Atmospheric pollution is one of the most common and most complex forms of urban exposure to the environment.
The air in the city is polluted by solid particles, dust, soot, ash, aerosols, gases, vapors, smoke, pollen, etc. The mixture of pollutants seriously complicates the assessment of the impact of each individual component, which, interacting, increase the negative consequences.
The leaves are able to perform an important sanitary and hygienic role, absorbing toxic gases, accumulating harmful substances in the covering and then internal tissues. Some toxic substances flow from the leaf and are localized in the shoots, growing leaves, fruits, tubers, bulbs, roots. The amount of fluorides, chlorides, oxides of sulfur, accumulating in all organs of plants, in total is not more than 20% of their content in the leaves.
Woody vegetation can perform these functions only under the condition that “the concentration of aerosols, especially in the liquid or gas phases, does not reach the limits that are detrimental to their living cells
In nature, there are no plants concentrating all heavy metals, each plant accumulates certain elements. For example, the dandelion medicinal and wormwood accumulate copper, zinc, iron, lead, manganese; mustard field and white – selenium; Sakhalin buckwheat and corn – lead; Highlander, sorrel and buckwheat – cadmium. Properly picking up the plants, you can clean the soil from impurities of heavy metals.
Forests are of great importance in protecting gardens from toxic compounds of automobile emissions. It is estimated that a single adult tree neutralizes the amount of lead contained in 130 liters of leaded gasoline during the growing season. Behind the three-tiered green curtains of the forest belts the concentration of sulfur dioxide decreases by a factor of 5 and nitrogen dioxide by a factor of 8. Copper, cadmium, zinc pedunculate oak and pine are the most intensively accumulated.
Most of us are convinced that vegetables, greens, berries and fruits grown in our garden are not only the most delicious, but also the most healthy. However, one can agree with this opinion only if the garden is located in an ecologically clean place and is provided with appropriate care. Quite a different situation on the garden plots, which are located near highways, industrial facilities or railways. There are other reasons that make you think about this difficult problem.
Also, Most plants show maximum antibacterial activity in summer, when the air of parks contains 200 times less bacteria than street air. When selecting plants for landscaping cities, it is necessary to take into account their bactericidal properties. Plantings should be placed on the windward side in relation to the place of stay of the person
With the development of cities, the problem of noise control is becoming increasingly acute. Noise adversely affects the human body: is the cause of its partial or complete deafness, causes cardiovascular and mental illness disrupts metabolism. To protect residential areas from noise, you must make the most of urban green construction.
Green spaces, located between the source of noise and residential buildings, areas for recreation, can significantly reduce the noise level. The effect increases as plants approach the source of noise; The second group should be placed directly near the protected object.
Sound waves, bumping into leaves, needles, branches, tree trunks of various orientations, are scattered, reflected or absorbed. Crown deciduous trees absorb about 25% of the incident sound energy.