposed.
3 Spatial Distributions in Emissions
At European level, EMEP (
http://www.emep.int
) and CORINAIR have compiled
inventories of the annual mean emissions on a grid with a spatial resolution of
50 km
10
resolutions, and the EUROTRAC GENEMIS project (
http://www.gsf.de/eurotrac
)
compiled inventories with a grid resolution of 16.67 km
50 km [
71
]. The EDGAR and GEIA databases are available on 10
16.67 km. The
GENEMIS data was for the year 1994, but this inventory has in some later studies
been used to redistribute EMEP emission inventories for subsequent years, assum-
ing unchanged relative distribution over the years [
72
,
73
]. The need for high-
resolution inventories has been recognised by the model groups within MACC and
MACC-II research programmes (
http://www.gmes-atmosphere.eu/
). They have
therefore adapted a high-resolution inventory on a 7 km resolution of the annual
emissions at SNAP code level [
54
]. This is a combination of the officially reported
inventories, information on geographic location of point sources and a correction
procedure for inconsistencies. There are therefore different estimates regarding the
spatial distribution in NH
3
emissions over Europe, a distribution that clearly is non-
uniform (Fig.
4
).
The distribution of NH
3
emissions from nonagricultural sources follows to a
large extent the population density but is also associated with the major road
network as road traffic contributes an important part of these emissions (Fig.
5
).
The relative importance of road traffic as a source of NH
3
is increasing as other
sources are going down and, at the same time, as traffic is still increasing in Europe.
In general, nonagricultural sources of NH
3
are, however, still poorly explored, and
there are thus significant uncertainties associated with both magnitude and distri-
bution of these emissions (Fig.
5
).
