Pollution - Class 4 Notes & Olympiad Questions

Causes of Environmental Degradation

a) There are different reasons why our environment gets damaged. Some of these reasons come from nature, like volcanoes erupting, earthquakes shaking the ground, floods, and tsunamis. These natural events can cause harm to the environment.
b) But there are also things that people do that harm the environment. One of these is cutting down trees or deforestation, which is done to make room for cities, buildings, and farms.
c) Another way is by digging up minerals and metals from the earth, which we use for making things like vehicles and machines. Using fossil fuels like coal, petrol, and diesel for transportation and industry also damages the environment.
d) Additionally, using chemical fertilizers and pesticides in farming and having a lot of people using up resources can lead to overusing and damaging the environment. It's important for us to take care of the environment and find ways to protect it.

Pollution

a) Pollution occurs when the environment when harmful substances, like chemicals or gases, are released into the environment. These harmful substances are called pollutants.
b) Pollutants can come from natural sources, such as volcanic ash, or they can be produced by human activities, like when factories create waste or trash.
c) Pollution can affect three main parts of the environment: the air we breathe, the water we drink, and the soil where plants grow.

Air Pollution

a) Air pollution is when the air around us becomes dirty and filled with harmful things. We need clean air to stay healthy.
b) Normally, we breathe in oxygen and breathe out carbon dioxide, and plants help balance this by taking in carbon dioxide and giving out oxygen.
c) But in many cities, the air is not clean. It contains different pollutants that can be bad for our health.

Causes of Air Pollution

Air pollution happens when gases and particles that are not good for us get into the air. Here are some ways this can happen:

a) When we burn things like fossil fuels in cars and factories, gases like carbon dioxide and sulphur oxides are released into the air.
b) Cars and factories also let out tiny particles of unburnt carbon and dust.
c) When volcanoes erupt, they release ash and dust into the air.
d) When we light firecrackers, it creates smoke and gases that can make the air dirty.
e) Some chemicals used in paints and dyes can make the air inside our homes polluted when we breathe them in.
f) When farmers spray chemicals on their fields to kill pests, those chemicals can also go into the air.
g) Burning garbage can create smoke and pollutants that spread through the air.

Effects of Air Pollution

Air pollution can have different effects on our health and the environment. Here are some of the things it can cause:

a) It can make us sick by causing respiratory diseases like asthma, coughing, bronchitis, and liver problems.
b) Breathing in polluted air can make us sneeze and irritate our eyes, nose, and throat.
c) Inhaling a gas called carbon monoxide, which is found in polluted air, can give us headaches and dizziness. Breathing in a lot of carbon monoxide can even be deadly.
d) Air pollution can also harm animals and water life. Pollutants in the air can settle on water bodies and affect the animals living in them. It can force animals to leave their homes and find new places to live. Sadly, air pollution has even caused some animal species to go extinct.

Ways to Prevent Air Pollution

There are many things we can do to stop air pollution and keep the air clean. Some easy steps that we can follow are:

a) Use clean fuels like CNG (Compressed Natural Gas) instead of fuels that make pollution.
b) Try to use public transportation or share rides with others instead of using your own car.
c) When possible, walk or ride a bike for short distances instead of using a vehicle.
d) Factories should make sure to clean the harmful solid particles from the gases they release before letting them out into the air.
e) Plant more trees because they can use up carbon dioxide through photosynthesis and make the air cleaner.
f) Avoid burning garbage, dry leaves, and wood because it can make the air dirty.

Water Pollution

a) Water pollution happens when harmful things get into water bodies like rivers, lakes, streams, seas, oceans, and even underground water. This can make the water dirty and unsafe for us and other living things.
b) Polluted water can have different signs. It might look a different colour, have things floating in it, smell bad, and taste unpleasant. It's important to have clean water that is safe to drink and use.
c) There are many reasons why water can become polluted, like when chemicals, trash, or waste from factories and homes end up in the water. It's important for us to take care of our water sources and find ways to keep them clean and healthy for everyone.

