VOCs (Volatile Organic Compounds / volatile hydrocarbons) include many different substances - see our blog article on VOCs or our wiki on VOCs.
At low concentrations, VOCs are usually completely odourless and therefore not perceptible, but can already be harmful to health depending on the type and source. Volatile organic substances can, however, be measured: VOCs are often measured by means of a resistive sensor - as in the air-Q. Molecules that reach the surface of the sensor cause a change in the electrical resistance in the sensor, which is converted into a measured value. Cross-sensitivities are an unavoidable (and in this case desired) feature of this measuring principle. The high-quality VOC sensor in the air-Q is calibrated to alcohol (ethanol) and also reacts to other VOCs such as aldehydes, ketone, toluene, benzene, acetone as well as hydrogen and methane and others.
Porous surfaces in particular can release VOCs more easily and likewise absorb them from other materials. Due to their volatile nature, VOCs are very unstable, which means that the circumstances under which emissions are released and how high they are varies greatly. Due to varying ventilation conditions and potential man-made sources, VOCs can often be more harmful indoors than outdoors.
To be able to interpret an increased VOC value requires a little skill and knowledge of sources of volatile organic compounds. In the following, possible sources of VOCs in the home are considered to give an overview. It is common to find some materials, furnishings or appliances that contain VOCs in every space.
Paints & Lacquers
Vapours from paints are probably one of the best known VOCs and are produced during mixing as well as during drying. In paints and varnishes, certain compounds are used both to keep them liquid before use and to ensure a faster drying process after they have been applied.
Paints, varnishes, paint strippers as well as sealants contain a large amount of chemicals, many of which can be toxic if humans are exposed to them over a long period of time. For example, some now-banned compounds in paints can still pose a risk, as even after years toluene, benzene or acetone, among others, can outgas. Many VOCs in paints, paint thinners and varnishes give off an odour that is perceived as unpleasant, indicating that increased outgassing is being emitted. Nevertheless, it should be borne in mind that the absence of such an odour does not mean that VOCs are no longer being emitted.
To reduce exposure to paint VOCs, adequate ventilation should of course be provided indoors during and after painting. In addition, wearing protective equipment for eyes, mouth and hands can ensure that inhalation and surface contact are minimised. Newer products also make it easier to reduce VOCs, as some brands now have lower VOC content. Nevertheless, even low-VOC or VOC-free paints are not necessarily completely free of these compounds either.
Floor coverings
While materials such as paint tend to emit VOCs more at the beginning of use, long-term use is particularly problematic for floor coverings. In particular, floors made of vinyl, carpet, wood and wood-based materials can continue to emit VOCs for years after installation. Formaldehyde is one of the most common VOCs used in flooring because it is often a component of the material, especially in vinyl, laminate or treated hardwood. It is also used in the sealant that protects the floor from wear damage.
The frequency of use or wear can determine when and how much is emitted from the floor covering. Due to regular contact with people and the resulting wear and tear, the release of VOCs also increases over time due to surface wear. Similarly, adhesives used to seal the material to the subfloor play a role as they may also contain VOCs.
Furniture
As with floor coverings, VOCs can be generated in furniture during the manufacturing process or the treatment process after construction. Especially furniture made of plywood or chipboard contains higher amounts of formaldehyde and toluene. Upholstered furniture is often made of polyurethane foam, which is associated with VOCs as well as SVOCs (Semivolatile Organic Compounds), among others. Surface coatings of many upholstered furniture or mattresses - e.g. to prevent stains or to make them flame retardant - usually also contain VOCs. Furthermore, office furniture also emits outgases, especially the components made of plastic. In offices, additional VOCs are also produced by printers and copiers.
To reduce VOC emissions, it can be helpful to choose furniture made of solid wood (and not chipboard), for example. Buying second-hand furniture can also help, as outgassing from furniture decreases over time. Some mattresses may tend to contain more toluene, which is why they need some time to outgas before use. This is especially important for beds for babies, children, the elderly and people who suffer from chronic respiratory problems or other illnesses.
Detergents and disinfectants
When using cleaning agents and disinfectants, one also frequently comes into contact with VOCs. For example, bleach, ammonia and other solvents produce strong smelling VOCs. Many cleaning agents contain VOCs such as isopropanol or acetone. Sometimes fragrances are added to some cleaners to mask the smell of the chemical vapours. However, these fragrances are also VOCs.
Using cleaning products with lower VOC content is one of the easiest ways to reduce VOC emissions. However, some studies showed that fragrance-free cleaning products can be more difficult to eliminate the accumulation of VOCs in the materials being cleaned. So it is a balancing act to find the right way. In addition, aggressive chemicals should not be used without windows or doors open or with ventilation running.
Dry cleaning
When clothes, upholstery or other textiles are dry cleaned, this is usually done using perchloroethylene (PER) - a substance that releases VOCs and is hazardous to the environment and health. Since a small amount of the cleaning agent usually remains in the textiles, they can also continue to emit VOCs.
Some dry cleaners now offer an alternative method - now also awarded the Blue Angel - and clean with carbon dioxide as a cleaning agent.
Personal care products
Many personal care products contain paraffin, which is derived from petroleum and contains VOCs. This can increase the likelihood of health effects. Products that commonly use VOCs include nail polish, nail polish remover, creams and lotions, deodorants, shampoos or perfumes. Due to their field of application, these personal care products often contain strong fragrances to mask unpleasant odours. However, a pleasant odour, or even no odour at all, does not mean that a product is free of VOCs.
Using products with lower VOC content is one of the easiest ways to reduce VOC emissions. Natural products tend to contain fewer or rather harmless VOCs.
Plastics
The VOC emissions from plastics in the household are relatively high due to the frequent use of the material and the fact that they very easily release chemicals or VOCs into liquids. Plastics appear in many forms, e.g. in toys, kitchen utensils or technical appliances. Many plastics in the household are made of polyvinyl chloride (PVC), which can release so-called phthalates, which are mainly used as plasticisers for plastics. Food and water are often stored in plastic containers, which can release VOCs into the food or water over time. Filling plastic containers with hot contents, using a microwave or dishwasher can additionally increase VOC emissions in the air.
Craft supplies
Recreational and hobby products can also often contain VOCs and release them over time; these include adhesives (especially spray adhesives), modelling clay, and the paints, varnishes, coatings and treated wood products mentioned above. Some materials emit VOCs during their curing process and then release fewer or none once they are completely dry.
As with other materials, the period of exposure to VOCs is important. Particular attention should be paid to this in the hobby sector, especially for young children.
Natural VOC sources
In addition to the VOC sources already listed, which are primarily of human origin, there are some VOCs that originate from biological sources. These include mould, vegetable oils, soil, animal hair, animal faeces, manure, and rotting and decomposition processes.
To reduce an increase in VOCs from organic sources in the home, care should be taken when cleaning clothes, bedding and other textiles, for example, to wash them at high temperatures to kill bacteria, mould, mildew and other residues. To eliminate another source of VOCs, pet bedding should also be changed regularly and pet hair removed.
In the domestic environment, there is little legislation governing the handling of VOCs, as the effect is highly dependent on the type of substance and their monitoring and control is relatively difficult. Although manufacturers may be legally limited in the amount of pollutants used that their products can emit as VOCs over a certain period of time. However, households are not bound by such limits on VOC-emitting materials they use in a particular room or in their homes in general. Accordingly, it is important to pay attention to what products and materials are purchased and used in the home. The recommendations of the Federal Environment Agency on limits of VOCs should also be taken into account.
Cover photo: Pixabay / Sarah Lötscher
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