Radon is the second-leading cause of cancer.
You can't smell it, see it or taste it but it might be present in your home

Keep Yourself and your Family Safe

In 1984, the scientific world woke up to the existence of radon in homes. A construction engineer triggered radiation alarms while entering the Limerick nuclear power plant near Philadelphia. His home in Boyertown was tested and the radon concentration was a shocking 2,700 pCi/L.

The family, including small children, was immediately evacuated. Very high radon levels were also sound in nearby houses. This region, known as the Reading Prong, has low-grade uranium deposits and encompasses parts of Pennsylvania, New Jersey, and New York. Source: American Academy of Pediatrics - The radon record.

Radon up your nose!

About 600,000 workers were exposed to radioactive materials in 14 nuclear weapons plants since the beginning of the Manhattan Project. Their radiation exposure was within the official "safety limits." However, increased rates of leukemia, cancers, vision difficulties, chronic fatigue syndrome and other health problems have been observed. The identified 22 types of cancers include cancer of the lung, prostate, bladder, kidney, and Hodgkin's lymphoma. Some scientists believe that radiation damages the human immune system, leaving people vulnerable to a wide range of other diseases.

Until 1999, the U.S. government disputed reports that low-level ionizing radiation is harmful. DOE and DOD waged media campaigns against "fear mongers" and spent tens of millions of dollars on lawyers. Then, after decades of denials, the government finally conceded that the radiation exposure to workers at nuclear weapons plants caused a wide range of cancers. President Clinton apologized to the "heroes of the nuclear age." But by then, many have died. The US Congress agreed to pay out $150.000 to each of the sick survivors, but denied them unlimited healthcare. Although private companies ran many of these plants for profit, the U.S. taxpayers will pick up the tab. Source: The New York Times, January 29, 2000

Dog saves people from radon
Back in the late 80's, I had a client whose dog died prematurely. They took it to the vet and x-rays showed the dog died from lung cancer. They then tested their home and found radon concentrations of 150 pCi/l! The owners stated that their dog probably saved their lives.

Source: Jay Bauder, Bauder Basement Systems, Inc

Radon is a chemically inert, naturally occurring radioactive gas without odour, colour or taste. It is produced from radium in the decay chain of uranium, an element found in varying amounts in all rocks and soil all over the world. Radon gas escapes easily from the ground into the air and disintegrates through short-lived decay products called radon daughters or radon progeny.

Airborne Radon causes over 21,000 lung cancer deaths every year in the United States. Radon is a cancer-causing natural radioactive gas that you cannot see, smell or taste. Its presence in your home can pose a danger to your family's health. Radon is the leading cause of lung cancer among non-smokers. Radon is the second leading cause of lung cancer in America.

The short-lived progeny, which decay emitting heavily ionizing radiation called alpha particles, can be electrically charged and attach to aerosols, dust and other particles in the air we breathe. As a result, radon progeny may be deposited on the cells lining the airways where the alpha particles can damage the DNA and potentially cause lung cancer.

When radon gas itself is inhaled, most is exhaled before it decays. A small part of the inhaled radon and its progeny may be transferred from the lungs to the blood and finally to other organs.

Due to dilution in the air, outdoor radon levels are usually very low. Radon can also be found in drinking water, the concentration depending on the water source, and this can sometimes present a hazard. Radon levels are higher indoors, and much higher radon concentrations can be found in places such as mines, caves and water treatment facilities. Health effects have been found in, for example, miners. However, the lower concentrations - found, for example, in normal buildings and to which large populations are exposed – also confer health risks. For most people, by far the greatest exposure to radon comes in the home.

Radon in homes
The concentration of radon in a home depends on the amount of radon-producing uranium in the underlying rocks and soils, the routes available for its passage into the home and the rate of exchange between indoor and outdoor air. Radon gas enters houses through openings such as cracks at concrete floor-wall junctions, gaps in the floor, small pores in hollow-block walls, and through sumps and drains. Consequently, radon levels are usually higher in basements, cellars or other structural areas in contact with soil.

Exchange of indoor air with the outside depends on the construction of the house, ventilation habits of the inhabitants, and sealing of windows. The radon concentration in houses directly adjacent to each other can be very different. Radon concentrations within a home can vary with the time of the year, from day to day and from hour to hour. Because of these fluctuations, estimation of the annual mean concentration of radon in indoor air requires reliable measurements of mean radon concentrations for at least three months and preferably longer. Short term radon measurements give only limited information.

