What You Cannot See on the Wall: Indoor Air Quality (IAQ) and European Regulations on Heavy Metals

When we decide to refresh the walls of a home, attention usually turns to ventilation, mould removal or clearing strong odours after the work. However, the chemical composition of the surfaces around us has a silent yet significant impact on the air we breathe every day.

On average, we spend around 90% of our time indoors—in homes, offices and schools. In these environments, coatings are not merely passive decorative features: they constantly interact with temperature, humidity and air currents, directly influencing Indoor Air Quality (IAQ).

Internationally, and particularly within the European Union, regulations governing material composition have progressively tightened controls on volatile solvents and substances of high concern, including heavy metals.

1. The Legacy of Heavy Metals in Coatings

Historically, the paint industry used heavy metal compounds to provide properties that we now consider standard:

• Lead (Pb) and Cadmium (Cd): Widely used for decades as pigments to produce vivid, durable yellow, red and orange shades.
• Chromium (Cr) and Cobalt (Co): Used as anti-corrosion agents and driers to accelerate film curing.
• Mercury (Hg): Present in older formulations as an in-can fungicidal preservative.

As scientific evidence grew concerning the bioaccumulation and cellular and neurological toxicity of these elements—even at low exposure levels through the inhalation of airborne dust or paint degradation—health authorities pushed for their gradual prohibition.

2. The European Regulatory Framework: REACH, the Paints Directive and EN 71-

To ensure that materials introduced into homes are safe, the European Union has established a stringent regulatory framework:

A.REACH Regulation (Regulation (EC) No 1907/2006)

This is the cornerstone of chemical safety in Europe. REACH restricts and prohibits the use of Substances of Very High Concern (SVHCs), strictly regulating limits on impurities and traces of heavy metals such as lead, cadmium and hexavalent chromium.

B.Directive 2004/42/EC (Paints Directive)

Although its main focus is limiting Volatile Organic Compound (VOC) emissions from decorative paints, it laid the groundwork for accelerating the transition towards cleaner formulations.

It is only fair to acknowledge that the paint industry has been moving in this direction for years. The widespread transition from solvent-based to water-based formulations, the replacement of heavy metal pigments and the sharp reduction in VOCs have laid the foundations for a much more aware market. Today, the challenge is not to question that progress, but to ask how we can take this same pursuit of sustainability and respiratory health one step further.

C.The Child Safety Benchmark: UNE-EN 71-3

In spaces with demanding environmental requirements, such as nurseries, children’s bedrooms and healthcare facilities, the sector uses UNE-EN 71-3 (Safety of Toys: Migration of Certain Elements) as a benchmark for the highest levels of purity.

This standard assesses the amount of soluble heavy metals that could migrate from the dry film—up to 19 elements, including lead, cadmium, mercury, barium, antimony and arsenic—if a child comes into direct contact with the surface or if the film breaks down into microparticles.

3.Indoor Air Quality (IAQ): The Role of Airborne Particles

The risk associated with paint components does not arise solely from evaporation into the air as gases. There is another silent mechanism that affects air quality: the degradation of the surface layer and the generation of indoor dust.

Over time, friction, mechanical wear and wall maintenance release airborne microparticles. If a formulation contains low-quality mineral impurities or traces of metals in its pigments:

1. The microparticles become part of the settled dust in the home.
2. Everyday activities resuspend this dust in the air, where it is inhaled by occupants.
3. Young children and babies are the most vulnerable group because of their higher breathing rate per kilogram of body weight and their proximity to the floor.

For this reason, the most demanding low-emission certifications—such as Eurofins’ Indoor Air Comfort® GOLD—assess both volatile emissions (VOCs and SVOCs) and the stability and purity of components.

4. Pure Minerals and Transparency in Formulation

Avoiding the complications associated with unnecessary additives does not require adding more corrective chemicals, but rather selecting raw materials carefully at the source.

Working with high-purity natural minerals and clean binders makes it possible to dispense with complex metallic pigments or heavy metal stabilisers. When a coating is designed around safety and transparency, the painted surface ceases to be a source of emissions and becomes a neutral, safe element.

Our Responsibility for the Air We Share

Ensuring indoor air quality requires an ongoing commitment, from strict compliance with the European REACH framework to the voluntary pursuit of the most rigorous environmental standards.

Recognising the progress made by an industry that has spent years reducing emissions and seeking safer alternatives is an essential starting point for continued innovation. It is not just about the colour on the wall, but about ensuring that the surfaces around us actively protect the health of those who live with them.

At ACTIVATE, we are part of this natural evolution of the sector, exploring how product physics and the conscious selection of components enable us to take indoor air protection to the next level.

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Sources and Technical References

1. Regulation (EC) No 1907/2006 (REACH): Regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals in the EU. Restrictions on lead, cadmium, chromium VI and substances of very high concern (SVHCs).
2. UNE-EN 71-3:2019+A1:2021: Safety of Toys – Part 3: Migration of Certain Elements. Test method for determining the extraction of 19 soluble heavy metals from dry materials.
3. Directive 2004/42/EC of the European Parliament: Limitation of Emissions of Volatile Organic Compounds (VOCs) Due to the Use of Organic Solvents in Certain Paints and Varnishes.
4. US EPA (United States Environmental Protection Agency): Indoor Air Quality (IAQ) & Lead and Heavy Metals Safety in Buildings. Guidelines for assessing indoor dust contamination and environmental health.
5. Eurofins Environment Testing / Indoor Air Comfort GOLD®: European regulatory standards for assessing low emissions and purity in building materials used indoors.