Different-sized aerosols were collected by an Andersen air sampler to observe the detailed morphology of the black carbon （BC） aerosols which were separated chemically from the other accompanying aerosols, using a Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer （SEM-EDX）. The results indicate that most BC aerosols are spherical particles of about 50 nm in diameter and with a homogeneous surface. Results also show that these particles aggregate with other aerosols or with themselves to form larger agglomerates in the micrometer range. The shape of these 50-nm BC spherical particles was found to be very similar to that of BC particles released from petroleum-powered vehicular internal combustion engines. These spherical BC particles were shown to be different from the previously reported fullerenes found using Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry （MALDI-TOF-MS）.
The mass concentration and size distribution of aerosols in Tokaimura were investigated using a high-volume and a low-volume Andersen sampler. A difference was found using the two samplers： the concentration of total aerosols determined with the high-volume sampler is smaller than that of the low-volume sampler by 70-90% throughout the year. Compared to the high-volume sampler, low-volume sampler gave lower concentration for aerosols 〉7 μm, higher concentration for aerosols of 3.3-7.0 μm and 〈 1.1 μm, though similar results for aerosols of 1.1-3.3 μm. The low-volume sampler was found to have better separation efficiency and higher accuracy.
