As we head in to National Lung Cancer Awareness Month, we are all aware of the role cigarettes and tobacco play in the cause of lung cancer. We also are aware that not ALL lung cancers are caused by smoking, and that 10% of men and 20% of women who are diagnosed in the U.S. with lung cancer are never-smokers.
So what other factors cause lung cancer in these patients? There are links between lung cancer and cooking oil fumes in homes without adequate ventilation in other parts of the world; links with air pollution both indoors and out; links with heavy metal exposures and concerns about diesel exhaust fumes. In the U.S. the second-most common cause of lung cancer behind tobacco exists as a silent presence inside a person’s own home.
Radon is a colorless, odorless gas. It is a naturally-occurring gas that forms as a breakdown product of the small quantities of uranium that exist in rock. As rocks break down over time, the gas is released upward. Radon gas in turn quickly breaks down into radioactive particles, which, when inhaled, can cause damage to the lung tissues leading to increased risk of lung cancer. In a ventilated outdoor area, radon is dispersed into the air into concentrations that are harmless. Radon can build up though in pockets in the earth, such as mines or contained caves, where there is little relative air movement. It can also build up in homes, where basements are a particular area of concentration.
Older homes as we are aware are drafty and not as well sealed as the newer more energy-efficient homes. In terms of radon, this is actually beneficial, as air does not stay contained inside an older home, but is ventilated through. In the more modern homes, however, things are sealed fairly tightly. As radon moves up from the bedrock, it can then collect in the lower areas in a home to levels that can become dangerous.
Radon from home environments initially came to attention in 1984. Stanley Watras was an engineer who worked at the Limerick nuclear power plant in Pennsylvania, andwho did not work directly with radioactive materials. On his way home from work one day, he set off the monitor at a radiation-detection section. He then continued to set off the monitor for 2 weeks as a search was conducted to find the source of the radioactive contamination. It turned out not to be related to a work-related exposure, but his home was found to have incredibly high radon levels. The basement of that home registered 4,400 picocuries of radon (over 1100 times what is thought to be “safe levels”). The relative risk of his (and his family’s) exposure was calculated to be equivalent to smoking 135 packs of cigarettes DAILY. Mr. Watras found a new career in radon mitigation, finding ways to reduce radon exposure.
Watras and his family outside of his home
According to the National Cancer Institute, radon may be responsible for 15,000 to 22,000 deaths from lung cancer each year in the United States.
So is radon everywhere? Are all homes equally at risk? The Environmental Protection Agency has published a map of the United States, measured by county, mapping different levels of radon, shown below.
Zone 1 represents the “highest-level” areas, with predicted average screening levels of at least 4 picocuries/liter. Zone 2 “moderate-potential” areas have an average predicted screening level of 2-4 picocuries/liter, and Zone 3 includes the “low potential” counties with <2 picocuries/liter predicted levels. Although different areas have different levels of risk, the EPA recommends that all homes be tested for radon.
The EPA recommends that if a home registers a level of 4 picocuries/liter or greater, that radon remediation be undertaken. The World Health Organization recommends radon remediation for levels greater than 2.7 picocuries/liter. The difficulty and lack of agreement lie in the fact that at this point it is not certain what the “safe” threshold is for radon exposure. As a comparison, standard outdoor air contains approximately 0.4 picocuries/liter of radon.
There are a number of different ways to test for radon, with test kits of varying cost and reliability. One thing to keep in mind is that radon levels may fluctuate in a home over time (less on windy days, lower in the summer when the windows are more open, etc). By convention some of the most reliable tests measure average radon levels over a long time, some over many months or even a year. I am not aware of any one ideal testing kit, but there is an entire industry now dedicated to this (despite the fact that most Americans still aren’t really aware of radon).
If elevated levels are found in homes, professional companies can install remediation systems. These generally involve a ventilation system for the low-lying areas in a home that would be collecting most of the radon gas in “still” air. The equipment is not terribly high-tech, although systems will vary in cost, with some incorporating ongoing monitoring of levels. Below are a couple of diagrams (courtesy of Google Images) to demonstrate the basic concept of the system.
In certain areas, radon testing is required at the time of sale of a home. As an example, when we purchased our home eight years ago, the mortgage company required radon testing be performed prior to allowing the sale of the house. This makes sense as in the Portland area, our home is located on what is informally termed “Radon Ridge”, due to the underlying rock formations. Our home tests (originally and then repeated) were negative. Some of our neighbors’ tests showed elevated levels. We had a radon reduction system installed in our home. Who needs any extra risk?
