The air-purification system at the new University of Guelph-Humber building in Toronto is anything but industry-standard.

And when visitors spot the four-storey wall of plants dominating one side of a light-filled atrium, the reaction is universally "Wow", says vice-provost Michael Nightingale.

But while the lush array that includes orchids, ferns, ivy and hibiscus is impressive, the truly innovative part of the biofilter - which has been operating for less than a year - is its capacity to break down hundreds of different kinds of contaminants found in indoor air.

Thanks to the action of microbes that live on the plant roots, common pollutants such as formaldehyde, toluene and benzene are transformed into harmless water and carbon dioxide. While the plants themselves have little impact on contaminants, they provide the environment for the microbes to work efficiently.

Ken Kerr, Business Edge
Vice-provost Michael Nightingale has the four-storey-high living wall as his neighbour.

The wall's innovative combination of form and function won an award of excellence from the Royal Architectural Institute of Canada in May, and has attracted numerous visitors to the campus.

Installing it was the idea of Toronto architect Birgit Siber of Diamond and Schmitt Architects Inc., which designed the 170,000-sq.-ft. building that houses classrooms, offices, labs and an Internet cafe for the joint venture between the University of Guelph and Humber College Institute of Technology and Advanced Learning. The integrated program allows students to earn a university honours degree and an applied college diploma in four years of studies.

A key motivation was how to represent the U of Guelph - which has a campus that is surrounded by nature - at Humber's more suburban campus near Toronto's Pearson Airport.

A biofilter not only brought additional greenery to a site that is almost surrounded with parking lots, but it represented a decade of University of Guelph research that began with a small system at the Canada Life Assurance building in Toronto in 1994.

Alan Darlington, an adjunct professor in U of G's department of environmental biology, got involved with that project as a grad student. At the time, engineers did not believe biofilters could handle the extremely low concentrations of contaminants in indoor air - levels in the parts per billion or even parts per trillion - but Darlington and his colleagues proved that was a myth.

"Frequently, nature has the answers that you need," he says. "You just have to figure out how to apply them."

Darlington has commercialized the research through a spinoff company, Air Quality Solutions Ltd., founded with funding from the Ontario Centres of Excellence.

One of the selling points of the wall is the potential to save money. Most buildings maintain indoor air quality by bringing in fresh air from the outside through ventilation systems. In the winter, outdoor air must be heated to room temperature, and in the summer it needs cooling.

That adds up to 10 per cent of the total energy a building consumes, Darlington says. A biofilter can substantially reduce the need to bring in fresh air by generating clean air indoors. If it is used to its fullest capacity, Darlington estimates it can save 0.3 to 3.5 kilowatts per person in the height of summer and winter.

And unlike standard filters, the living wall does not become saturated, because the microbes break down the contaminants rather than simply soak them up.

"It's a self-cleaning, self'-rejuvenating filter," he says.

Another advantage is the psychological benefit of green plants. A research study is trying to quantify that effect at University of Guelph-Humber. Darlington cites studies from Washington State University that found greening indoor space can reduce absenteeism by 10 per cent and boost productivity by 12 per cent.

Despite the potential benefits, Nightingale encountered a certain amount of skepticism when he tried to sell the idea of a living wall. Part of the resistance, he says, came from the capital costs: $500,000 for the design and installation as well as $21,000 annually for maintenance.

There were also a number of design and construction challenges, such as finding a suitable growth medium that could support the weight of the plants, was resistant to clogging and could handle high volumes of airflow.

"Everything had to be worked out from first principles," says Siber, who collaborated closely with Darlington, engineer Bob Cross and the contractor. "When you're doing something new like this, you need the co-operation of a lot of people."

Since its installation, there have been a few glitches, such as the time someone inadvertently turned off a switch, leaving the wall without water over a weekend.

But the end result is a stunning feature that has won over skeptics, Nightingale says. "We're pretty passionate about it."

Siber expects to see more biofilters over the next 10 years. Ratification of the Kyoto Protocol requires organizations to reduce energy use, while sustainable design criteria such as LEED Canada promote indoor air quality and energy conservation.

Siber says, however, that it takes time for people to get used to a new idea like this.

Air Quality Solutions has installed smaller biofilters at Queen's University in Kingston, the Toronto and Region Conservation Authority head office, and an office building in downtown Toronto, but the Guelph-Humber system is the largest so far.

This year, Darlington made his first sale in the United States and the systems have attracted interest from the United Kingdom, Saudi Arabia and South Korea. Darlington hopes to develop strategic alliances with groups throughout North America and Europe to create local manufacturing nodes.

Since he installed the Guelph-Humber wall, Darlington has managed to reduce the costs of a biofilter by 40 per cent. A square metre now costs $1,200 and can treat 100 sq. m of floor space.

Darlington also is busy developing several standardized units that can be prefabricated and shipped to clients, instead of custom-designing each system.

Down the road, Darlington would like to target the residential market. Not only are there many more homes than offices being built, he says, but the air quality in most homes is far worse than in the workplace.

But despite increasing commercial interest in his product, the newly minted entrepreneur confesses the lab bench still exerts a pull.

"There's still so much more we can get going on this," Darlington says. "We're just scratching the surface."

(Julie Stauffer can be reached at stauffer@businessedge.ca)