Photoacoustic determination of optical properties of aerosol particles collected on filters: development of a method taking into account substrate reflectivity.
The absorptivity of soot and methylene blue particles collected on Teflon filters is derived from photoacoustic measurements by least squares fitting a simple expression based on Beer's law to the experimental data. Refinements of the expression take into account the diffuse reflection of light by the filter substrate, yielding a base 10 absorptivity at 600 nm for soot of 3.00 +/- 0.37 m(2)/g. This value is in close agreement with the result of transmission measurements performed on the same samples (3.08 +/- 0.05 m(2)/g).
Röhl
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McClenny
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Palmer
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