This work reports the observation of a series of fullerene ions, indicating the occurrence of fullerene soot (FS) in ambient air for the first time using an Aerodyne soot particle-aerosol mass spectrometer (SP-AMS) deployed in eastern China. We found the distribution of these ions showed a pattern almost identical with that of an Alfa Aesar FS standard. Although the SP-AMS may provide only a semiquantitative measurement of the FS, the measured concentrations can still reflect the temporal variations of airborne fullerenes. Combining results from factor analyses and meteorological data, we identified the petrochemical plants situated northeast of the site as the major source responsible for the FS-like ions. Our findings indicate the general presence of FS in ambient air, especially in oil and gas production regions. The SP-AMS technique may offer new insights into characterizing fullerene-related species in other environmental samples, as well.