The use of small drones has led to more remote and manpower-saving industrial inspections. Furthermore, they are expected to be applied to environmental surveys of closed indoor spaces. Adding functionality to small drones is subject to payload limitations. We have developed a device to capture aerosols on the propeller surface of a small drone flying over an inspection site. It was demonstrated that the airflow generated by the drone during flight was directed toward the center of rotation of the propeller and collected airborne particulate matter on the air filter on the propeller surface. The collected material was available for individual particle analysis by electron microscopy.

Atmospheric deposition samples were collected in the vicinity of a steelworks before and after the shutdown of a blast furnace to investigate how the shutdown of the blast furnace in the steelworks affected the surrounding atmospheric environment. Water-insoluble spherical particles, which are emitted mainly in combustion process, were analyzed individually by using an electron probe X-ray micro analyzer with an energy dispersive X-ray spectrometer. The individual particle analysis showed that the contribution of iron-containing particles to spherical particles in the atmospheric deposition was significant throughout the observation period. After shutdown of the blast furnace, the deposition flux of spherical particles decreased remarkably in terms of number concentration. Decreases in the deposition flux were also observed for particles other than those containing iron. Among the spherical particles, iron-containing particles mainly existed in the particle size range corresponding to PM_2.5, and the tendency did not change before and after the blast furnace shutdown. These results indicated that 1) insoluble spherical particles in the atmosphere near the steelworks were mainly derived from the blast furnace and its surrounding facilities regardless of their composition, and 2) spherical particles derived from combustion processes other than the blast furnace existed although their contribution was minor.