NOVELTY - Gas samples are purified by conducting drawn gas sample to a lower section of a washing bottle having a solvent. Part of the contaminants are dissolved in the solvent. The gas with remaining contaminants is led against an aerosol filter, forming microbubbles of the gas. The microbubbles are further purified by rising through a solvent in an upper section of the washing bottle.    USE - For purification of gas samples, e.g. biomass.    ADVANTAGE - The novel method is simpler but more efficient, and is easier to use for non-laboratory trained personnel.    DETAILED DESCRIPTION - Purification of gas samples, comprising solid, fluid and gaseous contamination components, e.g. produced in a thermal gasifier or wood burning stove by burning wood, straw or wood chips, involves:    (a) drawing the gas sample from a discharge pipe; and    (b) conducting the drawn gas sample to a washing bottle, comprising upper and lower sections separated by an aerosol filter (16). The sample is conducted via an impinger (11) into the lower section (14) below the surface of a solvent (13) in the lower section. The gas sample bubbles up through the solvent, where part of the contaminating substances is dissolved in the solvent. The gas with remaining contamination residues in the form of inter alia aerosols is impinged against an aerosol filter in which the aerosols are filtered off and microbubbles of the gas are formed. The microbubbles are purified further by rising through a solvent (17) in the upper section, after which the analysis gas is discharged through the upper part of the upper section (15).    An INDEPENDENT CLAIM is included for the apparatus for use in purifying gas samples, as above, comprising a washing bottle in which the interior of the bottle is divided into sections. An impinger is in a lower part of the lowermost section, where unpurified gas may be supplied. An aerosol filter is placed between the two sections. A tapping through is in the upper section, where purified gas samples may be conducted.    DESCRIPTION OF DRAWING(S) - The figure shows an apparatus for the above gas sample purification process.    Impinger (11)    Solvent (13)    Lower section (14)    Upper section (15)    Aerosol filter (16)    Solvent (17)    Cooling jackets (19, 20)