What is the quantity of consumer goods stocked in a Japanese household? Estimating potential disaster waste generation during floods

This study aims to estimate micro material stock derived from consumer goods using fundamental data such as possession and expenditure of consumer goods in housing, considering the type of housing and class of total floor area of housing. A questionnaire survey of residents living in the eight cities of the Tama river basin was conducted to clarify the possession and expenditure of consumer goods in units of items/housing and JPY/housing. Identified consumer goods were 14 types and 97 items. The questionnaire also asked the storeys on which the consumer goods are installed. Material intensity coefficients (MIC) regarding the weight of consumer goods were calculated based on web-based and statistical surveys in units of kg/item and kg/USD. Micro material stock derived from consumer goods in housing totalled 5.84 t (t) in detached housing and 5.71 t in complex housing. Amount of the micro material stock derived from consumer goods corresponds to 10.9% of the macro material stock derived from detached housing. Reliability and validity of questionnaire results and the MIC were confirmed through two types of sensitivity analysis. As a case study, the total weight of all consumer goods in Kawasaki City was calculated as 3,667,000 t. The disaster waste derived from consumer goods considering the flood damage was estimated based on the total weight of all consumer goods in the city. The resulting estimation was 229,000 t. This estimation is 0.72 times bigger than the above-mentioned result that considered the storeys on which the consumer goods are installed.