However, the optical properties of such fresh OC-containing particles differ significantly from bare soot, exhibiting higher light scattering and absorption, by 45% and 12%, respectively. Hence, an improvement in the treatment of indirect effect of soot comes at the expense of a biased treatment of its direct effect. Additionally, when vapor saturation drops at night, the condensate does not evaporate off such mixed particles like in the case of fractal soot (Fig. ), making it impossible to explain observations of uncoated compact aggregates reported in field measurements. Hence, capillary condensation must be incorporated into atmospheric aerosol models explicitly to improve their predictive power.