Organic compounds in indoor air (VVOC, VOC, SVOC)

Indoor air can be contaminated with foreign substances for various reasons. Basically, particles and airborne substances are brought in with the outdoor air through ventilation processes. Examples include ozone, nitrogen oxides and sulphur dioxide. However, the major sources are increasingly found indoors due to the large number of different building materials and furnishings. The material can be a minor or major source of emissions depending on how it is used or lived in, the indoor climate parameters and the age of the material. Due to the fact that most of today's buildings are very airtight or renovated to make them more energy efficient, emissions can accumulate inside the building. 

Organic compounds are the most important substances detected indoors. According to the World Health Organization (WHO), this large group of substances is divided into the group of volatile organic compounds (VVOCs), volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and particles of organic origin (POM) based on the boiling points of the individual compounds (see table). The English abbreviations are also used in German-speaking countries.

In contrast to the WHO, the European Union defines organic compounds according to retention times in gas chromatography. Hexane (C6) and hexadecane (C16) serve as reference substances. Compounds eluting in this analytical window are classified as VOCs, substances eluting before C6 are classified as VVOCs and compounds with a retention time >C16 are classified as SVOCs. In principle, all materials and products used indoors are possible sources of organic compounds, such as paint systems, floor coverings and wall coverings, as well as furniture, electrical appliances, wood preservatives and pesticides.