Impactor cascade utilization for studying the distribution of atmospheric aerosol size. Application to marine aerosols

The aerosols are picked up by impactors cascades Casella MK2 and Andersen, and by nuclepore filters. The observations carried out by optical microscopy for the particles whose diameter is superior to 0,3 μm and by electronic microscopy for the others, which allows measures going from 8.10-3μm to 100 μm (in diameter). Marked differences are to be found between the granulometric repartition of the continental aerosol (peak at D=0,20μm, minimum at 0,14 μm) and the marine aerosol (inflexion about D=0,6 μm). In the same way the coefficient B of the Junge's Law (dN/dR=CRsup(-(B+1)) which varies according to the dimensions of the particles, varies according to whether the air is continental or maritime