What is Air Pollution?What is Air Pollution? Air pollution is caused by the presence of pollutatns in the airAir pollution is caused by the presence of pollutatns in the air

There are several main cause of air pollution which are There are several main cause of air pollution which are commonly discussed. These include:commonly discussed. These include:a) dusta) dust

b) carbon monoxideb) carbon monoxide c) CFCc) CFC d) leadd) lead

There are many effect of air pollution such as:There are many effect of air pollution such as: a) hazea) haze b) acid rainb) acid rain c) Greenhouse effect/global warmingc) Greenhouse effect/global warming d) Lung cancerd) Lung cancer e) allergye) allergy f) respiratory diseasesf) respiratory diseases

Outdoor Air PollutionOutdoor Air Pollution

Haze Haze

HazeHaze is a type of large-scale outdoor pollution. It is is a type of large-scale outdoor pollution. It is caused by chemical reactions between pollutants derived caused by chemical reactions between pollutants derived from different sources. Cities are often centers of these from different sources. Cities are often centers of these types of activitiestypes of activities

The rate of smog pollution depends on the following The rate of smog pollution depends on the following variables:variables:a) geographical location,a) geographical location,b) temperature,b) temperature,c) wind,c) wind,d) weather factors.d) weather factors.However, sometimes this does not happen and the However, sometimes this does not happen and the pollution can build up to dangerous levels too.pollution can build up to dangerous levels too.

Acid rainAcid rain Another consequence of outdoor air pollution is Another consequence of outdoor air pollution is acid acid

rainrain..

When a pollutant, such as sulfuric acid combines with When a pollutant, such as sulfuric acid combines with droplets of water in the air, the water (or snow) can droplets of water in the air, the water (or snow) can become become acidified acidified ..

The effects of acid rain on the environment can be The effects of acid rain on the environment can be very serious. It damages plants by destroying their very serious. It damages plants by destroying their leaves, it poisons the soil, and it changes the leaves, it poisons the soil, and it changes the chemistry of lakes and streams.chemistry of lakes and streams.

Damage due to acid rain kills trees and harms Damage due to acid rain kills trees and harms animals, fish, and other wildlife.animals, fish, and other wildlife.

Greenhouse EffectGreenhouse Effect

The The Greenhouse Effect,Greenhouse Effect, also referred to as global warming, is also referred to as global warming, is generally believed to come from the build up of carbon dioxide generally believed to come from the build up of carbon dioxide gas in the atmosphere.gas in the atmosphere.

Carbon dioxide is produced when fuels are burned. Plants Carbon dioxide is produced when fuels are burned. Plants convert carbon dioxide back to oxygen, but the release of convert carbon dioxide back to oxygen, but the release of carbon dioxide from human activities is higher than the world's carbon dioxide from human activities is higher than the world's plants can process.plants can process.

The situation is made worse since many of the earth's forests The situation is made worse since many of the earth's forests are being removed, and plant life is being damaged by acid rainare being removed, and plant life is being damaged by acid rain

The layer traps heat close to the surface of our earth. Changes The layer traps heat close to the surface of our earth. Changes of even a few degrees will affect us all through changes in the of even a few degrees will affect us all through changes in the climate and even the possibility that the polar ice caps may climate and even the possibility that the polar ice caps may meltmelt

WATER POLLUTION

Water pollution is caused by domestic wastes, and agriculture wastes that are

discharged directly to the river.

Sources of water pollution

(a) Discharge of untreated sewage and domestic waste into river

(b) Discharge of industrial waste

(c) Discharge of industrial waste

(d) Oil spillage

EUTROPHICATION

Eutrophication occurs as a result of abundant supply of fertilisers or sewage, in lakes, ponds and river.

Fertilisers and sewage contain high supply of phosphates and nitrates.

Phosphates and nitrate, promote rapid growth of algae. This phenomenon we call as eutrophication.

Effect of Eutrofication

When the algae grow rapidly, cover up the surface of river, ponds or lake, it

prevents the sunlight from reaching the plants in the lower depths of the water.

As a result the plant die

The aerobic bacteria will decompose the dead plants and increase the usage of

oxygen in the water.

This will increases the B.O.D (Biochemical Oxygen Demand) of the water.

Biochemical Oxygen Demand (B.O.D)

B.O.D is the amount of oxygen taken up by the microorganism that decompose

the organic waste matter in water

B.O.D high- water is more polluted

B.O.D low- water is less polluted.

Thermal Pollution

Thermal pollution is a harmful increase or decrease in the average temperature of a body of water caused by human activity.

It is the result of excess heat that is released into the water or air.

Causes of Thermal Pollution

• Use of water as a cooling agent

• Deforestation of shorelines

• Soil erosion

• Burning of fossil fuels

Use of Water as a Cooling Agent

When water is used as a cooling agent, especially in power plants and industries, the water that is taken from the environment is usually returned at a higher temperature.

This causes the water in the particular environment to have a higher temperature than before.

Deforestation

The deforestation of shorelines causes the land around the shorelines to lack trees and plants that provide shade for the water.

As a result, the water is exposed to direct sunlight and is warmed up to around 10°C.

Soil Erosion

Soil erosion causes the water to be muddy and contain mud suspensions. It causes the water to be darker in colour and will trap more heat than clear water which can reflect heat off its surface.

Burning of Fossil Fuels

The burning of fossil fuels produces heat in excess which will increase the temperature of the water that is near the area of where the heat is produced.

