en Radiation Biology Radiation Biology تحقيق بديع Original Research <p style="text-align: justify;"><strong>Background: </strong>The variation of the radon progeny concentration in outdoor environment and meteorological parameters at fine resolution were studied for one year at a continental location, National Atmospheric Research Laboratory, Gadanki, India.&nbsp; <strong>Materials and Methods: </strong>The concentrations were measured using Alpha Progeny Meter by collecting air samples at a height of 1 m above the Earth&rsquo;s surface at a known flow rate. <strong>Results:</strong> Radon progeny concentration shows temporal variations on diurnal and monthly scales, and is due to mixing in the atmosphere. Peak in the early morning hours and low values during afternoon compared to nighttime are due to differential heat contrast between earth&rsquo;s surface and its atmosphere. However, the activity during February shows maximum compared to June/July months.&nbsp; The diurnal variation of radon progeny shows positive correlation with the relative humidity and negative correlation with ambient temperature.&nbsp; The monthly mean activity of radon progeny for the year 2012 was found to be 4.76 &plusmn; 0.73 mWL. <strong>Conclusion:</strong> The mean concentration of radon progeny in the study region is relatively high compared to the other locations in India and may be due to the rocky terrains and trapping of air-masses near the observation site due to its topography. &nbsp;&nbsp;&nbsp;</p> <p></p> Radon progeny, NARL, alpha progeny meter, working level 105 111 http://ijrr.com/browse.php?a_code=A-10-1-605&slc_lang=en&sid=1 K. Charan Kumar 790031947532846008045 790031947532846008045 No Bangalore University T. Rajendra Prasad 790031947532846008046 790031947532846008046 No National Atmospheric Research Laboratory T. Narayana Rao 790031947532846008047 790031947532846008047 No National Atmospheric Research Laboratory M. Venkataratnam 790031947532846008048 790031947532846008048 No National Atmospheric Research Laboratory K. Nagaraja kamsalinagaraj@bub.ernet.in 790031947532846008049 790031947532846008049 Yes Bangalore University