According to the Japan Agency for Marine-Earth Science and Technology, observational surveys have been conducted in Fukue Island, Nagasaki Prefecture since 2009.During this period, we observed the concentration of black carbon contained in the atmosphere, and investigated whether black carbon, which originally has the property of being difficult to dissolve in water, has the property of being easily taken into rain, and its relationship with precipitation.

　As a result, it was found that the black carbon particles had the property of being easily dissolved in water due to the aging effect of mixing with other water-soluble air pollutant particles, and the removal by rainfall started when they crossed the East China Sea. ..Furthermore, it was possible to derive a relational expression that estimates the removal rate of black carbon from the accumulated precipitation.It has also become clear that this formula can be used as an index to calculate how far black carbon is transported from sources such as China.

　Black carbon is considered to have as great an impact on global warming as methane, and is considered to be a major factor in the warming effect of the Arctic Ocean.However, the residence time in the atmosphere is short, and it is said that if measures are taken, an immediate effect will be obtained, and correct knowledge about the abundance in the atmosphere and the range to be carried has been required.

* 1 Black carbon This is called because it looks black to the human eye and absorbs light.Generated when hydrocarbons are incompletely burned at high temperatures in boilers and engines