RADON HOT SPOTS IN OREGON AND THE UNDERLYING GEOLOGY

Radon exposure in homes is a huge concern because it is the leading cause of lung cancer in non smokers. In order to determine which areas in Oregon are at risk, the maximum and average radon reading and the percent of reports with a reading greater than 4 pCi/L were recorded, and the radon potential was calculated for 265 ZIP codes. Statewide, 232 ZIP codes have long term data and 207 have short term data. Based on long term data there are three ZIP codes with a high radon potential: 97281 (Silverton), 97630 (Lakeview), and 97862 (Milton-Freewater). Additionally, 42 ZIP codes have moderate radon potential, 46 have low radon potential, and 141 are uncategorized. Based on short term data there are 10 ZIP codes with high radon potential: 97002 (Aurora), 97103 (Astoria), 97304 (West Salem), 97306 (Salem), 97338 (Dallas), 97831 (Silverton), 97392 (Turner), 97457 (Myrtle Creek), 97850 (La Grande), and 97862 (Milton-Freewater). Additionally, 27 ZIP codes have moderate radon potential, 38 have low radon potential, and 132 are uncategorized. There are 33 ZIP codes for which short and long term test data conclude the same level of radon potential. Some increased or decreased a level or two from long to short term test types. There are 11 ZIP codes that increase by a level, 9 ZIP codes that decrease by a level, and 1 that decreased from high to low. Some moderate and high radon potential readings in Oregon are caused by structural weaknesses in rocks that allow radon to travel to the surface, like faults. Others occur where there are unconsolidated sediments like Missoula Flood deposits or landslide deposits. The higher permeability of these deposits allows radon to be released into the air easily. Rocks like granites release radon into the air, so areas with granitic terranes and intrusions are at risk of higher radon exposures.