Abstract
Plant has the capability to remediate the earth environment. Especially, it has high purification capability for air-pollution. In this paper, the capabilities of golden pothos and peace lily were experimentally examined. The subjects were planted in the plant pot. In the experiment, these subjects were installed in an experimental chamber of 300 liters respectively and the purification processes were monitored by a tin oxide gas sensor. The sensor can detect the concentration of air-pollutants. This sensor output reached at peek level for the concentration of an air-pollutant when it was injected into the chamber by a micro-syringe. The level decreased gradually because the concentration decreased by the plant purification capability. The sensor responding characteristic, which means a plant purification capability, keeps the first order system. The time constant was estimated from the measurement data. The derived data from a modeled dynamics using the time constant was almost correspondent to the measurement one. Therefore, the time constant is employed to evaluate the plant capability. The capabilities of golden pothos and peace lily were nearly constant even if the formaldehyde concentration was changed. The capabilities were examined at the concentration of 5ppm, 6.5ppm, 8ppm respectively. The capability of golden pothos was higher than the one of peace lily and the time constant was about two thirds. Three different sized golden pothoses, which were planted in the same dimension-pots, were also examined. As for a result, the purification capability became higher as an estimated leaf area was larger.
