First results of acidic and alkaline constituents determination in air particulates of Thessaloniki, Greece

Atmospheric aerosol samples were collected by a low volume sampler in a typical urban site of Thessaloniki city, from March 1989 to December 1990. The concentrations of the components Cl⁻, NO₃⁻, SO₄²⁻, Na⁺, K⁺, Ca²⁺, Mg²⁺ and NH₄⁺ were determined. Data obtained showed a significant correlation of SO₄²⁻ with NH₄⁺, Ca²⁺, Mg²⁺ and NO₃⁻. The contribution of the sea sprays was estimated to be 47% of aerosol chlorides but only 1.5% of aerosol sulfates. Aerosol sulfates are neutralized by atmospheric ammonia to form (NH₄)₂SO₄. Data evaluation considering wind direction led to the conclusion that local urban and industrial emission sources are primarily responsible for aerosol sulfates.