Nitrogen dioxide concentration was being grown ca. 8% per year although sulphur dioxide concentration was being reduced ca. 10% per year in Seoul from 1996 to 2003. The rainwater was heavily acidic with pH 4.19 to 4.68 in Seoul during 1980 to 1991. Acidity score on the basis of the total anion concentration of rainwater follows the higher in sequence with Seoul(Kwanaksan)(341.5 ${mu}equiv{cdot}L^{-1}$), Gwangneung(199.2 ${mu}equiv{cdot}L^{-1}$) and whole Korea mean(10.3 ${mu}equiv{cdot}L^{-1}$). Rainwaters from 38 sampling sites of 16 countries in the world, on the basis of the acidity score, are classified and designated as five acid rain grades(ARG): the least score is founded in Tana Rata(16.2 ${mu}equiv{cdot}L^{-1}$), Malaysia where has the best rain but the greatest founded in Chongquing(541.1 ${mu}equiv{cdot}L^{-1}$), China where has the worst rain in the world. Even though acidic deposition decrease with time in the world generally, it is expected to increase in Asia, Africa and Mid-South America.