Variation of radon (222Rn) progeny concentrations in outdoor air as a function of time, temperature and relative humidity

A sensitive grab sampling technique was used to measure the equilibrium equivalent concentration of radon (222Rn) progeny, EECRn, outdoors at Bathinda, Punjab (India), over a period of 6 months. The method was based on the beta counting of aerosol samples collected on glass micro-fiber filters by drawing the air through the filters. Measurements, covering two of the three sessions of the day (morning, afternoon, evening), were performed two times per day at a fixed place at a height of 1.8 m above the ground surface. The total average value of EECRn was 5.62 Bq m-3, while the morning, afternoon and evening averages were 9.15, 2.85 and 5.33 Bq m-3, respectively. Negative correlation was observed for air temperature and EECRn, while positive correlation was found for relative humidity and EECRn, EECRn was higher in winter than in summer.