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

Particle size, µm
 
The choice of optimal gas treatment methods is determined by 
aerosol concentration, their composition, presence of other gases, as 
well as economic considerations. 
 7.5. 
 Halogenated organic compounds in the 
atmosphere 
Typical air pollutants contained in the atmo 
spheric air 
composition are various halogen compounds. Since the elementary 
halogens are very reactive, they are not found in the atmo sphere 
in  a  free  form.  However,  production  processes  involve  significant 
amounts of various halogen derivatives, therefore both the living 
environ ment and the atmo spheric pollution by halogen derivatives 
is possible. Given the high toxicity of halogen compounds, environ-
mental pollution by halogenated compounds is considered to 
be dangerous, as these can be discharged, when many halogen 
compounds are released into the environ ment. For example, many 
metal and non-metallic chlorides, which are widely used in the 
manufacture, in contact with water or damp air intensively form 
hydrogen halides. Examples of such substances are aluminium, 
titanium and tin chlorides (AlCl
3
, TiCl
4
, SnCl
4
), as well as silicon and 
phosphorus chlorides (SiCl
4
, PCl
3
, PCl
5
, POCl
3
).
Among the many environ mental pollutants the organohalogens 
occupy a special place not only for their toxic effect, but also because 
of the fact that it is this group of substances, which historically 
enabled understanding of the pollution impact in the biosphere. 
Production of synthetic halogenated organic compounds, 
which  started  about  50-70  years  ago,  has  now  reached  significant 
dimensions and includes many groups of substances, as well as 
a wide scope of application: industrial production, agriculture,