A Study on Fine Particle Emission Characteristics in Dangjin Port Using High Resolution Scanning LiDAR

As emissions from ships and marine sources account for a high proportion of fine particle emissions, interest in air pollutants generated in port areas and the need to prepare countermeasures are increasing. For port air pollutants, it is necessary to consider substances emitted from ships and various emission sources from the yard around ports. This study uses a scanning LiDAR system capable of observing PM10 and PM2.5 in a radius of up to 5 km at a high resolution of 30 m horizontally and left and right to check high-concentration pollutants generated around Dangjin Port(36.985476°N, 126.745613°E) in real time and corresponding substances tried to distinguish. The scanning LiDAR used in this study provides the Ångström exponent calculated from the extinction coefficient at both wavelengths of 1064 and 532 nm and the depolarization ratio at 532 nm. First, the Ångström exponent can confirm information about the particle size. In addition, the depolarization ratio is a parameter representing information on the asphericity of particles. It provides information on the classification of aerosol types depending on whether the particles are spherical or non-spherical. The concentration of fine particle generated was identified using the extinction coefficient, and the kind of particle was determined using the Ångström exponent and the depolarization ratio. The primary source of fine particle in the vicinity of Dangjin Port was an industrial complex, such as a steel mill located on the west side of Dangjin Port, and fine particle was also generated from the port's coal yard and moving ships. The diffusion direction of fine particle was closely related to the wind direction. The type of fine particle confirmed by a low Ångström exponent between 0 and 1 and a high depolarization ratio degree between 0.1 and 0.2 was confirmed as non-spherical scattering dust. Through this study, it was confirmed that it was possible to identify the generation and movement of fine particle in a wide area and to distinguish the types of particles using scanning lidar.

Acknowledgement

This work was supported by the “Graduate school of Particulate matter specialization.” of Korea Environment Industry & Technology Institute grant funded by the Ministry of Environment. Republic of Korea.