The aim of the project is to improve the metrological foundation of measurements (devices and methods) for monitoring airborne radioactivity and to introduce pan-European harmonisation in data reliability for area dose rate measurements which are input to the European Radiological Data Exchange Platform (EURDEP) and other monitoring networks. One of the main aims of this project is the fastest possible determination of a potential contamination at a kBq m-2 level. Metrologically sound methods will be developed for the evaluation of correct dose rate and activity concentration data. Appropriate harmonised calibration procedures for existing radiological early warning network stations in Europe will be systematically developed in the JRP for both dose rate and airborne radioactivity stations for the first time. Novel traceable reference materials and standard sources will be developed, and proficiency tests and other comparison exercises will be performed to quantify airborne radioactivity and dosimetry data at field stations. Monte Carlo simulations of detector responses and benchmark experiments will be used for the validation of new approaches in environmental radiation monitoring. Improved detection methods and data analyses techniques will be developed to enable accurate measurements of low activity concentrations of radon (in the range from 300 Bq/m3 and below) taking account of the fact that radon contributes to the background responses of many detector systems. Moreover, and as a pure scientific application, harmonised area dose rate data will allow investigations into parameters affecting climate change, e.g. soil moisture, using the Europe-wide dose rate mappings of EURDEP.