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Radon Program Overview of Radon in Delaware

by Margaret Henderson

In “Overview of Radon in Delaware,” the Division of Public Health Radon Program reports findings from a review of radon testing in homes in order to identify where elevated levels of radon might be anticipated. Elevated levels were considered to be in excess of 4 pCi/L, the USEPA recommended action level.

The information is intended for use by residents of Delaware, to illustrate the potentials for excess radon exposure. The Division recommends testing all homes, regardless of the potential estimates. The reporting does explain to the public about other factors that can influence radon concentrations in homes:
• Geology (uranium)
• Depth of radon to surface of land
• Movement characteristics of radon in the soil and into the home
• Characteristics of the home structure and air movement within
• Sample result variations due to precipitation or barometric pressure changes during sample collection

The radon test results were organized by zip code, and have been collected from 1995. Testing was done in basements more predominantly but also on first floors. The study reviewed the distribution of radon throughout the state, but in particular, the majority of tests came from New Castle County (as of results collected through 2011).

The two areas within Delaware that have the highest potential for elevated radon concentrations are in New Castle County, and both are associated with specific geology that contributes to the presence of radon. Within New Castle County, 13% of the homes tested exceeded the 4 pCi/L limit on average. Within zip code areas in New Castle County, the averages ranged from less than 1% to 27% in prevalence. Two other counties, Kent and Sussex, were presented in the study. In Kent County, 10% of homes had elevated levels and in Sussex County, 2.4% had elevated levels. Tables of the findings by zip code are given in the publication. http://www.dhss.delaware.gov/dph/hsp/files/hhinsideradonzip.pdf

For more information, contact:
Radon Program Telephone: 302-744-4546