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Posted on November 2, 2009 at 10:50 am
Radon and Lung Cancer–Confident in My Ignorance
We think we know about radon and lung cancer, but do we?
Why was I so confident in my ignorance is the question I ask myself very often. In the months prior to my husband’s diagnosis of lung cancer, he mentioned to me that perhaps we should check our home for radon gas. Of course, I didn’t know anything about radon gas, but thought I did. I said that our home was relatively new—only twenty years old—and we had a tight basement. I was confident in my ignorance! Because radon cannot be detected through our senses, the only way to know if this silent killer is intruding into your home is to test. Recognizing what we can’t see, taste or smell is the problem.
In the year before his diagnosis, my husband Joe also said to me that he might have cancer. My husband had previously had two triple artery bypasses twenty years apart. Again, I said, you don’t have cancer; you have heart disease. I thought he was just worrying too much. I thought I knew but I didn’t. My husband Joe was a person to take preventive and safe measures. For 27 years he worked and exercised every day, kept a low fat, low cholesterol diet, and didn’t smoke. We had smoke detectors, carbon monoxide detectors, and fire extinguishers in our home; and we didn’t burn candles. Joe only lived six weeks after his diagnosis of lung cancer that had spread to his liver and bones. We had been living with a radon level of 17.6 picocuries per liter of air in our home for 18 years.
Knowing the word radon and that it is a gas does not constitute knowledge of the element and its danger. You’ve heard the saying “A little knowledge can be dangerous.” I would change that to “A little knowledge can be deadly.” We, the general public, don’t know the facts. We must replace our limited knowledge with a full base of all the facts on radon.
Dr. Bill Field, an American Academic Scholar and Professor in the Department of Occupational and Environmental Health and Department of Epidemiology within the College of Public Health at the University of Iowa, who has recently been appointed to the Advisory Board on Radiation and Worker Health by President Obama, stated that protracted radon progeny exposure is the seventh leading cause of cancer mortality in the United States and the leading environmental cause of cancer mortality. It is the leading cause of lung cancer deaths among non-smokers. Large and recent studies confirm that radon in homes increases lung cancer risks. Throughout our world up to 18% of the lung cancers can be attributed to indoor radon according to Professor Bill Angell, Chair of the Prevention and Mitigation Working Group of the World Health Organization’s International Radon Project. . Radioactive particles from radon gas are inhaled and attach to the air sacs in the lungs. These particles change the characteristic of the cells to cancer, and those mutated cells divide and multiply.
Radon is a radioactive gas that emanates from rocks and soils and tends to concentrate in enclosed spaces like houses. Soil gas infiltration is the most important source of residential radon and is present in every home (except ones on stilts) because of the way our homes are built and designed.
The analysis from recent studies in Europe, North America, and Asia indicates that lung cancer risk increases proportionally with increasing radon exposure according to the World Health Organization (WHO). There is no known threshold concentration below which radon is safe. On September 21, 2009 WHO, in view of the latest scientific data, released a reference level of 2.7 picocuries per liter of air (pCi/L) as a minimum level to minimize health hazards due to indoor radon exposure.
Radon is easy to measure. Every home needs to be tested for radon because each home has its own individual footprint on the earth. The homeowner cannot rely on the results of surrounding houses in the neighborhood. A short term (3-7 days) and/or long term (3-12 months) test kit can be used. Radon professionals can also perform the test with electronic devices. Test kits can be obtained from the radon hotline at (785) 532-6026 or email at Radon@ksu.edu or Web site: http://www.sosradon.org. Radon test kits can also be purchased at the local hardware stores.
It is easy to protect from radon gas. Addressing radon is important in new construction as well as existing buildings. Radon prevention strategies focus on sealing radon entry routes and using soil depressurization techniques to prevent the gas from entering the home. The cost is very reasonable. “How little it can cost to save a life!” is what I would say to someone who complained about the expense of a radon mitigation system installed by a licensed radon professional.
I write this in memory of my husband Joe –who was so very dear to me—my friend, my partner, my companion, my love. I ask you to test your home for radon during this month of November—National Lung Cancer Awareness Month. If your level is above 2.7, spend that little extra money to help save a life. That life may be someone you love.
October 22,2009
Gloria Linnertz
seascape@htc.net
Cancer Survivors Against Radon (CanSAR)