<P> Compressed air is air kept under a pressure that is greater than atmospheric pressure . Compressed air is an important medium for transfer of energy in industrial processes . Compressed air is used for power tools such as air hammers, drills, wrenches and others . Compressed air is used to atomize paint, to operate air cylinders for automation, and can also be used to propel vehicles . Brakes applied by compressed air made large railway trains safer and more efficient to operate . Compressed air brakes are also found on large highway vehicles . </P> <P> Compressed air is used as a breathing gas by underwater divers . It may be carried by the diver in a high pressure diving cylinder, or supplied from the surface at lower pressure through an air line or diver's umbilical . Similar arrangements are used in breathing apparatus used by firefighters, mine rescue workers and industrial workers in hazardous atmospheres . </P>

Write the four uses of air in daily life