| Abstract |
The main purpose of this study was to investigate the variability of the
atmospheric radon (222Rn) concentration. Radon is a radioactive element produced during the radioactive decay series of radium (226Ra) by ejecting an alpha- particle. In
the present work we investigate the reasons for the gradient change in the
concentration of radon and the mechanisms that control this change on Crete. For achieving this, targeted five year data (2002-2006) were used, from year 2002 to year 2006, from the monitoring station of Finokalia in the area of Lasithiou Crete. Using
these data, meteorological parameters (wind speed and direction, relatively humidity, temperature) and ozone, conclusions are drawn for the daily, annually and seasonally variability of radon.
The period 2002-2006 is characterized by daily average concentration of radon of 56,57 pCi/m3 ± 23,31 pCi/m3 and minimum maximum concentrations 9,805pCi/m3 ,
137,40 pCi/m3, respectively. The concentration of radon is related mainly with a) the
accumulation of radon, during days that wind speed is very low and the conditions of the atmospheric boundary layer are stable, b) the air mass movement and transfer of air masses rich in radon that have passed over land a few days before the observation.
c) the conditions that dominate in the atmospheric boundary layer, since days that are characterized by intense temperature inversion during the night favour the accumulation of radon.
In the present study radon was correlated not only with meteorological parameters and ozone but also with fine and coarse aerosols. The correlations were made by the
mean of the statistical programme SPSS and the analytical methods simple and multiple linear regression and principle components analysis.
The main conclusions drawn are summarized as follows: summer and fall are the seasons during which the transport of air masses affects most the concentration of radon. The wind speed modulates the concentration of radon because it affects its accumulation and long range transport. Synoptic scale meteorological phenomena can
impress the movement and the stability of the atmospheric boundary layer and
ultimately the concentration of radon. Radon was proved to be a good tracer for the evolution of the atmospheric boundary layer.
The correlation of radon with the fine and coarse fraction of aerosols indicate that the seasonality of radon is closer to the seasonality of the fine particles. Principle components analysis shows that radon can coexist with secondary particles, from anthropogenic activity (SO42-, C2O42-, NO3-, NH4+)whereas it doesn’t show any
correlation with the ions and elements from the earth’s crust.
|
Μελέτη της χρονικής διακύμανσης του ραδονίου 222 στο στρώμα ανάμιξης στη Φινοκαλιά
