The diffusive sampler for sulphur dioxide is based on the principle of the diffusion of sulphur dioxide molecules onto an absorbant medium, in this case a mixture of potassium carbonate and glycerine. The total amount of sulphur dioxide is extracted and ion-chromatographically determined.

The passive samplers are composed of a polypropylene housing with an opening of 20 mm diameter. To reduce wind disturbance a glass fibre  membrane is attached, supported by a wire net. To protect the sampler from weather influences, as well as minimising wind disturbance, a specially developed suspension device is recommended.