Clean Air, Naturally

March, 2022

Houseplants certainly make an interior feel healthier. Recent scientific research is explaining exactly why, and designers are beginning to harness the power of plants to naturally filter air.

Image courtesy of Pnat srl

As well as cleaning the air, the Fabbrica dell’Aria introduces plants into an interior at an architectural scale.


European Union research indicates that ‘air pollution is the main environmental risk factor for health in Europe and around the world.’ Advice during the pandemic to ventilate indoor spaces has made us all aware that opening windows is a healthy practice, but particularly in cities this can just be letting outdoor air pollution in. Moreover, environmental concerns for heat and energy loss mean new buildings are often sealed and simply opening a window is often not possible. Catherine Noakes, a Professor of Environmental Engineering for Buildings at the University of Leeds, points out that there are existing technologies that effectively ventilate buildings and prevent heat loss, but ‘we’re going to be living with most of our current buildings for probably the next 50 years so just designing a new building is not the answer. We’ve got to think how we manage existing buildings.’

In the last few years there has been an explosion of air purifying machines on the market, with Ikea recently joining the fray, but these are invariably electricity-powered and so exacerbate the issue. It is well known that plants have super-powers,  and these are being replicated or directly harnessed by designers into ‘biophilic’, or nature-based solutions. However, there are varying assessments of how effective simply keeping a few pot plants is for improving the air quality in an ordinary domestic interior, let alone a large commercial or public space.

The Fabbrica dell’Aria is an air filtration system using plants that rigorously applies the latest botanical engineering research. It has been developed by the botanist Stefano Mancuso with the team of designers and plant scientists at Pnat, a think tank that applies experimental research into plant life to sustainable design challenges. The Fabbrica is a glass tank of specially selected tall plants. Most recently installed in the Adidas Halo Store in Berlin, this system works on the principle of air phytoremediation and takes advantage of plants’ ability to assimilate, degrade or modify toxic air pollutants. Because the plants capture pollutants and either metabolise or sequester them, this filter has infinite duration. Air to be cleaned passes firstly through the growing medium, where pollutants can be absorbed by the roots, before entering the atmosphere so the leaves can absorb any remaining pollution through their stomata. The clean air is then piped back into the room it came from. Pnat are confident that the Fabbrica dell’Aria system could be installed at a much larger scale to tackle outdoor urban air pollution.

Courtesy of Pnat srl

Fabbrica dell’Aria is fully automated and includes fans, an irrigation system and technical light (if needed). Each installation is provided with sensors monitoring environmental data in real time and the level of air pollutants entering and leaving the system.

Air phytoremediation technology is a growing field as the science behind the system continues to be better understood. Different plant species have been found to be good at removing particular pollutants: Chamaedorea elegans (parlour palms) and Zamioculcas zamiifolia (Zanzibar gems) are capable of removing formaldehyde; the Opuntia microdasys, or bunny ears cactus, can get rid of benzene, toluene, ethylbenzene and xylene compounds; brassicas are particularly efficient at absorbing sulphur dioxide and nitrogen dioxide from air, utilising these as nutrients for growth; the humble spinach (Spinacia oleracea) is adept at taking up heavy metals.

The visual impact of so many plants is considerable and the Fabrica dell’Aria is a striking spatial intervention. The structural possibilities as well as the botanical ones open up exciting prospects at the intersection of engineering, interior and garden design.