The amount of radon in a building is dependent upon several factors. These factors include the geology, a driving force, pathways into the building, and the ventilation rate. As the concentration of uranium is in the underlying soil increases, so does the strength of the radon. Radon is transported to buildings more easily through permeable soils. Buildings can create pressure differentials that will draw in the soil gases. Radon can enter the building through many paths such as cracks in the foundation, utility penetrations, sumps, and floor drains. The ventilation rate of the building affects the final radon concentration.

Radon radioactivity is measured in becquerels (Bq). One becquerel corresponds to the transformation (disintegration) of one atomic nucleus per second. Radon concentration in air is measured as the number of transformations per second in a cubic metre of air (Bq/m3). The average radon level outdoors varies between 5 and 15 Bq/m3, but both higher and lower values have been observed.

Based on a series of surveys, the global mean indoor radon concentration is estimated to be 39 Bq/m3, with marked variation between countries reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Very high radon concentrations (>1000 Bq/m3) have been found in countries where houses are built on soils with a high uranium content and/or high permeability of the ground. In specific geological formations found, for example, in many European countries, radon released from underground waters easily permeates through the rock to the surface and into buildings. Overall, many countries around the world may have tens of thousands of houses with indoor radon concentrations above levels considered acceptable

Radon and Real Estate

Health effects of Radon

The main health hazard from high radon exposure is an increased risk of lung cancer. This has been substantiated in many studies of uranium miners.

Based on these studies, the International Agency for Research on Cancer (IARC), a WHO agency specializing in cancer, and the US National Toxicology Programme have classified radon as a human carcinogen. Scientists have also been investigating whether levels of radon found in homes and other places are a significant hazard to health. These studies are now complete and pooled analyses of key studies in Europe, North America and China have confirmed that radon in homes contributes substantially to the occurrence of lung cancers world-wide. Recent estimates of the proportion of lung cancers attributable to radon range from 6 to 15%. The pooling studies all agree on the magnitude of the risk estimates.

The recent pooled analysis of key European studies estimated that the risk of lung cancer increases by 16% per 100 Bq/m3 increase in radon concentration. The dose-response relation seems to be linear without evidence of a threshold, meaning that the lung cancer risk increases proportionally with increasing radon exposure.

The slow progress to safety

From the results of the same study, when a non-smoker is exposed to radon concentrations of 0, 100 and 400 Bq/m3, the risk of lung cancer by age 75 years will be about 4, 5 and 7 in a 1000, respectively. However, for those who smoke, the risk of lung cancer is about 25 times greater, namely 100, 120 and 160 in a 1000, respectively. Most of the radon-induced lung cancer cases occur among smokers.

Radon - the Killer in Tobacco

Guidelines for concentrations of radon in air and water
Most countries have adopted a radon concentration of 200–400 Bq/m3 for indoor air as an Action or Reference Level above which mitigation measures should be taken to reduce the level in homes. Other countries have chosen higher or lower Action Levels. The choice of Action Levels generally has been based on the concept of acceptable risk, i.e. these levels are thought to represent population health risks similar to other everyday risks.

Concerning drinking water, the 2004 WHO Guidelines for Drinking Water Quality and the European Commission recommend that controls - for example repeat measurements - should be implemented if radon in public drinking-water supplies exceeds 100 Bq/l. The United States has proposed a Maximum Contaminant Level for radon of 150 Bq/l for private water supplies. For public or commercial water supplies, the European Commission recommends that remedial action be taken if the radon level exceeds 1000 Bq/l. A tap water radon concentration of 1000 Bq/l contributes 100 to 200 Bq/m3 to indoor air and thus corresponds to the indoor air radon Action Levels discussed above.

Dealing with radon in homes
Radon levels in indoor air can be lowered in a number of ways, from sealing cracks in floors and walls to increasing the ventilation rate of the building. The five principal ways of reducing the amount of radon accumulating in a house are:

•Improving the ventilation of the house and avoiding the transport of radon from the basement into living rooms;
• Increasing under-floor ventilation;
• Installing a radon sump system in the basement;
• Sealing floors and walls; and
• Installing a positive pressurization or positive supply ventilation system.
Radon safety should be considered when new houses are built, particularly in high radon areas. In Europe and the United States, the inclusion of protective measures in new buildings has become routine for some builders and - in some countries - has become a mandatory procedure. Passive systems of mitigation have been shown to be capable of reducing indoor radon levels by up to 50%. When radon ventilation fans are added (active system) radon levels can be reduced further.

Radon is easy to detect and relatively easy to control. Radon test kits for homeowners are easy to use and provide accurate readings of home radon levels.

Sources

WHO Media centre
Telephone: +41 22 791 2222
E-mail: mediainquiries@who.int

National Service Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 45242-0419
http://www.epa.gov/radon/rnxlines.html

Radon Maps

http://employees.csbsju.edu/

http://www.mclaughlincentre.ca/