In Germany, routine measurements are made in the environmental areas of air, noise and water. These measurements are to ensure that the quality of such media are checked as well as to evaluate any measures necessary in order to insure safety or improve quality. The legal basis for measurements intended to monitor environmental air quality is the “Federal Immission Control Act” (Bundes-Immissionsgesetz, BImSchG [1]). It contains the requirements for the installation and operation of facilities which might potentially do damage to the environment. Legal and administrative regulations make these requirements more concrete.