General Radon Information

Radon -Symbol (RN)
Radon is a colorless, odorless, tasteless gas created by the natural decay of Uranium and Radium. It can be found on the Periodic Table of Elements, and its atomic number is 86.

Uranium and Radium are naturally occurring elements found in all rock and soil to varying degrees. Uranium is the "grandfather" of the radioactive decay chain to which radon is a part of.

The decay chain sequence of Uranium is as follows: Uranium à Radium à Radon à Polonium à Lead à Bismuth à Polonium à Lead (stable).

 

Radon is an inert gas, which means it's chemically inactive. Since it is chemically inactive, radon can move easily through all gas permeable materials. This is why basements with no visible signs of cracks or penetrations still have radon problems. It's because the gas can permeate directly through concrete.

The most common way radon concentrations are expressed is in "picoCuries per liter" (pCi/L). A pCi/L is one-trillionth of a curie. A "curie" (named after the famous radiation scientist Madame Curie) is the amount of activity given off by the decay of one gram of Radium, which is the equivalent of 2.2 disintegrations per minute, in a liter volume.

Radon is classified as a "Class A" Carcinogen which means positive links have been made between radon exposure and lung cancer from physical models, animal studies and most importantly, human epidemiological studies. The U.S. Surgeon General has stated that radon exposure is the second leading cause of lung cancer in the U.S.

The 4.0 pCi/L action level for airborne radon was established by the EPA because it is technologically feasible to achieve. However, the EPA's position is that there is no "safe threshold" for exposure to ionizing radiation,

therefore, the lower your exposure, the better. See airborne radon risk charts. The EPA also states that you should consider lowering radon levels between 2 and 4 pCi/L. It should be noted that Active Soil Depressurization (ASD)systems installed by Connecticut Basement Systems, often yield post installation airborne radon results below 2.0 pCi/L. See airborne radon mitigation.

There are currently no defined standards for waterborne radon. However, EPA has proposed a maximum contaminant level (MCL) of 300 pCi/L for municipal supplies with an alternative maximum contaminant level (AMCL) of 4,000 pCi/L for municipalities who adopt a multimedia mitigation (MMM) program. Currently, the state of Connecticut suggests that if your waterborne radon concentrations exceed 5,000 pCi/L, you should consider reducing the radon concentrations to below 5,000 pCi/L. Currently, different states have different action levels or guidelines. See waterborne radon mitigation.

Generally speaking, airborne and waterborne radon concentrations are in a constant state of fluctuation. The biggest reason behind air fluctuation is due to the ever-changing weather patterns.

Varying weather conditions create varying pressure differentials, which create varying degrees of influx of radon gas up into the structure from the soil. The foremost condition recognized to create the greatest influx of airborne radon into a structure is known as the "stack effect."

This scenario typically occurs in the heating season when the house is generally closed up the majority of the time. As indoor air is heated to a comfortable temperature, it begins to rise or move vertically through the structure. As the heated air moves vertically through the interior envelope of the structure, the structure itself begins to create suction upon the ground on which it sits. The greater the suction, the greater the influx of radon. It is not uncommon for airborne radon concentrations to fluctuate 100% or more from the cooling season to the heating season.

Waterborne radon levels fluctuate for different reasons, the biggest of which is that as water migrates through fissures and intercises in the sub-surface layers of the earth's crust, it is exposed to a wide array of soil and bedrock compositions. The longer the time frame that a sub-surface volume of water spends in contact with a radium bearing source, the greater the radon concentration that will dissolve into that volume of water. Furthermore, a well that taps into an aquifer that is fed from many different sources will have different degrees of influent water quality feeding in - and mixing together, producing ever-changing contaminant concentrations. For more on water quality, See well water treatment.

 

Some Common Radon Questions & Misconceptions

#1 most often asked question: The house has been closed for a "long" time, isn't that why the radon levels are high?

No. The reason: First, because radon is a radioactive gas, it has a half-life. The known half-life of radon is 3.8 days. Every 3.8 days half of whatever level of radon you have dissipates or decays away. So the radon that is recorded on a test is radon that has entered the building very recently (within the last several days). The radon that entered the house two months ago is long gone because of the 3.8 day half-life.

