The paint

A chemical process activated by sunlight

At Studio Steengoed we use specially developed paint to clean the air from nitrogen monoxide, carbon monoxide, bacteria, gases and even certain viruses. This works via a chemical process, which is activated by sunlight, just like the photosynthesis process that we know from the leaves of green plants. Any surface painted with this paint becomes an air-purifying painting that helps to protect people from harmful gases.

BOYSEN® KNOxOUT™ contains CristalACTiV™ photocatalytic technology, which is ultra-fine titanium dioxide, (TiO2) that absorbs energy from light and converts ordinary water vapor into hydroxyl and peroxyl free radicals at the surface of the TiO2.

Created in billionths of a second, these free radicals become reactive particles that break down harmful air pollutants such as nitrogen oxides (NOx) that come into contact with the surface. Harmful NOx gas is converted to nitric acid which is immediately neutralized by alkaline calcium carbonate particles in the paint, producing harmless amounts of calcium nitrate and negligible amounts of carbon dioxide and water. Calcium nitrate is water soluble and can be easily removed from the film, leaving a clean surface ready to clean the next contaminant that comes into contact with the film.

A major advantage of this photocatalytic reaction is that the ultra-fine TiO2 is not consumed in the reaction, but is only a catalyst that continuously generates free radicals as long as there is sufficient light, air and moisture. In addition, this reaction gives the paint self-cleaning and antibacterial properties.

Or more simple:

Using light, BOYSEN® KNOxOUT ™ with CristalACTiV ™ technology reacts to harmful nitrogen oxides (NOx) from motor vehicle emissions, solvents from factories and power plants and neutralizes them through a chemical process. The NOx is broken down and converted into harmless substances that are simply washed away with the next rain shower.


Various tests show that it works.

Extensive tests have been carried out with this paint in Manila and London. As a result of these tests, it was found that with a total painted exterior surface of 4,100 m2, up to 0.44 g NO2 per m2 per day was removed. This information is comparable to the fact that 1 mature tree filters 0.42 g NO2 per day.