Figure also shows a comparison between the viscosity of the phenolic BB-SOA and the viscosity of biomass burning primary organic aerosol (BB-POA) from Schnitzler et al. (2022). The BB-POA was generated by smoldering pine wood chips in a tube furnace at 400 °C. For RH values of 0-10%, the viscosity of the phenolic BB-SOA is at least ~2 orders of magnitude higher than the viscosity of BB-POA.