Sources and classification of indicators
Necessary sources localized to obtain a series of indicators backed up and contrasted were the following:
- Authorities and Bodies: EUROCONTROL, EUROSTAT, EIONET, OACI, Ministry of Environment, and Rural and Marine Affairs (MARM), United Nations Organizations (UNO), Escuela Técnica Superior de Caminos, Canales y Puertos, Junta de Andalucía, Manchester Metropolitan University, European Environmental Strategy Committee (ACI) and Global Reporting Initiative (GRI), Loughborough University.
- Airports: Boston-Logan International Airport, Copenhagen Airports, Dallas/Tort Worth International Airport, Frankfurt Airport, Munich Airport International, Norwegian Airports (Avinor), Brussels Airport, Aéroports de Paris, Amsterdam Airport Schiphol, Toronto Pearson International Airport, Vancouver International Airport y Heathrow Airport.
- Airports and/or air navigation managerial entities: Spanish Airports and Air Navigation (AENA), FINAVIA, Grupo LFV y UNIQUE.
- Airlines: Air Europa, Air Nostrum, Iberia, Spanair, Air France-KLM, Alitalia, Bristish Airways and Easy Jet Airline.
- Manufacturers: Airbus, Boeing, Bombardier and Industria de Turbo Propulsores (ITP)
After consulting such information sources, around 900 indicators were collected and catalogued in a database. Each indicator collected was classified as absolute or relative, element measured, information related to the entity which uses it, methodology, scope of the sector related to the indicator, temporary series covered, etc.
Indicators were catalogued under the Driving forces-Pressure–State-Impact-Response (DPSIR) model proposed by the European Environment Agency (EEA, 1998), which results in being one of the best ways to describe the origins and consequences of environmental problems.