The initial value of EEO2 and the observation that EEO2 increased over time were consistent with the other 1200 K silica NP oxidation experiments. The fact that EEO2 was similar to measurements at higher PO2 supports the idea that the initial EEO2 is at least roughly PO2-independent, and the fact that this NP showed no signs of EEO2 slowing is consistent with the passivation process being slower at lower PO2.