Carbon aerosol visibility vs particle size distribution.

The optical properties of an aerosol of given mass concentration are derived from Mie theory. The visibility is calculated, via the optical extinction coefficient, for several log-normal distributions of carbon particles. Normalizing the optical cross sections of particles by their mass allows clear identification of the diameters at which scattering, absorption, and extinction are greatest. For highly absorbing particles this occurs in the 0.15-0.5-lambda diameter range.