title: Assessment of inhalation exposure to indoor air pollutants: Screening for health risks of multiple pollutants in Japanese dwellings.
abstract: Over the past few decades, multiple low level indoor pollutants have been found in domestic dwellings. The types and concentrations of these indoor pollutants have not been consistent over time and have changed with alterations in lifestyle, the development of novel products used in housing, and the development of new measurement technologies. To clarify the highest risk pollutants for which health risks should be reduced, we conducted a health risk assessment of 49 indoor air pollutants measured in 602 houses during winter and summer from 2012 to 2014. Inhalation reference concentrations were determined, and the margins of exposure were estimated for each indoor pollutant from measured indoor air concentrations. Health risks due to ammonia and acidic gases, including formic acid, acetic acid, and hydrogen chloride, were also assessed. Overall, during both winter and summer, the highest risk pollutants were acrolein, nitrogen dioxide, benzene, formic acid, and hydrogen chloride. The health risks of propanal, acetaldehyde, and 1,4-dichlorobenzene were also high. Principal component analysis (PCA) suggested an independent principal component for 1,4-dichlorobenzene. The primary source of exposure to 1,4-dichlorobenzene in Japan is an indoor household insect repellent. The improvement of individual lifestyle and housing may be appropriate targets for reducing the risk associated with this compound. The provision of further information on the risk to consumers and promotion of changes in consumer consciousness are needed. PCA suggested that the health risks of indoor air pollutants are amalgamated into similar chemical families, such as aldehydes, aliphatic hydrocarbons, aromatic hydrocarbons, or acetic esters. Our results suggest that health-based guidelines or source control measures, based on these chemical families and similar health endpoints, are appropriate for reducing total health risk due to multiple low level indoor pollutants.
authors.affiliation: Department of Environmental Medicine and Behavioral Science, Kinki University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan; Sick-house Medical Science Laboratory, Division of Basic Research, Louis Pasteur Center for Medical Research, 103-5, Tanakamonzen-cho, Sakyo-ku, Kyoto 606-8225, Japan. Electronic address: kenazuma@med.kindai.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Azuma
authors.affiliation: Sick-house Medical Science Laboratory, Division of Basic Research, Louis Pasteur Center for Medical Research, 103-5, Tanakamonzen-cho, Sakyo-ku, Kyoto 606-8225, Japan. Electronic address: iwao-u@cyber.ocn.ne.jp.
authors.forename: Iwao
authors.initials: I
authors.lastname: Uchiyama
authors.affiliation: Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako-shi, Saitama 351-0197, Japan. Electronic address: uchiyama@niph.go.jp.
authors.forename: Shigehisa
authors.initials: S
authors.lastname: Uchiyama
authors.affiliation: Department of Environmental Health, National Institute of Public Health, 2-3-6 Minami, Wako-shi, Saitama 351-0197, Japan. Electronic address: kunugita@niph.go.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kunugita
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis*; D006305:Health Status Indicators; D006798:Housing / Q000592:standards; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects / Q000032:analysis*; D007564:Japan; D019055:No-Observed-Adverse-Effect Level; D025341:Principal Component Analysis; D018570:Risk Assessment; D012621:Seasons
chemical_list: D000393:Air Pollutants
keywords: Airborne chemicals; Indoor air quality; Nationwide survey; Risk assessment; Screening