Searching, PubMed (accessed Nov. 10, 2015) for “Air pollution” and “Health” resulted in 26,156 citations. Since the 1930 Meuse Valley episode in Belgium, Donora 1948 and the London fog of December 1952, the number of studies showing adverse health effects of short and long term exposure to outdoor air pollution has grown. This review looks at historical air pollution studies to get a general overview of the overall health effects that can be attributed to bad air quality. Then we specifically reviewed the important respiratory effects, the plausible mechanism and population at greater risk. Further research is central concern of researcher and policy maker to assess the plausible biological mechanisms of air pollution effects and identifying specific air pollutant that would be more dangerous.