Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

65Ai - Ai-1 [Bq.m -3 ]86420-2-4-6-8y = 0,58x + 0,00R = 0,38-6 -5 -4 -3 -2 -1 0 1 2 3 4ISi-1 - ISi-2Ai - Ai-1 [Bq.m -3 ]6420-2-4y = 0,55x - 0,08R = 0,99-6-6 -5 -4 -3 -2 -1 0 1 2 3 4ISi-1 - ISi-2Fig. 7 The dependence between the change of 222 Rn activity concentration in given interval and the changeof stability indexes in previous interval (August 1994). In the left picture all data are shown, in the pictureon the right arithmetical means of changes of radon activity concentration corresponding to the changesof stability indexes are depictedrelation between the change of atmospheric stabilityand the change of radon activity concentration.CONCLUSIONThis work deals with the potential use of radonas an indicator of atmospheric stability. There wasfound a rather good agreement between the coursesof radon activity concentration and stability indexescalculated on the basis of modified Turner classification.Moreover, it was found that the coursesof radon concentration lag behind the courses ofstability indexes. This lag is of the order of hours.Best agreement was found when the courses of stabilityindexes was shifted 4 hours forward in time.A possible cause of this is that while the reactionof stability indexes to a change of meteorologicalparameters is immediate (because they are definedby table values), it must obviously take some timeuntil an appropriate change in the atmosphere andin radon concentration occurs.It was also found out that, unlike the meandaily values of radon activity concentration, themean daily values of stability indexes do not varysignificantly during the month. This led us to theexamination of deviations from their mean dailyvalues. A very good agreement was found betweensuch courses.Further analysis showed that the dependencebetween radon activity concentration and stabilityindexes is not completely linear. A similar trendwas observed when the impact of stability indexeson the change of radon activity concentration wasexamined. However, a nearly linear dependencywas obtained when we examined the change ofradon activity concentration in the given intervalagainst the change of stability indexes in the previousinterval, which suggests that there is a closeconnection between these quantities.To sum up, radon gas seems to be a suitableindicator of vertical mixing processes in the atmosphere.However, drawing any final conclusionsshould be avoided until more extensive researchabout this matter has been conducted.AcknowledgmentsThe authors would like to express their thanksfor the financial support of the work to the Ministryof Education of the Slovak Republic (VEGA projectNo. 1/3046/06, ESF project JPD BA 3 2005/1-034)and Comenius University in Bratislava (Grant ofJuniors UK/369/2007).REFERENCES1. DUENAS, C., PÉREZ, M., FERNÁNDEZ, M. C.,CARRETERO, J.: Radon Concentrations in surfaceair and vertical atmospheric stability of the lower atmosphere.In: Journal of environmental radioactivity.1996, Vol. 31, No. 1, p. 87–102.2. FONTAN, J., DRUILHET, A., LOPEZ, A., BERNIS,M. J., CAUTENET, G.: Surveillance de la stabilitéverticale dans un site urbaine. In: Pollution Atmospherique.1971, No. 71, p. 231–249.3. HOSLER, C. R.: Urban–rural climatology of atmosphericradon concentration. In. Journal of GeophysicalResearch. 1968, Vol. 73, No. 4, p. 1156–1166.