This study analyzes the chemical composition of metallic elements and water-soluble ions in $PM_{10}$ and $PM_{2.5}$. $PM_{10}$ and $PM_{2.5}$ concentrations in Busan during 2010-2012 were $97.2{pm}67.5$ and $67.5{pm}32.8{mu}g/m^3$, respectively, and the mean $PM_{2.5}/PM_{10}$ concentration ratio was 0.73. The contribution rate of water-soluble ions to $PM_{10}$ ranged from 29.0% to 58.6%(a mean of 38.6%) and that to $PM_{2.5}$ ranged from 33.9% to 58.4%(a mean of 43.1%). The contribution rate of sea salt to $PM_{10}$ was 13.9% for 2011 and 9.7% for 2012, while that to $PM_{2.5}$ was 17.4% for 2011 and 10.1% for 2012. $PM_{10}$ concentration during Asian dust events was $334.3{mu}g/m^3$ and $113.3{mu}g/m^3$ during non-Asian dust events, and the $PM_{10}$ concentration ratio of Asian Dust/Non Asian dust was 2.95. On the other hand, the $PM_{2.5}$ concentration in Asian dust was $157.4{mu}g/m^3$ and $83.2{mu}g/m^3$ in Non Asian dust, and the $PM_{2.5}$ concentration ratio of Asian Dust/Non Asian dust was 1.89, which was lower than that of $PM_{10}$.