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The Fallacy of Plants' Impact on Indoor Air Quality |
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Office landscape contractors (plant suppliers and maintainers) have done a great promotional job trying to convince people that plants can impact a building's indoor air quality. Unfortunately, scientific research doesn't support thata conclusion.
Most of the research cited by landscape contractors is based on studies done by a Dr. E. Wolverton. Dr. Wolverton is a former NASA researcher who did only one plant / indoor air study while at NASA. He did the rest after he left, but the promotion of his work incorrectly implies that it was done while he was at NASA. [His work at NASA was on the use of plants in water purification - biological wastewater, a well-proven technology. But that that doesn't relate to indoor air quality.]
Although it is a seductive idea, and that accounts for our willingness to believe it, there are no scientific data to support the efficacy of using plants as an indoor air cleaning approach.
Even in a very careful look at the published work of Wolverton the concept of plants cleaning indoor air does not support the conclusions. Dr. Wolverton tried using fans to deliver air to the root system after he found that leaves do nothing to remove contaminants. He even tried adding charcoal to the soil when he learned that it wasn't the plants' at all, but the soil bacteria that live in the plants root zone that convert VOCs.
A quick calculation using his own study results shows that you would have to fill a house full of plants (from floor to ceiling) to remove as much contamination as is removed by air infiltration of 0.1 air changes per hour (the leakage in an extremely tight-built house). Office buildings leak at a range of 0.2 to 0.4 air changes, depending on the inside vs. outside temperature differential, so you get very little benefit from using plants.
Do plants help? Hard scientific evidence says NO! |
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