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Indoor Radon Risk Levels in Oregon

by Margaret Henderson

The Oregon Public Health Division, Radon Awareness Program, recommends testing all Oregon residences regardless of the risk level assigned to the home's geographic location. In Oregon an estimated 276 radon-related deaths occur each year, according to the department.

To help residents understand the level of radon risk associated with living in various areas of the state, the department presents data and assigns risk scores. The data includes long-term radon tests (more than 90 days) and short-term radon tests (2-90 days) that have been conducted primarily by homeowners among a group of homes, even those next door to each other.

Information is available in a risk level map for radon using arcgis (geographic information systems presentation).

The relative risk of radon data is based on three factors:
1. Maximum radon result
2. Average radon result
3. Percent of locations within the zip code area that had results exceeding 4 pCi/L (if there were at least five locations reporting).

Risk points were assigned within each of these categories. Risk factors were added to determine the risk score. Results from schools or crawl spaces were excluded from the reporting. Risk scores then were categorized into risk levels of low, moderate and high.

As an example, the arcgis map presents the following:

Zip Code Summary
Zip Code 97114
City Dayton
Relative Risk Level *High*
Total Risk Score 9
GTE4 Risk Score 4
Average Radon Risk Score 3
Maximum Radon Risk Score 2
Maximum Result in Zip 9.6
Average Result in Zip 4.1
Count of Locations GTE4 4
Count of Locations 8
Percent of Locations GTE4 50.0

Summary data is also available at https://public.health.oregon.gov/HealthyEnvironments/HealthyNeighborhoods/RadonGas/Documents/final2015_summarytable.pdf

For more information about radon in Oregon, contact:
Telephone: 971-673-0440
Oregon Radon Awareness Program (ORAP)
800 NE Oregon Street, Suite 640
Portland, OR 97232