Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv Microbial volatile organic compounds and dampness in 60 houses of East Japan Naohide Shinohara a,* , Kenichi Hasegawa b , Naoki Kagi c , Jun Sakaguchi d , Yasuyuki Shiraishi e , Teruaki Mitamura f a Research Institute of Science for Safety and Sustainability (RISS), National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba- City, Ibaraki 305-8569, Japan b Akita Prefectural University, 84-4 Aza Ebinokuchi Tsuchiya, Yurihonjo-City, Akita 015-0055, Japan c Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan d University of Niigata Prefecture, 471 Ebigase, Higashi-ku, Niigata- City, Niigata 950-8680, Japan e The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu-City, Fukuoka 808-0135, Japan f Maebashi Institute of Technology, 460-1 Kamisadorimachi, Maebashi-City, Gunma 371-0816, Japan ARTICLE INFO Keywords: Dampness index Indoor fungi Microbial volatile organic compounds Residential houses Questionnaire survey Mycotoxin ABSTRACT Concentrations of microbial volatile organic compounds (MVOCs) in the living rooms and bedrooms of sixty houses across East Japan were determined in February 2015. A questionnaire survey on indoor dampness was also conducted. Acetaldehyde, isobutyl acetate, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-penthylfuran, 1-pentanol, and 2-ethyl-1-hexanol were detected in 100%, 79%, 90%, 94%, 86%, 84%, 85%, and 98% of rooms, respectively. Concentrations in living rooms were significantly correlated with concentra- tions in bedrooms. Dimethyl disulfide, 2-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 1-pentanol, for- maldehyde, acetaldehyde, and propionaldehyde registered higher concentrations in living rooms than in bed- rooms. A comparison of the dampness index and individual MVOC concentrations indicates that MVOC concentrations appear to increase with increases in the dampness index, although no significant relationship was found. Concentrations of isobutyl acetate, 2-methyl-1-butanol, and 3-methyl-1-butanol in indoor environments where fungi were visible on walls were significantly higher than indoor environments where fungi were not visible. In addition, 2-hexanone concentrations in bedrooms where residents detected fungal odor were higher than concentrations in bedrooms where fungal odor was not detected. Indoor MVOC concentrations were not associated with the frequency of ventilation and combustion heater, which were collected data through ques- tionnaire to residents. 1. Introduction Over the last decade, concerns over indoor dampness and fungal problems have been increasing [1]. Previous studies have indicated that indoor dampness can induce and/or worsen allergic symptoms like asthma and other respiratory conditions [2–6]. Fungi are one possible factor responsible for dampness-related health effects, although the responsible factors have yet to be clearly identified. Many kinds of microbial volatile organic compounds (MVOCs) are emitted from microorganisms during metabolic processes [7–10]. There is correlation between MVOC concentrations and odor perception [11,12] and between MVOC concentrations and the presence of visible indoor fungi [13]. MVOC concentrations in flooded housing are higher than those in control houses [14]. Although MVOCs can be considered an indicator of indoor fungal growth [7,15–17], they are difficult to use as an indicator for hidden fungi [10]. In this study, we aimed to determine the association between indoor dampness and MVOC concentrations. For this purpose, we sampled and measured 24 kinds of MVOCs, all of which have been frequently de- tected in Japanese houses [18–21]. Samples were taken in 120 rooms (living room and bedroom) in 60 Japanese residential houses. In ad- dition, MVOC concentrations were compared with data about different hydrothermal conditions, activities of residents, building structures, and different severities of dampness. https://doi.org/10.1016/j.buildenv.2018.02.002 Received 26 October 2017; Received in revised form 1 February 2018; Accepted 1 February 2018 * Corresponding author. E-mail address: n-shinohara@aist.go.jp (N. Shinohara). Building and Environment 132 (2018) 338–344 0360-1323/ © 2018 Elsevier Ltd. All rights reserved. T