Clay plasters | a passive removal material for indoor pollutants

Luxuriating in the sublime and tonal beauty of clay plasters, we can easily forget about their compelling health benefits.

Clay’s natural ability to help regulate indoor humidity to levels recommended for the prevention of occupant health risks – such as asthma – is well known.

However, recent research by Corsi and Darling into the potential of clay plasters as passive removal materials for the removal of ozone in buildings is particularly exciting and further accelerates the material’s potential to be truly problem solving on so many levels.

Ozone is a respiratory irritant that seeps into our homes and the byproducts that are created when ozone reacts with materials such as carpets, cleaning products, materials and furniture are also toxic: they include hydroxyl radicals and other chemicals such as formaldehyde and acetaldehyde.

Dr Richard Corsi and E. Darling of the Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, state that the products of indoor ozone reactions may be irritating or harmful to building occupants.

In fact, some by products created when ozone hits skin oils are probably more toxic than the starting ozone according to a report by Science News.

Corsi and Darling conclude that: Results indicate that clay-based coatings may be effective as passive removal materials for ozone in buildings.

They add that: the addition of clay plaster when carpet and ozone were present result in significant improved indoor air quality and lower formaldehyde concentrations.

Formaldehyde is a Category 1B carcinogen that can also cause skin, eye and respiratory irritation.

The authors are clear that further research is required, but as understanding of the extraordinary health and sustainability benefits of clay plasters advance, and the aesthetic beauty of the material is further innovated, the material clearly has the potential to reframe the interior wall finish sector.