Chemical Composition and Sources of PM10 Particulate Matter Collected in San José, Costa Rica

ABSTRACT

Measurements of trace metals and inorganic ions were carried out on PM₁₀ aerosols sampled at two sites in the city of San Jose, Costa Rica. Samples were collected with a Thermo Andersen high volume PM₁₀ sampler on glass fiber and quartz filters. The ions SO₄^2-, NO₃^-, Cl^-, F^-, PO₄^3-, NH₄⁺, K⁺, Na⁺, Ca²⁺ and Mg²⁺ were analyzed by ion chromatography and the trace metals V, Cu, Cr, Pb, Ni, Mn, Fe and Al were analyzed using an atomic absorption spectrometer with a graphite furnace attachment. The results indicated that SO₄^2- was the most abundant ion, and Al the trace metal with the highest concentration.

Pearson's correlation applied to all data showed a high correlation among SO₄^2-, NO₃^- and NH₄⁺, indicating a common anthropogenic origin. In addition, the correlation found between Na⁺-K⁺ and Ca²⁺-Mg²⁺ indicated a crustal origin. No correlation was found among the trace metals except Cu-Cr and Fe-Cr. The influence of wind direction on trace metal concentrations is also discussed.

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