Second, every structure has some form of a natural air exchange or ventilation rate. This means that interior air in the house "escapes" or "exfiltrates" out of the home with new air infiltrating into the home on a regular consistent basis.

Does the presence of exposed ledge or numerous rocks and boulders on the property the house sits on give an indication of a potential radon problem?

 
No. The Physical characteristics or appearance of an area is not necessarily a reliable indicator for assessing whether or not a structure will have a radon problem. There needs to be a radium bearing source on which a structure is built to have an airborne radon problem, and for water, the water needs to be exposed to radium bearing sources in the aquifer for radon to dissolve into it. A "rocky" or "ledgy" area is not always an automatic indicator of a problem when it comes to radon.

"A previous test showed no problem with airborne or waterborne radon. Should I bother re-testing?" Yes! Refer to previous explanation on fluctuation of radon levels.

"My builder or realtor says there's no radon in this section of town, county, state, etc." - should I bother to test?  Yes.  Radon is naturally occurring and is found everywhere in the world to some degree - Test!...it's the only way to know for sure.

"We have a new home...radon is only found in older homes - right?"  Wrong! Radon can be found in very old and very new homes.  Soil composition and time of year are the two biggest influential factors.  Age of the home most often has little to do with an airborne radon problem.

For clarification on other common radon myths and misconceptions, see "Home Buyers and Sellers Guide to Radon" at http://www.epa.gov.iaq/radon/pubs/index.html or call our office at 1-800-319-8867.

RADON RISK IF YOU SMOKE Radon If 1,000 people who smoked were exposed to this level over a lifetime… The risk of cancer from radon exposure compares to… WHAT TO DO: Stop Smoking and… 20 pCi/L 10 pCi/L 8 pCi/L 4 pCi/L 2 pCi/L 1.3 pCi/L 0.4 pCi/L About 135 people could get lung cancer About 71 people could get lung cancer About 57 people could get lung cancer About 29 people could get lung cancer About 15 people could get lung cancer About 9 people could get lung cancer About 3 people could get lung cancer <--100 times the risk of drowning <--100 times the risk of dying in a home fire <--100 times the risk of dying in an airplane crash <--2 times the risk of dying in a car crash (Average indoor radon level) (Average outdoor radon level) Fix your home Fix your home Fix your home Fix your home Consider fixing between 2 and 4 pCi/L (Reducing radon levels below 2 pCi/L is difficult) Note: If you are a former smoker, your risk may be lower. RADON RISK IF YOU HAVE NEVER SMOKED Radon Level If 1,000 people who never smoked were exposed to this level over a lifetime… The risk of cancer from radon exposure compares to… WHAT TO DO: 20 pCi/L 10 pCi/L 8 pCi/L 4 pCi/L 2 pCi/L 1.3 pCi/L 0.4 pCi/L About 8 people could get lung cancer About 4 people could get lung cancer About 3 people could get lung cancer About 2 people could get lung cancer About 1 person could get lung cancer Less than 1 person could get lung cancer Less than 1 person could get lung cancer <--The risk of being killed in a violent crime <--10 times the risk of dying in an airplane crash <--The risk of drowning <--The risk of dying in a homefire (Average indoor radon level) (Average outdoor radon level) Fix your home Fix your home Fix your home Fix your home Consider fixing between 2 and 4 pCi/L (Reducing radon levels below 2 pCi/L is difficult) Note: If you are a former smoker, your risk may be higher. Based on information contained in the National Academy of Sciences 1998 report, The Health Effects of Exposure to Indoor Radon, your radon risk may be somewhat higher than shown; especially if you have never smoked.  It’s never too late to reduce your risk of lung cancer.  Don’t wait to test and fix a radon problem.  If you are a smoker, stop smoking. ALL INFORMATION TAKEN FROM THE HOME BUYER’S AND SELLER’S GUIDE TO RADON.

 

We can help you better than anyone - PERIOD!

 

Call us to schedule a free evaluation at - 1-800-319-8867

 

Back to top