Photoacoustic and nephelometric spectroscopy of aerosol optical properties with a supercontinuum light source

摘要

A novel multi-wavelength photoacoustic-nephelometer spectrometer (SC-PNS)has been developed for the optical characterization of atmospheric aerosolparticles. This instrument integrates a white light supercontinuum laserwith photoacoustic and nephelometric spectroscopy to measure aerosolabsorption and scattering coefficients at five wavelength bands (centered at417, 475, 542, 607, and 675 nm). These wavelength bands are selected fromthe continuous spectrum of the laser (ranging from 400–2200 nm) using a setof optical interference filters. Absorption and scattering measurements onlaboratory-generated aerosol samples were performed sequentially at eachwavelength band.To test the instrument we measured the wavelength dependence of absorptionand scattering coefficients of kerosene soot and common salt aerosols.Results were favorably compared to those obtained with a commercial3-wavelength photoacoustic and nephelometer instrument demonstrating theutility of the SC light source for studies of aerosol optical properties atselected wavelengths. Here, we discuss instrument design, development,calibration, performance and experimental results.