Line fluxes as functions of outer CO₂ abundances for models with constant dust mass (g/d_gas) and varying gas/dust ratios. The upper panel shows the flux of the R(7) line from the fundamental asymmetric stretch band at 4.3 μm. The lower panel shows the flux contained in the 15 μm Q-branch feature. The grey region denotes the full range in CO₂ fluxes from the disks that are reported in Salyk et al. (2011b), scaled to the distance of AS 205 (N). The 15 μm feature contains the flux from multiple Q-branches with Δv₂ = 1. The CO₂ flux depends primarily on the outer CO₂ abundance and the total g/d ratio and does not strongly depend on the inner CO₂ abundances. Only for very low outer CO₂ abundances is the effect of the inner abundance on the line fluxes visible. The fluxes for models with g/d_dust are given in Fig. D.1.