Characterization of Aerosol Particles in the Tokyo Metropolitan Area using Two Different Particle Mass Spectrometers

Abstract

Particle mass spectrometers of two types—a time-of-flight aerosol mass spectrometer (AMS) of Aerodyne Research Inc. and a laser desorption/ionization single particle aerosol mass spectrometer (LISPA-MS) developed at Nagoya University—were deployed to characterize aerosol particles in the Tokyo metropolitan area during the summer of 2008. Based on the ensemble measurements by AMS, equivalent mass concentration of organic aerosol, traced by mass-to-charge ratio (m/z) 44, showed a closer correlation with particulate nitrate and gas-phase odd oxygen, [O 3 +NO 2 ], whereas equivalent mass concentration of organic aerosol, traced by m/z 57, did not. On a particle-by-particle basis, the relative signal peak area of various target species in the LISPA-MS spectra, which was calculated as the ion-signal fraction of the species relative to the total signal peak area summed over all the ion peaks in each spectrum, was used as a measure of the relative amount of the species. A rough qualitative agreement was obtained ...