Aerosol characterization and snow chemistry at Terra Nova Bay

Antarctic aerosol was sampled at Terra Nova Bay using an inertial spectrometer at high flow rate. This instrument can sample aerosol and deposit particles on a membrane filter with size separation. The density of single particles and average density vs. aerodynamic diameter has been evaluated. Chemical composition of aerosol particles was determined by analyzing samples taken on millipore filters by scanning electron microscope and x-ray energy spectrometer. The results from this investigation are such that for particles with radius > 0.5 micron, frequency of sea-salt increases when aerodynamic diameter decreases. An opposite behavior is displayed by crustal elements. A chlorine loss in sea-salt particles has been observed. The suggested mechanism for this loss is: H2SO4 2NaCl = Na2SO4 2HCl. Condensation nuclei (CN) concentrations were measured at Terra Nova Bay with an alcohol-based particle counter. In January 1989 the mean value for CN was 490. The concentrations of eight major ions (Cl-, NO-3, SO42-, Na , K , Ca2 , Mg , H ) were determined from fresh snow samples. These showed that precipitation is acidic, a fact depending on H2SO4, HCl and HNO3.