Fig. 1

Characterization of ferrocene-doped diesel exhaust particle Ferrocene-doped diesel exhaust was collected and characterized with scanning electron microscopy. DEP-0: Diesel exhaust particles from diesel fuel with 0 mg/L ferrocene. DEP-205: Diesel exhaust particles from diesel fuel with 205 mg/L ferrocene. DEP-410: Diesel exhaust particles from diesel fuel with 410 mg/L ferrocene. DEP-820: Diesel exhaust particles from diesel fuel with 820 mg/L ferrocene. (A) Representative scanning electron microscopy images of ferrocene-doped diesel exhaust particles. (B) Quantification of length-diameter ratio and fiber-particles length (N = 6 per group). (C) Semi-quantification of element mass fraction of diesel exhaust particles