The Aurora 4000 - Polar Nephelometer is an integrating nephelometer that can measure continuously and in real-time light scattering in a sample of ambient air at three wavelengths: 450, 525, and 635 nm (blue, green, and red). It can provide the measurements in several angular sectors: fully-integrated scattering (standard option), as well as an integrated scattering of up to 17 different angular sectors from 10˚ to 90˚ through to 170˚. The measurement itself is based on the light scattering on both air molecules and aerosol particles. The air sample is sucked up into the instrument (with a speed of 5l per min), where the measurements are taken in the defined ranges of angles - it allows for the estimation of the size of particles and the asymmetry parameter. The instrument is equipped with both humidity and air temperature sensors and a processor-controlled inlet heater that can eliminate the effects of relative humidity on scattering behavior. Instrument calibrations are fully automatic, with checks initiated at user-selectable intervals.
Instrument PIs: Iwona Stachlewska UW / Fatima Mirza Montoro UW