A comparison between the derived column densities of relevant chemical species for a specific chemical model of PDS 70 (Cridland et al. 2023) and the column densities estimated from this work. Left: comparison between the C₂H column density values of the different chemical networks mentioned in the text. The networks are Miotello et al. (2019) which include C, H, O, & N (C/H/O/N) and Miotello et al. (2019) + Bruderer (2013) which include C, H, O, N, & S (C/H/O/N/S). We tested that the resulting column density showed minimal change when adding the extra sulphur reactions to the network of Miotello et al. (2019). There is minimal change in the column density for the different networks regardless of the elemental abundance of carbon and oxygen, which we vary between the ISM value (C/O = 0.4) and the abundance inferred for PDS 70 (C/O = 1.01) by Cridland et al. (2023). The dashed lines show the orbital positions of the b and c planets. Middle: same as left panel, but for SO. In the Miotello et al. (2019) network, SO and other more complex sulphur-bearing species are not included. The models shown in the left panel corresponding to that network are thus left out here. The dot-dashed line shows the estimated column density from our chemical model along the streamlines. Right: same as middle panel, but for SO₂.