Visualization of the effect caused by PAH destruction below a critical column density  [N_H] _crit = 10²¹   cm^-2. The density structure is derived using a cube of 256³ Pixel, a power index of n = −10/3 and a maximum length scale of 0.4 times the cube size. To the left the column density for two standard deviations σ_{ρ/ ⟨ ρ ⟩}  of the local density is shown. The images to the right for each turbulent cube gives the PAH abundance along individual sight lines for two assumptions of the extinction A_V through the cube. The white fields correspond to no PAH molecules while the black fields have the normal PAH abundance necessary to produce the extinction bump at 2175 Å.