Vivetha

POLLUTION

Pollution is the introduction of substances into the environment such that it results in unpleasant or damaging effects on people, animals, plants and buildings. Human activities and natural events cause pollution.

Air Pollution

Air pollution occurs when substances such as dust, smoke or harmful gases are released into the environment.

Smog, a serious form of air pollution, forms when air pollutants like dust and smoke particles combine with water vapour and toxic gases.

•  common in industrialised areas of China, India and some eastern European countries.eg.Brown-air’ smog over Sao Paulo, Brazil. Nitrogen dioxide gives the smog its brown colour.

Causes of air pollution

• Natural causes of air pollution
• Volcanic eruptions
• Forest fires
• High temperatures and low rainfall can create dry conditions which spark forest fires. Large amounts of ash, smoke and gases are released into the air during a volcanic eruption.Human causes of air pollution
• Industries
• Motor vehicles
• Construction work
• Vehicle emissions,contain harmful gases like carbon monoxide and nitrogen oxides. Manufacturing industries emit large amounts of dust and smoke into the air. Construction work pollutes the air with dust and smoke particles.
• Air Pollution
• Extent of air pollution
• Air pollutants can be carried by winds from their source to other places, regions and countries.
• For example, smoke carried by winds from burning forests in Indonesia often causes haze in the Southeast Asian region.
• Haze observed over the Straits of Malacca and Peninsular Malaysia.
• Air Pollution
• Extent of air pollution
• Health problems
• Dust and smoke can irritate throats and eyes and cause breathing difficulties for people.
• People can develop respiratory problems such as bronchitis and asthma due to prolonged exposure to dust and smoke.
• Air pollutants such as nitrogen oxide and sulphur dioxide can cause severe health problems and increase the risk of developing lung and heart diseases.
• Toronto, Canada, covered in smog
• Air Pollution

Extent of air pollution

• Traffic hazards

When countries experience haze, visibility conditions deteriorate and airports may have to suspend operations and ground flights.

• Bad visibility conditions caused by haze may make driving inconvenient and dangerous.
• Environmental problems
• Acid rain is rain that is many times more acidic than normal rain due to the sulphur dioxide and nitrogen oxides present in the air.
• Acid rain destroys forests, kills aquatic life and corrodes buildings.
• It is a common problem in places that are heavily industrialised.

Water Pollution

• Water pollution occurs when pollutants are discharged directly into water bodies such as rivers, lakes and seas.
• It also occurs when air and land pollutants are blown by wind or washed by rain into water bodies.
• Urban settlements discharge many forms of pollutants into canals, drains and sewer pipes which eventually find their way into the rivers and seas. Sources of pollutants include factories, sewage treatment plants, runoff of chemicals from agricultural plantations and live-stock farms.

Causes of water pollution

• Improper disposal of sewage
• Sewage refers to solid or liquid waste that is produced by households or industries. It contains human waste, detergent and chemicals.
• When untreated sewage is discharged into rivers and seas, water pollution occurs.
• A sign warns people that the river is polluted with sewage.
• Water Pollution
• Causes of water pollution
• Improper disposal of sewage
• Industrial waste contains large amounts of toxic chemicals. Heavy water pollution occurs when untreated industrial waste is irresponsibly discharged into water bodies.
• Sewage is treated at sewage treatment plants to remove its waste products before it is released into water bodies.
• Sewage treatment process Some substances in detergents, sprays and even body lotions and shampoo are non-biodegradable and cannot be removed by sewage treatment processes.
• Water Pollution
• Oil spills

Oil spills occur when the hull of an oil tanker is torn by sharp rocks or when a tanker collides with another ship, causing the oil it is carrying to spill into the sea.
In 1989, the Exxon Valdez oil tanker went off course, hit rocks, and released large amounts of oil into Alaska’s Prince William Sound. This accident cost some US$2.1 billion to clean up.
In 2002, the oil tanker Prestige sank off the coast of Spain and over two years leaked twice as much oil as the Exxon Valdez.

• However, much more oil is released from other smaller, day-to-day and less visible activities.
• Current studies have shown that most ocean oil pollution comes from activities on land.
• These include normal operation of offshore wells, washing oil tankers, loading and unloading of oil tankers at ports, and leaks from oil pipelines, refineries and storage tanks.
• Water Pollution
• Extent of water pollution
• Endangering plant and animal species
• In an oil spill, sea birds cloaked with oil will freeze to death as their feathers cannot insulate air to protect them from the cold.

The oil also clogs the birds’ feathers and makes them unable to fly or float on water. They will drown as a result.

Extent of water pollution

• Endangering plant and animal species
• Household waste contains excess nitrogen and phosphorus which encourage the growth of algae on river and ocean surfaces.
• With the algae covering the water surface, sunlight cannot penetrate and reach the aquatic plants beneath the water surface, causing them to die as photosynthesis cannot occur.
• As a result, aquatic and marine animals that depend on these plants for food will be affected.

