In recent years, pollutant standard index (PSI) of I-Lan air quality area is getting worse and worse. There are only two monitoring stations, I-Lan and Ton-San, in this air quality area. Monthly average concentrations of monitoring air pollutants were used in this study to analyze the time variations of air pollutants, especially suspended particles (PM10) and ozone. Preliminary results of this study show ozone concentration of I-Lan monitoring station is higher than that of Ton-San, however, the month concentration of PM10 increased for I-Lan station, but that of ozone decreased for the same station. Positive correlation results are obtained for concentrations of PM10 and O3 between those two monitoring stations.