Formaldehyde: Interpreting Your Indoor Air Quality Test Results

Formaldehyde (CAS No. 50-00-0) is a volatile organic compound (VOC) in the aldehyde family that is ubiquitous in homes. Given that this pollutant is a known carcinogen, an indoor air quality test is recommended for bedrooms, children’s rooms, and living areas.

You have conducted an indoor air quality test using a Scan4Home test kit and received your test results. Here are some guidelines to help you interpret your results.

WHO guideline value for formaldehyde

The WHO recommends that formaldehyde concentrations remain below 123 µg/m³.

Reference values for formaldehyde in France

ANSES (the French Agency for Food, Environmental and Occupational Health & Safety) has established an Indoor Air Quality Guideline Value (VGAI) for formaldehyde of 100 µg/m³.

As part of indoor air quality monitoring in childcare facilities open to the public, an information threshold has been set at 30 µg/m³. This value is lower than the VGAI because children are particularly sensitive to indoor air pollution. It has been adopted and recommended by the High Council for Public Health (HCSP).

Reference statistical values for formaldehyde in residential buildings in France

The Observatory for Indoor Environmental Quality (OQEI) conducted the National Housing Campaign 2 between November 2020 and February 2023.

The data collected during this campaign provide an overview of formaldehyde pollution in French homes.

• The median formaldehyde level measured was 14.0 µg/m³, indicating that one in two homes has a formaldehyde concentration higher than this value.
• The measured 90th percentile (P90) value was 25.8 µg/m³, which means that one in ten homes has a formaldehyde concentration higher than this value.

Scan4Toxic Interpretation Chart for Formaldehyde

When interpreting your test results, Scan4Toxic recommends using the reference values of 30 µg/m³ and 100 µg/m³.

• A result below 30 µg/m³ indicates low indoor air pollution from formaldehyde, posing no health risk to occupants during daily exposure.
• A result above 30 µg/m³ indicates moderate indoor air pollution from formaldehyde. It is recommended that measures be taken to improve indoor air quality.
• A result above 100 µg/m³ indicates high indoor air pollution from formaldehyde, and health risks to occupants cannot be ruled out. It is urgent to take action to improve indoor air quality.

What steps should be taken to improve indoor air quality in the event of formaldehyde contamination?

Improving indoor air quality rests on three pillars:

• Identify and eliminate sources of pollution: Formaldehyde can come from particleboard furniture, hardwood floors, household products, and combustion processes (candles, incense, etc.)
• Ventilate to refresh indoor air: Outdoor air is 5 to 10 times less polluted than indoor air. Ventilating your home daily can significantly reduce the concentration of formaldehyde in the indoor air. It is recommended that you ventilate your home at least twice a day for 10 minutes by creating a draft.
• Treating indoor air: Using an indoor air purifier should be considered a last resort if the first two solutions are not effective enough, especially since few air purifiers today are capable of addressing formaldehyde pollution.