Statistical characteristics of aerosol in Baltic Sea region

The article presents the results of the aerosol measurements carried out on the eastern coast of the Baltic Sea during 1986 - 1993. Aerosol size distributions in the diameter range of 0.01-10 mu m have been measured with the electric aerosol spectrometer (EAS). A short description of EAS is given. The majority of number distributions obtained by measurements were of monomodal shape. Modal diameter varied at 0.01 - 0.1 mu m. Seven percent of all number distributions were of bimodal shape with modes at 0.010 - 0.032 mu m and at 0.032 - 0.1 mu m, separated with a minimum at 0.018 - 0.056 mu m. The majority of aerosol mass distributions were of bimodal shape and consisted of an accumulation mode varying at 0.18 - 1.0 mu m and of a coarse particle mode at 1.8 - 10 mu m separated by a minimum varying at 0.56 - 3.2 mu m. Parameters of the Junge distribution and the 4-parameter KL distribution have been obtained. The variability of aerosol concentrations and the stability of aerosol at a fixed site have been studied analyzing the time sequences of aerosol number distributions. The variability of concentrations depended on particle size. The variability was about 0.7 at 0.1 - 0.3 mu m and rose toward both the smaller and larger diameters up to values 1.4 at 0.01 mu m and 1.7 at 10 mu m.