The wet chemical measurement method specified in this guideline is suitable for determining the mass concentration of nitrogen monoxide and nitrogen dioxide in exhaust gases. The nitrogen oxides are determined as a sum and expressed by convention as nitrogen dioxide in milligrams per cubic metre. The method can be used in the concentration range from approximately 30 mg/m3 to approximately 3000 mg/m3 of NO2. The method can be used as a reference method for mandatory comparative measurements (for example TA Luft, 13. BImSchV and 17. BImSchV) according to VDI 3950 Part 1 or DIN EN 14181.