Carbon-based adsorbents are rarely used to measure volatile organic compounds (VOC) and semi-volatile organic compounds (SVOC) in indoor air. Herein, Tenax GR and spherical activated carbon-filled glass tubes were assessed for their applicability to VOC and phthalate (SVOC) analyses via heat desorption and solvent extraction, respectively. Recovery and stability tests were conducted for VOC and satisfactory results were obtained. A method for extraction and recovery of phthalates using commercially available spherical activated carbon-filled glass tubes for VOC measurement was investigated and a method with good recovery rate was developed. Parallel measurements were conducted using the present method and a method using a styrene-divinylbenzene copolymer, the official method for phthalates standardized by ISO 16000-33. The quantification results were generally in agreement. These results show that the carbon-based adsorbent tubes are useful for VOC and phthalate analysis.

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Nanosized electrostatic atomized water particles (NEAWPs) contain reactive oxygen species such as hydroxyl radicals. In this study, we investigated the effects of NEAWPs on pollen allergen (Cry j 1) and mite allergen (Der f 1), which are typical causes of allergies in Japan, using the dot-blot method. Two hours of treatment with NEAWPs inactivated Cry j 1 and Der f 1 on polyvinylidene fluoride membranes. Furthermore, we investigated whether NEAWPs can inactivate pollen function and kill living mites. Japanese cedar pollen lost its ability to rupture after treatment with NEAWPs in a time-dependent manner; after 72 hours of treatment, all the pollen lost its ability to rupture. Mites exposed to NEAWPs died over time, with most dying after 12 hours. The allergen levels detected in pollen and mites exposed to NEAWPs was lower than those in pollen and mites not exposed to NEAWPs.

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Acanthamoeba castellanii is a protozoan that is found in natural and indoor environments and has been problematic in the development of intractable acanthamoeba keratitis and as a possible factor in the respiratory disease legionellosis. Acanthamoeba keratitis is mainly caused by the wearing of contaminated contact lenses, and it has been noted that disinfectant solutions have low anti-amoebic efficacy. In addition, in legionellosis, control of amoebae in biofilms in cooling towers is necessary to prevent outbreaks of Legionella spp. In this study, we investigated the amoebicidal effect of branched fatty acids and their salts, isoC12 and isoC12K, against A. castellanii. isoC12K, which was highly effective, was also evaluated for its bactericidal effect against S. aureus and E. coli. isoC12K showed an amoebicidal effect of 4 log of magnitude after 10 minutes of contact, at a concentration of 110 mM (2.5 wt%). Even at 1000 mM (20 wt%) of isoC12, complete killing could not be observed after 10 minutes of contact. (>1000 mM). In E. coli and S. aureus, 6 log reductions were observed at 2.5 wt% (105 mM) and 0.63 wt% (26.2 mM), respectively, after 10 min of contact. In amoebae, isoC12K caused plasmalemma disruption within a short period of time, suggesting that the mechanism of action is membrane action. We expect that isoC12K, which is highly effective in killing amoebae and has no characteristic pungent odor, will be used in care products and amoebicides.

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The water extract of igusa (Juncus effusus var. decipiens) had a wide range of antibacterial activities against Bacillus subtilis, Salmonella typhimurium, Escherichia coli, Legionella pneumophila, and resident skin bacteria. Among these, the effect against L. pneumophila and E. coli is expected to be useful for microbial controlling in bathrooms, especially in recirculating bathtubs. The inside of igusa has a porous structure with well-developed spongy tissue made up of stellate cells, which gives it a high ability to adsorb odorous components, formaldehyde, nitrogen dioxide. Since igusa has antibacterial properties against microorganisms that cause bad odors, it is suggested that a tatami is also useful in preventing household odors and indoor pollutants caused by microorganisms. Regarding fungi, it had an antifungal effect against trichophyton fungus but was ineffective against Aspergillus and Rhizopus spp. Since almost no mold was detected on the tatami before delivery, it was suggested that the mold that tends to grow on unused tatami does not originate from the tatami, but rather grows due to mold spores that fall from the air in the indoor environment. The aroma components of igusa did not show any antibacterial effect against E. coli, suggesting that the antibacterial effect of igusa may be mainly due to water-soluble components.

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