PM<SUB>2.5</SUB> has negative effects on human health and the environment. The major components of PM<SUB>2.5</SUB> are composed of ionic components, carbonaceous components, and trace metallic elements, and ionic and carbonaceous components account for approximately 50% and 30%, respectively. The purpose of this study was to collect PM<SUB>2.5</SUB> and determine its major chemical components in two different functional areas. PM<SUB>2.5</SUB> was collected at Samhwa Elementary School (SES), located near a cement factory in Donghaesi, Gangwon-do and Bukpyeong-dong Administrative Welfare Center (BAWC), located near the industrial complex. NO₃- showed the highest concentration at both locations. Since [NO₃-/SO₄<SUP>2-</SUP>] showed relatively higher values in BAWC than in SES, it was anticipated that PM<SUB>2.5</SUB> in BAWC was more affected by mobile sources than in SES. It was observed that SO₄<SUP>2-</SUP> and NO₃- mainly existed in the form of (NH₄)₂SO₄ and NH₄NO₃ at both sites. In addition, high concentrations of PM<SUB>2.5</SUB> appeared when NH₄+ was deficient, indicating that NH₃ was likely to play an important role in forming secondary NH₄NO₃. At both sites, good correlation between organic carbon (OC) and elemental carbon (EC) was found. Relatively high OC/EC ratios observed at both sites indicate that a significant portion of OC was formed secondarily in atmosphere.