N2O has a singlet ground state, the N2-O bond energy is 1.73 eV (3.69 eV to N2 + O 1 D), and dissociative adsorption produces a single -C(O) surface group that can result in, at most, loss of one C atom as CO. O2 is a triplet, with 5.16 eV O-O bond energy, but adsorption produces two -C(O), that can remove, at most, two C atoms as CO. It is, thus, interesting to compare N2O and O2 etching measured under similar conditions. Our studies of O2 etching of carbon NPs 1, 2 were mostly done with PO2 between 2 x 10 -5 and 4.3 x 10 -5 Torr, with the fastest mass loss rates observed for 1200 K ≤ TNP ≤ 1600 K, dropping slowly at higher TNP. As shown above, the mass loss rates for N2O were small at 1600 K, and increased as TNP was increased to 1900 K. PN2O values in the 10 -4 or 10 -3 Torr range were needed to give etching rates substantially faster than Rbaseline (≈Rsublimation) at higher TNP, where the N2O etching was fastest.