WBBSE Class 6 Geography Chapter 8 Air Pollution Notes
1. When air is polluted by different poisonous gases, chemical substances, smoke from vehicles, dust particles, and organic compounds, it causes air pollution.
2. Air pollutants are those harmful organic and inorganic substances that pollute the air.
3. The layer of ozone gas present in the upper reaches of the stratosphere is known as the ozone layer.
4. Different toxic gases (such as carbon dioxide, oxides of nitrogen, and sulfur dioxide) react with rainwater and fall upon the earth as acid rain.
5. Greenhouse is an artificial chamber made of glass and is used to cultivate vegetables and flowers in regions having a cold climate.
This glass absorbs sunlight and does not allow the heat to move out of the chamber, thereby maintaining a high temperature in the chamber.
As a result, the inner environment of the chamber remains warm and is conducive to plant growth in such climatic regions.
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6. Carbon dioxide, methane, nitrous oxide, CFCs, and ozone are some examples of greenhouse gases. The presence of these gases increases the temperature of the atmosphere manifold.
7. During the daytime heat from the Sun reaches the Earth which returns to space during the night.
However, greenhouse gases like carbon dioxide, methane, nitrous oxide, and water vapor present in the air absorb some amount of this heat and radiate it back to the Earth’s atmosphere.
This leads to a rise in the temperature of the atmosphere and this phenomenon is known as global warming.
8. The mode of transport by which a large number of people can travel from one place to another is called mass transport or public transport such as buses, trains, trams, etc.
WBBSE Class 6 Air Pollution Notes
9. In 2007, on 31 March the residents of Sydney in Australia switched off all the lights in the city for one hour (8.00 pm-9.00 pm) to reduce the impact of global warming.
At present, citizens of almost 1000 cities in 85 countries switch off lights for one hour every year on a day in the last week of March and this is termed Earth Hour.
10. Every year 22 April is celebrated as Earth Day all over the world to create awareness among people about protecting the environment.