We have measured insoluble particle size distributions covering the radius range 0.05--1.31 μm for 15 samples from a 3-year (1782--1785) section of ice core from Crete, central Greenland, and for a 2500-year old, 2-year section of south pole ice. We predict that 60% of all the insoluble particles in this range in the northern hemisphere background aerosol are in the radius range 0.05--0.13 μm, 30% are in the range 0.13--0.38 μm, and 10% are in the range 0.38--1.31 μm. The corresponding values for the southern hemisphere are 74, 22, and 4%. Also, we have found that the small and large particle profiles for our Crete ice core section show similar variability features, but peaks in the large particles are much more pronounced.