Integrating Nephelometer Response Corrections for Bimodal Size Distributions

Correction factors are calculated for obtaining true scattering extinction coefficients from integrating nephelometer measurements. The corrections (specific to MRI 1560/1590 instruments) are based on the bimodal representation of ambient aerosol size distributions and take into account the effects of angular truncation and sampling efficiency cutoff. Numerical values of correction factors appropriate to the conventional governing equation of the integrating nephelometer are shown to be indistinguishable from those of the more complex governing equation of Rabinoff and Herman.