Radon in the Home Instructional Module

Note: This Instructional Module information comes from our Training Manual. The complete Training Manual can be ordered from our Program and comes with a video, transparency masters, module publications, and many other educational resources. 

Module Learning Objectives

  • Radon is known to cause lung cancer in humans over a long exposure time
  • Radon is present nearly everywhere in small concentrations and is the largest source of radiation exposure for the U.S. population
  • Radon cannot be detected without testing for it specifically because it is invisible, odorless, and chemically inert
  • Testing is simple, relatively inexpensive, and harmless to do
  • Radon is a manageable risk, and help is available to assist the homeowner

Support Publications 

Video (See "lAQ Video Sampler" included with the manual)

  • Radon: the Health Risk Indoors, American Lung Association, 1991, 10:00

Notes to the Program Leader:

This is a suggested presentation plan for a 60- to 75-minute overview on the topic of radon. It is intended for general audiences. Topics to be covered are: general information about radon, where it comes from, why it is a hazard, and how it gets into your house. An excellent supplement or introduction is the American Lung Association radon video, "Radon: the Health Risk Indoors (included with this manual)." Use the video in conjunction with this module as a lead-in for the presentation. The running time for the video is 10 minutes.

The format provides a series of overhead transparency masters and a script to accompany each visual. The script is in recitation form. Read the script before the presentation, as it provides a background for the presentation. Particularly helpful is a list of Radon Myths, on the last two pages of this module, taken from "A Citizen's Guide to Radon... (included in this module)." The myths are a series of misunderstandings relating to radon.

This module can also be used in a shortened version (about 30 minutes), in which case it is recommended that the following overheads be used: 1, 2, 4, 5, 7, 8, 9, 12, 13, and 20. As in the longer presentation, you may wish to hand out "A Citizen's Guide to Radon..." as a supplement. Another good supplement to a 30-minute presentation is "Home Buyer's and Seller's Guide to Radon (included in this module)," particularly if your audience is anticipating real estate transactions.


Script for Transparency #1

The Anatomy of a Natural Hazard

Radon originates in the soil from Uranium 238. On this overhead, the numbers within the larger circles (in parentheses) are the half-lives of the various radio nuclides. Uranium is radioactive and has a long decay chain in the soil through a series of heavy metals to the precursor of radon, Radium 226. Radium 226 decays into Radon 222. Suddenly what used to be a solid radioactive material now has become a radioactive gas.

Because radon is a gas, it can leak into your house with air that is in contact with the soil. This overhead shows what is actually occurring in the soil. Radon can move through air into the house where it further decays to a series of four additional radioactive elements. The graphic shows various options for how radon might enter your house, including through cracks in the foundation and basement, and also through well water.

Script for Transparency #2

What is radon? 

Radon is an odorless, tasteless gas. It occurs from the natural radioactive decay of uranium and radium in the soil. The radioactive decay products of radon are charged ions. The ions have a static charge that enables easy attachment to water vapor, dust, and smoke particles in the air. Radon is measured in units called picoCuries per liter (pCi/L) of air. Annual radon levels above 4 pCi/L are considered excessive and require remediation.

Script for Transparency #3

Sources

Radon comes from various sources. It can come from rock, with four likely sources being: granite, shale, phosphate, and pitchblende. Other rocks also have some percentage of uranium naturally occurring in them. Radon moves easily through permeable materials. It can come from well water, natural gas, and, in rare cases, some building materials (such as concrete) that have the potential to contain and emit radon.

Script for Transparency #4

Radon Locations

Elevated indoor concentrations of radon can be found in every state. Uranium is present in most of the soil in the world. However, some places are definitely "hot spots" for radon. Risk is more diverse in other locations. Testing is the only way to know for sure if you and your family are at risk. 

Note to the Program Leader: Show EPA National Map of Radon Zones here. More information about this map is available on EPA’s website at: http://www.epa.gov/radon/zonemap.html

Script for Transparency #5

Help is Available

Help is available, often locally, for mitigating radon. Good information resources include your State Department of Health or your State Radon Contact. The phone number for your State Radon Contact is listed on the back cover of EPA's publication, Building a New Home: Have You Considered Radon? (included in this module). You can also call the EPA’s toll-free Indoor Air Quality Information Clearinghouse at (800) 438-4318 to obtain a current listing of State Radon Contacts.

Script for Transparency #6

Drinking Water

EPA also has a national hotline if you suspect your drinking water is a source of radon. The toll-free number is (800) 426-4791. This national service will supply phone numbers and local addresses of state-certified water testing laboratories throughout the country. These labs can advise citizens about testing water and also about local conditions where radon in water may be a concern. However, you should always test the air in your home for radon before testing well water.

Script for Transparency #7

How Does Radon Enter Your Home?

Four conditions must be present to enable radon to enter your home. The first two conditions are geological: 1) there must be uranium in the soil as a source material, and 2) there must be permeable soil, which allows radon to move into your basement or crawlspace.

The other two conditions are determined by the house and its construction: 3) there must be pathways for radon to enter the basement, such as holes, cracks, plumbing penetrations, or sumps (found in every foundation), and 4) there must be lower air pressure in the basement or crawlspace than in the surrounding soil. 

