This document specifies a manual method of measurement including sampling and different analytical methods for the determination of the mass concentration of ammonia (NH3) in the waste gas of industrial plants, for example combustion plants or agricultural plants. All compounds which are volatile at the sampling temperature and produce ammonium ions upon dissociation during sampling in the absorption solution are measured by this method, which gives the volatile ammonia content of the waste gas. This document specifies an independent method of measurement, which has been validated in field tests in a NH3 concentration range of approximately 8 mg/m3 to 65 mg/m3 at standard conditions. The lower limit of the validation range was determined under operational conditions of a test plant. The measurement method can be used at lower values depending, for example, on the sampling duration, sampling volume and the limit of detection of the analytical method used. This method of measurement can be used for intermittent monitoring of ammonia emissions as well as for the calibration and validation of permanently installed automated ammonia measuring systems.