2020 Volume 55 Issue 2 Pages 27-33
Aerosol particles are serious concern for human health effects. Moreover, it is necessary to focus on not only the particle mass but also the chemical composition to characterize their toxicity. We focused on chromium whose toxicity changes depending on the oxidation state. Therefore, we carried out the chromium speciation by the X-ray absorption fine structure (XAFS) method. In this study, fine and coarse particles in the powder form were collected using cyclone at Kanagawa, Saitama and Fukuoka during the four seasons of 2017. In Kanagawa, fine particles were also collected by conventional filter sampling. The XAFS spectra of chromium in the aerosol particles and standards were then obtained. To identify the oxidation state of the chromium, the obtained XAFS spectra were applied to the linear combination fitting. The XAFS spectra obtained from pelletized samples showed a better signal/noise ratio and could be applied to the linear combination fitting. The XAFS analysis indicated that Cr (III) was the dominant oxidation state in most of all the particles. Fine particles included more Cr (III) than the coarse particles. Moreover, the aerosol particles collected in Fukuoka included about 15% more Cr (III) than those collected in the other two locations. Furthermore, a Cr (VI)-containing particle was present in one of the coarse particles.
