How did plants become part of the solution to the indoor air pollution problem?

The disadvantage of a tightly closed environment became apparent during the NASA’s manned SkyLab Space station missions. There were four Skylab missions. The first manned mission was Skylab 2. Skylab 3 took air samples, the results of which were reportedly unexpected.

During the (1973) SkyLab 3 mission (the second manned Skylab mission), samples of the Skylab interior atmosphere were returned for analysis. Over 300 VOCs were detected in the SkyLab samples and 107 of those were identified in the crew compartments.

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In 1971, Dr. Bill Wolverton had been recruited to head the Environmental Research Laboratory at NASA’s Mississippi Test Facility. The primary objectives of the Environmental Research Laboratory were to 1) Research the environment’s natural abilities to cleanse itself; 2) Research a closed ecological life support system for long-term space habitation; and 3) Provide usable Spin-off technologies to the American public.

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Following the SkyLab missions, Bill Wolverton and colleague, Rebecca McDonald, turned their attention to the problem of indoor air quality. They asked themselves whether plants could remove toxic chemicals from the air in the same manner that aquatic plants were removing toxins from the environment.

Bill approached the Center Director in 1980 for funding, and was provided a modest budget from the Center Director’s Discretionary Funds to assess the ability of foliage plants to purify the air from energy efficient homes and future space stations. They choose to focus on formaldehyde, a VOC that was receiving considerable attention as an indoor pollutant at the time, due to its widespread use in pressed wood, and insulation used in the home and in house trailers. A small test chamber was built, and Golden Pothos (Scindapsus aureus), nephthytis (Syngonium podophyllum) and sweet potato (Ipomoea hatatas) were tested for their ability to remove formaldehyde from the atmosphere. It was found that the concentration of VOC’s could be reduced when common houseplants were introduced into the closed environment. This was a very important finding, and they began to further research plant removal of formaldehyde and other VOCs from the air.

Source: NASA on phytoremediation.

These initial experiments were very encouraging, with all three species showing dramatic reductions in formaldehyde concentrations in the chambers over a 24 hour cycle. These results were first published as an internal NASA technical memorandum in 1982.

Additional testing was performed and the results of the NASA research were published in the Journal of Economic Botany in 1984.

One of the conclusions of the research was that one spider plant in a 1 gallon pot can effectively remove formaldehyde from an enclosed space.

To meet the air purification needs of the home just described, 8-15 spider plants (3.8 I pot size) would be need to purify the air continuously.

This article does not identify the square footage of the [German] home which is the subject of this article. If three 4-inch spider plants (or one 8- to 9-inch plant) will purify 100 square feet, according to Wolverton’s formula, the article may be speaking of a home between the size of a FEMA trailer (300 square feet) and a mobile home (840 square feet).

Click next page to review how Dr. Wolverton’s botanical air filters evolved, from BioHome to FEMA trailer to the present time.