Net reaction rate of SH hydrogen abstraction, subtracting the reverse from the forward rate. We show the output of five VULCAN models, one with the fiducial TP profile as described in Fig. 1, the others with the temperature profile shifted by a set amount throughout the atmospheric column. We see that if we decrease the temperature, at a pressure of 10⁻⁶ bar, SH reacts with atomic H to produce atomic sulfur.