Aerosol particle formation in the Lithuanian hemi-boreal forest

Abstract

Aerosol particle observations are needed to determine the conditions of particle formation and growth in dif - ferent environments. This research focuses on new particle formation (NPF) events in the hemi-boreal forest envi - ronment at the Aukštaitija Integrated Monitoring Station (IMS) (55°26 ʹ N and 26°04 ʹ E, 170 m above the sea level). The parameterisation of aerosol particle Nucleation I (3–10 nm), Nucleation II (10–20 nm) and Aitken (20–100 nm) modes was performed, their inputs to the total particle number concentration (PNC) and distribution were assessed. It has been estimated that around 40% of days in spring and 22% in summer were NPF event days. The highest contribution of Nucleation mode I aerosol particles was observed in June, reaching up to 38% of the total PNC val - ues. The mean growth rate ( GR ) and condensation sink ( CS ) values at the Aukštaitija IMS in April and May were 2.9 nm·h –1 , 1.30·10 –3 s –1 and 5.3 nm·h –1 , 1.35·10 –3 s –1 , resp e c tively. The GR and CS values were well in agreement with the results obtained from other hemi-boreal forest sites in the Baltic Sea region.