Effects of Thermal Pollution

• Decrease in oxygen content in the water

• Killing of organisms in the water

• Disruption of the food chain

• Sensitivity of organisms

Decrease in Oxygen Content in the Water

The decrease in O2 solubility in the water causes the organisms in water that depend on oxygen to suffer from a lack of O2 that will interfere in their natural processes.

It may include changes in metabolic rates and processes and also changes in the reproductive processes of organisms in the water as well as immunity to diseases.

Killing of Organisms in the Water

Because of the sudden change in temperature, organisms living in the water may not be able to adapt to the changes in the temperature and will die gradually or immediately.

Disruption in the Food Chain

Because of the sudden deaths in the aquatic ecosystem, the food chain is disrupted because there are many deaths at all levels of the food chain.

This will cause some of the organisms to not be able to find food to keep them alive. It may also change the composition of the ecosystem

Disruption in the Food Chain (2)

The metabolic rate of organisms also rises with increasing water temperatures, resulting in even greater oxygen demand. The life cycles of aquatic insects tend to speed up in warm water. Animals that feed on these insects can be negatively affected, particularly birds that depend on insects emerging at key periods during their migratory flights.

Sensitivity of Organisms

Because of the increase of heat, certain plants may be more sensitive to toxic wastes, parasites and diseases. This causes them to die easily because they cannot resist the effects of foreign substances on their bodies.

Solutions

• Controlling the amount of water used as coolants

• Replanting the forest areas

• Cooling water before returning it to the environment

• Using other sources of water

Controlling the Amount of Water Used as Coolants

By controlling the amount of water used as coolant, we are reducing the impact of the excess heat from the water cooling process in industries to the environment.

The less heat is released back to the environment, the less the effect will be.

Replanting Forest Areas

By replanting the forest areas, the function of the forest as a shade for the water will be restored.

This will result in a lower amount of heat being absorbed by the water and lower the effects of thermal pollution.

Cooling Water

By cooling water in cooling towers, the heat from the water used to cool the products in the industry will be removed or lessened before the water is returned to the environment. This will lower the effects of thermal pollution of the water.

Using Other Sources of Water

By using other available sources of water like contaminated water that is of no use to human life or the environment, the amount of water taken from rivers and seas is reduced. This will reduce the effect of thermal pollution on the rivers and seas.

Some pictures showing the concept of

greenhouse effect

This Is a real, modern

greenhouse in RHS WISLEY

THINNING THINNING OF OF

OZONE OZONE LAYERLAYER

By RAJ CorporationBy RAJ Corporation

OZONEOZONE

OZONE LAYEROZONE LAYER

The ozone layer is a layer in Earth's The ozone layer is a layer in Earth's atmosphere which contains relatively high atmosphere which contains relatively high concentrations of ozone (Oconcentrations of ozone (O33).).

This layer absorbs 93-99% of the sun's This layer absorbs 93-99% of the sun's high frequency high frequency ultravioletultraviolet light, and light, and prevent them from reaching the Earth’s prevent them from reaching the Earth’s surface.surface.

It is mainly located in the lower portion of It is mainly located in the lower portion of the the stratospherestratosphere from approximately 10 from approximately 10 km to 50 km above Earth's surface.km to 50 km above Earth's surface.

view of stratosphere from airplane

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. The stratosphere is situated between about 10 km (6 miles) and 50 km (31 miles) altitude above the surface at moderate latitudes, while at the poles it starts at about 8 km (5 miles) altitude.

DEPLETION OF OZONEDEPLETION OF OZONE Today, the ozone layer is becoming thinner Today, the ozone layer is becoming thinner

because of the destruction of the ozone gas.because of the destruction of the ozone gas. The depletion of ozone is caused by the The depletion of ozone is caused by the

increasing use of chlorofluorocarbons (CFC) increasing use of chlorofluorocarbons (CFC) which can break down and destroy ozone which can break down and destroy ozone molecules into other elements.molecules into other elements.

Chrolofluorocarbon are widely used as a Chrolofluorocarbon are widely used as a cooling agent in refrigerators and air cooling agent in refrigerators and air conditioners, in aerosol sprays, polystyrene conditioners, in aerosol sprays, polystyrene food container, and rubber foams for making food container, and rubber foams for making cushions, pillows, and mattresses.cushions, pillows, and mattresses.

Other pollutants such as halons, chlorine and Other pollutants such as halons, chlorine and nitrogen oxides can also destroy the ozone.nitrogen oxides can also destroy the ozone.

THE PROCESS OF OZONE THE PROCESS OF OZONE DEPLETION BY CFCDEPLETION BY CFC

Cl

Carbon

Cl

ClFluorine

Ultraviolet Rays

O

O

O

Cl

Ultraviolet radiation reacts with CFC by breaking the chlorine atom bond in the CFC

The highly reactive chlorine atom that released will destroys the ozone by reacting with the ozone to produce chlorine monoxide and oxygen molecules

ClO

Chlorine Monoxide

OO

Oxygen

O

Free oxygen atoms in the atmosphere will break the chlorine monoxide bond.As a result, a chlorine atom is released and this chlorine atom can destroy more ozone molecules

Free oxygen atom

OO

Chlorine

EFFECT OF OZONE EFFECT OF OZONE DEPLETIONDEPLETION

An increase of UV radiation would be expected to affect crops. A number of economically important species of plants, such as rice, depend on cyanobacteria residing on their roots for the retention of nitrogen. Cyanobacteria are sensitive to UV light and they would be affected by its increase.

It was found that the depletion of the ozone layer occurred over both the Artic and Antartic, creating ozone holes. The ozone hole in Antartic is found to be as big as the continent of U.S.A.

ULTRAVIOLET RAYSULTRAVIOLET RAYS