Ground-level Ozone Air Pollution in Vilnius City

This study aspires to assess distribution of the ground-level ozone concentration in Vilnius city. A portable Aeroqual series 300 ozone monitor has been used for measuring purposes. Sampling was carried out in Vilnius city during four seasons in the period of 2006-2007. Results of this study have revealed that annual mean of ground-level ozone concentration in Vilnius city was 30.3 µgm-3. The highest ground-level ozone concentration was in Viršuliškiai district (43.1 µgm-3), the lowest - at a highway of Eišiškės (17.9 µgm-3). The highest average seasonal concentration was determined in summer (49.6 µgm-3) and the lowest - in autumn (16.9 µgm-3). The ground-level ozone concentration has also a clear diurnal cycle - with higher values in the day-time and notably lower values at night. A minimal ground-level ozone concentration was at 06 am (4.0 µgm-3), the maximal one - at 01 pm (87.0 µgm-3). During the measurement period the concentration of ground-level ozone in Vilnius has never exceeded the stated value (120.0 µgm-3). Meteorological conditions are known to influence the formation and dispersion of ground-level ozone. The results of this work show that the ground-level ozone concentration noticeably correlates with the temperature (r=0.554 p= 0.000) and the wind speed (r= -0.785 p= 0.000).