The French indoor-air value for formaldehyde changed on 1 January 2023. The annex to article R221-29 of the environment code, rewritten by decree no. 2022-1689 of 27 December 2022, now sets 100 µg/m³ for short-term exposure, and no longer 30 µg/m³ for long-term exposure. The 10 µg/m³ deadline announced by the 2011 decree was replaced before it ever applied, which has not stopped trade literature from quoting it. On the product side the selection benchmark has not moved: the order of 19 April 2011 reserves class A+ for products whose formaldehyde stays below 10 µg/m³ after twenty-eight days of testing.
Understanding VOCs and formaldehyde on your job sites
What the term VOC covers (sources and pollutant families)
The term VOC covers organic compounds that evaporate at room temperature. The order of 19 April 2011 defines them precisely as compounds whose initial boiling point lies between 50 °C and 286 °C. On site, they are found in paints, varnishes, glues, sealants, solvents, foams, floor coverings and some cleaning products. Depending on the product you meet hydrocarbons, terpenes, glycol ethers and aldehydes. The common thread stays the same. They move from the material into the air, sometimes for several weeks after installation.
Formaldehyde: why it is watched especially closely indoors
Formaldehyde is an aldehyde very present in indoor air. It can be emitted by wood-based panels, glues, textiles, or during certain combustion processes. It is highly irritant and subject to close monitoring because it is linked to respiratory effects and a carcinogenic risk. In retrofits it deserves particular attention when replacing flooring, kitchens, cupboards and linings, which are precisely the packages where the exposed panel area is largest.
The values that count, and since when
Two reference frameworks coexist and do not do the same job. The first sets what is tolerated in the air of a room, the second what is tolerated at the emission of a product. Confusing them is the most common source of error on this subject.
| Pollutant | Value in force | Exposure type | Text |
|---|---|---|---|
| Formaldehyde | 100 µg/m³ | short term | annex to article R221-29 of the environment code, since 1 January 2023 |
| Benzene | 2 µg/m³ | long term | same annex |
| Radon | 300 Bq/m³ | reference level | same annex |
| Formaldehyde, Anses guideline | 100 µg/m³ | short term, to be met repeatedly and continuously through the day | Anses update, 2018 |
| Formaldehyde, former value | 30 µg/m³ | long term | decree no. 2011-1727, superseded on 1 January 2023 |
The second framework is the health emissions label. Concentrations are measured after twenty-eight days in an emission test chamber, in a conventional 30 m³ reference room ventilated at 0.5 air changes per hour. That 0.5 ach is a test convention, not a ventilation recommendation for your jobs, and it is frequently quoted as though it were one.
| Substance, exposure concentration in µg/m³ | A+ | A | B | C |
|---|---|---|---|---|
| Formaldehyde | < 10 | < 60 | < 120 | > 120 |
| Total VOCs | < 1,000 | < 1,500 | < 2,000 | > 2,000 |
| Acetaldehyde | < 200 | < 300 | < 400 | > 400 |
| Toluene | < 300 | < 450 | < 600 | > 600 |
| Styrene | < 250 | < 350 | < 500 | > 500 |
| 1,4-dichlorobenzene | < 60 | < 90 | < 120 | > 120 |
The letter shown on the label is the worst class obtained across all substances, total VOCs included. A product can therefore be rated C because of a single line, and it is the technical data sheet, not the label, that tells you which one. On a quotation the consequence is simple: "A+ rated products" commits to nothing if the work package is not named. Write the required class package by package, boards and floor substrates, adhesives and primers, paints and varnishes, sealants and joints, because those are the four families that weigh most on the formaldehyde load of a freshly refurbished room, and because it is the only wording that lets you refuse a substitution mid-job.
Identifying the main sources of VOCs after a renovation
Paints, glues, varnishes, panels: the materials that off-gas the most
Right after the work, the biggest VOC emitters are wet products (paints, varnishes, glues, sealants) and some wood panels (chipboard, MDF, OSB) that release solvents and formaldehyde. Aim for low-emission products, let them dry through according to the data sheet, and leave ventilation running continuously for the first few days. Developed area matters as much as the product: a lining package shifts the order of magnitude of a job far more than a tin of paint.
