This paper presents the results of a chemical characterization analysis of fine particulate matter measured at three elementary schools in Central Ohio. This project supports a larger study underway at Ohio University. The core focus of the Ohio study was to determine the potential risk associated with air pollutants on children in Ohio. PM2.5 aerosol samples were collected from an outdoor monitor, an indoor sampler and from a personal exposure sampler at each monitoring location for the period of January 1, 1999 through August 31, 2000. The collected samples were then analyzed at Texas A&M University – Kingsville using an ion chromatography unit and an X-ray fluorescence spectrophotometer. Concentrations of Cl-, NO3-, SO4-2, PO4-3, Li+, Na+, NH4+, K+, Mg+2, Ca+2, Si, P, S, Cl, K, Ca, Ti, Co, Ni, V, Mn, Fe, Cu, and Zn were determined for each site and inter-compared. Sulfate comprised the largest amount by weight, nearly 20-25% of the total fine PM concentration. Sulfate concentrations were found to be highest at East rural site, which is located near the Ohio River valley, a large source of sulfur dioxide emissions from power plant combustion. Other abundant components included nitrate ion, ammonium ion and silicon. The anion and cation average concentrations in a decreasing order were observed as SO4-2 >NO3- >Cl- and NH4+ > Ca+2 > Na+ > K+ > Mg+2, respectively. Significant levels of sodium, chloride and potassium were found in the rural samples when compared with the urban samples. Heavy metals such as titanium, vanadium, manganese, iron, copper, and zinc were found in all the samples, and iron was the most abundant species in the filter samples. A preliminary analysis of the mass concentration distribution revealed higher PM2.5 concentrations at the urban site than at the suburban and rural sites. There were significant seasonal differences in the mass concentrations of fine particulate matter observed at all three sites. Sulfate ion concentration showed an increase from the winter to the spring months. The analysis of the indoor samples revealed indoor concentrations were sometimes higher than the outdoor concentrations at all three sites.