Spectrum of flame-generated soot acquired at Boston College, including data from our lamp-laser PAS (red circles), the UC-Davis PAS (blue squares) and a commercial cavity attenuated phase shift instrument (CAPS-SSA, Aerodyne, Inc., green triangle).  The measurements agree well with literature values of the mass absorption coefficient for soot at 550 nm,\cite{Bond_2013} and an AAE of 1.0 (the assumed value in the literature) fits the visible data well.  However, significant deviation is observed in the UV, enough to bring the AAE to 1.21 (solid line).  Plot by Dr. Geoff Smith, reproduced from Fischer et al. (2018 - in preparation, see below).