Aerosol light absorption coefficient

Filter substrates were chosen that were suited for subsequent determinations of aerosol mass, total carbon, elemental carbon, trace metals and aerosol light absorption coefficient The three filter assemblies contained, a 47 mm Pallflex Tissuquartz filter (2500 QAO), a 47 mm Nuclepore polycarbonate filter (0.40 ym pore size) and a 13 mm Pallflex Tissuquartz filter (2500 QAO). 

Horvath, H., Size Segregated Light Absorption Coefficient of the Atmospheric Aerosol, Atmos. Environ., 29, 875-883 (1995). 

Huffman, H. D., Comparison of the Light Absorption Coefficient and Carbon Measures for Remote Aerosols An Independent Analysis of Data from the Improve Network—I, Atmos. Environ., 30, 73-83 (1996). 

As noted in Section 4.04.2.3, key optical properties of aerosols are represented by the light-scattering coefficient, and light-absorption coefficient, both with reference to the particulate matter. The light-scattering coefficient of an aerosol can be measured by using nephelo-metry (Table 2). The integrating nephelometer (Anderson et al., 1996) exposes an aerosol to... 

To test the applicability of statistical techniques for determination of the species contributions to the scattering coefficient, a one-year study was conducted in 1979 at China Lake, California. Filter samples of aerosol particles smaller than 2 ym aerodynamic diameter were analyzed for total fine mass, major chemical species, and the time average particle absorption coefficient, bg. At the same time and location, bgp was measured with a sensitive nephelometer. A total of 61 samples were analyzed. Multiple regression analysis was applied to the average particle scattering coefficient and mass concentrations for each filter sample to estimate aj and each species contribution to light scattering, bgn-j. Supplementary measurements of the chemical-size distribution were used for theoretical estimates of each b pj as a test of the effectiveness of the statistical approach. 

Aerosol scattering, absorption, and extinction coefficients are functions of the particle size, the complex refractive index of the particles m, and the wavelength X of the incident light. The extinction coefficient for a monodisperse ensemble of particles was given in terms of the dimensionless extinction efficiency by (15.27). With a population of differentsized particles of identical refractive index m with a number size distribution function of n(Dp), the extinction coefficient is given by1... 

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