Emissions of the main air pollutants in Europe have declined since 1990. Over the past decade, this reduction has resulted – for some of the pollutants – in improved air quality across the region. However, due to the complex links between emissions and air quality, emission reductions do not always yield a drop in atmospheric concentrations. Concentration levels depend on year-by-year variations in weather conditions including sunlight, natural emissions of ozone precursor substances by vegetation, increased global background ozone concentrations and transportation of ozone and/or ozone precursors from source areas outside the studied area. This study presents a comparative analysis of air quality in the three cities located in Moldova region (Romania), which are characterised by similar geo-climatic conditions. Thus, the differences found in air quality are not due to the different geoclimatic conditions but to specific features of the three cities.