Environmental Science (2+1)

Introduction

• A clean air supply is essential to our own health and that of the environment. But since the industrial revolution, the quality of the air we breathe has deteriorated considerably - mainly as a result of human activities. Rising industrial and energy production, the burning of fossil fuels and the dramatic rise in traffic on our roads all contribute to air pollution in our towns and cities which, in turn, can lead to serious health problems. For example, air pollution is increasingly being cited as the main cause of lung conditions such as asthma - twice as many people suffer from asthma today compared to 20 years ago.


• The multilayered gaseous envelope surrounding the planet earth is called atmosphere. It is an ocean of air which blends into outer space some 1000 km. The atmosphere is a reservoir of several elements essential to life and it serves many functions, including the filtering of radiant energy from the sun, insulation from heat loss at the earth’s surface and stabilization of weather and climate owing to heat capacity of the air. There are five concentric layers within the atmosphere, which can be differentiated on the basis of temperature. These include the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere. The Atmosphere is divided into layers according to major changes in temperature. Gravity pushes the layers of air down on the earth's surface. This push is called air pressure. 99% of the total mass of the atmosphere is below 32 kilometers.