CUBAIR: a prototype for purifying indoor air

Improving indoor air quality? That’s what the CUBAIR project aims to do. By developing a new treatment system, researchers have managed to significantly reduce fine particle concentration and nitrogen oxides.

An important reminder: indoor air is often more polluted than outdoor air. In addition to the automobile exhaust and industrial pollution that enter our homes and offices through the windows, molds and pollutants also come from building materials or cleaning products. What can we do to make the air we breathe inside our homes and offices healthier? That is the big question for researchers working on the CUBAIR project funded by ADEME.

For four years, the group of researchers from Cerema, IMT Atlantique and LaTep (laboratory of Université de Pau et des pays de l’Adour) have been developing a prototype for an air purification system. The air is cleaned through a 3-step process. First, the air taken into the system is filtered by activated carbons with different characteristics. These materials are able to capture organic compounds present in the air —pesticides are one such example. As the air leaves the system, it goes through a more traditional filtering stage to eliminate fine particles. The last step is a photocatalysis stage. When exposed to ultraviolet light, titanium dioxide molecules react with some of the pollutants that remain in the air.

Last year, this prototype was tested at the Human Resource Development Centre in Paris. The goal was to study how effective it was in real conditions throughout an entire year. The device’s performance was measured for different kinds of pollutants: volatile organic compounds, fine particles, mold etc. The results were especially promising for nitrogen oxides— particularly nitrogen dioxide, a major air pollutant— since the treatment system reduces their concentration by 60% in the treated air. Positive results were also observed for fine particles, with the concentration dropping by 75% for particles with diameters less than 1 micron.

The only drawbacks: volatile organic compounds are not eliminated as effectively and the system tends to heat up during use which leads to extra air conditioning costs in summer. The researchers noted, however, that this can be an advantage in cooler weather and that this inconvenience should be weighed against the significantly improved air quality in a room.

Overall, the CUBAIR project offers good prospects for breathing healthier air in our future buildings. Figures published by the World Health Organization in 2018 serve as a reminder that air pollution causes 7 million premature deaths worldwide every year. This pollution also represents an annual cost of approximately €20 billion in France. Combating this pollution is therefore a major health, environmental and economic issue.

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