Keywords: , radiological protection standards, environmental radiation, outdoor radiation, gamma radiation, low radiation, Sao Paulo, Brazil, Sao Paulo, Brazil
Assessment of the environmental outdoor gamma radiation levels in Sao Paulo City
Dose values from natural radiation sources in several sites of Sao Paulo City were assessed from environmental outdoor gamma radiation levels, by using CaSO-
4:Dy thermoluminescent dosimeters. Twelve monitoring stations were placed in different regions of the town including both urban and outskirts areas and the measurements were carried out quarterly and seasonally. The average annual effective dose, calculated according to the ICRP-60 procedures, was 1.23 ± 0.19 mSv.y
-1. The result is of the same order of magnitude as the average annual background effective dose of 1.00 ± 0.18 mSv.y
-1obtained from a ten years follow-up of the IPEN - CNEN/SP Environmental Monitoring Programme. This environmental outdoor average annual effective dose is slightly higher than the UNSCEAR 2000 value of 0.9 mSv.y
-1, estimated as the world average contribution from terrestrial and cosmic gamma rays.