Indoor air quality and post-disaster public housing : a case study of a Japanese post-disaster public housing on the effect of VOC emissions from building materials

摘要

Since the beginning of the 20th century indoor air has produced distinctive pollution problems. The most critical pollutants in relation to indoor air quality (IAQ) are chemical contaminants which, in the form of volatile organic compounds (VOCs), have been identified as arising mainly frombuilding materials. Conventional solutions such as ventilation systems and bake-out processes have been developed, but the IAQ problem, oftenreported as sick building syndrome (SBS), still persists.This study set out to establish to what extent VOCs may affect the health of occupants in a particular built environment, and how much architecturaldesign factors, the use of particular building materials, and human activities may contribute to the problem of SBS. A further question was toestablish to what extent current attempted solutions to IAQ problems, namely ventilation and bake-out, were in practice effective in a specific builtenvironment.While previous research and attempted solutions have focused on work places as areas of concern for SBS, the problem is especially significant inresidential housing and is particularly concentrated in post-disaster public housing (PDPH). For this reason the research was based on the case of aPDPH project in Abuta, Japan.To analyse the separate components of the problem, several distinct studies were undertaken. The level of pollutants in the air was analysed bymeans of chemical sampling of VOCs in two units of the PDPH, while the a SBS survey and assessment of the residents of the entire project, as wellas interviews with the building professionals involved was designed to identify the human causes and effects of the situation. The effectiveness ofthe attempted solutions to the problem were considered by means of a study of the bake-out procedure, and finally an airflow simulation bycomputational fluid dynamics (CFD) was conducted to consider the design and ventilation features of the units in relation to IAQ.The study results have indicated that IAQ problems existed after the completion of construction. It was found that certain VOC levels were far abovethe guidelines, and the health hazard symptoms known for these VOCs matched the SBS symptoms found in participants’ health complaints.Interviews with building professionals involved in the project revealed that the lifestyles of the occupants were not seriously considered in the projectdesign. The results of the airflow simulation also revealed problematic aspects of the planning design, exacerbating rather than limiting the pollutionproblem as intended.The study concludes with a number of recommendations for taking these inter-related aspects of the problem into consideration in future, so that thehealth of residents is not adversely affected.