This paper aims to find the characteristics of concentration distribution of coastal urban air pollutants. For this purpose, It was used the daily meteorological data and the hourly concentration data for O3 and NO2 in Busan metropolitan city from 1994 to 1996. It was investigated the annual and monthly distribution of ozone and nitrogen dioxide concentration at each site in Busan, and also investigated the characteristics of concentration change of air pollutants with time under the sea breeze. As a results, the concentration of nitrogen dioxide and ozone tend to be increased every year and nitrogen dioxide concentration is higher than ozone concentration at all sites in Busan. The concentration of ozone is high in summer season and low in winter season, but the concentration of nitrogen dioxide have a reversed trend. The monthly peak concentration of ozone occurred in April and September, while the monthly minimum concentration of nitrogen dioxide occurred in August. Their trend were identified by sites near the coastline than sites stands apart from the coastline. The sea breeze occurred annual mean 81 day in Busan from 1994 to 1996. The main wind direction of sea breeze was classified into southwesterly and southeasterly. In case of southwesterly, It was pronounced the south wind and southwest wind. In case of southeasterly, the occurrence frequency of east wind was high. Especially, the concentrations of urban air pollutants, such as ozone and nitrogen dioxide, were high on time which the sea breeze flow, and the areas that ozone concentration was high moved from outside part to central part of city with time. In costal urban such as Busan, the wind direction of sea breeze is influenced the change of ozone and nitrogen dioxide concentration on time which the sea breeze flow at each site and also influenced the change of air pollutants concentration of sites on the pathway of sea breeze.

To investigate air quality away from the coastal urban source region, we used a hybrid Eulerian-Lagrangian method which can describe the formation, transport, transformation and deposition processes in complex terrain. with inclusion of shipping sources that were considered to be important emission in the coastal urban region. The result of the Eulerian advection - diffusion prediction was quite similar to that of the Lagrangian particle diffusion prediction. It showed that pollutants emitted from piers can affect the part of inland, especially Dongrae and the coastal area. Those emitted from Sasang and Janglim industrial complexes can affect Hwamyeong and the coastal, respectively. During the daytime the concentration was low due to large deposition flux and terrain effect.

To predict diffusion and movement of air pollutants in coastal urban region a numerical simulation shoud be consider atmospheric flow field with land-sea breeze, mountain-valley wind and urban effects. In this study we used Lagrangian particle dispersion method in the atmospheric flow field of Pusan coastal region to depict diffusion and movement of the pollutants emited from particular sources and employed two grid system, one for large scale calculating region with the coarse mesh grid (CMG) and the other for the small region with the fine mesh grid (FMG). It was found that the dispersion pattern of the pollutants followed local circulation system in coastal urban area and while air pollutants exhausted from Sasang moved into Baekyang and Jang moutain, air pollutants from Janglim moved into Hwameong-dong region.