Furniture, textiles, cleaning products: the off-site contributions not to forget
A home handed over new then reloads with furniture and textiles. Mattresses, sofas, curtains, rugs, scented sprays and household products bring VOCs you did not install. The point of documenting that is not to lecture the occupant, it is to bound what belongs to your package before a late measurement is held against you.
Airtightness and humidity: when energy performance traps pollutants
As insulation and airtightness improve, concentration rises unless ventilation is brought up to standard in the same job. Drying renders, leaks and showers add a moisture load that encourages odours and emissions. Check the ventilation flow rates against the values in the order of 24 March 1982 and record the readings. To go further, rely on ventilation flow rate measurement to concretely verify that the air is properly renewed.
Ventilating effectively to reduce VOCs and protect air quality
Site ventilation: what you control during and after the work
During application and drying, ventilation is a site resource, not an instruction to hand to the occupant. Keep the ventilation running continuously, open up across the plan during application, and avoid raising the temperature sharply to speed up drying: you push emissions rather than clearing them. The tipping point is recommissioning, when control passes from you to the installation, and when the settings have to be made and recorded.
Single-flow, humidity-controlled, heat-recovery ventilation: choosing by home and budget
Once site ventilation stops, only the permanent installation sustains air renewal. Self-regulating single-flow is the most accessible. Humidity-controlled systems modulate flow with humidity, provided the system holds a technical approval. Heat-recovery ventilation reclaims warmth, but demands ductwork, filters and space. In a retrofit the decision follows fabric airtightness, available loft space and duct accessibility. To go further on installing heat-recovery ventilation, its constraints and its benefits, see our dedicated guide.
Settings, balancing, air inlets: the control points that make the difference
Ventilation performs when it is set and recorded. Check that the air inlets are unobstructed, that extract points are correctly placed, that ducts do not leak and that the network is clean. On a heat-recovery unit, check filters and flow balancing. A missed adjustment lets pollutants stagnate and cancels the health gain of your product selection, which makes the premium for A+ references impossible to defend on the quote.
Measuring and proving the improvement in air quality in 2026
When to run VOC and formaldehyde measurements (before/after work, handover)
To get objective evidence of the work's effect, start with a baseline before the job. Run another campaign after commissioning and setting the ventilation, then at handover, once the materials are dry. On fresh paint, glue or flooring, an early measurement overstates emissions and turns against you: it documents a drying peak you will then have to explain.
Consumer sensors vs laboratory measurements: what is actually defensible
Consumer sensors (CO2, humidity, particulates, TVOC) are for steering and for spotting a drift. CO2 is in fact the only one of those parameters whose measurement is framed by a text, and only for premises open to the public, a subject covered in our article on CO2 sensor control. To prove a reduction in VOCs or formaldehyde, only an accredited laboratory working to a standardised protocol produces a defensible result.
Tracking your actions: ventilation record, photos, manuals and emission classes
Keep a ventilation record with measured flow rates, extract point positions, filter change dates, and before and after photographs. Add the technical data sheets and emission classes of the products used, the air inlet references, and the usage instructions handed over. That file is what turns a technical choice into evidence, and it is the only thing still standing twelve months later.
Best practice to limit VOC emissions from the product choice onward
Product selection: labelling, technical data sheets, indoor emissions
When buying, aim for the A+ indoor air emissions label wherever possible, knowing it corresponds to under 10 µg/m³ of formaldehyde and under 1,000 µg/m³ of total VOCs in the test conditions. Cross-check against the technical data sheet and the safety data sheet. Look for water-based or low-odour wording, and rule out solvent-heavy products where an alternative exists. For glues and sealants, insist on an emission class, not just a VOC content on the packaging.
Site organisation: storage, drying times, temperature rise, air purging
Store tins closed, away from heat, and open them at the last moment. Respect the drying times stated by the manufacturer. If you heat the space, raise the temperature gradually so you do not push the off-gassing. During and after application, keep the ventilation running and purge the air with short, effective airing, especially in small volumes where concentration climbs fastest.
Defending the premium on A+ products against a cheaper bid
The premium on an A+ range is defended with a figure, not with a general health argument. Class C allows over 120 µg/m³ of formaldehyde as an exposure concentration, class A+ under 10: a factor of twelve on the same test method, at identical installed area. Put the emission class in plain text on every affected quote line. That is what makes your offer comparable item by item, and it is also what protects you if a measurement is requested afterwards. On the quote, that information belongs line by line, alongside the technical characteristics each measure has to carry.
