ATMOSPHERIC RADON CONCENTRATION LEVELS

Systematic monitoring experiments of radon and gamma dose rate in air were conducted at the site of the Nuclear Center of Mexico. The data w ere obtained over a time period of 9 months during which a total solar eclipse took place on 11 July 1991. The outdoor radon concentration w as recorded with a continuous electronic radon monitor and with track detectors. The gamma dose rate was measured with an ionization chamber . The results show that the fluctuations of radon in air are influence d by meteorological seasonal changes. Long-term variations in atmosphe ric radon are correlated accordingly with those of the external temper ature, while short-term radon determinations show an inverse correlati on with temperature. The latter results are also discussed with respec t to drastic short-term seasonal atmospheric changes and to the mild c hanges resulting from the total solar eclipse. The observed gamma dose rate shows geographic and temporal stability.