Observations of new particle formation events in the south-eastern Baltic Sea

New particle formation and growth were observed at a coastal site (Preila station, Lithuania) during 1997 and 2000-2002. The total amount of data analysed covers 291 one-day periods, 45 (15%) of which were long-term, new particle formation days. Short-term nucleation events (from a few minutes to one hour) and long-term events (from one to eight hours) were identified. The mean particle growth rate, condensation sink and condensable vapour source rate during nucleation events were 3.9 nm h(-1), 1.45 x 10(-3) cm(-3) S-1 and 7.5 x 10(4) cm(-3) s(-1) respectively. The average formation rate J(10) was 0.4 cm(-3) s(-1). The nucleation events were accompanied mainly by air masses transported from the north (43%) and north-west (1.9%). Meteorological parameters and trace gas (O-3, SO2, NO2) concentrations were also analysed. It was found that nucleation events are related to high levels of solar radiation.