*2.4. Limitations*

The approach used in this study has several limitations with regard to the data and methodology employed. First, to conduct SDA, it is necessary to prepare time-series data on both household consumption expenditures and environmental burden intensities that are consistent with the IO table and to deflate according to the base year price information. In this regard, this study used the TJIO covering the periods 1990–1995–2000–2005. We recognize that the latest year analyzed in this study is more than 10 years in the past; however, it is currently impossible to prepare more recent deflated data for consumption expenditure and embodied CO2 emission intensity. The latest domestic IO table describes the economic transactions accounting for household consumption expenditures in 2011, and the embodied CO2 emission intensity values for 2011 have already been published. However, it is relatively di fficult to deflate consumption expenditures and intensities due to the disconnection between commodity sectors and their definitions.
