The graph shows development of specific NOx emissions, defined as emissions of NOx per transport unit (passenger-km or tonne-km), by transport mode (road, rail, maritime, inland shipping, air) in 1995 and 2009.
Specific NOx emissions data for all transport modes are modelled data derived from TREMOVE (http://www.tremove.org/model/index.htm) and TRENDS (http://www.forum.europa.eu.int/Public/irc/dsis/pip/library?l=/environment_trends).
Specific NOx emissions are expressed in grams per passenger-kilometer (for passenger transport) or tonne-kilometer (for freight transport).
EEA standard re-use policy: unless otherwise indicated, re-use of content on the EEA website for commercial or non-commercial purposes is permitted free of charge, provided that the source is acknowledged (http://www.eea.europa.eu/legal/copyright). Copyright holder: Directorate-General for Environment (DG ENV), Directorate-General for Energy and Transport.