Total suspended particulate (TSP) in the atmosphere was collected and size-fractionated by Andersen high volume air sampler for the past two years (Mar. 1987-Feb. 1989) in Seoul. The concentrations of several polycyclic aromatic hydrocarbons and heavy metals were determined to investigate the atmospheric concentrations, seasonal variations and its relationship with the size distribution of suspended particulate matter. The arithmetic mean concentration of total suspended particulate was $229.48;{mu}g/m^3$. The concentrations of heavy metals were $2971.94;ng/m^3$ for Fe, $767.75;ng/m^3$ for Zn, $765.80;ng/m^3$ for Pb, $218.40;ng/m^3$ for Cu, $129.91;ng/m^3$ for Mn, respectively. And the concentration of PAHs were $3.23;ng/m^3$ for benzo(a)pyrene, $2.71;ng/m^3$ for benzo(k)fluoranthene, $4.53;ng/m^3$ for benzo(ghi)perylene, respectively. The mass-size distribution of TSP was lowest in the particle size range $1.1-3.3;{mu}m$ increased as the particle size increased or decreased. But PAHs, Pb and Zn abounded in particles below $2.0;{mu}m$, while Fe and Mn abouned in particles above $2.0;{mu}m$. TSP and its chemical compositions showed the seasonal variations. The concentrations of anthrophogenic origin like TSP, PAH and heavy metals in the fine particles were highest in winter and lowest in summer. PAH and Ph analyzed showed significant correlations with each other and with TSP concentration in fine particles, indicating that the particles in which they are contained have a similar behavior in the atmosphere.