Radon Levels Inside Residences in Mexico City

Abstract

Levels of radon were measured during winter and spring seasons inside 55 colonial and modern houses and 30 multi-family apartment buildings representative of middle and upper income families. The modern houses and apartment buildings in the southern section of the city had average radon levels exceeding 150 Bq.m-3 with a maximum single measurement of 458 Bq.m-3. The colonial houses in the central downtown section had radon levels nearly all averaging below 100 Bq.m-3. Between the ground and third floor of the apartment buildings, radon levels diminished tenfold, indicating that entry of radon-bearing soil gas was largely responsible for the elevated concentrations of radon. The radon levels in winter exceeded by about 30% the radon levels during spring. The potentially adverse health effects of these radon levels may be exacerbated by the quality of air in Mexico City which is often highly polluted during winter.