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

Figure 5.14. 
Changes in 
the total sulphur dioxide 
emissions in the EU 
Member States 
Figure 5.15. 
Sulphur 
dioxide emissions 
according to their 
sources in the EU 
Member States (2007)

---

5. GLOBAL ENVIRONMENTAL PROBLEMS
 89
sulphuric acid solution is the end-product of these transformations. 
The fallout of compounds formed as a result of sulphur dioxide 
oxidation occurs in the forms of rain and snow (wet deposition) as 
well as dust (dry deposition).
In high concentrations, sulphur dioxide causes severe respiratory 
irritation. Since sulphur dioxide is soluble in water, when breathed 
in, it can already be sorbed by the nasal and airway mucosa, 
whereas sulphur dioxide penetrates the lungs. This is one of the 
factors causing the harmful effects of smog, as it is formed in humid 
air and has a high dust content.
When the daily average concentration of sulphur dioxide 
reaches 500 µg/m
3
, it aggravates the condition of people suffering 
from asthma and pulmonary diseases, whereas an increase in 
hospitalisation rate has been observed at concentrations reaching 
750  µg/m
3
. The sulphur dioxide concentration in the air reached 
4000 µg/m
3  
during the London Great Smog of 1952.
Sulphur  dioxide  also  adversely  affects  plant  growth.  High 
concentrations of sulphur dioxide can cause necrosis or death of plant 
tissue, while chlorosis – pale, yellow or yellow-white leaves because 
of  insufficient  chlorophyll  –  is  characteristic  of  chronic  exposure. 
The harmful effects of sulphur dioxide are amplified with increasing 
humidity. Sulphur dioxide inhibits the photosynthesis and respiration 
process in plants and causes damage to cell membranes. The extent of 
plant damage depends on the balance of nutrients and trace elements 
and also on the presence of alkaline compounds in the soil in which 
the plant is growing. The indirect effects of sulphur dioxide – causing 
environ mental acidification because of a drop in the pH level of 
precipitation – affect the condition of plants and forests, as well as 
aquatic ecosystems and processes taking place there.