Atmospheric particle number size distribution in central Europe: Statistical relations to air masses and meteorology

Atmospheric particle number size distributions determined over 1.5 years at a central European site were statistically analyzed in terms of their relation to time of day, season, meteorology, and synoptic-scale air masses. All size distributions were decomposed into lognormal particle modes corresponding to the accumulation, Aitken, aged nucleation, and nucleation modes. The concentration of nucleation mode particles (< 30 nm) behaved in a strongly diurnal fashion as a result of both anthropogenic source influence and secondary new particle formation events. The concentrations of Aitken and accumulation mode particles (> 30 nm) lacked such diurnal behavior, and proved to be indicative of different synoptic-scale air mass types. Over 70% of the time, air masses of Atlantic origin and maritime character prevailed, showing obvious signs of anthropogenic influence most of the time (accumulation mode: 500 cm(-3); Aitken mode: 2300 cm(-3)). During a limited period of time (10%), however, continentally aged air with significantly 3 enhanced concentrations of aerosol was observed (accumulation mode: 1200 cm(-3); Aitken mode: 3300 cm(-3)). These air masses were advected from source regions in Russia, and eastern, southeastern, and central Europe, mainly under anticyclonic and high-pressure influence. The analysis provides a refined picture of the behavior of the particle number size distribution and provides parameterizations that are representative for a variety of air masses in Europe and thus suitable for future climate modeling applications.