The average diamond NP EEO2 was just ~6.5 x 10 -4 Da/O2 collision, however, this includes near-zero values for three NPs that were pre-heated before the EEO2 measurements, as well as values obtained at TNP < 1500 K for several NPs, ranging up to ~3 x 10 -3 Da/O2 collision at 1200 K from Fig. . Excluding the three preheated diamond NPs, the average EEO2 is ~1.0 x 10 -3 Da/O2 collision -similar to that for the black carbon NPs, albeit measured at lower TNP.