Factors determining the fluctuation of fluoride concentrations in PM10 aerosols in the urbanized coastal area of the Baltic Sea (Gdynia, Poland).

Fluoride concentrations were determined in PM10 samples collected in the urbanized coastal area of the Baltic Sea (Gdynia) in the period between 1 August 2008 and 8 January 2010. F(-) concentrations remained within the range of 0.4-36.6 ng · m(-3). The economic transformations which have taken place in Poland increasing ecological awareness have had an excellent effect on the levels of fluoride pollution in the air of the studied region. In our measurements, fluoride concentrations increased in wintertime, when air temperature dropped, at low wind speeds (<1 m · s(-1)) and with low dispersion of pollutants originating from local sources (traffic, industry, domestic heating). At times when wind speed grew to >10 m · s(-1), fluorides were related to marine aerosols or else brought from distant sources. Apart from wind speed and air temperature, other significant meteorological parameters which determined the variability of F(-) turned out to be air humidity and precipitation volume. Aerosols were washed out effectively, even with small precipitation (h = 4 mm), and if a dry period lasted for several days, their concentrations grew rapidly to over 30.0 ng · m(-3).