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

Figure 7.10. 
Formula of 
sulphur dioxide

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7. AIR POLLUTION
 127
Industrial Revolution. The sulfur compounds have been extracted 
from the litho sphere in such processes as mining of ores (many 
metals are in the form of sulfide and sulfate ores), fuels (coal, oil, 
peat) burning and fertilizer production.
Natural sulfur compound sources are evaporation from water 
reservoirs (potassium, sodium sulphate-containing aerosols are 
form ed), volcanic activity, forest fires. As a result of natural sulfur 
emission from biological sources the most widespread substances 
released in the atmo sphere are hydrogen sulphide and sulphates. 
Hydro gen  sulfide  lifetime  in  the  atmo sphere  is  only  a  few  hours. 
In contrast, SO
2
 and sulfates last quite a long time and by the air 
masses can be carried over long distances. 
Actually,  the  atmo spheric  concentration  of  sulfur  compounds 
in the air in Europe almost undoubtedly depends on the proximity 
of pollution sources. The comparatively unpolluted parts of Europe 
(12% of the territory) are characterized by SO
2
 concentration of 
0.35  µg/m
3
 (converted to elemental sulfur). In a slightly polluted 
environ ment  SO
2
 concentration is 3.5 to 4 µg/m
3
. In heavily conta-
mi nated areas SO
2
 concentration in the air can reach 50 µg/m
3
. 
0
100
200
300
400
500
600
700
1991
1995
2000
2005
2010
Th. tons/yea
r
Year
Mobile sources
Stationary sources
0
5
10
15
20
25
30
35
40
45
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2010
2015
2020
Amount, 
Th. tons
NO
x
SO
2
The main source of ant‑
hropogenic sulfur dioxide 
is burning of fossil fuels. 
All fossil fuels include 
sulfur, either as organo‑
sulfur compounds, or to a 
lesser extent as elemental 
sulfur and hence, as a 
result of fuel combustion, 
sulfur(IV) oxide is formed.
S + O
2
 → SO
2
 
SO
2
, which is released 
into the atmosphere 
as a result of various 
anthropogenic processes, 
oxidizes forming sulfur(VI) 
oxide SO
3
.
SO
2
 + O → SO
3