Inventory models are tools used for monitoring the progress towards emission targets, for example targets set in international agreements such as the CLRTAP convention and the UNFCCC Kyoto protocol agreement setting targets on emission of pollutants and greenhouse gases respectively. Moreover inventory models, coupled with economic models estimates the impact of future policies and produce cost benefits analyses.
The core of any transport inventory model is constituted by the emission factors and accurate emission factors are indispensable for building reliable transport emission inventories.
Emission factors are determined by averaging a large set of measurements carried out in each vehicle category and employing vehicle simulation models to extend the information contained in the measurements.
The models overseen by the ERMES group are based on a common set of measurements in order to produce consistent emission factors and emissions estimates. The ERMES emission factors are then fed in the most widely used inventory models across Europe.
Collaborations on the use of other models are also in place.