2018 Volume 67 Issue 2 Pages 95-101
Fresh snow and rain samples were collected at remote areas that were 15 km far from a provincial industrial city, in order to suppress any influences of coarse particulates. The concentrations of lead and cadmium in fresh snow collected in remote areas along Japan Sea in Honshu Island, Japan in 2014 and 2015 were reported along with these concentrations in fresh snow and rain occuring in remote areas in Shikoku Island, Japan at 2010, 2014 and 2015. The origins of air mass providing snow and rain were estimated by using a 24 h back-trajectory. The correlation between Pb and Cd was obtained to be [Pb]/[Cd] = 27.4±2.8 (R2 = 0.979) in fresh snow derived from a cold air mass from North Eastern China (Heilongjiang) – Far Eastern Russia (Maritime Province) and [Pb]/[Cd] = 2.8±0.4 (R2 = 0.732) in rain and fresh snow derived from Japan. The origin of air mass for Pb and Cd included was assigned to AREA’s (A, Hebei; B, Liaoning-Jilin; B2, Korea Peninsula; C, Heilongjiang- Maritime Province; D, Japan) corresponding to the regression line at a short distance from the plotted point observed in fresh snow samples in remote areas of Honshu Island on a Pb-Cd diagram. There were some samples that indicated a different AREA assigned by between hexagonal raidar plot of the chemical composition of inorganic small spherical particles and this Pb-Cd plot diagram method. The difference in the air mass origin assigned by different tracers used could be caused by differences in the long-range transport mechanism between the inorganic spherical small particles (φ 1–3 μm) and aerosol of Pb and Cd as sulfate. The reason can also be explained by varying back-trajectory line during the snow falling event.