Trend in NO2 and NOX annual mean concentrations (2001– 2010) per station type (top); percentage frequency distribution of estimated annual change of NO2 annual mean concentrations at urban stations and at traffic stations (bottom) - eps file | Trend in NO2 and NOX annual mean concentrations (2001–2010) per station type (top); percentage frequency distribution of estimated annual change of NO2 annual mean concentrations at urban stations and at traffic stations (bottom)