Ayako Sawada

Characteristics of potted plants for removing offensive odors

Abstract Plants have the capability to remove indoor air pollutants and furthermore to decompose odor molecules in an indoor environment. Hydrogen sulfide (H2S), ammonia (NH3) and methyl mercaptan (CH3SH) are the three main offensive odors in a nursing home. It is strongly desired to develop an effective method for reducing those substances. In this study, the pollutant-removing characteristics of a potted plant for three substances, ammonia, formaldehyde and acetone, are examined using a tin oxide gas sensor. As for the results, it became obvious that the removing characteristics for ammonia gas could be indicated using an approximate function of y=a exp (−bx)+c . In this function, the coefficient b stands for the removing effect and c means the offset level of sensor output. The coefficient a stands for the intercept from that level. It can indicate the number of pots and the kind of plants to maintain the clean air quality in an indoor environment. The pothos plant is very available for putting this to practical use.

A Novel Formaldehyde-Degrading Fungus, Trichoderma virens: Isolation and Some Properties

We succeeded in isolating two formaldehyde-degrading fungi, the strains BDF001 and 002, from the rhizospheric soil of formaldehyde-exposed potted golden pothos (Epipremnum aureum), and from the formaldehyde-exposed cultivation soil without plants, respectively. Sequence analysis of the ITS-5.8S rDNA regions confirmed that both fungi were of the same species, Trichodenna virens. These two strains, however, obviously differed from each other in formaldehyde resistance and formaldehyde-degrading ability. The formaldehyde concentration allowing a growth during cultivation for 10 days for the strain BDF001 was up to 0.6%, and that for the strain BDF002 was up to 0.35%. The strain BDF001 showed a formaldehyde-degrading activity 2.3 times higher than that of the strain BDF002. Ranges of the possible growth pH and temperature in the presence of 0.21% formaldehyde were between 4 and 9, and around 25°C, respectively.

Healing effects of foliage plants using physiological and psychological characteristics

Foliage plants serve as interior accessories and are placed in indoor spaces, such as offices, hotels, restaurants, and homes. Recently, their healing effects have attracted much attention. In this investigation, the healing effects of foliage plants on human subjects performing a computer task were examined by measuring salivary amylase activity, blood pressure, and pulse as physiological indices, and by using the profile of mood states (POMS, the Japanese edition) as a psychological index. The salivary amylase activities of the subjects working in a room with foliage plants were significantly decreased compared with those of the subjects working in a room without plants. When comparing average increase/decrease rate between cases immediately after and 30 min after task-loading, the rates of the salivary amylase activity, anger-hostility, vigor of the subjects in the cases with and without plants, are −11.1 and 3.5%, −3.4 and 0.3%, and 3.2 and −0.6%, respectively. It is evident that foliage plants have healing effects in workers.

Tourism State in Kaga City and the Application of the Resources for Foreigners

The number of visitors for spa areas in Kaga city in Japan was analyzed. Based on the analysis, measures to increase the visitors were considered. Although foreign tourists have increased exponentially, the number is still considered small. Kaga city has many tourism resources which are popular among foreigners, such as spas, golf courses and traditional industries. Kaga city is situated close to an airport which has direct flights to Seoul and Shanghai. From the analysis, proposals of new types of tourism resources for foreigners which include golf and ski are necessary. Language and costly accommodation are some of the factors that discourage foreign tourists to Japan. We proposed that a package tour which had a wide price-range should be planned, allowing an attraction not only to the rich but also the middle- class. Increase in the number of foreign tourists is strongly expected in the city.