Causes of Water Pollution

Water pollution is caused by different things that make the water dirty and unsafe to use. Some of the main causes are:

a) Factories and manufacturing units release waste directly into nearby water bodies, which makes the water polluted.
b) Sewage waste, which comes from toilets and drains, can contaminate the water and make people sick.
c) When people wash clothes, and dishes, or take baths, they can add pollutants to the water.
d) Oil from activities like oil spills or ships can get into the oceans and seas, which harms marine life.
e) When farmers use a lot of pesticides and fertilisers on their crops, rain can wash those chemicals into the water bodies, which is not good for the water or the creatures that live in it.

Effects of Water Pollution

Water pollution can have harmful effects on the environment and living things.

a) It can harm aquatic life like plants, fish, and frogs.
b) Water pollution can disrupt the food chains in the water, causing an imbalance in the ecosystem.
c) It can also make living organisms, including humans, sick with diseases like cholera and diarrhoea.

Ways to Control Water Pollution

To control water pollution, we can take some important steps:

a) We need to educate people and make them aware of how serious the problem of water pollution is.
b) Sewage waste should not be allowed to flow into water bodies without first being treated to remove harmful substances.
c) We can reduce the use of chemicals in farming practices, like pesticides and fertilizers, to prevent them from washing into the water.
d) Opt for eco-friendly and biodegradable household products, such as cleaning agents and personal care items. Avoid using products that contain harmful chemicals that can end up in water systems.

By taking these actions, we can help protect our water and keep it clean for the plants, animals, and people who depend on it.

Purification of Water

Water purification is the process of making water clean and safe to drink by removing harmful things from it. Some ways to purify water are:

Filtration: Water can be filtered by passing it through filter paper or a fine cloth. This helps to remove solid impurities, leaving behind clean water.

Boiling: By boiling water at a high temperature, the germs and bacteria present in it are killed. Once the boiled water cools down, it becomes safe to drink.

Chlorination: Adding a chemical called chlorine to water can also kill germs and make it safe for drinking. This process is known as chlorination.

Soil Pollution

a) Soil pollution happens when garbage and waste materials are dumped on land or underground, which makes the soil dirty and harmful. This can cause many problems.
b) When garbage decays, it becomes a place where diseases can spread because mosquitoes, rats, and houseflies breed there. Also, dangerous chemicals can go into the soil and make it unsuitable for growing crops.
c) There are different sources of soil pollution. Some of them are the use of pesticides and fertilisers in farming, and burning things like coal, plastic, wood, paper, and rubber, which leaves behind debris that pollutes the soil.
d) Mining activities and industrial waste can also make the soil dirty.
e) These pollutants can go into the soil and water reservoirs underground, affecting the life around them.

It's important to take care of our soil and not pollute it so that we can have healthy crops, clean water, and a safe environment for everyone.

Effects of Soil Pollution

Soil pollution can have harmful effects on plants, animals, and humans.

a) When harmful chemicals from industrial and agricultural waste get into the soil, plants and vegetables grown in that soil can absorb those chemicals.
b) If animals and humans eat these plants, they may get sick or fall ill because of the chemicals in them.
c) Pollutants in the soil can leach into underground water sources, such as groundwater or aquifers, contaminating them.
d) Soil pollution can decrease the fertility of the soil, making it difficult for plants to grow.

Ways to Control Soil Pollution

To control soil pollution, we can take several important steps. Some of them are:

a) It's important to dispose of garbage in designated bins for different types of waste like food scraps, paper, plastic, and glass. Avoid throwing garbage in open areas or on the ground.
b) Dumping garbage far away from cities helps to prevent soil pollution near residential areas.
c) Instead of throwing away kitchen scraps and garden waste, we can create a compost pit in our gardens. By layering the waste with ash and leaves, it slowly turns into compost or natural fertiliser. This can be used to nourish the soil in our gardens.
d) Incineration is a modern method of waste disposal. It involves burning garbage at high temperatures in special facilities called incinerators. This helps to reduce the amount of waste and prevents harmful pollutants from entering the soil. However, it's important to ensure that incineration is done properly to avoid air pollution.