Mass outflow rate versus AGN luminosity. The purple line corresponds to the linear fit of the ionized outflow mass rates calculated by Fiore et al. (2017) for a sample of AGN at z < 0.5 (purple squares) assuming a value of the density of 200 cm⁻³. The black dot-dashed line corresponds to the linear fit from Davies et al. (2020), that includes the mass rates of Fiore et al. (2017), but corrected by using individual electron densities. The other symbols correspond to the four QSO2s with spatially resolved [O III] outflows, with different shapes and colors indicating the values of n_e adopted to perform the outflow mass rate calculations: green circles correspond to densities of 200 cm⁻³, and cyan squares and light-green triangles to those measured from the [S II] doublet and the trans-auroral lines, respectively. The outflow mass rates of the QSO2s vary up to 2 orders of magnitudes depending on how the n_e is measured.