Ammonia is a colorless, penetrating smelling corrosive pollutant. The main sources of NH3 are natural processes as decay of organic matter or from excreta. Man made sources are the use of fertilizers, waste disposal or industrial processes. Besides the unpleasant odour, high concentration of ammonia is severely harming the vegetation.
The passive sampler collects gaseous NH3 by absorption on phosphoric acid. The amount of NH3 is determined spectrophotometrically by the indophenol method.
The sampler is composed of a polypropylene housing with an opening of 20 mm in diameter. To exclude wind and weather disturbances, a glass fibre membrane supported by a wire net is attached and set up in a protective shelter. The sampler is placed in a specially designed shelter to protect it from weather conditions during its exposure.