Measuring indoor air

Indoor air is examined on the basis of a measurement strategy defined in advance, which includes the time, duration and location of the measurement. 

When planning indoor air analyses, the geometry and type of use of the room and, if known, the type of emission source must therefore be taken into account. Materials, products and technical devices present in the interior can release pollutants into the room air regularly (continuously) or irregularly (discontinuously). Continuous emission sources are, for example, floor coverings and wall paints, while discontinuous sources include handicraft and cooking activities.

Time of measurement

The timing of the measurement is therefore of crucial importance for the measurement result, especially since indoor air measurements are often carried out using discontinuous methods instead of real-time measurement methods. Intermittent sources, ventilation processes, changing usage scenarios, etc. are therefore of great importance. DIN ISO 16000-5 describes the basic aspects to be considered when developing a sampling strategy for the detection of volatile organic compounds (VOCs) in indoor air.

Duration of the measurement

Usually, discontinuous methods are used for measurements in private or public spaces, which allow sampling on site with subsequent analysis in the laboratory. The duration of sampling varies depending on the type of target substances to be detected and the selected measurement method (see also Measuring air pollutants). The duration of the measurement must also take into account whether the target substances have a significant impact on the occupancy of the rooms (e.g. odor-intensive or toxic compounds). 

Location of the measurement

The location of the measurement must also be determined specifically depending on the question being asked. Whether it is a representative survey of the air quality in a building or an investigation of an obvious situation, measurements may need to be carried out at different locations or in different rooms. If technical devices that significantly influence the indoor air are installed, such as a ventilation system, this must be taken into account when determining the measurement point(s). Whether it is a representative investigation of the air quality in a building or an investigation of an obvious situation, measurements may need to be carried out at different locations or in different rooms. The results of the measurements depend mainly on whether the measurements are carried out in the vicinity of the air intakes or exhausts of the respective ventilation systems.

• DIN ISO 16000-5:2007-05. Innenraumluftverunreinigungen - Teil 5: Probenahmestrategie für flüchtige organische Verbindungen (VOC) (ISO 16000-5:2007); Deutsche Fassung EN ISO 16000-5:2007