Saurer Regen#
Acid rain, one of the most crucial environmental problems in many parts of Europe; a constant drop in the pH levels of precipitation has been registered since the sixties. Along with other factors, acid rain, has been responsible for damage to forests throughout Europe ( Forest Dieback). Air pollutants, in particular sulphur dioxide (SO<sub>2</sub>) and nitrogen oxide, are the chief causes of acid rain. Along with pollutants deposited by dry air and fog, acid rain damages vegetation and historic buildings, and chemically alters soil composition. As air exchange takes place irrespective of national borders, international agreements aimed at combating acid rain are necessary. Although Austria reduced its SO<sub>2 </sub>emissions by over 80 % between 1980-1994, no improvement has yet been registered.