Grow Clean Air!

The myth that plants will clean the air is a seductive one: if true, we could fix indoor air quality problems without expensive changes to mechanical systems and without worrying about what materials we introduce to the indoor environment.

There is scientific evidence that plants clean the air, pulling formaldehyde and other pollutants out of the air and turning CO2 to oxygen (after all, this is what trees and outdoor plants do for the earth). But plants are not necessarily a practical approach to fixing indoor air problems.

Kamal Meattle's talk on TED.com is a good example of how the myth of plants is promising, but not necessarily practical. He claims that three common plants can clean the air in homes and offices, and has shown this in an office building in New Delhi. Sounds great! But then you get to the numbers: four shoulder-high Areca Palm plants per person in a room that need their leaves wiped once a day; six to eight waist-high Mother-in-Law's Toungue plants per person in a bedroom; and several Money Plants, grown hydroponically, to remove formaldehyde.

In his office building in New Delhi, he has 1200 plants in 50,000 square feet for 300 occupants. That's one plant for every 41 square feet (think of a large houseplant in an average office cubicle). In a new project, he has 60,000 plants in a building that's just over a million square feet--one plant for every 16 to 20 square feet!

Meattle's talk is short (that's the beauty of TED talks), and he doesn't get into some of the potential problems with plants in buildings: added moisture levels, insecticides, soil contamination, and so on. Nor does he show any pictures of the office building with such a high plant load.

I'm starting to think of Audrey II, that friendly meat-eating plant in the picture.