The two graphite NPs had by far the largest mass losses before finally becoming inert and for both, EEO2 remained significant for >10 hours, but varied by orders of magnitude during that time. The EEO2 values for both initially increased by factors of 2 and 3 during the first ~half hour, then declined slowly for several hours, before increasing to 5 to 20 times the initial EEO2 values, resulting in a 2 nd wave of fast etching that lasted between 2 and 2.5 hours, and removed an additional ~17 to ~20 % of Minitial. Both the initial increase in EEO2 and the second etching wave with EEO2 were well above the initial values and seen only for graphite NPs. For one graphite NP (open black) the second wave ended as EEO2 gradually decreased, reaching ~10 -5 Da/O2 collision at the 11 hour mark when the experiment was ended. The 2 nd wave for the other graphite NP (green) ended when EEO2 suddenly dropped by >4 orders of magnitude, then almost immediately rebounded, starting a 3 rd oxidation wave that ended at the ~10.5 hour mark when the EEO2 dropped below ~10 -6 Da/O2 collision and remained negligible for >10 hours, at which point the experiment ended.