Dust originating from arid and semiarid areas in Central Asia can reach Taiwan during springtime. However, aerosols in a metropolitan region, such as Taipei city, also have significant local sources. In this work, the influence of long-range transport and local pollution, on various water-soluble ions in fine and coarse modes, was investigated for several dust events. Concentration differences between dust-event and non-dust-event days were assessed. Field measurements were conducted in Taipei from February to May 2002. Twelve-hour samples of PM_2.5 and PM₁₀ were taken. Ion chromatography was used to analyze water-soluble ions (Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻, and SO₄²⁻). The mean concentrations of Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻, SO₄²⁻, and PM in the fine mode during the entire sampling campaign were 0.29, 2.87, 0.29, 0.029, 0.13, 0.57, 0.92, 2.68, and 28.2 µg m⁻³, respectively. The corresponding mean concentrations in the coarse mod (PM_2.5-10) were 0.75, 0.30, 0.096, 0.14, 0.63, 0.84, 2.33, 1.60, and 34.0 µg m⁻³, respectively. Results of Principle Component Analysis showed that elevated concentrations of fine Na⁺, K⁺, Mg²⁺, Ca²⁺, and Cl⁻ and coarse Na⁺, Mg²⁺, Ca²⁺, NO₃ , and SO₄²⁻ on dust-event days were a result of long-range transport. A prolonged influence of long-range transport on concentrations of fine and coarse ions, after dust peaked, was also observed. K⁺ , Mg²⁺ , and Ca²⁺ increased by about 1.7 to 3.8 fold and Na⁺ and Cl⁻ increased by 45 - 210% on dust-event days. Fine modes of NH₄⁺, NO₃⁻ , and SO₄²⁻ were derived from local pollution, while most coarse NO₃ − and some coarse SO₄²⁻ were derived from long-range transport. On average, coarse NO₃⁻ and SO₄²⁻ increased by 67% and 97%, respectively, during dust events