Unequal age-based household emission and its monthly variation embodied in energy consumption - A cases study of Tokyo, Japan

City is the main place to consume goods and services throughout the world. Among the various consumption terminals, household-level consumption is highly behavior driven, which can be affected by various factors such as household income level, age, living environment etc. However, city-level household emissions characteristics are still not fully understood due to the complexity of consumption behaviors and the lack of the supply chain's data. To include the environmental responsibility embodied in residential consumption and reveal how it varies among household type and season, this study investigates city-level household consumption as it relates to energy demand using a city-scale input-output model and urban residential consumption inventories. Importantly, age- and month-based emission are analyzed from different aspects such as emission type, source, fuel types and consumption items. Findings indicate that (1) household emissions differ substantially among the various household age groups; older households generally produce higher emissions levels on a per capita basis; (2) decreases in temperature are the main reason for the increased emissions in older households, while this is not a significant factor in younger households; (3) the high per capita household emissions in older households indicate inefficient energy usage among elder citizens, which strongly suggests that aging societies will face long-term emissions increases if appropriate measures are not taken.