Охотник Е. К., Тимошенко Ж. И., Демиденко А. С.

Днепропетровский национальный университет имени Олеся Гончара

METEOROLOGICAL ASPECTS OF AIR POLLUTION IN THE BUILT ENVIRONMENT

Atmospheric air is a basic essential elements of the environment, and is significant for the normal existence of most terrestrial organisms.

Most of the world's population lives in cities. This is primarily due to the fact that the city is the center of the financial, economic and scientific development. However, there is an opportunity to select not only the positive aspects of urbanization, but negative, for example, disruption of the ecological balance. One of the most important environmental problems of urban areas is a significant pollution of surface layers of air. Primarily, this is due to the amount and intensity of the source of pollution, but also the important role played by the meteorological conditions that may contribute to a dispersion of pollutants and cause the increase of their concentration.

The goal of our research is to study the influence of meteorological factors on the air of the city. Methods of study of the relationship based on the results of theoretical and experimental study of the laws of distribution of pollutants.

The climate city of Dnepropetrovsk city is temperate, with mild winters and warm summers. The average annual temperature is 9,0°C, the lowest it in January (minus 3,7°C), the highest – in July (22,1°C). In an average year in Dnepropetrovsk falls 513 mm of precipitation, less of them in March and October, most of all – in June and July. The relative humidity in an average year is 74%, the lowest (61%) in August, the highest (89%) – in December. The smallest clouds observed in August, the highest – in December. The most frequency in the city there are winds from the north, the least – from the north-west and south-west. The highest wind speed – in January and February, the lowest – in the summer. In January, it was an average of 5.4 m/s in July – 3.7 m/s.

In calculating and modeling air pollution should consider architectural and planning features of the urban area that contribute to the formation of the local climate, and are the cause of differences in climate built environment on climate suburban area. The city has a special microclimate conditions which depend on topography, emissions enterprises, heat balance changes.

All meteorological factors affect air pollution. There is a relationship between the concentration of the pollutant and the speed of the wind. Increasing wind speed facilitates dispersion of contaminants in the atmosphere and drives out of the city a lot of polluted air, clean the urban industrial environment. However, strong wind promotes mixing the air layers, as a result of contaminants received from high sources, fall into the lower layers of air, there is a growth in their concentrations at the surface. But defined dangerous wind speed does not exist, which influence on the increase of air pollution. Precipitation cleanse the air, the effectiveness of cleaning depends on the amount and duration of precipitation. Increased humidity can cause both air purification and increase the toxicity of pollutants.

The spreading of pollutants depends on the type of the sources of pollution. According to some experts who have investigated the influence of meteorological factors on the level of air pollution of big cities, it was found that the relationship between the level of contamination by some impurities and meteorological conditions is low. This is related with a wide range of heights of sources of pollutants in the atmosphere and lots of them.

Thus, it may be noted that apart from the obvious advantages of urbanization creates a number of problems, including environmental ones. Human activity affects the micro-and mesoclimate characteristics of urban areas, thus forming climate, typical for large cities. In turn, climate change leads to changes in weather that affect the nature of the spread of pollutants and the atmospheric air of the city as a whole. An important objective is to study the pollution, and the need to take into account the natural and human factors, to select for this purpose the most appropriate mathematical model and visualize the data with the help of modern information technology.

Implementation of all these conditions is the basis for reasoned decision making. Thus, taking into account the formation of the actual weather conditions and the conditions of the climatic zones activities to improve the urban environment carry out:

· management measures wind speed and ventilation of the city (urban planning and streets, orientation of buildings, creation of trees and shrubs and herbaceous plantings of various types, water systems, etc.);

· measures to control the relative humidity of the air (creating ponds and streams, increasing the surface area with natural permeable cover, watering green areas, cleaning streets and squares, etc.);

· measures to combat air pollution by placing polluting facilities outside the city or in the lee of the city (creating chimneys which contribute to pollutant dispersion, effective use of abatement equipment, transition to less toxic fuels, etc.);

· measures to regulate the incoming solar radiation (layout of streets and neighborhoods, green spaces, the use of different-level building, painting the walls, roofs and bridges, the design of buildings and their components, etc.).

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