An innovation for monitoring formaldehyde in the air

An innovation for monitoring formaldehyde in the air

Indoor air pollution by formaldehyde is a major public health concern. In 2008, prolonged exposure to this compound was associated with 9 million deaths worldwide. Today, 25 to 30% of the population shows sensitivity or allergy to it. Classified as carcinogenic to humans in 2004 by the International Agency for Research on Cancer (IARC), accurate monitoring has become essential to develop effective solutions for reducing its concentration in the air.

In this context, researchers from ICPEES and ICS, members of Carnot MICA, developed within the GMG2 project an innovative device for the calibration of formaldehyde analyzers. Compact, robust, and easily transportable, this generator paves the way for more reliable measurements in real-life conditions.

Overcoming the limitations of existing approaches

Generating formaldehyde is complex: highly unstable, it cannot be stored in gaseous form at low concentrations. The objective of the GMG2 project was therefore to design a system capable of producing a controlled flow of formaldehyde at low rates, transportable using a simple gas cylinder weighing less than 1 kg—a solution that did not previously exist on the market.

An initial prototype based on a microfluidic system quickly showed its limitations, particularly due to formaldehyde’s tendency to polymerize upon contact with water, leading to clogging of the printing head.

A breakthrough device based on controlled diffusion

The researchers then adopted a radically different strategy. They developed a device in which a liquid formaldehyde solution is crossed by an airflow passing through a tube containing a microporous section produced by 3D printing. The diffusion of molecules from the liquid to the gas phase enables controlled enrichment of the air with formaldehyde.

This architecture offers several control parameters:

• length and position of the microporous zone,
• solution temperature,
• formaldehyde concentration,
• gas flow stability.

The result is a stable, durable generator operating at very low flow rates, perfectly suited for field use.

Unprecedented performance

Tests demonstrate excellent stability of gas concentration across three different flow rates. The device can generate concentrations ranging from a few micrograms/m³ to over 1,000 micrograms/m³, meeting the needs of:

• indoor air monitoring,
• outdoor air monitoring,
• individual occupational exposure assessment.

A strong lever for further innovation

This project has led to major advances. In collaboration with Chromatotec, new generations of the device have been integrated at ICPEES for a wide range of applications. The generator has notably enabled:

• the development of a high-sensitivity formaldehyde analyzer (LABCOM anaVOC),
• the study of humidity effects on analyzer performance,
• the creation of complex gas mixtures reproducing real exposure conditions.

Research is ongoing, particularly to better understand the adsorption and capture mechanisms of formaldehyde and other pollutants by depolluting materials, and to generate even more representative mixtures including various VOCs and SVOCs. The ambition is also to provide a sustainable solution for indoor air purification.