Carbon Dioxide (CO2) and Carbon Dioxide Equivalent (CO2-e)

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Carbon Inventory
- Localization Based
- LCA Based
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Embodied carbon (EC) contributes a significant portion of the life cycle carbon footprint of the built environment. According to WWF, the construction sector is the second largest contributor of the carbon footprint in Hong Kong and 85% of the carbon footprint associated with the construction sector is embodied in imported goods and services. This study investigates the embodied carbon of locally used construction materials and develops the Embodied Carbon Of Construction Materials (ECO-CM) database for Hong Kong.

Before controlling the greenhouse gas (GHG) emission, people need to measure the GHG emission of a project, a process or an organization. Hence, a quantitative unit of the GHG emission is required. Carbon footprint or GHG emission can be measured in terms of CO2 (carbon dioxide emitted) and CO2-e (carbon dioxide equivalent).

Carbon dioxide equivalent (CO2-e) is the unit to measure the impact of global warming caused by a given type of GHG within a defined system boundary. To calculate the CO2-e of a specific greenhouse gas, the global warming potential of the gas should be used with reference to one unit of CO2. Usually, 100-year global warming potential (GWP100) values are used. In this study, six types of GHGs identified in Kyoto Protocol are included. They are carbon dioxide, methane, nitrous oxide, hydro fluorocarbons (HFCs), per fluorocarbons (PFCs), and sulfur hexafluoride (SF6).