Objectives: The changes in atmospheric $PM_{2.5}$ concentrations were extensively studied in one metropolitan city (Incheon), two small and medium sized cities (Gunsan, Cheonan), and a rural area (Gosan in Jeju). The concentrations of heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, Al, Pb) and the component features of $PM_{2.5}$ were determined for these areas. Methods: This study sampled $PM_{2.5}$ at the designated locations in the metropolitan (Incheon), small and medium sized cities (Gunsan in Jeonbuk and Cheonan in Chungnam), and rural area (Gosan in Jeju) to investigate concentrations with a sampling device (Sequential sampler, APM Eng., Korea). Sampling was undertaken over months, from June 26 to November 26, 2009. Sampling was conducted a total of 44 times, with routine sampling at intervals of six days (24 total times) and intensive sampling (20 total times) during the summer and fall. Mass concentration of $PM_{2.5}$ was evaluated and the concentrations of heavy metals (Cr, Mn, Fe, Ni, Cu, Zn, Al, Pb) were analyzed. Results: The geometric average of concentrations of $PM_{2.5}$ per district was $35.289{\mu}g/m^3$ for Cheonan, $29.955{\mu}g/m^3$ for Incheon, $24.119{\mu}g/m^3$ for Gunsan, and $18.773{\mu}g/m^3$ for Jeju, respectively. The average concentration of $PM_{2.5}$ in Cheonan was the highest. The seasonal concentration distributions per district showed Cheonan $33.387{\mu}g/m^3$, Incheon at $31.550{\mu}g/m^3$, Gunsan $22.900{\mu}g/m^3$, and Jeju $18.900{\mu}g/m^3$ in the summer. For the autumn, the concentrations were $36.873{\mu}g/m^3$ in Cheonan, $28.625{\mu}g/m^3$ in Incheon, $25.227{\mu}g/m^3$ in Gunsan, and $18.667{\mu}g/m^3$ in Jeju. According to the collected data, the concentration showed a tendency to rise during the autumn in all of these regions with the exception of Incheon. For heavy metal distribution per district, Fe showed an elevated concentration during the summer while high concentrations of Pb and Zn occurred during the autumn. Conclusion: These results demonstrated that atmospheric factors affected the concentrations of heavy metals. The results of this study could be used as foundational data for setting environmental air standards focusing on a $PM_{2.5}$ receptor.