What are VOCs? Volatile Organic Compounds (VOCs) are a set of substances belonging to different chemical families. Their only common point is that they evaporate quickly at room temperature. They are mainly made up of carbon and hydrogen compounds.

Their source can be:
• anthropogenic: from the refining, evaporation of unburned organic solvents, etc;
• natural: emissions by plants or some fermentations.

Depending on the situation, they are biodegradable to a faster or slower extent through bacteria and fungi, or even through plants, or degradable by UV or ozone. Their volatile nature allows them to spread near or far from their place of emission.

They can thus have direct and indirect impacts. They, along with nitrogen oxides, are the precursors of ground level ozone and also of greenhouse gases.

What is the impact of VOCs on health?

The total VOCs are an indicator of organic pollution of indoor environments. But contrary to popular belief, there is no direct effect of VOCs as a whole on health.

• Primarily, the effects of individual substances must be examined. Some are more problematic than others. Some are harmless to current concentrations in indoor air (ethanol), some affect the respiratory tract (formaldehyde), others are allergens (limonene), others are carcinogenic (benzene, formaldehyde), etc. For each substance of the VOC family, a specific risk assessmentis required.
• The "cocktail effect" of certain combinations of substances in the environment must not be confused with the effect of VOCs in general. In fact, a mixture of pollutants from different sources can have a detrimental effect on the environment or the health while individual substances taken separately do not show these effects. But this is not necessarily the combination of VOCs with each other. For example, the effect of the particles on lungs is exacerbated in the presence of formaldehyde (which is a VOC).

The main VOCs to be monitored in the indoor environment are

• (+/-) alpha pinene: deodorant, home fragrance, essential oils, cleaning agents
• 1,4 dichlorobenzene: anti-mite, deodorant, talpicide
• 1,1,1-trichloroethane: glue
• 1,2,4-trimethylbenzene: petroleum solvents, fuels, tar, varnishes
• 1-methoxy-2-propanol: lacquers, paints, varnishes, soaps, cosmetics
• 2-butoxyethanol: paints, varnishes, fungicides, herbicides, wood treatment, silicone caulking
• 2-ethoxyethanol: paints, lacquers, varnishes
• 2-ethoxyethyl acetate: unknown sources
• 2-ethyl-1-hexanol: aqueous solvents
• Benzene: fuel, cigarette smoke
• Butyl acetate: parquet, solvents
• Cyclohexane: paints, varnishes, glues
• Decane: white spirit, adhesives for floor, waxes, wood varnishes, floor, carpets, rugs
• Ethylbenzene: fuel, waxes
• Formaldehyde ( wood panel, plywood, detergents, paints, textiles, DIY products, smoke from candles/incense, gas stove, extra gas or oil heating, tobacco smoke, adhesives, polyurethane insulation, etc. Formaldehyde is a ubiquitous compound found everywhere.  
• Isopropyl acetate: unknown sources
• Limonene: deodorant, home fragrance, essential oils, waxes, floor cleaners
• m / p-xylene and o-xylene: paints, varnishes, adhesives, insecticides
• Styrene: plastics, insulation materials, fuels, cigarette smoke
• Tetrachloroethylene: dry cleaning, carpets, rugs
• Toluene: paints, varnishes, adhesives, inks, carpets, rugs, silicone caulking, gasoline vapours
• Trichloroethylene: paints, varnishes, adhesives, metal degreasing
• Undecane: white spirit, adhesives for floor, waxes, wood varnishes, floor cleaners