POLLUTION OF AIR & WATER

POLLUTION OF AIR& WATER

AIR We know that we can survive for some time without food, but we cannot survive even for a few minutes without air.

This simple fact tells us how air is very important for us.

You already know that air consist of a mixture of gases. By volume, about 78% of this mixture is nitrogen and about 21%is oxygen. Carbon dioxide, argon, methane, ozone and water vapour are also present in very small quantities.

AIR POLLUTION

Do you know where the smoke could have come from? Addition of such substances to the atmosphere modifies it. When air is contaminated by unwanted substance which have a harmful effect on both the living and the non-living, it is referred to as air pollution.

Video of AIR POLLUTION

The Gaseous Composition of Unpolluted AirThe GasesParts per million (vol)Nitrogen756,500Oxygen202,900Water31,200Argon9,000Carbon Dioxide305Neon17.4Helium5.0Methane0.97-1.16Krypton0.97Nitrous oxide0.49Hydrogen0.49Xenon0.08Organic vapoursca.0.02

How does Air Get Polluted? The substance which contaminate the air are called air pollutants. Sometimes, such substances may come from natural sources like smoke and dust arising from forest fires or volcanic eruptions. Pollutants are also added to the atmosphere by certain human activities. The sources of air pollutants are factories, power plants, automobile exhausts and burning of firewood and dung cakes.

Do you know? Vehicles produce high levels of pollutants like carbon monoxide, carbon dioxide, nitrogen oxides and smoke. Carbon monoxide is produced from incomplete burning of fuels such as petrol and diesel. It is a poisonous gas. It reduces the oxygen-carrying capacity of the blood. If the vehicles registered in Delhi are lined up one after the other, the total length would be nearly equal to the combined lengths of the two longest rivers in the world, Nile and Amazon.

Many industries are also responsible for causing air pollution. Petroleum refineries are a major source of gaseous pollutants like sulphur dioxide and nitrogen dioxide. Sulphur dioxide is produced by combustion of fuels like coal in power plants. It can cause respiratory problems, including permanent lung damage.

Indoor air pollution It refers to the physical, chemical, and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. Indoor air pollution is a concern in the developed countries, where energy efficiency improvements sometimes make houses relatively airtight, reducing ventilation and raising pollutant levels. Indoor air problems can be subtle and do not always produce easily recognized impacts on health. Different conditions are responsible for indoor air pollution in the rural areas and the urban areas.

In the developing countries, it is the rural areas that face the greatest threat from indoor pollution, where some 3.5 billion people continue to rely on traditional fuels such as firewood, charcoal, and cowdung for cooking and heating. Concentrations of indoor pollutants in households that burn traditional fuels are alarming. Burning such fuels produces large amount of smoke and other air pollutants in the confined space of the home, resulting in high exposure. Women and children are the groups most vulnerable as they spend more time indoors and are exposed to the smoke. In 1992, the World Bank designated indoor air pollution in the developing countries as one of the four most critical global environmental problems. RURAL AREAS

Daily averages of pollutant level emitted indoors often exceed current WHO guidelines and acceptable levels. Although many hundreds of separate chemical agents have been identified in the smoke from biofuels, the four most serious pollutants are particulates, carbon monoxide, polycyclic organic matter, and formaldehyde. Unfortunately, little monitoring has been done in rural and poor urban indoor environments in a manner that is statistically rigorous.

URBAN AREAS In urban areas, exposure to indoor air pollution has increased due to a variety of reasons, including the construction of more tightly sealed buildings, reduced ventilation, the use of synthetic materials for building and furnishing and the use of chemical products, pesticides, and household care products. Indoor air pollution can begin within the building or be drawn in from outdoors. Other than nitrogen dioxide, carbon monoxide, and lead, there are a number of other pollutants that affect the air quality in an enclosed space.

