engleski

SEASONAL VARIATIONS OF OZONE MASS CONCENTRATIONS IN THE AIR OF ZAGREB

This paper presents the results of measurements of ozone in the air of Zagreb, Croatia. Twenty-four hour samples were taken at four sampling sites (city centre, northern, western and southern part of the town) for one month during each season (winter, spring, summer and autumn) of 2001. The samples were collected in carbonate alkali absorption solution of sodium nitrite (active sampling). Nitrite ion reacts with ozone, forming nitrate which is determined by ion chromatography. Regardless of the sampling location, ozone concentrations significantly differed (P<0.001) between seasons, showing higher values in summer and lower values in winter. Throughout the sampling period, ozone concentrations were low, and did not exceed the recommended value for the 98th percentile (110 &#956; g m-3), given in The Ordinance on Recommended and Limit Air Quality Values, at three sampling sites. The recommended and the limit values were exceeded only in the city centre, the limit values in summer (two times) and the recommended values in summer (three times) and in autumn (two times).

Air quality; ozone; sampling site; seasonal variations

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