Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

Nitrogen oxide emissions and major sources of emissions in Latvia, 
tons per year 
Sector / Year
1990
2000
2005
Emission
Proportion, 
%
Emission
Proportion, 
%
Emission
Proportion, 
%
Energy production
1648
24
696
18
635
1544
Fuel use and production
1022
15
341
9
426
1037
Transport
2660
40
1903
50
2150
5228
Commercial, household and other 
incineration unrelated to production 
906
13
520
13
529
1285
Industrial production processes
346
5
284
7
319
775
Agriculture and forestry
22
0.3
41
1
0.4
1
Total emissions
6604
100
3788
100
4112
100
Nitrogen  oxide  emissions  from  traffic  are  significantly  more 
difficult  to  control  because  the  lowering  of  fuel  –  air  mixture 
temperature leads to an increase of CO and hydrocarbons in 
the exhaust gases. The applied methodology includes electronic 
ignition timing control, recirculation of exhaust gas enriched with 
fuel,  however,  one  of  the  most  effective  methods  is  considered  to 
be the catalytic reduction of nitrogen oxides in the presence of CO 
and hydrocarbons with their subsequent oxidation, additionally 
supplying air.
Of the other nitrogen compounds that are relevant regarding 
the environ mental pollution, the ammonia should be mentioned. 
Relatively large quantities of ammonia are released into the environ-
ment  as  a  result  of  different  natural  processes.  The  main  natural 
sources of ammonia emissions are the organic matter decomposition 
processes.
Elevated ammonia concentrations can be found in the human 
living and working environ ment, such as cattle, drainage systems, 
etc.  Ammonia  is  widely  used  in  various  technological  processes, 
production of fertilizers, agriculture and as a refrigerant.

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