Other factors influencing the plant filter’s effectiveness
1. Temperature
Temperature influenced the rate at which formaldehyde off-gassed from the paneling in Wolverton’s experiments. The greater the temperature, the more rapidly formaldehyde was released.
Source: Temperature effect.
2. Lighting
A change to full spectrum fluorescent lighting was shown by Professor Jove Fjeld to increase effectiveness of VOC removal by 35%.
Source: Lighting effect.
The more beneficial lighting affects the ability of the plant to accomplish photosynthesis. A good explanation of the role of light in photosynthesis is found here: Light in photosynthesis.
3. Well-sealed space
An important finding by Wolverton was that plants are most effective in removing VOCs in non-ventilated, energy-efficient buildings
Source: Energy-efficiency buildings boost plant filter effectiveness.
This is due to the fact that a ventilated building is constantly exchanging the indoor air, which has accumulated carbon dioxide from human exhaling, with outside air, which may or may not be polluted. The air exchange removes the plant-purified air along with the CO2.
On the other hand, an energy-efficient building is sealed and does not exchange air with outside air. Therefore, the plant-purified air remains in place, where it was generated.
4. Irrigation system
Automated irrigation:
A timer or some sort of automation has been used in the test systems. Use of a fan subjects plants to possibility of drying out, unless irrigation is monitored. However, a timer system is a convenience that is unnecessary if a watering pattern is established that keeps water in the pot. Automation of irrigation may be accomplished with use of an Arduino board.
Manual irrigation:
A Luwasa pot demonstration at this link has a water indicator. This pot, like the Andrea plant-based air filter seen here, appears unavailable for purchase at this time.
Wolverton’s newest commercially available hydroculture planter, called the Plant Air Purifier, contains a water indicator.
A Do-It-Yourself water indicator may be as simple as a long straw and a pipe in which to insert it before capping the straw with a finger and lifting it to see if it contains any water. (See a diagram of the use of a straw in tubing at www.hydro-culture.net.)
Click next page to see a brief discussion of other “phytoremediation” capabilities of plants, before moving on to Kamal Meattle’s use of 1200 plants to purify an office with 300 workers, without outside ventilation, in India’s most polluted city, New Delhi.
