Does work make you sick … literally? Studies have shown that poor indoor air quality affects our health and productivity. Commonly known as sick building syndrome, poor indoor air quality can cause headaches, watery eyes, itchy nose, fatigue, and difficulty concentrating.

While people typically associate these symptoms with allergies of the great outdoors, one Canadian scientist and entrepreneur is seeking to combat sick building syndrome by bringing the great outdoors inside. His solution: an air filter system that captures airborne pollution in a living wall of plants. And you can fi nd its first installation in the United States in Baltimore.

Found at the new headquarters of Biohabitats, Inc., the living wall is a vertical garden dotted with semi-tropical and tropical plants typically used for interior plantscaping. It includes a variety of plants, including peace lily, croton, and fi cus. It adds grace and beauty to the renovated offi ce space and inspires workers, but it is more than just an aesthetic focal point. It's a cutting-edge application of an old science called biofi ltering.

In nature, many pollutants are broken down and turned into harmless byproducts by microorganisms like bacteria and fungi, which are found in and around the root systems of trees and plants. Biofiltering is the general term given to the multiple plant and microbial processes that enact this conversion, which are also key components in plants' production of oxygen. Scientists have controlled pollution using biofi ltering for decades, traditionally in treating waste water and eliminating unpleasant odors created by industrial processes. Now, however, the concept is being expanded to new realms.

The vanguard of the movement to apply biofiltering to control indoor air quality is Dr. Alan Darlington of Guelph, Ontario, who has spent the last eleven years developing the science behind his living walls. It is only in the past few years that Darlington has sought to commercialize the living wall (known as a Naturaire System). He founded the company Air Quality Solutions in 2001 and has installed several large walls up to 1500 square feet in size (over 50 feet high and 30 feet wide) in universities and commercial spaces in Canada. A classic example of the growing trend in natural capitalism, Air Quality Solutions overlaps business and environmental interests by better satisfying customers' needs, increasing profits, and helping solve environmental problems all at the same time.

Darlington's living walls are essentially gardens built upwards, with a few key differences. First and foremost: There's no dirt. Vines and other types of plants are rooted into a substructure made of foam and reinforced with a compound typically used by mining companies to secure their mineshafts, over which a sheet of fabric is laid. Water trickles down this structure, nourishing the plants and eventually falling into a pool at the base of the wall, where it is sent back to the top by a small pump. The lack of dirt is essential to the effectiveness of the living wall, as bacteria on the exposed roots of the plants metabolize air impurities such as the volatile organic compounds leached from paint and plastics. It also illustrates why just having more plants around the office doesn't have the same effect, and it makes the wall a less messy proposition.

So how does it work? Traditional buildings are sealed so that cold air in the winter and hot air in the summer can be shut out, thereby making the temperature more stable and controllable. The problem in a sealed system is that not only is the air locked in, but so are the contaminants. The air inside buildings accumulates pollutants over time, which get circulated through the building by the HVAC system—hence the onset of sick building syndrome. To reduce the percentage of pollutants in the air, standard HVAC systems draw in fresh air from the outdoors.

In Darlington's system, a living wall is attached to the HVAC system and acts as a fi lter. By running the building's air supply through the living wall, the contaminants are controlled and broken down, while the plants themselves manufacture "fresh" air by acting as a repository for excess carbon dioxide and producing oxygen. As a result, the HVAC system requires less air from the outside, making it more efficient and cheaper to operate. The living wall represents an industrial redesigning of biological models. It is an entirely self-sustaining system that creates zero waste other than the occasional pruning.

Biohabitats brought the living wall to Baltimore last September, just prior to moving into its completely renovated office in October. When designing the new space with architecture firm Cho Benn Holback + Associates, Biohabitats' president Keith Bowers had wanted an inspiring offi ce space for his ecological restoration and conservation planning company. When it came to creating the offi ce environment, Bowers wanted to live up to the company's motto "Restore the Earth and inspire ecological stewardship." Biohabitats has contributed to and guided environmental and ecological recovery in Baltimore and around the country since the early 1980s, and Bowers felt it was important that the company follow its motto not just through its work, but in its own practices. Working with Furbish Company, a sustainable building contractor, Bowers was able to utilize green materials, sustainable building practices, and eco-friendly technology like the living wall.

For Bowers, the decision to install the living wall was not diffi cult. With a company full of engineers, ecologists, biologists, geologists, landscape architects, and people who love the outdoors, bringing in a wall of plants that would inspire employees promised a high return on investment. Tim Burkett, operations team leader, says, "Our firm's greatest asset is its people, so it's important to ensure that our staff is happy and to provide a creative, enjoyable work environment."

And while this may sound well and good for an eco-friendly company, it's actually worth investigating for all companies since happy, healthy workers translate directly into higher profi ts. In an article on productivity and health that appeared in the September 1997 issue of Indoor Air: International Journal of Indoor Environment and Health, researchers William J. Fisk and Arthur H. Rosenfeld estimate potential U.S. annual savings and productivity gains of $6 billion to $19 billion from reduced respiratory disease, $1 billion to $4 billion from reduced allergies and asthma, $10 billion to $20 billion from reduced sick building syndrome symptoms, and $12 billion to $125 billion from direct improvements in worker performance that are unrelated to health.

While Baltimore boasts the fi rst living wall built in the U.S., Air Quality Solutions' installations are popping up in every direction. Not only is Air Quality Solutions expanding to offi ce buildings and shopping malls around North America, Darlington's technology may soon provide air quality solutions down in the recesses of mines or up in space where renewable air is less prevalent or nonexistent.