Physicochemical risk factors for building-related symptoms in air-conditioned office buildings: Ambient particles and combined exposure to indoor air pollutants

Kenichi Azuma; Koichi Ikeda; Naoki Kagi; U Yanagi; Haruki Osawa

doi:10.1016/j.scitotenv.2017.10.147

Physicochemical risk factors for building-related symptoms in air-conditioned office buildings: Ambient particles and combined exposure to indoor air pollutants

Sci Total Environ. 2018 Mar:616-617:1649-1655. doi: 10.1016/j.scitotenv.2017.10.147. Epub 2017 Oct 22.

Authors

Kenichi Azuma¹, Koichi Ikeda², Naoki Kagi³, U Yanagi⁴, Haruki Osawa⁵

Affiliations

¹ Department of Environmental Medicine and Behavioral Science, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan. Electronic address: kenazuma@med.kindai.ac.jp.
² Department of Architecture, College of Science and Technology, Nihon University, 8-14 Kanda-Surugadai 1-chome, Chiyoda-ku, Tokyo 101-8308, Japan. Electronic address: ikedako1@aol.com.
³ Department of Mechanical and Environmental Informatics, Graduate School of Information Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan. Electronic address: kagi.n.aa@m.titech.ac.jp.
⁴ Department of Architecture, School of Architecture, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677, Japan. Electronic address: yanagi@cc.kogakuin.ac.jp.
⁵ Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako, Saitama 351-0197, Japan. Electronic address: osawa.h.aa@niph.go.jp.

PMID: 29070452
DOI: 10.1016/j.scitotenv.2017.10.147

Abstract

We conducted a cross-sectional epidemiological study to examine the correlation between indoor air quality (IAQ) and building-related symptoms (BRSs) of office workers in air-conditioned office buildings. We investigated 11 offices during winter and 13 offices during summer in 17 buildings with air-conditioning systems in Tokyo, Osaka, and Fukuoka, and we included 107 office workers during winter and 207 office workers during summer. We conducted environmental sampling for evaluating IAQ and concurrently administered self-reported questionnaires to collect information regarding work-related symptoms. Multivariate analyses revealed that upper respiratory symptoms showed a significant correlation with increased indoor temperature [odds ratio (OR), 1.55; 95% confidence interval (CI), 1.11-2.18] and increased indoor concentration of suspended particles released from the ambient air pollution via air-conditioning systems (OR, 1.31; 95% CI, 1.08-1.59) during winter. In particular, smaller particles (particle size>0.3μm), which possibly penetrated through the filter media in air-conditioning systems from ambient air, were correlated with upper respiratory symptoms. The use of high-efficiency particulate air filters in air-conditioning systems and their adequate maintenance may be an urgent solution for reducing the indoor air concentration of submicron particles. Several irritating volatile organic compounds (VOCs) (e.g., formaldehyde, acetaldehyde, ethylbenzene, toluene, and xylenes) that were positively correlated with the indoor air concentration among their VOCs, were associated with upper respiratory symptoms, although their indoor air concentrations were lower than those specified by the indoor air quality guideline. A new approach and strategy for decreasing the potential combined health risks (i.e., additive effect of risks) associated with multiple low-level indoor pollutants that have similar hazardous properties are required.

Keywords: Airborne particles; Building-related symptoms; Combined exposures; Temperature and humidity; Volatile organic compounds.