Radon risk high in 7 areas of city

Natural radiation, easily remedied, exceeds safety levels in some ZIP codes

By Ben Jacklet

The Portland Tribune, Dec 16, 2003, Updated Oct 30, 2009

A study by researchers at Portland State University and the state health department has found the risk of radon to be high in areas clustered in seven Portland ZIP codes.

Radon is an odorless form of natural radiation that seeps out of the soil and into basements, spreading through buildings and affecting indoor air quality. The Environmental Protection Agency considers it the second-leading cause of lung cancer, behind smoking.

The latest radon figures from Portland update a study that was first released in 1994. They break down radon test results from 3,189 homes into 43 local ZIP codes, then grade each ZIP code by radon risk.

Neighborhoods in seven ZIP codes were found to have high radon potential, while 21 were graded moderate and 15 low.

Six of the seven ZIP code areas with high radon potential are in North and Northeast Portland, along the Alameda Ridge and north to the Columbia River. The seventh is in Southeast Portland.

Scott Burns, a PSU geology professor, explained that the Alameda Ridge has high radon potential because it contains highly permeable granite gravel that was washed into the area during the Missoula Floods.

The floods occurred about 15,000 years ago, when an ice dam in Montana gave way and sent a torrent of water down the Columbia, along with sediments that remain in the soil to this day.

Those soils are believed to be the source of high radon findings at places such as Whitaker Middle School at Northeast 39th Avenue and Killingsworth Street, which since has been closed because of poor air quality.

All homes along the Alameda Ridge should be monitored closely for radon, Burns said, especially older homes where people spend a lot of time in the basement.

“Radiation at any level in your life is a problem,” Burns said.

The good news is, radon levels usually can be decreased easily and relatively cheaply. Burns and other radon experts recommend airing out the radon-afflicted home frequently, either by opening the windows or installing a ventilation system.

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