2017 Volume 52 Issue 4 Pages 129-139
To estimate the dry deposition of atmospheric mercury, it is important to determine the size distribution of particle-bound mercury (particulate mercury, PHg) because the dry deposition velocity mostly depends on the particle size. Size-segregated particle matters (PM) were collected using two types of impactor samplers, namely, the PM2.5 sampler and Andersen cascade impactor sampler, on the roof of the Niigata Institute of Technology located in the rural area of Kashiwazaki City, Niigata Prefecture. The mercury contents in the PM were measured by flameless cold atomic absorption spectrophotometry using a combustion gold-trapping heat vaporization method. The ratios of the coarse PHg to total PHg indicated significant positive correlations at ambient temperatures during the sampling periods in both methods, i.e., higher percentages of coarse PHg were observed during the warm season and the percentages of the fine PHg increased in the cold season. When estimating the dry depositions of atmospheric mercury in a coastal area via such an inferential method, it is necessary to consider the ambient temperature dependence of the PHg size distribution.
