NO and HO₂ profiles at 100 and 0.1% PAL O₂ for planets around the Sun and M5V hosts. Plots containing NO profiles indicate the NO_x-saturated regime by a gray background, while the NO_x-limited regime has a white background. When NO profiles enter the NO_x-saturated regime, a corresponding depletion of HO₂ appears in the same part of the atmosphere. The Sun-hosted planet often enters the NO_x-saturated regime, due to the efficient conversion of N₂O into NO_x. By contrast, the M5V-hosted planet is less efficient at creating NO_x in its low UV environment and remains in the NO_x-limited regime.