Abstract
This study analyzed the temporal variation of tropospheric ozone (O3) in Poznan (midwestern Poland) on the basis of data collected from a State Environmental Monitoring air quality assessment station. The aim was to investigate the distribution and variation of O3 levels and to assess the relationship with nitrogen oxides (NOx) and meteorological conditions. These relationships were assessed by multiple regression analysis and cluster analysis. The O3 levels showed a high annual, seasonal and daily volatility, and were significantly influenced by meteorological conditions and NOx levels. High O3 levels were accompanied by above-average levels of radiation (Rad), air temperature (Ta) and wind speed (Ws), together with below-average values of NOx and humidity (Rh). Atmospheric pressure (Ph) had an ambiguous effect on O3 levels.