Formaldehyde is a gaseous, organic compound with the empirical formula CH2O, which can occur in nature, among other things, during the incomplete combustion of carbonaceous material.
Formaldehyde is technically produced and used in very large quantities, e.g. for disinfection and preservation (formaldehyde solution, cosmetics), for the production of chipboards, adhesives, aminoplast local foams, lacquers, paints, wood preservatives, etc.. In the case of the materials, the binding and adhesive agents are produced with the participation of formaldehyde. The most critical materials are chipboard and glued wood-based materials such as laminated parquet or plywood. Urea resin bonded chipboards are particularly noticeable. These materials emit formaldehyde continuously, especially when exposed to moisture (humidity). In extreme cases, this continues until no material produced from formaldehyde is left: the chipboard decomposes.
The main component of formaldehyde emissions in the outside air is likely to come from combustion (car exhaust fumes, wood fire, waste incineration, etc.). In the indoor air, the materials mentioned in the previous paragraph are likely to be the main causes. In addition, there are emissions from combustion processes (cooking with wood and gas, smoking).
Formaldehyde is mainly absorbed through respiration. It is completely absorbed in the respiratory tract. The excretion takes place partly after transformation to formic acid over the urine, partly as carbon dioxide over the lung.
Chemicals Act / Hazardous Substances Ordinance
According to the Ordinance on Hazardous Substances and the Ordinance on the Prohibition of Chemicals, only particleboard with a test room concentration not exceeding 0.1 ppm is permitted in Germany.
Formaldehyde is permitted as a preservative, in cosmetics it must be indicated if the concentration exceeds 0.05 %. Permissible here are 0.1 % for oral care products, 0.2 % in general and up to 0.5 % for nail hardeners.
Limits and guideline values
MIKD (for explanation see chapter "Guide values") 0.02 ppm
MIKK (for explanation see chapter "Guide values") 0.06 ppm
WHO ("little or no concern") 0,05 ppm
WHO guideline ("concern") 0.08 ppm
BGA (intervention value) 0.1 ppm
MAK value 0.5 ppm
Values found in the domestic environment in Germany:
Normal values: unpolluted outside air normally below 0.002 mg/ m³; in pollution areas up to 0.020 mg/ m³, peak values up to 0.10 mg/ m³; inside according to our experience below 0.04 mg/ m³. Load at: > 0.05 ppm = 0.06 mg/ m³ (WHO); 0.10 ppm = 0.12 mg/ m³ (BGA) Urine: as formic acid 20 - 30 mg/ 24 hours.
Tendency to increased excretion only exists from about 0.5 ppm = 0.6 mg/ m³ in indoor air. Compliance with these normal values therefore does not indicate the absence of formaldehyde exposure.
Effects on health
The effects of formaldehyde on short-term exposure
(intake inhaled via air):
Concentration in ppm
Note: 1 ppm = 1.2 mg /m3 lead to physiological phenomena!
0.05 - 0.125 Odour threshold
0,01 - 1,6 Threshold for eye irritation
0,08 - 1,6 Eyes and nose irritated
0,5 Threshold for throat irritation
2,0 - 3,0 Stinging in nose, eyes, back throat
4.0 - 5.0 30 minutes tolerable, increasing discomfort, lacrimation
10.0 - 20.0 after a few minutes of lacrimation, persists until 1 hour after exposure, immediate shortness of breath, cough, burning nose and throat,
30.0 Danger to life, toxic pulmonary edema
The effects of formaldehyde on prolonged exposure
Formaldehyde is absorbed into the organism through the respiratory tract, the skin (cosmetics) and the gastrointestinal tract. 95 - 100% of the inhaled formaldehyde is resorbed by the body, i.e. no longer exhaled as formaldehyde. Most of it is retained in the upper airways, while only a fraction of the inhaled formaldehyde reaches the deeper bronchi and lungs.
In addition to the symptoms mentioned above, the following symptoms may occur during short-term exposure: Coughing, headaches and earaches, inflammation of the nose and throat. In addition, general signs of discomfort such as respiratory and circulatory problems, dizziness, nausea, vomiting, insomnia, nervousness, depression, susceptibility to stress, memory disorders and allergic diseases (including asthma) are possible. The susceptibility to chemical stress is increased.
In the case of prolonged exposure to formaldehyde, central nervous alterations are also reported which go beyond the observed clinical pictures. The following systematic toxicity is observed in a number of patient histories:
Concentration disorders, word-finding disorders, nausea, restlessness, often with diarrhoea, even vomiting. These symptoms are often interpreted as psychosomatic complaints.
Formaldehyde is carcinogenic