A speech on air around us for 3 minutes.
Answers
Causes of Air Pollution:
There are two sources of air pollution:
(a) Natural Sources:
hTere are many natural sources of air pollution, such as volcanic eruptions, forest fires, dust storms, pollen grains of flowers, spores of fungus, etc.
(b) Man-made Sources:
Air pollution is also due to human activities.
There are many causes of air pollution which are discussed below:
(1) Pollution by Industries:
The problem of industrial pollution is acute in areas where petroleum refineries, chemical industries, pulp and paper and textile industries are concentrated. Even small scale industries like foundries, and brick making are significantly air polluters.
(2) Pollution by Vehicles:
Increasing vehicular traffic is the most important source of air pollution in big cities. Other reasons for this are two stroke engines, old vehicles, traffic congestions, bad roads and obsolete automotive technologies and lack of traffic management system.
(3) Old Methods of Cooking:
People residing in shanty towns, slums and poorly ventilated houses and using household stoves, wood and coal for cooking, further increase air pollution in underdeveloped countries. Smoky indoor air mainly affects the health of women and children.
(4) Agricultural Activities:
Most of the pesticides are applied through spraying in the fields. This spraying increases the quantity of many chemicals used in pesticides in the surrounding atmosphere and hence pollutes the environment.
(5) Mining Activities:
Air pollution is mainly the outcome of the dust generated during mining and processing activities. During mining, dust arises from blasting excavation, crushing and transportation of ore, and from tips, stockpiles and de watered tailing. Huge quantities of dust become wind borne.
(6) Thermal Power Stations:
The power stations that use the combustion of coal or petroleum for the generation of heat and power produce smoke and sulphur dioxide (SO2). It has been estimated that thermal power stations emit about two-thirds of total sulphur dioxide released in air. These gases result in air pollution.
(7) Other Activities:
At many other sources which cause small amounts of air pollution. These include cigarette smoking, burning of heaps of solid wastes, air conditioning appliances, diesel generation sets, and construction activities etc.
Effects of Air Pollution:
Pollution of air differs in some aspects from pollution of waste. Discharges from industrial premises in the atmospheres are often more or less continuous during working hours and they can drift high or low and in any direction, depending on the wind and weather.
Air pollution is more widespread in its effects than other forms of pollution for people who have to breathe the air. Air pollution creates cancroid not only for the animates but also for the in-animates. World wonder Taj Mahal at Agra is a burning example of stone cancer. But the immediate effect of air pollution can be seen on human beings.
(i) Effects on Human Beings:
It is a universal truth that air pollution has an adverse effect upon human health. Cause and effect relationships have been proved between air pollution and diseases. It has been proved that people living in polluted areas are suffering from certain diseases than people living in fresh air.
Air pollution generally enters human body through the respiratory system and thus causes many respiratory disorders. Moreover, toxicity due to absorbed toxic substances also affects human health. For example, lead particles from vehicle exhaust in higher dose can kill outright but in lower dose, can shorten life span by causing deterioration of the nervous system.
(ii) Effects on Vegetation:
Air pollution can affect plants to changing degrees, depending upon the level of air pollution. It causes injury to sensitive plants. Suspended particulates after deposition on leaves affect the photosynthetic activity. Several chemicals such as insecticides, herbicides, fungicides and pesticides used widely in agriculture are known to produce foliar lesions, chlorosis and abscission of leaves and reduction in fruit set. Several other types of particles in air such as coal dust and asbestos have been linked with necrotic lesions, reduction in fruit set in plants, silicosis and lung cancer respectively.
(iii) Change in Weather:
Emissions into the air that are intended to cause changes in the weather, such as local rainfall, and others that are suspected of causing permanent atmospheric changes are of special nature. Quite recently concern has been expressed over the fate of the ozone layer enclosing the earth and the possible effects on climate.
(iv) Effect on Visibility:
Atmospheric particulate due to fuel combustion for industrial and household heating purposes can scatter and absorb sunlight and hence reduce visibility.
(v) Other Effects:
The effect of particulate matter includes corrosion of metals, erosion and soiling of buildings, sculptures, etc.