Satoko Chino

Measurement of 2-ethyl-1-hexanol emitted from flooring materials and adhesives

It has been reported that 2-ethyl-1-hexanol (2E1H) was emitted through hydrolysis between di-2-ethylhexyl phthalate used as plasticizer in flooring material and moisture generated from a strongly alkaline material such as concrete slab. The purpose of this study was to clarify the relationship between diffusion of 2E1H in flooring material and 2E1H emission rate from floor surface. In this study, we measured 2E1H emitted from floor paper, poly(vinyl chloride) (PVC) tile, cushion floor and carpet for 200, days and effective diffusion coefficients for 2E1H in various flooring materials were measured. Effective diffusion coefficients of 2E1H for cushion floor and PVC tile were 115 × 10−9 and 7.8 × 10−9 m2/s, respectively. Emission rate of 2E1H emitted from flooring material significantly depends on the kind and shape of flooring materials and was influenced by the effective diffusion coefficient for 2E1H of flooring material. Emission rates of 2E1H from floor surface varied with the amount of 2E1H and resin present in the adhesive. When carpet was attached to the flooring material with high water content using adhesive, emission of 2E1H significantly increased. The results show that primary and secondary emissions of 2E1H from the adhesive influence the emission rate of 2E1H for flooring material.

Biosensing of an indoor volatile organic compound on the basis of fungal growth

A fungal biosensor plate was applied to assessment of the harmfulness of air polluted by formaldehyde. Alternariaalternata, Eurotiumherbariorum and Aspergilluspenicillioides were used as fungal species. Fungal mycelium length and optical transparency of the biosensor plate were employed as indices of the fungal growth. Formaldehyde in air was detected on the basis of growth inhibition, reflected by suppression of the growth indices. Dynamic range of the measurement was 700-4000 microg m(-3) or broader. Eurotiumherbariorum and Aspergilluspenicillioides were the most suitable fungal species to formaldehyde sensing based on the mycelium length and that based on the transparency, respectively.

Influence of water content in sub-flooring materials using adhesive on chemical compounds emission

Indoor air pollution is caused predominantly by emission of primary pollutants from building materials or finishing materials. Recently, there has been increasing interest in the new secondary pollutants caused by chemical reaction of the primary pollutants. In this study, the pollutants emitted from poly(vinyl chloride) (PVC) flooring material were measured, and 2-ethyl-1-hexanol (2E1H) and volatile organic compounds (VOCs) emitted from composite building materials made of PVC flooring material used as a self-leveling flooring were measured to identify the mechanism of emission of 2E1H. The moisture sorption isotherm was measured with a Magnetic Suspension Balance to examine the moisture content of the self-leveling flooring material and its effect on emission of 2E1H. 2E1H was emitted from the PVC flooring material through hydrolysis or oxidation of di-2-ethylhexyl phthalate (DEHP). The composite building material including the self-leveling flooring material emitted more 2E1H through hydrolysis over time. It was determined that liquid prevails in the self-leveling flooring material when the water content is higher than 4% and vapor prevails when the water content is lower than 4%. The prevailing liquid in the flooring material contributes to the increased emission of 2E1H and the prevailing vapor in the material did not cause increase in emission of 2E1H. It is considered that control of water in the self-leveling flooring material or concrete slab is very important in order to inhibit emission of 2E1H through hydrolysis of DEHP on the floor.