• Data reference period
• Geographic localization (Portugal)

• REFERENCE PERIOD:  The length of time for which data are collected, e.g. a specific day, month or year.
• DOMESTIC EXTRACTION:  All solid, liquid and gaseous materials (excluding water and air but including e.g. the water content of materials) that are extracted from economic territory, to be used in production or consumption processes.
• RAW MATERIAL CONSUMPTION:  The amount of material in terms of Raw material equivalents (RME) needed to produce the products consumed in the geographical reference area.
• RAW MATERIAL EQUIVALENTS:  Conversion factors used to express a unit of product traded into the amount of material extraction needed, anywhere in the world, to produce the traded product.
• MATERIAL FOOTPRINT:  See RAW MATERIAL CONSUMPTION

Material footprint = Raw material equivalent of imports (RME_IM) + domestic extraction (DE) - raw material equivalents of exports (RME_EX)