All four conditions must be present to have a radon problem in your home. If you reduce any one of these conditions, less radon will enter your home. The last two conditions, determined by the house and its construction, are the key ones for mitigation.

Script for Transparency #8

This graphic depicts the relative contribution of radon to the total average radiation exposure in the U.S. population. As we can see, 55% of the total natural radiation exposure is due to radon. And the important thing to realize is that natural radon sources account for 82% of radon’s radioactive dose. 

This gives some idea of the magnitude of radon exposure compared to the total of all radioactive exposures. Also, radon has none of the beneficial properties that other radioactive sources (such as x-rays, etc.) might have.

Script for Transparencies #9 and #10

Smoking and Radon

Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these particles release small bursts of energy that can damage lung tissue and lead to lung cancer. Not everyone exposed to elevated levels of radon will develop lung cancer. And the amount of time between exposure and the onset of the disease may be many years.

Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, we know more about radon risks than risks from most other cancer-causing substances because estimates of radon risks are based on studies of cancer in humans (underground miners).

These two risk charts on overheads #9 and #10 are from EPA's Risk Assessment Summary contained in A Citizen's Guide to Radon... (included in this module). The first chart shows the risks if you smoke and the second shows the risks if you've never smoked. The main difference between the two charts is that you have more than a ten times greater risk of contracting lung cancer if you smoke than if you have never smoked, regardless of what level the radon is in your home. 

Smoking combined with radon is an especially serious health risk. Stopping smoking and lowering radon levels in your home will reduce your lung cancer risk. 

Your chances of getting lung cancer from radon depend mostly on: 1) how much radon is in your home, 2) the amount of time you spend in your home, and 3) whether you are a smoker or have ever smoked.

Script for Transparency #11

Seasonal Influences on Radon Concentrations

Typically, radon induction into homes is maximum during winter months. With the ground frozen, radon follows the path of easiest escape from the soil below the frost line to the foundation.

Also, home heating systems can create a negative pressure in the house which helps to induct radon. 

Script for Transparency #12

Home Construction

Your home’s foundation construction type is not very important in terms of whether or not you will have radon in your home. All conventional house construction types built on a slab with a crawlspace or basement have been found to have levels of radon exceeding 4 pCi/L.

Construction quality is not necessarily an insurance against radon either. Both energy efficient and poorly-weatherized homes have been found to have levels of radon exceeding 4 pCi/L.

Script for Transparency #13

Radon Monitoring and Testing

There is an option for "Do-It-Yourself" monitoring. Short-term testing is often done with an Activated Carbon Detector. This method is designed for initial short-term tests of two to seven days. Detectors cost around $15 per test kit. These types of tests require careful control of closed-house conditions. For real estate transactions, tests are performed twice with the average result used for reporting purposes.

Script for Transparency #14

More Monitoring and Testing

Long-term testing usually involves the use of an Alpha Track Detector. Generally, it takes at least a month to measure a reliable average radon concentration using this method. To get more accurate results, the detector should be left in place for 90 days and can even be left in place for up to one year.

These long-term tests are usually considered more valid because there is a wider window of exposure to the average radon levels in the house over a longer period of time. Detectors cost about $25 per test kit, which includes postage and test results. 

For professional radon monitoring, you can check in your yellow pages for EPA listed contractors or call your State Department of Health for a list.

Script for Transparency #15

Radon Detector Placement

Follow the instructions included with your kit. You should place the detector at least 20 inches above the floor and in a location where it won't be disturbed. For short-term testing, keep windows and doors closed as much as possible and test during winter months.

You should place the detector in the lowest, lived-in level of the home. Some states have different recommendations, however, so you may want to check with your local radon office to see what they recommend.

If you place the detector in a basement, don't place it next to floor drains, floor/wall cracks, or near a sump. Also, you should place the detector out of a draft. Keep detectors away from ceiling fans, air registers, vents, and exterior walls. And keep detectors away from high heat and moisture areas such as the bathroom, kitchen, laundry room, and utility room (where the water heater is typically located).

Script for Transparency #16

Mitigation Strategies in Existing Homes

Mitigation strategies are based on modifying the four factors discussed earlier. Each strategy is based on preventing radon from entering the home.

You should try to seal entry points and reduce the pressure-driving forces moving radon into the home. For homes with basements, the most successful mitigation method has been to install active soil depressurization systems (a later overhead shows how this works). For homes with crawlspaces, ventilate the crawlspace or install submembrane depressurization, which is similar to the system you would use in a basement. A membrane must be installed on the floor (earth) of a crawlspace, not on concrete.

Script for Transparency #17

Sealing Cracks and Openings

This overhead shows where typical cracks and openings are in a basement and indicates where you should seal them. You may also seal walls with waterproof paint, cement, or epoxy, and put water traps in floor drains to keep air from coming in through the floor drains when the traps are dry. Sealing cracks with a flexible, polyurethane membrane sealant is also an effective way to limit air leakage into the house.

