engleski

COPPER LEVELS IN SUSPENDED PARTICULATE MATTER IN ZAGREB AIR

Copper was recognised as an essential element in the environment at the beginning of the 20th century. It is released in the atmosphere in the form of particulate matter or is adsorbed on particulate matter. It is removed by gravitational settling (bulk deposition), dry deposition (inertial impaction characterized by a deposition velocity), washout by rain (attachment to droplets in clouds), and rainout (scrubbing action below clouds). Its removal rate and distance travelled from the source depend on source characteristics, particle size and wind velocity. Gravitational settling governs the removal of large particles, whereas smaller particles are removed by other forms of dry and wet deposition. The relative importance of wet deposition, compared to dry, is that it generally increases with decreasing particle size. Monitoring of copper in total suspended particulate matter (TSPM) started in Zagreb, Croatia in 1972 at two measuring sites, located in the city centre and in the northern part of the city. Monitoring of copper concentrations in PM10 started in the northern part of the city in 2003. This paper presents the trends in annual mean values for copper concentrations in TSPM. The obtained data show a decreasing trend of copper in TSPM, especially in the northern part of the city. Copper measurements performed in PM10 particles over the last three years showed that, in comparison to copper in TSPM, 69-75% of copper was in the small PM10 particles.

air pollution; heavy metals; city areas; total suspended particulate matter; PM10

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