Formaldehyde

Formaldehyde is a colorless gas with a sharp smell, commonly used in building materials such as glues, resins, particle board, MDF, and some types of insulation. It can slowly release (or off-gas) into indoor air.

Why it matters:

• At high concentrations, formaldehyde can irritate the eyes, nose, and throat.
• Long-term exposure is linked to health risks, so many countries regulate its use in building products.
• Especially in tiny houses or well-insulated buildings, where ventilation is limited, formaldehyde levels can build up more quickly.

How to recognize it:

• Products are often classified by emission classes, e.g. E1 (low emission, commonly allowed in Europe) and E0 (very low emission).
• Materials with natural glues or solid untreated wood generally emit little or no formaldehyde.

Example:

• MDF board with standard glue → higher formaldehyde emissions.
• Plywood with E0 rating → much safer for indoor air quality.