Extent of water pollution

• Negative impact on human health
• Chemicals and toxic metals contaminate shellfish beds, kill spawning fish and accumulate in the tissues of bottom marine feeders.
• These chemicals and toxins can be passed on in the food chain and eventually reach us when we consume the contaminated animals.
• People, especially in poor developing countries, can suffer from cholera and typhoid when they drink contaminated water.
• Economic loss
• Oil spills threaten the fishing industry and fishermen’s livelihood.
• Oil spills can also pollute beaches and affect tourism.
• Cleaning up oil spills requires an international effort and is a very expensive task. Scientists have estimated that no more than 15 percent of the oil from a major oil spill is recovered in a cleanup operation.
• The cheapest way and the most effective approach is to prevent oil pollution.

Land Pollution

• Land pollution occurs when waste is not disposed of properly on land, or when chemicals are used excessively on farms.

• Improper disposal of waste and the excessive use of chemical fertilisers and pesticides are some causes of land pollution.

A landfill. It is important is to realise that we can never truly throw anything away. Waste often ends up somewhere and can cause land and other forms of pollution

Causes of land pollution
Improper disposal of waste

With the increase in the world population, more goods and services are consumed and more waste is produced.

Without proper waste disposal management, the rubbish is often left at public places or illegal dumping grounds.

A slum in Smokey Mountains, the Philippines Proper waste disposal management

Causes of land pollution

Excessive use of chemical fertilisers and pesticides

When chemical fertilisers and pesticides are used to improve soil fertility or to eliminate pests, the soil gets contaminated.

In addition, these chemicals also pollute groundwater and may find their way into rivers and cause water pollution.

A man spraying pesticide over some crops

Extent of land pollution

• Negative impact on human health
• Improper disposal of waste attracts pests which spread germs and diseases.
• Farmers exposed to large amounts of pesticides risk developing cancer and liver failure.
• Poisoning of animals
• Pesticides and chemicals may pass on into the food chain and affect the reproductive systems and survival of some animals.
• The American Bald Eagle is now endangered because of the use of pesticides like DDT.

Measures Taken to Reduce Pollution

International effortsPollution can become a regional problem. Therefore, governments and international organisations like the United Nations Environment Programme (UNEP) need to work together to resolve the problems associated with pollution.
For example, after the 1989 Exxon Valdez oil spill, many countries have made it compulsory for oil tankers to have double hulls to prevent oil spills.

• The United States has implemented the Oil Pollution Act of 1990 which requires all oil tankers to have double hulls by 2015. The European Union has also voted to ban single hull oil tankers from their waters by 2010.

The United Nations organised the Earth Summit in 1992 and 2002 for world leaders to commit their countries to sustainable development.

Sustainable development is development that meets the needs of present generations without compromising the ability of future generations to meet their own needs.

Beijing, China

• National efforts
• Enforcing laws and regulations
• • Laws are enacted and enforced to monitor, reduce and prevent different forms of pollution.
• Using alternative sources of energy
• • ‘ Clean’ energy which does not release harmful pollutants into the environment can be utilised. Examples are solar and wind energy and hydroelectricity.
Windmills in Spain
• Measures Taken to Reduce Pollution
  • National efforts
  • Using advanced technology
  • • Sewage treatment plants can be built to treat waste water before releasing it into the environment.
  • Developing proper waste disposal methods
  • • There are two methods to carefully manage the disposal of waste — landfill and incineration. For example, Singapore has built the Pulau Semakau Landfill to manage solid waste. However, landfills are expensive to build and maintain and not a long-term sustainable solution to solid waste management.

Measures Taken to Reduce Pollution

National efforts

Developing proper waste disposal methods

• By 2009, Singapore will have five incineration plants to burn solid waste. Although incineration plants can produce electricity and reduce the volume of waste, they still emit air pollutants and are very costly to build.

• The government, under the Singapore Green Plan 2012, has decided to reduce the amount of solid waste generated. This is done by reducing waste going through incineration plants and landfills and by promoting waste recycling and minimisation.

Measures Taken to Reduce PollutionNational efforts
Educating the public
• An effective method to reduce pollution is to encourage people and industries to cut down on waste production.
This can be done through public talks and campaigns aimed at informing people about the harmful effects of generating excessive waste.

• Environmental conservation concepts like the 3Rs — Reduce, Reuse and Recycle, can be promoted through public education.

Individual efforts

• As individuals, we can help protect the environment by adopting practices which reduce waste.
• Go ‘green’ Ride bicycles, take public transport, recycle old newspapers

We should be informed about national and international plans for environmental conservation so that we can do our part to help.

We can help protect and conserve the environment by reducing, reusing and recycling waste.

It is important to realise that the best and cheapest way to deal with waste and pollution is to produce less pollutants and to practise the 3Rs for most of the materials we use.

• Be informed and get involved.