The fine particles in the range of $30~500nm$ are monitored at Hanyang University campus in Ansan using house made DMA (differential mobility analyzer) and commercial CPC (condensation particle counter, TSI inc.) in SMPS mode. The monitoring period is March 16th 2004 through May 7th, 2004. During the monitoring period, Aitken nuclei mode $(30~100nm)$ particle concentration has a tendency of increase in the morning and evening hours. However, the accumulation mode $(100~500nm)$ particle concentration stays rather stable than that of Aitken mode.