Directive on odour in ambient air: an established system of odour measurement and odour regulation in Germany

The legal basis for any requirement with respect to ambient air quality is the German Federal Protection Act for Ambient Air. According to article 3 Federal Protection Act all odours caused by plants are defined as an annoyance. The problem is to find out whether an annoyance has to be considered as a significant disturbance. In the Directive on Odour in Ambient Air a complete system is designed, beginning with measurement methods and concluding with ambient air quality requirements. In the following paper the tenor of the Directive on Odour is presented, some main aspects of more than five years of practical experience will be shown and a perspective on some future investigations and developments will be given. As a conclusion it is pointed out that in practice, the Directive on Odours has been successful. Both methods, field measurements with panels and dispersion modelling, are generally qualified for the determination of odour loads. The restriction of odour loads by limit values expressed as odour frequency per year for certain areas has been established in a lot of cases.