Formation of bioaerosol is an important process of mass and energy exchange between sea and atmosphere by means of droplets of marine dust. Studies on aerosol activity of the sea was developed in the last decades of the 20 th century. Those studies revealed that concentrations of bacteria in aerosol droplets were hundreds times higher than their concentrations in superficial parts of seawater. The research also proved that aerosol activity of the sea can influence the sanitary condition of the air, especially at the seacoast areas. Surveys of air structure in coastal regions were performed on the Tricity beaches as well as in Sobieszewo and Komary. Atmospheric air sampling stations in the marine zone were located on the Gulf of Gdansk at the Vistula river mouth. Air samples were collected from the front platform on the ship R/V Baltica at 4m above the sea surface. The air samples were collected by filtration method using Sartorius apparatus. Airborne microbes were deposited onto sterile gelatine Sartorius filters. All filters were exposed directly towards the oncoming wind. After sampling, the exposed filters were placed onto the agar media on Petri plates and incubated. All measurement results were depicted in (CFU/m3) i.e. colony forming units in 1 m3 of the examined air. Meteorological measurements included: temperature, humidity wind speed and direction. The obtained results revealed that statistically significant trends were observed between the total number of bacteria or moulds and a season of sampling. The greatest number of microorganisms was noted in spring and autumn. Correlation analysis showed that statistically significant relationship exists between microbial abundance and the wind direction or speed and location of sampling site. Large quantities of fungal spores was detected in the areas of Gdynia and Gdansk - Brzeêno when south-west winds were blowing from the land. The highest number of bacteria were observed at the sampling stations located closest to the Vistula river mouth (Sobieszewo and Komary).