2017 Volume 32 Issue 1 Pages 20-28
Elemental carbon (EC) is one of the most important aerosol species that damage human health and affect global climate. The Soot Particle Aerosol Mass Spectrometer (SP-AMS) was recently developed for the measurement of refractory black carbon (rBC) via laser induced incandescence and mass spectrometry. In this study, a SP-AMS was used to measure the rBC in both diesel exhaust and aerosols at a traffic intersection. The comparison of rBC with EC concentrations determined by a thermal optical method suggested a necessity of special caution during the data analysis. Namely, (1) rBC must be determined by subtracting the signals at the laser-off from those at the laser-on for the analysis of unit mass resolution data, and (2) because the collection efficiency of the laser evaporator depends on particle morphology, simultaneous measurements of rBC by SP-AMS and EC or BC by other instruments should be carried out to determine the collection efficiency. We also found that the spectrum of carbon cluster ions in the particles emitted from a direct–ignition gasoline vehicle was different from that of diesel exhaust particles. Therefore, the ratio of cluster ions C＋/C3＋ may be a good indicator for distinguishing these two types of particles in the environment.
