Measurement of Particles in Aerosols – Challenge and Solutions

Ambient air is a mixture of gases, droplets and solid particles and therefore a typical aerosol. Natural and anthropogenic processes govern the actual composition of the air. In some cases the generated components are toxic and should be avoided. The key issue of the identification, reduction, and limitation of a component is the measurement. Unfortunately an aerosol cannot be stored in containers and is not available as a reference material. Therefore the calibration of measuring instruments is fundamental to obtain reliable results. Because various measuring principles are used for many applications such as cleanrooms, engine emissions, ambient air etc., the calibration procedures must be adopted. Metrological institutes such as METAS have recognised the need for reliable reference values and have initiated calibration services and international collaboration. Therefore international harmonised reference values for particle number concentration and particle size are available