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The relationship between chemical concentrations in indoor air and the human sense of comfort and relaxation have been reported. We investigated the effect of the sum of volatile organic compounds (ΣVOCs; sum of 79 VOCs) on the level of relaxation in two laboratory houses with almost identical interior and exterior appearances. The electroencephalogram (EEG) was monitored to evaluate the degree of personal relaxation objectively. The experiments were conducted in laboratory houses (LH) A and B with lower and higher levels of ΣVOCs, respectively. A total of 168 healthy volunteers participated, who each performed the task for 20 min, followed by a 10-min break, and EEG was measured during the break. Simultaneously as subjective evaluations, the participants were asked to fill a questionnaire regarding the intensity of odor and preference for the air quality in each LH. The subjective evaluation showed a significant association between ΣVOCs and participants' relaxation (OR: 2.86, 95%CI: 1.24-6.61), and the objective evaluation indicated that the participants were more relaxed in the LH with lower levels of ΣVOCs than that with higher levels (OR: 3.03, 95%CI: 1.23-7.50). Therefore, the reduction of ΣVOCs and odors in indoor air would have an effect, which is the promotion of relaxation.

It is well known that the indoor environment, particularly indoor air quality (IAQ), has significant effects on building-related symptoms (BRSs) in humans, such as irritation of mucosal membranes, headaches, and allergies, such as asthma and atopic dermatitis. In 2017, Chiba University launched the "Chemiless Town Project Phase 3" to investigate the relationship between IAQ and human health. Two laboratory houses (LHs) were built on a university campus in which the interiors and exteriors were similar, but the levels of indoor air volatile organic compounds (VOCs) were different. A total of 141 participants evaluated IAQ using their sensory perception. There was a significant relationship between differences in VOC levels and BRSs occurrence (OR: 6.89, 95% CI: 1.40-33.98). It was suggested that people with a medical history of allergies (OR: 5.73, 95% CI: 1.12-29.32) and those with a high sensitivity to chemicals (OR: 8.82, 95% CI: 1.16-67.16) tended to experience BRSs. Thus, when buildings are constructed, people with a history of allergies or with a sensitivity to chemicals may be at high risk to BRSs, and it is important to pay attention to IAQ to prevent BRSs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Recently, people have become increasingly aware of potential health issues related to indoor environments. In this study, we measure the concentrations of various volatile organic compounds, carbonyl compounds, and semi-volatile organic compounds, as well as the ventilation rates, in 49 new houses with light-gauge steel structures one week after completion. The proper indoor air quality of new residential environments can be ensured by characterizing people's exposure to certain chemicals and assessing future risks. Our results show that the concentrations of the measured compounds were lower than the guideline values set by the Ministry of Health, Labour and Welfare of Japan, and would continue to decrease. However, we observed that unregulated compounds, assumed to be substitutes for regulated solvents, contributed substantially to the total volatile organic compounds. To reduce indoor chemical exposure risks, the concentrations of these unregulated compounds should also be minimized. In addition, their sources need to be identified, and manufacture and use must be monitored. We believe it is important to select low-emission building materials for reducing residents' exposure to indoor chemicals.

Nowadays, people spend most of their time indoors; thus, the indoor environment greatly affects human health because of exposure to chemicals indoors. Thus, in collaboration with Japanese house builders, a list of building materials having low volatile organic compound concentrations was compiled herein. The air-quality samples from seven newly built houses (seven bedrooms and seven living rooms) were collected and tested for 64 volatile organic compounds and two aldehydes. Air samples were obtained from the house with no furniture or household goods and were sampled 1 week after construction and repeated after a month. Furthermore, the test results with a 2009 survey of indoor air quality in newly constructed houses were compared. One week after construction, the xylene, styrene, toluene, formaldehyde, and ethylbenzene concentrations were less than half the standard guideline values set in Japan. The main substances detected in the samples were 2-butanone, acetone, ethanol, ethyl acetate, butyl acetate, and undecane. The statistical significance of the changes in substance concentrations over time was examined via Wilcoxon signed-rank test. One month after construction, the concentrations of all chemical substances had undergone a statistically significant reduction, except butyl acetate. The median of total volatile organic compounds in living rooms was 291 µg/m3, and the maximum was 354 µg/m3; both were under Japan's provisional total volatile organic compound target of 400 µg/m3. These values were significantly lower than those recorded by other researchers. This study concludes that using experimentally identified low volatile organic compound materials effectively improves the indoor air quality. [ABSTRACT FROM AUTHOR]

Globally, sick building syndrome remains a considerable social issue. It is primarily caused by the emission of volatile organic compounds (VOCs) from construction materials. Among these, paints and sealers are used over wide swaths of are a and their use causes chemical substances to be released in a room. To prevent sick building syndrome, it is necessary to clarify the cause of air quality changes due to the different types of paints and sealers available. Recently, low-VOC paints (containing 0.3–1.0% VOCs) have been used widely; however, the effects of reducing VOC levels have not yet been fully quantified. This study aims to clarify the chemical compositions by conducting an emission rate test of these low-VOC paints and sealers. We prepared six specimens and used them for chamber testing. Three types of paint with and without a sealer were tested. The minimum and maximum total volatile organic compound (TVOC) concentration was 96 and 4750 μgm−2 h−1, respectively. Differences in the VOC content of the paints and sealers could be confirmed. The main TVOC was Texanol™ and glycerol ethers. The results demonstrate that using paints containing less than 0.3% VOCs can decrease the VOC emission rate considerably compared to paints classified as less than 1% VOCs. Moreover, because different kinds of sealers affected the results, it is possible to decrease VOC emission rate using a variety of sealers. [ABSTRACT FROM AUTHOR]