Bioaerosols on Tri-city (Gdańsk-Sopot-Gdynia) beaches.

Bioaerosol formation is an important process of mass and energy exchange between the sea and the atmosphere by means of droplets of marine dust. Studies of marine aerosol activity developed in the last decades of the 20th century. Those studies revealed that concentrations of bacteria in aerosol droplets were hundreds of times higher than were those measured in superficial marine waters. Moreover, it was determined that aerosol activity at sea can influence the sanitary condition of the air, especially in seaside areas. Examinations of air composition in coastal regions were performed on the beaches of the Tri-city, Sobieszewo, and Komary. Airborne microorganisms were also investigated in the marine zone at the Vistula river mouth. The air samples were collected by a filtration method using Sartorius apparatus. The exposed filters were then placed onto agar media in Petri dishes and incubated. All measurements are expressed in CFU/m3, i.e. colony forming units per cubic metre of examined air. Meteorological parameters such as temperature, humidity, and wind speed and direction were also measured. The obtained results revealed statistically significant trends between the total number of bacteria and fungal spores, and the sampling season. The greatest number of microorganisms was noted in spring and autumn. Correlation analysis showed that a statistically significant relationship exists between the microbial abundance and the wind direction, wind speed, and the sampling site location. The maximum number of fungal spores was detected in the areas of Gdynia and Gdansk Brzeźno when south-west winds were blowing from the land. The highest number of bacteria was observed at the sampling stations located closest to the Vistula river mouth (Sobieszewo and Komary).