What is Radon?

H&H Real Estate Consulting

Radon is a naturally occurring radioactive gas, which has always been a part of our environment. It’s a natural decay product of uranium and is found in soil everywhere in varying concentrations.

Radon gas can accumulate in enclosed places, such as a house, but its presence, even in high concentrations, cannot be detected by human senses because the gas is invisible and has no odor.

Long term or chronic exposure to radon has been linked to lung cancer.

The greater the concentration and the longer a person is exposed, the greater the risk, so all people are encouraged to reduce their exposure.

However, because of its physical characteristics, the only way to detect the presence of radon gas and measure the level is by a test.

So people wanting to limit their exposure must first conduct a test to determine what their exposure levels are.

Lung cancer is the only known health effect linked to radon exposure at this time. The EPA estimates that between 15,000 and 22,000 of the 125,000 annual deaths from lung cancer may be attributable to radon exposure.

Based on EPA’s national residential radon survey completed in 1991*, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in air in the United States, while the average outdoor level in the United States is about 0.4 pCi/L.

The EPA Action Level is 4.0 pCi/L and above. There are thousands of individual homes across the U.S. with elevated radon levels in Zone 2 and 3. One state is of particular concern – Florida.

According to the EPA Map of Radon Zones for Florida, the state does not contain any counties in Zone 1 containing the highest levels of radon. However, the map shows 58 counties in Zone 3 and nine counties in Zone 2.

Zone 1 – Highest Potential: counties have a predicted average indoor radon screening level greater than 4 pCi/L (picocuries per liter) (red zones)

Zone 2 – Moderate Potential: counties have a predicted average indoor radon screening level between 2 and 4 pCi/L (orange zones)

Zone 3 – Low Potential:  counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones)
According to another source, the Florida Department of Health, Division of Environmental Health, identifies five (5) counties in Zone 1, with 1 in 5 Florida residences having elevated radon levels.

While Florida’s soils have naturally occurring radioactivity, these elevated levels can be attributed primarily to phosphate mining.

It is well documented that old phosphate mines in Florida generate elevated radon concentrations within several miles of the mines, especially on reclaimed land.

The mining process takes what is underground (soils and rock) and puts it at the surface. In doing so, some of the radioactive elements that were buried underground are exposed.

There are various methods to prevent radon entry into homes or reduce radon concentrations after entry.

These modifications are not required by law and contractors don’t usually include them in house design. The EPA has a Radon Contractor Proficiency (RCP) Program to certify contractors in these methods.

Most often house modifications are made when residents of an existing home have the house radon tested and find the radon level is too high for their comfort.

Testing for radon is easy and inexpensive.

Because of the conditions and the resulting elevated radon levels in Florida, the state has a mandatory radon testing program for specific public facilities, including public and private schools, state-licensed daycare centers, and 24-hour care facilities such as nursing homes and hospitals.

However, according to the EPA, all homes and public facilities should test for radon, regardless of geographic location or zone designation, therefore, single-family residential buildings with averages of 4.0 pCi/L should have radon

Mitigation system, which can cost $500 to $2500, depending on the modification needed. One example of a good mitigation system for slab-on-grade home construction is called sub-slab ventilation.

This system uses a pressure differential is used to draw air from under the house and vent it out before the radon gas can enter through cracks in the floor.

Radon gas can be easily reduced to outdoor levels by opening a window(s) to let the outside air mix in and the radon level reaches equilibrium with the atmosphere.

Doing this about every other day would solve the problem for most houses; however, this is considered as a temporary measure, until a mitigation system is installed.

Any air handling system that exchanges air with the outside environment would be helpful.