Radon survey related to construction materials and soils in Zacatecas, México using LR-115

Indoor radon gas (Rn222), present in the air inside buildings, is one of the most important sources of radiation exposure to the population. This gas originates in the U238 radioactive decay chain, which is contained in rock and solid soil particles. Radon accumulation in confined spaces, inside buildings, depends on several factors such as the type of soils, type of constructions, building materials, and ventilation. The aim of this work is to present indoor and outdoor radon concentrations for 202 dwellings and indoor concentrations for 148 public clinics; and the radon concentrations relate to the type of predominant soils, the construction years; and building materials used in the ceilings, walls and floors, for cities and towns of the 57 municipalities in the State of Zacatecas, Mexico. The Rn222 concentrations were measured with a passive-type radon monitor, with LR-115 as detector material; and the radon survey was made during four stages of three months each throughout Zacatecas from 2001 to 2002. The indoor and outdoor radon concentration averages in dwellings were 55.6±4.9Bqm-3 and 46.5±5.3Bqm-3, respectively. The indoor radon concentration average in public clinics was 57.8±5.4Bqm-3. These values were lower than the US EPA action limit of 148Bqm-3.