Abstract
The main purpose of this paper is to assess the concentration levels of pollutants at six urban sites in Bucharest, Romania in order
to draw conclusions on their temporal variability in different sources and under different meteorological conditions. The analysis
of measured pollutant concentrations (NOx, NO2, CO, PM10) runs over three years: 2005, 2006 and 2007, and uses data from the
network of monitoring stations of Environmental Protection Agency of Bucharest, which was established in 2004. The study has
shown that the highest NOx and SO2 concentrations occur in winter, with NOx (195.20±70.38) μg.m-3 at a traffic station (Cercul
Militar) and SO2 (70.60±22.35) μg.m-3 at another traffic station (Mihai Bravu), with the latter being close to a power plant. The
levels of pollutant concentration are related to human activities, such as traffic and the distribution of thermal power plants. The
unfavorable meteorological dispersion conditions have clearly influenced the concentrations in winter. The highest PM10
concentration values (~ 80 μg.m-3) measured in summer at all monitoring stations are explained by traffic (Diesel engines),
buildings and re-suspension of road dust. The results make possible the evaluation of the input requirements of air quality models
and can also be used in air quality management in Bucharest.