Volatile organic compounds Volatile organic compounds originate mainly from solvents and chemicals. The main indoor sources are perfumes, hair sprays, furniture polish, glues, air fresheners, moth repellents, wood preservatives, and many other products used in the house. The main health effect is the imitation of the eye, nose and throat. In more severe cases there may be headaches, nausea and loss of coordination. In the long term, some of the pollutants are suspected to damage to the liver and other parts of the body.

Tobacco smoke Tobacco smoke generates a wide range of harmful chemicals and is known to cause cancer. It is well known that passive smoking causes a wide range of problems to the passive smoker (the person who is in the same room with a smoker and is not himself/herself a smoker) ranging from burning eyes, nose, and throat irritation to cancer, bronchitis, severe asthma, and a decrease in lung function.

Pesticides

Pesticides , if used carefully and the manufacturers, instructions followed carefully they do not cause too much harm to the indoor air.

Biological pollutants Biological pollutants include pollen from plants, mite, hair from pets, fungi, parasites, and some bacteria. Most of them are allergens and can cause asthma, hay fever, and other allergic diseases.

Formaldehyde Formaldehyde is a gas that comes mainly from carpets, particle boards, and insulation foam. It causes irritation to the eyes and nose and may cause allergies in some people.

Asbestos Asbestos is mainly a concern because it is suspected to cause cancer.

Radon Radon is a gas that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house causing harm to the dwellers.

Acid rainAnother effect of air pollution is acid rain. The phenomenon occurs when sulphur dioxide and nitrogen oxides from the burning of fossil fuels such as, petrol, diesel, and coal combine with water vapour in the atmosphere and fall as rain, snow or fog. These gases can also be emitted from natural sources like volcanoes. Acid rain causes extensive damage to water, forest, soil resources and even human health.

Many lakes and streams have been contaminated and this has led to the disappearance of some species of fish in Europe, USA and Canada as also extensive damage to forests and other forms of life. It is said that it can corrode buildings and be hazardous to human health. Because the contaminants are carried long distances, the sources of acid rain are difficult to pinpoint and hence difficult to control. For example, the acid rain that may have damaged some forest in Canada could have originated in the industrial areas of USA. In fact, this has created disagreements between Canada and the United States and among European countries over the causes of and solutions to the problem of acid rain. The international scope of the problem has led to the signing of international agreements on the limitation of sulphur and nitrogen oxide emissions.

Video of ACID RAIN

CHLOROFLUOROCARBONS (CFCs) Chlorofluorocarbons are other kinds of pollutants which are used in refrigerators, air conditioners and aerosol sprays. CFCs damage the ozone layer of the atmosphere i.e. ozone layer protect us from harmful ultraviolet rays of the sun.

Automobiles burn diesel and petrol, also produce tiny particles which remain suspended in air for long periods. They reduce visibility. When inhaled , they cause diseases. Such particles are also produced during industrial processes like steel making and mining. Power plants give out tiny ash particles which also pollute the atmosphere.

The Taj Mahal also get affected from pollution Taj Mahal located in Agra has become a matter of concern. Experts have warned that pollutants in air are discoloring its white marble. So, it is not only living organisms that get affected by polluted air but non-living things like buildings, monuments and statues also get affected.

GREENHOUSE EFFECT A part of the radiation that falls on the earth is absorbed by suns rays and a part is reflection back into space. A part of the reflected radiation is trapped by the atmosphere. The trapped radiations further warm the earth. The trapped heat warms the green house. The trapping of radiations by the earths atmosphere is similar. That is why it is called the greenhouse effect. Without this process, life would not have been possible on the earth. But now it threatens life. CO2 is one of the gases responsible for this effect.

GLOBAL WARMINGA Serious Threat! Global warming can cause sea levels to rise dramatically. In many places, coastal areas have already been flooded. Global warming could result in wide ranging effects gases at the present level. Otherwise, the temperature may rise by more than 2 degrees Celsius by on rainfall patterns, agriculture, forests, plants and animals. Majority of people living in regions which are threatened by global warming are in Asia. A recent climate change report gives us only a limited time to keep the greenhouse the end of the century, a level considered dangerous.

