Fine and ultrafine aerosol particles at the GAW station Schneefernerhaus/Zugspitze

Abstract

Number size distributions of atmospheric aerosol particles (diameter range 10 to 600 nm) have been measured continuously since 2004 at the GAW Station Schneefernerhaus/Zugspitze (2 650 m a.s.l.) in the German Alps. During the measurement period 12/2004 to 3/2007 the median particle number concentrations was 1000 p. cm(-3), with an estimated mass concentration of 2 mu g m(-3). An analysis of the annual and diurnal cycles of the particle number concentration suggested that the low concentrations usually observed in wintertime are representative for free tropospheric air. During the seasons of intense vertical atmospheric exchange (spring and summer), however, aerosol from the boundary layer may reach the observation site regularly due to thermal convection. We characterised the influence of boundary layer air by high concentrations of accumulation mode particles (diameter 80 to 600 nm) and peroxyacetyl nitrate as well as high decay rates of (214)Po, a daughter nuclide of Radon.