Certain things like shaving foam, deodorants, paints etc., come in aerosol cans. These are kept under pressure in the aerosol can and come out in the form of foam or spray, when the button at the top of the can is pressed. This device has become very popular because of the ease of use. For example, when we use shaving cream, or shaving soap or cake, we have to work up a lather using a brush. However, shaving foam can be applied directly on the face, without using a brush.
Certain chemicals like fluorocarbons and chlorofluorocarbons (CFC) are used as propellents in aerosols. It has been found that when these chemicals are released, they react with ozone of the atmosphere and destroy it. The layer of ozone in the atmosphere blocks ultraviolet radiation from the sun. Damage to the ozone layer enables ultraviolet rays to reach the earth. These rays can cause cancer and cataract. It is a necessary to stop the use of harmful chemicals like CFC which cause damage to the ozone layer. Scientists are working on developing other chemicals which can be used in aerosols.