Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide.Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution.Outdoor and indoor air pollution cause respiratory and other diseases and are important sources of morbidity and mortality.