Air pollution

Air pollution designates a mixture of atmospheric smoke, mineral rich dust, sulphur dioxide, nitrogen oxides, sulphur and nitrogen based acidifying compounds, fluorine, photo-oxidants such as ozone and PAN, and air toxics.

 

Air pollution in the Czech Republic is negatively affected by its position in the middle of industrial Europe. In practically all directions polluted air is drawn into the Czech Republic, particularly by northern and western winds (see Figure 1, Wind direcion and speed over Europe 24.10.94 - 1.11.94 see Figure 2, Wind direction and speed over Europe, 28-10-95 - 1-11-95). The Czech Republic, however, produces a lot of its own pollution where large amounts of high sulphur coal are burned at relatively unsophisticated plants.     

 

Figs. 3 and 4 show the high sulphur emissions and deposition for the Czech Republic. Changes in the types of fuels used, economic shifts and desulphurisation have led to reductions in primary pollutants such as sulphur emissions. By 1995 total emissions of principle pollutants decreased by 36% and solid pollutants by 68% in comparison with the emissions of 1990. But despite these positive trends S02 emissions remain high, 106kg annually per capita, in comparison with 28kg annually per capita in European OECD countries.

Figure 3, The emissions and deposition of sulphur for some countries in Europe

     

Figure 4, Sulphur precipitation for Europe

 

Acid precipitation, as with much of Europe has been a problem in the Czech Republic. It is rain or snow possessing a pH less than 5.6 (the pH of pure water in equilibrium with atmospheric concentrations of C02). It is produced by regional enrichment of air with 502 and N02 which subsequently oxidise to form sulphuric acid (H2504) and nitric acid (HN03). It can have a disastrous effect on the environment

 

    Damage to vegetation:

 

- Acid mists cause direct damage through attack on the leaf

- Acid precipitation can acidify poorly buffered soils

- Soil acidification can lead to changes in biota and mobilisation of toxic heavy metals

- Forest decline has been well documented with the mobilisation of toxic aluminium (AI) and the reduced availability of magnesium (Mg) leading to foliar magnesium deficiency

 

    Effects on surface waters: 

 

- Decreasing pH of surface waters

- Fish and amphibian populations of lakes decrease, a pH range of 6-9 is desirable to support a good fish stock, below 5 the health of fish is affected

- Lower pH increases aluminium (A1) solubility which is toxic to fish, affecting the gill by altering the active uptake of sodium ions (Na+)

- Acid rain arriving as snow can lead to a massive pulse of acid when the snow melts destroying aquatic life

 

The worst air pollution in the Czech republic occurs in the Black Triangle where northern Bohemia borders Germany and Poland. Industry here emits some 1,400000 tonnes of sulphur annually).

 

Figs. 5 show that the average pH for rainfall from 1993-1995 in Vsetín region is 4.5-4.9 pH which is classed as acidic. But precipitation can be variable, from 31. 10.95-3. 11.95 the pH was very acidic 4.0-4.4 over Vsetín region .Figs. 6 show pH rainfall for Czech Republic from 24.10.95 - 1.11.94.  Figs. 7 show pH of rainfall for Czech Republic from 28.10.95 - 3.11.95.

 

Vsetín region, and especially the Beskydy mountains, however, have some of the cleanest air in the Czech Republic, second only to Šumava. This is proven by mainly the high diversity of Lichens in the region . Lichen diversity offers an excellent method of estimating the pollution concentration at a given site and are particularly sensitive to S02 (see Table).

 

The physiological responses of lichens after exposure to fumigated pollutants

 

Response

Pollutant

Reduced photosynthesis

S02, NaHSO3, NaS2O5, 03, PAN

Reduced respiration

S02

Decreased chlorophyll content

S02, NO2,HF

Increased electrolyte leakage, loss of K

S02, HF

Reduced nitrogen fixation

S02, H2S04>1oss with <pH>exposure, NaHS03, NaF

 

The east and southern parts of Vsetín region have the largest diversity and number of lichens with the north and northwest having less species due to the greater air pollution here from Ostrava. The industrial development of Vsetín region itself has had an effect on air quality and subsequent growth of lichens around industrial areas. Crustose are the most resistant lichens and were the only type found to be growing near the DEZA Corporation plant in Valašské Meziříčí. But downwind of the plant no lichens were found at all. Most lichens cannot survive extended periods of S02 exposure above 60mg/m3 and so possibly reflects the emissions downwind of DEZA Corporation.

 

There are considerable fluctuations of air pollutants in the event of very infavourable dispersion conditions. Persistent temperature inversions can cause a high concentration of pollutants and mainly occur in NW and central Bohemia and Ostrava region (north Moravia) in the Czech Republic. Since a substantial part of the Czech Republic's industrial potential is concentrated in these areas this particular regional climate feature has negative impacts on air quality.The Vsetín region has two main valleys of the Rožnovská Bečva and Vsetínská Bečva. Valleys can create inversions with cool mountain air draining into warmer valleys at night producing an advective inversion, concentration pollutants.