1. Definitions – Reference methods

To ensure traceability of measurements, quality assurance and quality control procedures must be implemented. To this end, several tools have been developed within a regulatory framework:

• the definition of priority pollutants to be monitored, in accordance with the possibilities of measurement techniques;

• the determination of limit values which condition the various stages of the measurement protocol and the performance of the methods;

• the establishment of documented measurement standards, describing analytical procedures with minimum quality requirements, as well as calibration procedures.