As we just breafly explained in the previous article Pure Air, air is the most important for our survival. However, air can be easily polluted by the changes in atmosphere due to human occupation. For example, 1. changes due to respiration op people and animals – these are chiefly carbon dioxide, water vapors and organic matter and oxygen diminishes. It also raises the temperature; 2. changes due to combustion (of coal gas, oil, etc.) – mainly air pollution derived from coal in the process of combustion by the oxidation of carbon of the air is carbon dioxide. Carbon monoxide may also be formed by combustion; 3. decomposition (of organic – animal and vegetable matter) there are released poisonous gases such as carbon dioxide, hydrogen sulphide, ammonia, carbon disulphide etc. Bacteria and fungi also grow rapidly in such air; 4. trade, traffic and manufacturing processes which give off dust, fumes, vapors, gases (due to dust etc.) – the inorganic particles of dust are chiefly composed of silica, aluminium silicate, carbonate, carbon magnesium and sodium
In cities, the most complex anthropogenic formations, a specific and often unfavourable ecological environment for man’s life has been created. All around we can find only concrete buildings, pavements, cars, crowded streets, therefore air pollution can not be avoided. If we compare the quality of air in cities with those in rural areas, it can be concluded that it has much less oxygen and more bacteria and germs. One of the best assistants in the fight against harmful gases, dust and soot, and a good regulators of gas exchange are green areas, and their most important element – vegetation.