• Data reference period
• Geographic localization (Portugal)
• Economic sector (CAE Rev. 3)
• Current environmental practice

• REFERENCE PERIOD:  The length of time for which data are collected, e.g. a specific day, month or year.
• ENTERPRISE:  Legal entity (natural or legal person) that is an organisational unit producing goods or services, which benefits from a certain degree of autonomy in decision-making, especially for the allocation of its current resources. An enterprise carries out one or more activities at one or more locations.
• ECONOMIC ACTIVITY:  Combination of resources such as labour, raw materials, equipment, etc., are joined, leading to the creation of specific goods or services. Regardless of the factors of production integrating the good or service produced, all activities generically imply an input of products (goods or services), a production process and an output of products (goods or services).

[Enterprises carrying activities on pollution abatement and control and current environment practices (economic activity)/ Enterprises carrying activities on pollution abatement and control (ecinomic activity)]*100