File Name: pollution of air and water class 8 notes .zip
Pollution of Air and Water. Which of the following is not a greenhouse gas? Which air pollutant reduces the oxygen-carrying capacity of the blood?
Environmental pollution can be defined as undesirable changes that happen in the surrounding. These changes have negative and adverse effects on animals, plants, and other physical and biological components of the environment. Pollutants can either be present in gaseous, solid, or liquid form. A substance can also be classified as being a pollutant when the concentration of that substance is greater than its natural levels.
Also, this increase in the concentration of the substance can be caused due to natural or human activities. Apart from air and water pollution, there are other different types of pollution. The different types of pollution are:. Light pollution. Sound pollution. Soil pollution. Students can learn about these other types of pollutants in other Science Class 8 Chapter Notes.
It is also possible for air to get polluted from natural sources like dust and smoke. This dust and smoke can arise from volcanic eruptions or forest fires. There are also man-made pollutants like power plants, automobile exhaust, and the burning of firewood. Further, nitrogen oxides, carbon dioxide, methane, carbon monoxide, and sulphur dioxide are major pollutants of the air.
It should be noted here that increasing levels of carbon dioxide is one of the major causes of global warming.
We will look at the topic of global warming at a later point in these Class 8 Science Ch 18 Notes. Air pollution can be explained as the introduction of organic molecules, pollutants, and other harmful substances into the atmosphere of the earth. The sources of air pollution can also be classified into two types.
These types are:. Natural For example, dust storms, forest fire, and volcanic activity. Man-made For example, homes, power plants, industries, transportation, and oil refineries.
Endangers animal welfare and health of vegetation and plants. Results in birth defects in new-born babies. Can result in allergies, diseases, and even death to humans.
Earlier, we talked about some air pollutants. Now, we will look at all those air pollutants in detail. Some sources of carbon monoxide are incomplete combustion of carbon-containing compounds, like fuels and other toxic air pollutants. Carbon dioxide, on the other hand, can be produced as a by-product of burning fuels like coal, wood, natural gas, oil, and gasoline.
It can also be produced during deforestation and cement production. It is important to mention in the notes of Chapter 18 Science Class 8, that both sulphur dioxide SO 2 and nitrogen dioxide NO 2 are major pollutants of air.
Some sources of sulphur and nitrogen dioxide are the combustion of fossil fuels like coal in power plants and petroleum refineries. There are also various effects of nitrogen and sulphur dioxide, including acid rain, respiratory diseases like permanent lung damage, and photochemical smog-like breathing difficulties. Particulate matter is also an important pollutant that is mentioned in the notes of Chapter 18 Science Class 8. It can be defined as particles of liquid or solid that remain suspended in water, gas, or air.
Dust, debris, pollens, smoke, and acid droplets are some examples of particulate matter. Causes of particulate matter are construction, combustion, power plants, road dust, agricultural activities, industries, and deforestation. Particulate matter can cause birth defects, heart diseases, respiratory diseases, and asthma. Smog is the combination of fog and smoke. There are different types of smogs. These types of smogs are:.
Photochemical Smog - Photochemical smog is mainly found in areas that have a sunny and dry climate. It is caused due to a large number of automobiles. It is also the result of chemical interactions between sunlight and nitrogen oxides. Classical Smog - Classical smog occurs in areas that have a humid climate and high concentrations of sulphur oxides in the air. It is the combination of fog, smoke, and sulphur dioxide gas. Some of those effects are:. It causes issues in plant growth and can also result in widespread damage to forests and crops.
Breathing problems like cough, asthma, and wheezing. It can also cause corrosion of building materials, metals, and painted surfaces. CFCs are mainly used as components of aerosol sprays and refrigerants in ACs, refrigerators, and cooling plants. CFCs harm the ozone layer, which protects the earth from the ultraviolet UV radiation from the sun.
Because of the increased amount of UV rays, individuals can suffer from diseases like eye damage, skin cancer, and suppression of the immune system. There are various components or pollutants in the air that get accumulated in the air. This acid drops down with the rain to make it acidic. The reactions involved in this phenomenon are:. This acid rain corrodes the marble of the Taj Mahal. This results in the marble turning from white to black.
Many steps have been taken by the government to solve this problem and protect the marble of the Taj Mahal. According to experts, global warming can be defined as a phenomenon in which gases that are responsible for the greenhouse effect, accumulate and trap more heat.
This is different because most of the solar radiations that are passing through the atmosphere should bounce back into space. But due to the excess of greenhouse gasses, these radiations get trapped in the atmosphere. This makes the earth hotter than it should be. In other words, it can be said that if greenhouse gases are trapping an appropriate amount of heat, then that is called the greenhouse effect.
But if there are more greenhouse gases and more heat is being trapped than necessary, then that is called global warming. Readers should also know what greenhouse gases are. The greenhouse gases mainly are - carbon dioxide, nitrous oxide, water vapes, and methane.
