Notes: Measurement of radon concentration in dwellings in four regions of Peru, Lima, Arequipa, Puno and Cuzco. Some initial radon measurements were carried out in Peru in the 1990s, but this never developed into a national program. In recent years, there has been a strong interest in radon measurement. More recently, the Ministry for Health identified indoor radon as an important public health risk and the need for more information to quantify the extent of the risk. Peru also has a national plan [Plan Esperanza] to reduce the incidence of cancer throughout the country and reducing the risks from indoor radon is seen as a part of this program. Peru is divided into 24 regions (and the independent province of Callao). Each region is further divided into provinces. Eight of these regions have some high uranium potential zones. There is also extensive phosphate mining in the north of the country - uranium/radium/radon.  