This chapter explores the properties of air, the composition of the Earth's atmosphere, and the importance of air for living organisms. Air is a mixture of gases that surrounds the Earth and is essential for the survival of all living organisms.
Composition of air: Air primarily consists of nitrogen (approximately 78%), oxygen (approximately 21%), and traces of other gases such as carbon dioxide, water vapor, and noble gases.
Properties of air include its transparency, colorlessness, odorlessness, and compressibility. Air exerts pressure, known as atmospheric pressure, on objects at the Earth's surface.
Earth's atmosphere is a layer of air that surrounds the Earth. The atmosphere is divided into several layers, including the troposphere (closest to the Earth's surface), stratosphere, mesosphere, thermosphere, and exosphere.
Air pollution: Different sources of air pollution are vehicular emissions, industrial pollutants, and burning of fossil fuels.
Wind is the movement of air from areas of high pressure to areas of low pressure. Factors that influence wind patterns are temperature differences and the Earth's rotation.