NUKLEONIKA 2010, 55(4):543-547

 


SEASONAL AND DIURNAL VARIATION OF OUTDOOR RADON (222Rn) CONCENTRATIONS IN URBAN AND RURAL AREA WITH REFERENCE
TO METEOROLOGICAL CONDITIONS



Agnieszka Podstawczyńska1, Krzysztof Kozak2, Włodzimierz Pawlak1, Jadwiga Mazur2

1 Department of Meteorology and Climatology, University of Łódź,
88 Narutowicza Str., 90-139 Łódź, Poland

2 Laboratory of Radiometric Expertise,
The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences,
152 Radzikowskiego Str., 31-342 Kraków, Poland



The objective of the study was to investigate temporal variability of outdoor radon (222Rn) concentration registered in the center of Łódź (urban station), at Ciosny (rural station) and Kraków (suburban station) in relation to meteorological parameters (i.e. air temperature, temperature vertical gradient, wind speed, soil heat flux, volumetric water content in soil) with special consideration of urban-rural differences. Continuous measurements of 222Rn concentration (at 60 min intervals) were performed at a height of 2 m above the ground using AlphaGUARD® PQ2000PRO (ionization chamber) from January 2008 to May 2009. 222Rn levels were characterized by a diurnal cycle with an early morning maximum and a minimum in the afternoon. The well-marked 24 h pattern of radon concentration occurred in summer at anticyclonic weather with cloudless sky, light wind and large diurnal temperature ranges. The urban measurement site was characterized by the lowest atmospheric 222Rn concentration and an urban-rural differences of radon levels increased from winter to summer and during the nighttime periods. The maximum contrasts of 222Rn levels between Łódź and Ciosny, reaching – 30 Bq m–3, were registered in June and July during the urban heat island (UHI) phenomenon (a positive thermal anomaly of a city if compared to rural area) and strong thermal inversion near the ground in the rural area.


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