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A method to discriminate artificial fine iron particles floating in the atmosphere

Iron is an important material for our daily lives, for the history of the Earth, and for the Earth’s current and future. The use of iron greatly changes the civilization of mankind, and even now the articles made of iron can not be known to the number of people around. The iron that we are now digging up as iron ore is originally precipitated by the oxygen that plants have spilled from the Earth and connected to the iron content in the sea.

Iron is also an essential nutrient for plant growth. Phytoplankton floating near the surface of the ocean supports the living things of the Earth through the food chain of the zooplankton that feeds on photosynthesis based on carbon dioxide dissolved in the atmosphere, and the small fish that feeds on it…….However, there are many areas in the world where there is a chronic shortage of iron in the ocean. There are some studies that attempt to activate phytoplankton by spraying the sea with iron. If the phytoplankton activity becomes active with iron, the productivity of the sea increases, it may be related to the suppression of global warming by consuming a lot of carbon dioxide of the atmosphere.

How is the iron content of this sea supplied? In fact, this basic matter is not well understood. There are two types of iron that come to the sea as fine particles called aerosols (aerosols) drifting in the air: those of natural origin where sand is rolled up and flying, and those of human origin when coal and oil are burned on land. What is the origin of iron in the sea? In the first place, how can we distinguish the origin?

Research groups such as Professor Michiko Kurisu (professor at the University of Tokyo) and Yoshio Takahashi (professor at the University of Tokyo’s doctoral program are focusing on the isotopic ratios of iron contained in aerosols. There are 4 different types of iron that are slightly different in weight. These are called isotopes of iron. That 9 percent is a kind of”iron 56″, about 6% is a little lighter than that “Iron 54”.Mr. and Mr. Kurisu examined the proportion of iron 56 and iron 54 contained in the iron of the aerosol, that is, the isotope ratio in detail.

Kurisu San et al. 2016 Years 9 month, was collected aerosol on the roof of the Chiba City office. About 4 km southwest of here there is a steel plant. At steelworks, iron is heated to about 1000-2000 degrees Celsius. Because the Iron melts at about 1540 ° C, the”iron” that is different from the sand-like aerosols of natural origin should fly.

Considering the wind direction at the time of collection, it was found that the ratio of Light Iron (54%) was high for the iron contained in the fine aerosol with a particle size of 1000 min (about 1 mm or less). When I examined the shape of the aerosol with an electron microscope, small balls were gathered and it became a lump.Mr. Kurisu says that this is a material that was formed by the cold of iron, which was once vaporized and turned into gas due to the high temperature. On the other hand, for larger aerosols, the proportion of iron 56 and iron 54 did not differ from the natural origin of sand rolled up from the Earth’s surface. In other words, by examining the isotope ratio of iron, it is possible to distinguish whether it is an aerosol of natural origin or an aerosol of artificial origin containing iron when exposed to high temperatures.

There is a close relationship between the number of aerosols in iron and past climate changes. Today, a large amount of iron is produced and consumed to support our civilization, and the Iron aerosol of human origin is considered to be easier to dissolve in the sea than the iron of natural origin. The current global warming is due to the fact that we are burning coal and oil to emit a lot of carbon dioxide. The coal and oil, when burned, also produce anthropogenic iron aerosols. The Iron affects the “carbon” that surrounds the Earth in the form of carbon dioxide and the bodies of living things. Iron plays an important role in determining the balance of the global environment.

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