Abstract
The purpose of this paper is to document the key literature references and to describe the design philosophy. the principles of the instrument, the various possible designs, calibration, systematic errors, applications to scientific problems and inherent limitations. According to the design philosophy established in the original publication, instruments are devised to directly measure the relevant integral aerosol parameters, thus eliminating the need for assumptions about particle size distribution, particle shape and composition, complex Mie calculations, and the unknown uncertainties associated with them. The key parameter measured by the integrating nephelometer is the scattering component of extinction as a function of wavelength. This philosophy subsequently allows two approaches to the determination of several parameters—direct measurement with the aid of the integrating nephelemeter and calculation via the Mie formalism. Comparison of calculated and measured values for a parameter allows closure studies; that is, the difference between them is an objective measure of the uncertainty that is inherent in the combined set of measured and calculated parameter values.
