The man-made sources of air pollution are broadly categorized into three:
Point or stationary sources: it includes such sources which pollute at particular. Pollutants from point sources affect only restricted areas.eg: industries, refineries, power- plants.
Line or mobile sources: the line or mobile sources of air pollution are automobiles as these add pollutants along narrow belts and over long distances.
Area sources: towns and cities add smoke and gases over wide areas and so qualify as area sources of air pollution.