What is Radon?

Radon is a radioactive, colorless, odorless, and tasteless gas. It is formed when natural deposits of uranium throughout the earth's crust decay. The inhalation of the radon decay products is where the problem begins.  These products decay again releasing alpha particles. The particles hit the cells in the lungs and alters them. The damaged cells replicate and this it where lung cancer begins.

Radon is produced by the radioactive decay of the element radium. Radioactive decay is a natural, spontaneous process in which an atom of one element decays or breaks down to form another element by losing atomic particles (protons, neutrons, or electrons). When solid radium decays to form radon gas, it loses two protons and two neutrons. These two protons and two neutrons are called an alpha particle, which is a type of radiation. The elements that produce radiation are called radioactive. Radon itself is radioactive because it also decays, losing an alpha particle and forming the element polonium.

Elements that are naturally radioactive include uranium, thorium, carbon, and potassium, as well as radon and radium. Uranium is the first element in a long series of decay that produces radium and radon. Uranium is referred to as the parent element, and radium and radon are called daughters. Radium and radon also form daughter elements as they decay.
The decay of each radioactive element occurs at a very specific rate. How fast an element decays is measured in terms of the element "half-life", or the amount of time for one half of a given amount of the element to decay. Uranium has a half-life of 4.4 billion years, so a 4.4-billion-year-old rock has only half of the uranium with which it started. The half-life of radon is only 3.8 days. If a jar were filled with radon, in 3.8 days only half of the radon would be left. But the newly made daughter products of radon would also be in the jar, including polonium, bismuth, and lead. Polonium is also radioactive - it is this element, which is produced by radon in the air and in people's lungs that can hurt lung tissue and cause lung cancer.

Radon levels in outdoor air, indoor air, soil air, and ground water can be very different. Radioactivity is commonly measured in Pico curies (pCi). This unit of measure is named for the French physicist Marie Curie, who was a pioneer in the research on radioactive elements and their decay. One pCi is equal to the decay of about two radioactive atoms per minute.

Because the level of radioactivity is directly related to the number and type of radioactive atoms present, radon and all other radioactive atoms are measured in Pico curies. For instance, a house having 4 Pico curies of radon per liter of air (4 pCi/L) has about 8 or 9 atoms of radon decaying every minute in every liter of air inside the house. A 1,000-square-foot house with 4 pCi/L of radon has nearly 2 million radon atoms decaying in it every minute.

Radon levels in outdoor air, indoor air, soil air, and ground water can be very different. Outdoor air ranges from less than 0.1 pCi/L to about 30 pCi/L, but it probably averages about 0.2 pCi/L. Radon in indoor air ranges from less that 1 pCi/l to about 3,000 pCi/L, but it probably averages between 1 and 2 pCi/L. Radon in soil air (the air that occupies the pores in soil) ranges from 20 or 30 pCi/L to more than 100,000 pCi/L; most soils in the United States contain between 200 and 2,000 pCi of radon per liter of soil air. The amount of radon dissolved in ground water ranges from about 100 to nearly 3 million pCi/L.

Why do radon levels vary so much between indoor air, outdoor air, soil air, and ground water? Why do some houses have high levels of indoor radon while nearby houses do not? The reasons lie primarily in the geology of radon - the factors that govern the occurrence of uranium, the formation of radon, and the movement of radon, soil gas, and ground water.


How Does Radon Get in My House?

As stated in previously, radon is a naturally occurring gas that is present in the soil below your home. The radon migrates through the soil under your floor and eventually finds its way into your home. Radon can enter your home through many paths such as cracks in the foundation, cracks in a concrete floor, utility penetrations, sumps, floor drains and the list continues. It only takes very few minute openings for the radon to enter your home. In theory, you could keep the radon out by building an air tight foundation and basement floor however, due to normal shifting of your home and cracks that develop in the concrete, it is an impossible task with today's technology.

Attributing to the migration of the gases are the pressures of the dwelling. Buildings create negative pressure differentials that can draw in the radon gases. A good example of this is the stack effect. When we heat our homes, the warm air rises from the basement up to the upper levels. Eventually some of this warm air escapes through places like windows, doors, attic access panels and etc. When any air escapes, a slight negative pressure develops because your home is trying to draw in new air to replace the old air. Since the upper levels of you home has air going out, the air will enter your home from much lower points, such as the basement. This causes your home to act like a vacuum cleaner, in a sense, sucking on the soil below your basement.

Ventilation of a building can effect the radon concentration too however, in Minnesota, contractors follow extensive energy codes set forth by the state. These codes produces houses that are extremely tight, meaning there is not a lot of transfer of outdoor air with indoor air. This gives the radon one less path to leave your home, in fact, it will cause the radon to accumulate in your home.

Why is Radon Bad?

The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today causing over 21,000 deaths per year. At 21,000 this makes it a bigger killer than drunk driving which accounts for approximately 17,000 deaths per year. You would not let your family ride in a car with a drunk driver, so why would you let them live in a home with high levels of radon?

If you smoke you are at an even higher risk for developing lung cancer. The cumulative effects of smoking and exposure to radon will greatly increase your risk.

Unlike may other types of cancer, lung cancer has a very low survival rate. Even with today's medical technologies, only 7% of the people diagnosed with lung cancer will survive.

Many scientific studies of radon exposure indicate that children may be more sensitive to radon. This may be due to their higher respiration rate and their rapidly dividing cells, which may be more vulnerable to radiation damage.