Asian Journal of Research and Reviews in Physics

Atmospheric concentrations of ⁷Be and ²¹²Pb were measured for 11 years (2008 – 2018) in Dar es Salaam, Tanzania. The mean activity concentrations of ⁷Be and ²¹²Pb were found to be within the range of 1.29 – 5.71 mBq/m³ and 10.85 – 50.06 mBq/m³, respectively. The annual mean activity concentrations of ⁷Be and ²¹²Pb were 4.72 ± 1.18 mBq/m³ and 29.76 ± 13.63 mBq/m³, respectively. Distinct annual trends were depicted on ⁷Be and ²¹²Pb, suggesting that the two radionuclides were affected differently with atmospheric conditions. Monthly atmospheric concentrations of ⁷Be showed a strong seasonal variation trend with the highest in January and February and lowest in April. ²¹²Pb depicted the highest concentration during June and July and lowest in January and December. The regression analysis for ⁷Be and ²¹²Pb activity concentrations together with number of meteorological parameters revealed that the relative humidity, rainfall, air temperature, absolute humidity and wind speed are the most significant parameters affecting radionuclides activity concentrations in the atmosphere. The sunspot numbers show 66.7% of its variability with ⁷Be activity concentration which further suggesting that other parameters may influence its variation. ²¹²Pb, on the other hand, shows only 27.3% of its variability which clearly indicates that the existence of cosmic rays does not affect its activity concentration in the atmosphere.