Outdoor Concentrations of the Equilibrium-Equivalent Decay Products of 222Rn in the Netherlands and the Effect of Meteorological Variables

Abstract

Airborne radioactivity monitors put up in a network as a warning system in case of nuclear accidents were used to gain insight in the temporal variations of 222Rn and its decay products. Average equilibrium equivalent decay product concentrations (EEDCs) over a period of five years for stations a,cross the country range from I to 3 Bq.m ". Hourly averaged concentrations show a diurnal variation at all stations. The amplitude of this variation is maximal in summer and minimal or nonexistent in winter. Superimposed is a seasonal variation with a maximum in late autumn and a minimum in spring, Wind velocity appears to be the major variable controlling the variation in EEDC in the outdoor environment of the Netherlands, Humidity seems to be correlated with the EEDC of 222Rn, probably because, due to plateout, a better equilibrium between 222Rn and its decay products is installed, Reduced EEDC during and shortly after rainfall seems to indicate a dilution of 222Rn in ground surface air due to enhanced vertical mixing below the rain cloud.

Variation of radon (Rn) progeny concentrations in outdoor air as a function of time, temperature and relative humidity

“…Their experience contradicts our results, but the buildings in their case were air conditioned which may have significant effect not only on air temperature, but also on relative humidity and concentration of aerosol particles. Blaauboer and Smetsers (1997) found positive correlation between EEC Rn and absolute humidity (measured in g m −3 units) outdoors and found that EEC Rn can be approximated by the function EEC Rn = Constant + 0.007 × (humidity) 2 .…”

Long-term variations of radionuclides in the Bratislava air

“…There are also other possible sources of 210 Pb like traffic or industrial activities. Simultaneous study of 222 Rn and 210 Pb thus enables to evaluate possible sources of lead from other than natural sources (Fujinami and Esaka, 1987;G€ aggeler et al, 1995;H} otzl and Winkler, 1996;Blaauboer and Smetsers, 1997;Baskaran and Shaw, 2001).…”

Radon daughters’ concentration in air and exposure of joggers at the university campus of Bangalore, India

“…This may be due to the reason that the aerosol particles which carry with them the radon daughters have been known to be hygroscopic in nature. Also, humidity avoids the back radiations from the soil and opposes the formation of inversion layer near the ground [11].…”