Concentration, Chemical Composition and Origin of PM1: Results from the First Long-term Measurement Campaign in Warsaw (Poland)

This paper presents a 120-day-long variability of chemical composition of submicron particulate matter (PM1) over Warsaw. The content of the following components was examined in the PM1 mass: primary (POM) and secondary (SOM) organic matter, secondary inorganic matter (SIM), elemental carbon (EC) as well as Na and Cl ions (primary inorganic matter). The 24-hour concentrations of PM1 were subject to seasonal fluctuations which are typical of urban areas in Poland; their values averaged 11 mu g m(-3) in summer and 17 mu g m(-3) in winter. Most of the PM1 components and gaseous pollutants (SO2, NO2 and NOx) revealed higher mean concentrations in winter than in summer. A statistical analysis of meteorological parameters and 24-h concentrations of PM1, PM10, SO2, NO2 and NOx confirmed a significant influence of air temperature and precipitation on the concentration patterns of these pollutants over Warsaw. The highest concentrations of PM1 occurred in winter for the following wind directions: S, SE, N and NE; in summer for NE, E and S. The analysis of back trajectories demonstrated that on days with the highest 24-h concentration of PM1 polluted air masses arrived from S and SE and affected the concentration of PM1 over Warsaw. The submicron particulate matter, in as much as 62%, comprises secondary matter (SOM and SIM). The primary sources of its precursors and-to a smaller extent - of the primary matter as well - are traffic and combustion of various fuels for the purpose of heat and power generation. Their average contribution to the development of PM1 was 15% and 51%, respectively, for the entire period of observations.