Video of GREENHOUSE EFFECT AND GLOBAL WARNING

What can we done to reduce air pollution? There are many success stories in our fight against air pollution. For example, a few years ago, Delhi was one of the most polluted cities in the world. It was being choked by fumes released from automobiles running on diesel and petrol. A decision was taken to switch to fuels like CNG and unleaded petrol. These measures have resulted in cleaner air for the city.There is a need to switch over to alternative fuels instead of the fossil fuels for our energy requirements. These could be solar energy, hydropower and wind energy.

WATER POLLUTION Water becomes dirty when we use it for washing clothes, bathing, etc. This means that we art adding some materials to the water, which spoil its quality and changes its smell and colour. Whenever harmful substances such as sewage, toxic chemicals, silt, etc., get mixed with water becomes polluted. The substances that pollute water are called water pollutants.

How does Water Get Polluted? Ganga is one of the most famous rivers of the India. It sustains most of the northern, central and eastern Indian population. Millions of people depend on it for their daily needs and livelihood. However, recently a study by the World Wide Fund for Nature found that Ganga is one of the ten most endangered river in the world. The pollution levels have been rising for many years. We have reached this stage because the towns and cities, through which the river flows, throw large quantities of garbage, untreated sewage, dead bodies, and many other harmful things, directly into the river. In fact the pollution levels are so high that aquatic life cannot survive. This Ganga story tell us how does Water Get Polluted

Many industries discharge harmful chemicals into rivers and streams, causing the pollution of water. Examples are oil refineries, paper factories, textile and sugar mills and chemical factories. These industries cause chemical contamination of water. The chemicals released include arsenic, lead and fluorides which lead to toxicity in plants and animals. There are regulations to prevent this. Industries are supposed to treat the waste produced before discharging it into waters, but quite often the rules are not followed. The soil is also affected by impure water, causing changes in acidity, growth of worms, etc.

Sometimes untreated sewage is thrown directly into river. It contains food wastes, detergents, microorganisms, etc. Water contaminated with sewage may contain bacteria, viruses, fungi and parasites which cause diseases like cholera, typhoid and jaundice.

Video of WATER POLLUTION

Do you know?

Hot water can also be a pollutant! This is usually water from power plant and industries. It is released into the rivers. It raises the temperature of the waterbody, adversely affecting the animals and plants living in it

Potable Water andWaterPurification

Portable Water Water which is suitable for drinking is called potable water. You have seen how various physical and chemical processes in the sewage treatment plants help to clean water before discharging it into water bodies. Similarly, municipal bodies treat the water before supplying it to households.

Do you know?

25% of the worlds population is without safe drinking water!

How is Water Purified?You have already seen how water is filtered. This is a physical method of removing impurities. A popular household filter is a candle type filter.Many household use boiling as a method for obtaining safe drinking water. Boiling kills the germs present in the water.Chlorination is a commonly used chemical method for purified water. It is done by adding chlorine tablets or bleaching powder to the water. We must be cautions. We should not use more chlorine tablets than specified.

We can think of creative ideas like reusing water used for washing and for other household tasks. For example, water used for washing vegetable may be used to water plants in the garden.

Pollution is no longer a distant phenomenon. It is affecting the quality of our daily lives. Unless we all realise our responsibility and start using environment-friendly processes, the very survival of our planet is in danger.

Do you know? While brushing your teeth, leaving the tap running may waste several liters of water. A tap that drips once every second wastes a few thousand liters of water every year. Think about it!

SLOGANS FOR POLLUTION1. Be part of the solution, not of air pollution2. Earth loves you. Love it back.3. Join the revolution and stop the pollution4. Enjoy nature. Recycle.5. I have a dream and it's Green

6. Give our children a Green Future7. Nature is life. No nature no life.8. Forever Green 9. Fresh air and clean water. Deserve it.10. We created pollution. We have a debt.11. Keep earth green not grey.

THANK YOUAkhil bhartiClass - viii-c roll no. - 22