Absorption cross section of the aggregate particles as a function of wavelength for three different particle sizes compared to the approximate methods. The upper panels show the aggregates for a volume-equivalent radius of 0.2 μm, the middle panels show 1.2 μm, and the lower panels4.0 μm particles. The left panels show spherical particles with and without added porosity, the right panels show the opacities computed with the DHS method with and without porosity.