1. When AIR is contaminated with unwanted particles or substances which plays a harmful impact on the Earth, it is known to be air pollution. These substances that contaminate the Earth's atmosphere are known as air pollutants. They are produced or emerged by industries, factories, forest fires, etc.

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2. There are several causes for air to get polluted. They are →

• Smog ⇒ Smog is made up of smoke and fog. They contain nitrogen OXIDES which when combined with the air pollutants and fog form smog. Smog causes breathing difficulties like asthma, coughing and wheezing in children.

• CFC (Chloro Fluro Carbon) ⇒ CFC's are present in refrigerators, ACs and aerosol sprays. When these vapours go into the upper atmosphere, they deplete the ozone layer. So we can SAY that CFC's damage the ozone layer and the depletion of this layer can cause skin disorders.

• Carbon Monoxide ⇒ Carbon monoxide is produced due to the INCOMPLETE burning of fuels. When there isn't a sufficient amount of oxygen it results in incomplete burning of fuels. This produces carbon monoxide rather than carbon dioxide. Carbon monoxide is a poisonous gas and it reduces the oxygen-carrying capacity of the blood. This is really harmful to human beings and can also lead to death.

• Unburned Particles ⇒ Tiny particles are suspended in the air for a long period of time in automobiles which burn diesel and petrol. Such particles are known as SPM (Suspended Particulate Matter). If we inhale it, it can lead to diseases like bronchitis. These particles are also produced by industrial processes. Even the power plant releases tiny ash particles when leads to air pollution and is really harmful if inhaled.

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3. The process in which the infrared radiation of the sun is absorbed by the greenhouse gases and not reflected back into space is known as the greenhouse effect.

So, a greenhouse is made up of glass and it is used to grow plants in it. The sun's radiation provides warmth to the plants and the air present within the greenhouse. The HEAT that is trapped inside the greenhouse can't escape out and it provides warmth which is necessary for the growth of plants.

This is a similar case with the Earth's atmosphere. In the day time, the sun warms the Earth's atmosphere and during the night time when the Earth cools down, the heat is reflected back into the atmosphere. The heat is absorbed by the greenhouse gases in the atmosphere of the Earth during this process. This results in the surface of the Earth to be warmer and makes the survival of living beings possible on Earth.

However, the increased levels of greenhouse gases leads to an increase in the temperature of the Earth which leads to global warming.

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