Chemistry Reference
In-Depth Information
Fig. 8 The relative distribution between different NH
3
sources in national emissions for selected
European countries. Data is here derived for the year 2000. Source: [
1
]
1989
2000
12
12
10
10
8
8
6
6
4
4
2
2
0
0
1
31
61
91
121
151 181
211 241
271 301
331 361
1
31
61
91
121
151
181 211
241 271
301 331
361
Day
Day
Buildings
Crops
Grazing
Other
Art. Fertilizer
Manure
Fig. 9 Temporal variation in daily NH
3
emission [g N/ha/day] from different source categories at
the monitoring site Tange, Denmark, for the years 1989 (
left
) and 2000 (
right
). Source: [
51
]
4 Site-Specific Long-Term Trends in Emissions
Before 1989, Danish NH
3
emissions were relatively low during winter time as a
result of low activity and low ambient air temperatures. The accumulated manure
during winter was applied not only to crops in the fields during spring but also to
grass fields during summer. The manure storages were emptied in autumn, thereby
leading to autumn emissions (Fig.
9
). This pattern is still typical in Northern Europe
with moderate to large agricultural activity and limited legislative control.
In the 1990s, strong regulation was implemented to reduce Danish agricultural
emissions to air, soil and water [
16
,
51
,
84
]. This regulation had various steps and
included improving the entire production chain with respect to reducing NH
3
emissions. The farmers had to increase the fraction of manure applied during
growth of the crops in spring and similarly decrease application in summer and
autumn. This is seen in the results for 2000 shown to the right of Fig.
9
, where the
