Theme 7. Danger in the modern urban environment.
Session 1. Danger in the modern urban environment.
content
| Name of question | time |
| Introduction | 5' |
| 1. Air pollution of cities | 20' |
| 2. Contamination of urban space | 20' |
| 3. Contamination of drinking water in urban areas | 20' |
| 4. Noise, vibration and electromagnetic pollution of cities | 20' |
| The final part. | 5' |
Tasks for independent work
1. Examine the lecture material [3], p. 234-246.
2. Search the web MPC(maximum allowable concentration) harmful substances in the atmosphere settlements MPC pollutants in drinking water.
Entry
Modern human civilization inherent rapid pace of urbanization. They are caused by two factors - the "population explosion" of the second half of the XX century, scientific and technological revolution in all spheres.
Urbanization (from Lat. Urbanos - City) refers to the process of urban growth and urban populations and enhance their role in the socio-economic and cultural life of society. Methods of cities in history were different. City emerged as a consistent settlement of craftsmen, which facilitated their production activities, as centers of trade as a military fortification (Fortress).
The process of global urbanization began in Europe, where he first began to form due to the concentration of the means of production, heavy industry. Becoming urbanization began at the turn of XVIII-XIX century, when the city in Western Europe focused most important means of production, and sat down key positions in the world economy. Local Development spawned a spatial sequence of global urbanization: Western Europe - North America - Australia and Oceania - Eastern Europe - Latin America - Asia - Africa.
Even today in many countries, especially industrialized, the proportion of urban population is 85-90% or more in its general population. According to the UN Commission on Population at the beginning of the XXI century in cities will live at least 51% of the total world population, while in 1970 the share of the urban population was 38.6%. Emerging and growing multi-city - metropolises (New York, London, Tokyo, etc.)., Increasing their number, size and problems.
Manifested urbanization process in Ukraine. Until 1918 the country was agrarian, and in urban areas 18% of the population. Intensive urbanization started in Ukraine in 1926-1939, during which time embarked on industrialization of the economy, that is just over 13 years, the urban population has increased by 2.4 times. Over the years 1940-1970, the urban population in Ukraine is growing much slower pace, because for 30 years it increased only 1.9 times. Since the mid 50-ies of XX century began a new phase of intensive growth of cities and urban population in Ukraine. Only in the last 30 years the share of urban population in Ukraine increased by 2.2 times and totaled at the end of XX century, about 70% of the total population. As the number of large cities (with a population of over 100 thousand), our state now occupies one of the leading countries of the world, these cities now - 61. In Ukraine there are 7 cities with a population that exceeded or almost reached a million people: Kyiv, Dnipropetrovsk, Odessa, Donetsk, Kharkiv, Zaporizhzhya and Krivoy Rog. By the way, for Kyiv last 30 years was characterized by extremely intense demographic growth: the number of its population grew almost 2.5 times and reached 3 million inhabitants.
Urbanization can not be considered without regard to the development of production, including heavy industry, energy, chemical industry and so on. Along with increasing industrial capacity, creating new industries in major cities growing population. Modern cities - centers of a diversified industry, an extensive transportation network in densely populated residential areas. And the most important source of urban population growth has been and still remains migration of rural residents to cities. It accounts for more than half the urban population growth in Ukraine.
The modern city offers its residents many advantages of economic, social and subjective nature, namely:
Ø availability of work and the ability to change work;
Ø concentration of institutions of science and culture;
Ø providing high quality medical care;
Ø to create better living and social conditions of life;
Ø development of international and regional culture.
Despite the advantages of urban life, urban environment for people is artificial and detached from the natural order, which took place thousands of years of their lives. Artificial urban environment harmful to human health through air pollution, lack of sunlight, water, and stress factors caused by traffic life gatherings population, lack of green space and more. Also dangerous for people in make noise, vibration loads, traffic problems, the influence of electric, magnetic, field ionization.
So, in large cities exacerbated all parties livelihoods of people: supply enough full of food and drinking water, control and prevention of air pollution, water resources, soils, recycling and disposal piling harmful industrial and household waste, as well as social problems, connected associated with a sharp decrease in free "living" space, urban growth in height, increasing diseases caused by pollution, and others.
Define the main dangers of life in urban environments.
Air pollution of cities
The main sources of air pollution are transport, energy and industry of the city.
In urban areas concentrated the bulk of vehicles. This cargo, private and public transport. Motor provides 70% of all toxic emissions. The share of road transport pollution in their total number is: in Uzhgorod - 91%, Yalta, Poltava - 88%, Ukraine - 79%, Kiev - 75%. Recently in urban air volume increased carbon oxides, hydrocarbons, oxides of nitrogen, carbon black. But the greatest danger, except for nitrogen oxides, sulfur and are lead compounds. their concentration in urban air greatly increased. Cities are not adapted to such a number of vehicles. Length of run nonstop between lights is only 400-600 m, resulting in an average speed of night in the city center (including Kyiv) and major highways reduced to 12-20 km / h, and it increases fuel consumption by 3-4 times. According increases and emissions. Motor also leads to specific forms of air pollution. When the motion blurred bus and thousands of tons of rubber in the form of dust into the air. Urban road transport not only pollutes the air combustion products, it leads to an increase of lead in the environment. In Ukraine still use gasoline containing lead 0.36 g / l, while in England, Germany and the U.S. - 0,013-0,15.
Cities - the main consumers of energy. City consumes energy in various forms. Quite commonly used fossil fuels - coal, oil and natural gas. This in itself defines pollution containing products of combustion. In residential buildings and industrial facilities energy falls in the form of electricity, gas, steam heating.
Reduced air quality is dangerous to the health of urban residents. Person per day takes an average of 25 kg of air. Even if the relative content of pollutants in the air is negligible, their total amount that enters the body when breathing, may be toxic. The most common contaminants air pollution is carbon monoxide. Excessive amounts of this gas in air leads to rapid fatigue Rights, headache, dizziness, weakening of memory, disorders of the cardiovascular and other body systems.
Contamination of urban space
Specificity of residence in the city leads to the fact that people are 80 - 95% of their time indoors (houses, subway, offices, etc.). One measure of the quality of urban life is the air space. According to the Agency by the U.S. EPA, the air inside the urban areas polluted 100 times higher than outside.
Other toxic materials - oil paints and solvents, carpet glue, furniture polish, of which stand benzene, toluene and other substances.
Causes of air pollution areas
Ø pollution from burning
Ø wood charcoal in fireplaces
Ø unventilated fumes from gas stoves and water heaters
Ø aerosols
Ø cleaners that contain chlorine or ammonia
Ø lacquer and wax flooring
Ø humidifiers
Ø spray against insects (insecticides)
Ø tobacco smoke
Ø Measures to improve indoor air quality:
Ø effective tool against toxins - house plants;
Ø instead of air fresheners use vinegar, pour it into a bowl and putting 1-2 hours in the room, enclosed in small spaces (refrigerators, WC) put an open box of baking soda, make the room a fresh branch of fir or pine;
Ø instead of bleach to use baking soda or borax;
Ø do regular wet cleaning and ventilation;
Ø a kitchen exhaust cabinet;
Ø not leave open bottles of cleaners and disinfectants.
