Episodes of extremely high concentrations of tropospheric ozone in the urban environment in Bor - Serbia

This paper presents results of measuring episodes of extremely high ozone concentrations in urban area of the town of Bor in Serbia. The measured ozone concentration of 3000 μgm−3 in two episodes, which lasted 3-5 days in November 2010, has not been recorded in the literature in this field. Sensitivity of generated ozone to the NOx was determined, since the concentrations of NOx in the same period were also high. In the morning when working hours start, episodes of increased NOx concentrations appear after several hours, leading to episodes of increased ozone concentrations reaching up to twenty times more than the threshold value, defined as harmful to vegetation and human health.

► In this study we investigated very high episodes of the ground-level ozone. ► We examined impact of the primary pollutants on the ozone formation. ► Influence of the metorological paramethers on the ground-level ozone was analyzed. ► Measured mean hourly values of ozone varied in a large interval (7.38-3213 μgm−3). ► Strong NOx sensitivity of the generated ozone, above 120 μgm−3, has been proposed.