Mixing ratio profiles of HO_x (OH + HO₂) and NO_x (NO + NO₂) species that power the catalytic cycles which destroy O₃ for models with 100%, 10%, 1%, and 0.1% PAL O₂. Here, we show models for the hottest (GOV) and coolest (M5V) stellar hosts. For decreasing O₂ levels photolysis reaches lower levels of the atmosphere, causing OH and HO₂ formation to occur at lower levels. The HO_x is not significantly impacted by these changes since O₃ formation is pushed deeper into the atmosphere as well. NO_x species experience depletion via N₂O and NO photolysis, although are less affected for models around cooler stars with lower photolysis rates. The efficiency of the NO_x catalytic cycle decreases consistently for all host stars with decreasing O₂ levels. See Sect. 4.3 for full details.