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

Particle size, mµ
100
80
60
40
20
Removal degree, %
Nose
Trachea
Alveoli
A significant group of aerosols are those of an organic compo-
si tion. Their source can be either natural processes (plants, forest 
fires, decomposition of organic matter), or anthropogenic processes. 
Human health can be particularly negatively affected by metals (Pb, 
Hg, Cu, Ni, Be), radioactive isotopes and organic matter present 
in  the  aerosol  composition.  Aerosol  effect  most  rapidly  manifests 
itself when the particles are inhaled and held in the lungs (coarser 
dust particles are retained in the nasal cavity and upper airways, 
while the finer particles may be exhaled). Such aerosols are called 
inhalable aerosols. These aerosols have the following effect:
1. When the substances sorbed on aerosol surface desorb and move 
into  the  blood  or  lymphatic  system.  This  effect  is  particularly 
charac teristic of various combustion products. The aerosols 
which are products of combustion consist of carbon, and the 
The most probable aero‑
sol constituent elements 
come from the following 
sources:
Al, Fe, Ca, Si – soil erosion, 
C – incomplete combus‑
tion of fossil fuels;
Na, Cl, SO
4
2–
 – sea, ocean 
aerosol, the burning of 
fossil fuels;
Pb – fuel and waste 
burning.
Figure 7.19. 
Retention 
of the aerosols in the 
human respiratory 
system depending on 
the size distribution 

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7. AIR POLLUTION
 141
aerosol surface usually holds quite high concentrations of 
different organic substances, which are created both due to in-
complete combustion, as well as thermosynthesis process. Such 
aerosols contain the following groups of substances: 
 
Š
aliphatic hydrocarbons. Usually, they are very long-chain 
alkanes with carbon atom numbers reaching even 24; 
 
Š
aromatic hydrocarbons.  Aerosols  of  combustion  contain  not 
only low molecular weight aromatic hydrocarbons (benzene, 
toluene),  but  also  the  polyaspartic  hydrocarbons  –  benzo[a]
pyrene, chrysene, benzo[a]fluoranthene, benzo[a]anthra cene, 
naphthalene, anthracene and others. Desorbing and entering 
the body, these substances can cause malignant tumors not 
only in the lungs but also in other organs; 
 
Š
aldehydes and ketones, as well as carboxylic acids; 
 
Š
polyaromatic and heterocyclic compounds, such as benz acri-
dine, dibenzacridine, which also are characterized by highly 
carcinogenic effect; 
 
Š
organochlorine compounds. 
2. Particularly  fine  particles  can  get  into  the  blood  or  lymphatic 
system from the lungs. An example of such particles is asbestos 
fibres.
3. Aerosol particles can remain in the lungs, become calcified, thus 
causing permanent irritation. This type of aerosol exposure is 
inherent  to  occupational  diseases  –  asbestosis  and  silicosis, 
caused by inhalation of air polluted by mineral particles. 
4. Micro-organisms, bacteria or fungi residing on aerosol and dust