Radon: Hazard or Hype?

From my experience as a home inspector, radon is an often confused subject among many real estate agents and home buyers and sellers. I hear many agents tell their clients 'not to worry about radon' or that 'radon is not real'. Well, radon is indeed a real thing; its number 86 on the periodic table of elements. Am I bringing back memories of high school chemistry class?

According to the US Environmental Protection Agency (EPA), radon exposure is the second leading cause of lung cancer, after smoking. Approximately 22,000 Americans die from radon-related lung cancer annually, according to the EPA. The use of tobacco substantially multiplies the risk of radon-related lung cancer (by a factor of approximately 15 times).

What is radon?

Radon is a radioactive gas born from the normal breakdown of uranium and other elements in the ground. Radon has no smell, no taste, and you can’t tell its concentration in your home without a radon test. As a normal part of nature, some substances within the Earth rise to the surface and radon gas is one of them. Some amount of radon is present in the vast majority of homes, and, according to the EPA, south central PA has the highest average concentration of radon. This conclusion is based upon many years of actual radon test data collected from professional radon tests performed across the USA.

How does radon get into my home?

The EPA recommends that every home be tested for radon. Most radon emanates from the soil. Radon can enter the home in various ways, the most common is through cracks and voids in foundation walls and floors, and to a lesser degree via well water and building materials. We all know that warm air rises, so radon gas is also affected by indoor ventilation, such as the stack or 'chimney' effect. High radon levels have also been measured in schools and other buildings.

The stack effect relates to warm air rising within a structure and the need for replacement air to take its place from beneath. The stack effect can be driven by the type of heating in the home, direction and force of exterior winds, open vents and flues, and other combustion appliances. The space beneath a basement is most often the source of much of the replacement air. Since this space is in direct contact with the earth and radon most commonly emanates from the soil, this is the common transport mechanism.

Some real estate agents and home owners are erroneously under the belief that radon levels can’t be high in a city home or if the home is built on concrete slab or over a crawl space. I have personally measured high radon levels in city homes and in homes on concrete slabs or above crawl spaces. All homes should be tested for radon.

What on earth is a “picoCurie”?

Radon concentrations are most commonly measured in picoCuries (pronounced "peek-o-cure-ees") per Liter of air and abbreviated as pCi/L. A ‘Curie’ is a unit of radiation measurement named for Pierre and Marie Curie. Radiation is all around us; much of it naturally occurs from sources such as space and inside our bodies, but also comes from many other places, such as radon and medical sources (such as X-rays). There is much more radiation exposure from radon and X-rays than from nuclear power plants, cosmic rays, etc. Since breathing is the easiest way for a gas to enter the body, lung cancer is the primary result of radiation exposure from radon.

Any level of radon (and radiation) can be a health hazard, but the US EPA has compiled a considerable amount of data relating to radiation exposure and results on the body. The EPA has chosen 4.0 pCi/L as the Recommended Action Level for radon. If a radon test result is 4.0 pCi/L or higher, radon mitigation is recommended. Radon levels under 4.0 pCi/L can also be unsafe, but reduction methods in some cases may be more difficult under this level in some homes. Even if a radon test shows concentrations less than 4.0 pCI/L, simple things like remodeling a home, weather-stripping doors or windows, reglazing windows, replacing HVAC equipment, or nearby blasting can change or create new entry points of radon into the home or affect internal drafting. In cases where one of the above occurs, performing another radon test is recommended.

What is used to measure radon?

Radon concentrations can be tested using several different devices, including continuous radon (CR) monitors, e-Perms (Electret), activated charcoal (AC). These are the 3 most popular testing devices.

Since radon concentrations depend on air movement, to properly and reliably test for radon in a structure, the EPA has set specific standards or protocols for testing. Namely, closed house conditions must exist to help limit exterior effects. The EPA defines “Closed House Conditions” as all exterior doors and all windows in the home (not just basement windows) kept closed starting at least 12 hours prior to the start of a radon test. This does NOT mean close the windows and doors once the inspector arrives to places the radon test. Exterior doors can be opened and closed momentarily for normal entering and exiting the home, but must otherwise remain closed during the radon test. Central heating or A/C systems must be run normally beginning 24 hours prior to the test and for the test duration. This helps ensure real life occupancy conditions in the home. Whole-house fans and window or wall mounted A/C units (unless in circulating mode) must not be operated during the radon test since these exchange air with the exterior.

When the inspector arrives to drop off and retrieve the radon test, he will do his best to verify that closed house conditions have been met. Having the home occupant (in most cases, the seller) complete a radon test agreement is wise to make sure the seller was aware of the required conditions prior to the radon test, maintained these conditions through the test period, and didn’t interfere with or damage the test device. Should any violations be found, the radon test must be voided per PA DEP regulations since the results can not be relied upon for accuracy. The test results may not be released to the client since their integrity are in question.

The EPA and PA DEP also have specific requirements regarding where in the home radon testing can occur. This is related to things such as proximity to windows, vents, and outer walls as well as near sources of moisture like kitchens, bathrooms, and laundry rooms. The PA DEP (Dept. of Environmental Protection) requires that radon testing occur in the lowest possible living level. This normally is in the basement unless there is a dirt floor or the ceiling height does not allow for normal living conditions (such as an average adult can not stand up-right).

What if a radon test indicates a high radon level?

If a radon test shows a high levels, mitigation can be successful in lowering the home’s radon level in most circumstances. The most common method of remediation is a sub-slab depressurization system. To put it simple, one (or more) hole is drilled through the basement's concrete slab, a small amount of dirt is excavated under the slab, PVC pipe is installed with a radon fan, and this system vents to the exterior away from doors and windows. Radon fans can only be placed in an attic or exterior of the home. Radon fans can not be installed in the home’s living spaces or garage; they must be installed in an unoccupied attic or at the home's exterior. The Commonwealth of PA has specific requirements about how and where radon systems can be installed (called the "PA Radon Mitigation Standards"). The cost of a professionally installed radon mitigation system is most commonly in the $600~$1,200 range. Mitigation system designs may vary a little depending upon the home’s layout, the initial radon test result, type of system installed, etc.

Who performs a radon test and remediation?

The PA DEP requires that all individuals or firms performing radon testing or radon mitigation for a fee must be certified by the Commonwealth of PA. A home owner or builder can perform radon testing and mitigation in their own home, however a PA DEP licensed radon tester should be used for a home transaction to ensure a non-compromised test done to DEP standards. Any changes to an installed radon mitigation system should only be performed by a licensed radon mitigator, as well. Contractors (plumbers, electricians, etc.) who are not PA DEP certified for radon mitigation should never modify a radon mitigation system in any way. This is against the law in PA. Minor changes to mitigation pipes and fans may cause the system to not work properly or malfunction. The PA DEP updates the list of certified radon testers and mitigators each month. This info can be obtained from the PA DEP website or by calling the radon hotline.

Radon: Hazard or Hype?

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