The importance of the environment of air arises from the fact that though the mass of the pollutants that could be transported by it is small, they could be transported fast and for long distances. Air pollution has both acute and chronic health effects, such as irritability of ocular and respiratory systems, foul smells, reduced visibility, reduced mental acuity, etc. Aerosol particles are so small that millions can dance on a pin-head, but yet they have a profound influence on the climate of the globe. They are abundant in the air we breathe, they may originate on land or the ocean, their sources may be natural or anthropogenic, they range in size from sub-microscopic to almost visible, and they are characterised by a wide variety of chemical compositions. Iron, aluminium, manganese and chromium are generally found in the form of coarse particles, whereas cadmium, lead, zinc and antimony occur in the form of smaller particles.