engleski

ZINC LEVELS IN SUSPENDED PARTICULATE MATTER IN ZAGREB AIR

Zinc is an essential element in the environment. There is a range of optimum concentrations for essential elements such as zinc. The toxicity of zinc will depend on environmental conditions and habitat types ; thus any risk assessment of the potential effects of zinc on organisms must take into account local environmental conditions. Zinc is released into the atmosphere as dust and fumes from mining, zinc production facilities processing of zinc-bearing raw materials, brass works, coal and fuel combustion, waste incineration, and iron and steel production. However, refuse incineration, coal combustion, smelter operations, and some metalworking industries constitute the major sources of zinc in air. More efficient emission control technology and changes in zinc refining methods have resulted in 73% decrease in air emissions. Zinc in the atmosphere is primarily in the oxidized form in aerosols. Zinc is found on particles of various sizes, the size being determined by the source of zinc emission. Waste incinerators release small zinc-containing particles into the atmosphere, whereas the wear of vehicle tires produces large particles. In general, zinc levels in urban and industrial areas are higher than in rural areas. Monitoring of zinc 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 zinc concentrations in PM10 started in the northern part of the city in 2003. This paper presents the trends in annual mean values for zinc concentrations in TSPM measured in a densely populated area in the city centre, and in a sparsely populated housing area in the northern part of the city. The obtained data show a decreasing trend of zinc in TSPM. Over the past three years, the measurement of zinc in PM10 particles has been performed, and the obtained data, in comparison to zinc in TSPM, have shown that 82-93% of zinc was in the small PM10 particles.

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

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