We also know that global warming has many negative effects on the earth. But what are those effects? If you want to learn about those effects, then you should go through the list that is mentioned below. Global warming has resulted in an increase in the average temperature of our planet. There has also been an increase in the severity and occurrence of natural disasters like cyclones, floods, and earthquakes. Climate patterns have shifted dramatically all across the globe.
There has also been a rise in the average sea levels all across the globe. This is happening because the polar ice caps are melting. It is recommended that everyone should try to protect the environment as much as possible. There are some steps that can be practised at an individual level. Some of those measures are:. Use cleaner fuels as compared to diesel and petrol. Use unleaded petrol. This is because unleaded petrol does not emit harmful gases into the environment.
Waste should be properly managed. It should not be left in the open. Instead, waste should be incinerated or disposed of in a safe manner. You should try to carpool or use public transport because it is economical, prevents congestion on roads, and also reduces the emission of harmful gases to a large extent. Water pollution can be defined as the contamination of water bodies because of harmful waste. It can be caused due to industries, urbanization, social practices, religious practices, and agriculture.
In recent years, the biggest example of water pollution has been the river Ganga. The river Ganga has been polluted by many water pollutants like insecticides, hospitals, chemicals, detergents, and herbicides.
Apart from the river Ganga, there are many rivers that are filled with nothing but garbage, untreated sewage, and dead bodies of animals. All of this is choking aquatic life and hindering the growth of plants inside water bodies. According to various sources, Ganga is one of the ten most endangered rivers in the world. Potable Water: It is the water that is suitable for drinking. It is free from all harmful bacterias and contaminants. Raw Water: It is the water that is not potable or fit for drinking.
It is possible to kill all the bacteria and microbes in water by boiling water. Boiling water also protects individuals against various waterborne diseases. Filtering water can also work. It is the process that separates suspended solid matter from a liquid.
Register Now. Hey there! We receieved your request. Air is a combination of different gases that form the atmosphere of the Earth. This constituent of air may vary on other planets. However, some planets do not have air.
Air consists of a mixture of gases. Carbon dioxide, argon, methane, ozone, water vapour are also present in very small quantities. Air Pollutants: The substances which contaminate the Eiir Eire called air pollutants. Carbon monoxide, nitrogen oxides, carbon dioxide, methane and sulphur dioxide Eire the major pollutants of air. Acid Rain: Oxides of sulphur Eind nitrogen react with water vapour present in the atmosphere to form sulphuric acid and nitric acid. When these come down with the rain, it makes the rain acidic.
Carbon dioxide, argon, methane, ozone and water vapour are present in very small quantities. It reduces the oxygen-carrying capacity of the blood. It causes respiratory problems, including permanent lung damage. Ozone layer protects us from ultraviolet rays of the sun. The acid drops come down with rain which is known as acid rain. This phenomenon is called marble cancer.
Free PDF Download - Best collection of CBSE topper Notes, Important Questions, Sample papers and NCERT Solutions for CBSE Class 8 Science Pollution of.
Polluted air or water contains substance that are harmful for human beings and environment as well. Following three observations indicate that a given sample of water is polluted. Chemical pollution of water means pollution of a water body caused by addition of harmful chemical substances into it.
Air is the most important element for any living thing to survive. We find air around the earth in the form of a blanket which is known as the atmosphere.
Environmental pollution can be defined as undesirable changes that happen in the surrounding. These changes have negative and adverse effects on animals, plants, and other physical and biological components of the environment. Pollutants can either be present in gaseous, solid, or liquid form. A substance can also be classified as being a pollutant when the concentration of that substance is greater than its natural levels. Also, this increase in the concentration of the substance can be caused due to natural or human activities. Apart from air and water pollution, there are other different types of pollution. The different types of pollution are:.
All questions and answers from the Living Science Book of Class 8 Science Chapter 19 are provided here for you for free. Which of these causes water pollution? Which of these processes cannot remove germs from water? Which of these methods does not result in conservation of water? Recycling also conserves water, and planting more trees increases the ground water level. But cutting vegetation does not help in the conservation of water. Which of the following is not a pollutant unless present in excess?
The things which are responsible for contamination of air are called air pollutants. These pollutants may result from natural causes like smoke or dust from forest fires or volcanic eruptions and from man-made causes like burning of fuels, smoke from factories etc. Effects of Air Pollution: 1. Many problems related to respiratory system might be caused due to air pollution. Oxygen carrying capacity of blood reduces because of improper burning of vehicle fuels; As the vehicles emit high levels of pollutants like carbon monoxide, carbon dioxide, nitrogen oxides and smoke into atmosphere.
Air is the most important element for any living thing to survive. We find air around the earth in the form of a blanket which is known as the atmosphere. This air is a mixture of various gases.
Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks. Covers the following topics:. Source of Water Pollution. Effect of Water Pollution.
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2. Water Pollution: The addition of undesirable and unwanted material in water which makes water harmful for biotic and abiotic components is called water.