Determination of the levels of Na, K, Ca, Mg, Fe, Zn and Cu in aerosols of the western Venezuelan savannah region

The determination of seven elements in cellulose filters loaded with air particulate matter (total and size distributions) was carried out in two rural western Venezuelan savannah sites during dry and rainy seasons. After acid digestion of the filter material with high purity nitric acid, analysis of the metals was carried out by atomic absorption spectroscopy. The level of possible error at the analytical stage was found to be insignificantly small. The K and Ca excess concentrations in relation to sea water were ∼90%. A large concentration of Ca in coarse particles >1.5 μm was observed, probably coming as carbonates from soil and cement production emissions, which should have a good potential to neutralize the acidity of the atmosphere. In both dry and rainy seasons, K was present in a large fraction (>50%) of coarse particles >1.5 μm, indicating that the western Venezuelan savannah region is little affected by vegetation burning emissions in comparison with other Venezuelan savannah regions. The release of water soluble K salt particles from vegetation is the most likely additional K source other than sea-salt. A very high concentration was found for Cu (233–394 ng m−3) in the rainy season, which is up eight times higher than found in other Venezuelan savannah regions. This range of concentration is well above the range of 3–100 ng m−3 found in other rural areas of the world, indicating possible natural and/or anthropogenic sources for the atmospheric concentration of this element.