Atmospheric Chemistry and Physics Assessment of parameters describing representativeness of air quality in-situ measurement sites

Abstract. The atmospheric layer closest to the ground is strongly influenced by variable surface fluxes (emissions, surface deposition) and can therefore be very heterogeneous. In order to perform air quality measurements that are rep-resentative of a larger domain or a certain degree of pollu-tion, observatories are placed away from population centres or within areas of specific population density. Sites are of-ten categorised based on subjective criteria that are not uni-formly applied by the atmospheric community within differ-ent administrative domains yielding an inconsistent global air quality picture. A novel approach for the assessment of pa-rameters reflecting site representativeness is presented here, taking emissions, deposition and transport towards 34 sites covering Western and Central Europe into account. These parameters are directly inter-comparable among the sites an