Clarification of emission source by inorganic elements in pm_2.5 collected in the daytime and night at the top of mt.fuji

In order to clarify long-range transported PM_2.5, a PM_2.5 sequential sampler was installed at the Fuji meteorological station (3776 m a.s.l.) in the free troposphere and carried out PM_2.5 sampling in daytime and the night from July 21 to August 15, 2017. Eight components of water-soluble inorganic ions and 68 elements were measured. The PM_2.5 average concentrations in the daytime and night were 1.7±1.5 μg m^–3 and 1.6±1.1 μg m^–3, respectively. The total of NH⁺₄ and SO^2–₄ concentration was 67 % of total inorganic ion concentrations. 2– SO₄ concentrations in the daytime was 1.3-times higher than those in the night. The concentrations of 17 elements (Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Pb) were over the detection limit in more than a half of all 44 samples. The correlation coefficients (r) were evaluated between 21 components, including 17 elements and 4 ions. Components related with soil, urban pollutants and long-range transportation in the daytime and only long-range transportation in the night showed a high positive relationship (r ≧0.7). Four samples with a high As/V ratio ( ≧0.9) were collected in the night, and their backward trajectories showed that the air mass was directly transported from the Asian continent. Anthropogenic V* was calculated with a concentration ratio of V based on Al in topsoil particles of Mt.Fuji. Three samples with V* ≧0.2 ng m^–3 were collected in the daytime, and their backward trajectories showed that the air mass was transported through over the Kansai area, including the Osaka city and Chukyo area, including Nagoya city. The As/V* ratio were consistent with those of PM_2.5 collected in these area. Long-range transported PM_2.5 was clearly detected by sample collection in the night on the top of Mt.Fuji.