Script for Transparency #18

Reduce Pressure-Driven Air Flow

There are several methods you can use to reduce pressure-driven air flow when attempting to control radon. Some of these include: sealing penetrations in the ceiling, weatherstripping the attic hatch, avoiding the use of recessed lights, providing an outside air supply to combustion appliances, ventilating with a balanced air-to-air heat exchanger, providing air-supply ports for exhaust-only ventilation, and ventilating the crawlspace. 

Script for Transparency #19

Negative Pressure Sources

The faster the air leaks out of the house, the more it inducts radon by increasing negative pressure in the bottom of the house. Different combustion appliances and exhaust devices produce negative pressure by exhausting air from the house.

Script for Transparency #20

Sub-Slab Suction

This overhead shows an active (because there is a fan) soil depressurization system known as a sub-slab depressurization system. In this system, air is pulled from below the concrete slab in the basement. This lowers the pressure beneath the floor and allows the soil gas (including possible radon) to move through the exhaust pipe rather than into the house.

Script for Transparency #21

Crawlspaces

Basic radon control ventilation for a crawlspace foundation is similar in intent and design to the sub-slab depressurization system for basements.

Script for Transparency #22

Radon and Real Estate

States have various requirements for disclosure of radon awareness in real estate transactions. You should contact your State Radon Office or the Real Estate Board for up-to-date information about this aspect of real estate transactions. You can also find more information in EPA’s Home Buyer’s and Seller’s Guide to Radon (included in this module). 

Clearly, radon can be a major concern in any real estate transaction. You will want to know this information to avoid any problems with a sale.

Script for Transparency #23

BEIR VI Report

These last three overheads are concerned with the results of the Biological Effects of Ionizing Radiation (BEIR) VI Report, which has the subtitle, "The Health Effects of Exposure to Indoor Radon."

This report was released by the National Academy of Sciences (NAS) in February 1998. It is the first time NAS has reviewed this information since its previous study in 1988. An Executive Summary of the entire report is available at the EPA website: http://www.epa.gov/iaq/radon

Script for Transparency #24

Key Points

There are several key points from the BEIR VI study. It confirms that radon is the second leading cause of lung cancer in the U.S. Radon causes 15,000-22,000 lung cancer deaths each year. The report also affirms that EPA’s radon policies of the past are grounded in strong science. 

The National Academy of Sciences found that even small exposures to radon can result in lung cancer, and that no evidence exists of a threshold below which radon levels are harmless. The report concludes that many smokers will get lung cancer due to their radon exposure, which exacerbates the effects of smoking. 

As a result of the BEIR VI study, EPA reconfirmed its commitment to protecting the public’s health and recommends a simple home radon test for residences. The EPA still recommends reducing high radon levels (above 4 pCi/L) in residences with EPA-endorsed techniques.

Script for Transparency #25

Further Information

Further information on the BEIR VI report and EPA radon actions are available on EPA’s website (which also provides access to other indoor air quality information) at http://www.epa.gov/iaq. The National Academy of Sciences’ home page at http://www.nas.edu has more information as well. Your local Extension Healthy Indoor Air for America’s Homes State Coordinator can also help with access to this information.

In addition, the National Academy Press has the BEIR VI report on-line in a searchable version at http://books.nap.edu/books/0309056454/html

Prepared by:
Richard D. Seifert
Professor/Housing and Energy Specialist
Alaska Cooperative Extension Service
University of Alaska - Fairbanks
October 1996, Revised October 1999

RADON MYTHS

 
MYTH: Scientists aren't sure radon really is a problem. FACT: Although some scientists dispute the precise number of deaths due to radon, all major health organizations (like the Centers for Disease Control, the American Lung Association, and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non-smokers.
MYTH: Radon testing is difficult, time-consuming, and expensive. FACT: Radon testing is inexpensive and easy -- it should take only a little of your time.
MYTH: Radon test kits are not reliable and are difficult to find. FACT: Reliable test kits are available through the mail, in hardware stores, and other retail outlets. Call your state radon office for a list of test kit companies that have met EPA requirements for reliability or are state certified.
MYTH: Homes with radon problems can't be fixed. FACT: There are simple solutions to radon problems in homes. Thousands of homeowners have already fixed radon problems in their homes. Radon levels can be readily lowered for about $500 to $2,500. Call your state radon office for a list of contractors that have met EPA requirements or are state certified.
MYTH: Radon only affects certain kinds of homes. FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements, and homes without basements.
MYTH: Radon is only a problem in certain parts of the country. FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.
MYTH: A neighbor's test result is a good indication of whether your home has a problem. FACT: It's not. Radon levels vary from home to home. The only way to know if your home has a radon problem is to test it.
MYTH: Everyone should test their water for radon. FACT: While radon gets into some homes through the water, you should first test the air in your home for radon. If you find high levels and your water comes from a well, contact a lab certified to measure radiation in water to have your water tested.
MYTH: It's difficult to sell homes where radon problems have been discovered. FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is sometimes a good selling point.
MYTH: I've lived in my home for so long, it doesn't make sense to take action now. FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.
MYTH: Short-term tests can't be used for making a decision about whether to fix your home. FACT: A short-term test followed by a second short-term test may be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk. Radon levels can be reduced in most homes to 2 pCi/L or below.
 
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