Applies to the following main measuring methods: automatic null balance, thermomagnetic or mangetic wind and differential pressure or "Quinke". Deals with ancillary units and applies to analyzers installed both indoors and outdoors. Indends to specify terminology and definitions, unify methods, specify tests and provide basic documents to support the application of standards of quality assurance ISO 9001, ISO 9002 and ISO 9003.The contents of the corrigenda of January 2003 and May 2003 have been included in this copy.