Portable device to determine particle asymmetry parameter

Accurate characterization of the asymmetry parameter g is of crucial importance for radiative transfer calculations. Here. we present a portable light scattering (PLS) device designed for in situ, real-time, and contact-free measurements of the particle phase function. The integration time is 20ms for each measurement. Using this device. we measured g values for laboratory-generated brown (organic) carbon aerosol and soot. and commercially available Arizona Road Dust. For the three types of aerosol, the g values were 0.664 +/- 0.002, 0.506 +/- 0.004, and 0.701 +/- 0.020, respectively. The smallest angle our PLS device approaches is 0.7 degrees, which is an order of magnitude smaller than that of commercial nephelometers, thus facilitating more accurate determination of g. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement