August 2021

1. Description

Formaldehyde, the most important aldehyde, is perhaps the most common indoor toxic substance. Under normal conditions of temperature and pressure, formaldehyde occurs as a gas, with a pungent, intense and penetrating odour. It is water soluble and highly volatile.
It is a substance widely used in industry as an adhesive, biocide, preservative, degreaser, disinfectant, solvent, hardener, fungicide, waterproofing agent, cleaner, lubricant, microbiocide, pesticide, wood preservative, or even as a refrigerant. Very present in building interiors, due to building materials - chipboard and other wood-based materials, equipment, hygiene and cosmetic treatments or products, exhaust fumes and tobacco smoke - as a result of slow combustion.

2. Recommended levels

The limits established in Spain for short-term occupational exposure (VLA-EC) are 0.3 ppm or 370 µg/m³.
There is no reference value for indoor residential use.
The technical standard for measurement in Bioconstruction SBM2015 gives the following indicative values for rest areas for formaldehyde concentration in indoor air:

  • Not significant : < 20 µg/m³
  • Weakly significant : 20 - 50 µg/m³
  • Strongly significant : 50 - 100 µg/m³
  • Extremely Significant : >100 µg/m³

3. My inBiot Ranks

The value ranges used in the MICA device as indicators take into account the SBM values for resting areas as well as the values above which allergic and sensitising reactions occur:

  • GREEN: < 70 µg/m³
  • YELLOW: 70 - 120 µg/m³
  • RED: > 120 µg/m³

4. Unit of measurement

Formaldehyde concentration in air is measured in µg/m³, ppm or ppb (parts per billion). MICA collects the values in µg/m³.
The conversion between µg/m³, and ppm/ppb - like other common concentration units - depends on the type of compound and the indoor environment conditions. For a typical inhabited room, with a temperature around 20°C, the values are given in µg/m³:

  • 0.1 ppm ~ 0.125 mg/m³ or 100 ppb ~ 125 µg/m³

5. Sources

Formaldehyde is commonly detected in building interiors (offices, dwellings). On the one hand, it is a compound widely used in the wood-based particleboard manufacturing industry in the form of glues and adhesives, for furniture, equipment and building boards. It is also frequently used in finishing products (glues, adhesives, laminates), as well as in hygiene, cleaning and cosmetic products. As a highly volatile gas, it is easily emitted into indoor air.
It is also naturally present in solid wood, although in very low concentrations compared to chipboard or other products.

6. Benefits of optimal levels

We spend 80-90% of our time indoors. Our interaction with factors such as temperature, humidity, air renewal or the presence of pollutants such as formaldehyde characterise an adequate indoor environment and condition our health.
An indoor environment without the presence of formaldehyde will be an indoor environment focused on health, or at least with the absence of one of the most frequent indoor pollutants. The quality of the overall indoor environment and the presence of other pollutants and health risk factors should be assessed.

7. Risks of inadequate levels

Formaldehyde can cause allergies, headache, irritation of mucous membranes, itchy nose, red eyes, coughing, hair loss. It is also a substance included in the ISTAS black list due to its classification as:

  • Carcinogenic 1B according to RD 1272/2008 and group I IARC
  • Mutagenic, grade 2, according to RD 1272/2008
  • Neurotoxic level 2
  • Sensitising according to RD 1272/2008
  • Allergen, according to REACH

8. Recommendations for improvement

  • Adequate air renewal
  • Elimination of the polluting source
  • Use of formaldehyde-free products
  • Sealing of contaminant source - with expert advice to avoid secondary contamination by VOCs and/or isocyanates:
    - Formaldehyde sealing varnish.
    - Sealing of open edges or holes by gluing, aluminium adhesive tape, silicone, etc.

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