Actual use emissions of road transport

Traditional ways for evaluating emission factors, especially for new engines or vehicles, are based for engines on the measurement of engine emission maps or of some points of the map, and for passenger cars on the procedure described in the emission standards. The measurement conditions of these methods are quite far from the actual conditions of the emissions on the road. The actual conditions of the emissions on the road are described and compared to the standards. The different sources of error in building emissions factors are listed. The influence of the different parameters on emissions are shown, in order to assess the necessity of using actual use emissions rather than standard emissions. The different methods of emission factor measurement are presented, together with the main parameters of the emission models, and the present research carried out in Europe to increase the accuracy of the emission factor assessment for road vehicles.