Radon Gas and Cancer Risk: Separating Fact From Fiction

Imagine a tranquil afternoon, your feet resting upon a granite coffee table, savoring a potassium-rich banana after an hour-long revitalizing sun bath. It’s a blissful moment, isn’t it? However, it is important to be aware of a constant and silent environmental threat – radiation.

Radiation is a naturally occurring and omnipresent phenomenon. It is all around us and we encounter it daily. This background radiation comes from various sources at varying degrees, including cosmic radiation from the sun, a small amount of radioactive elements in our food, or the radioactive minerals in the ground, soil and groundwater. Even the banana mentioned earlier contains radiation.

A big contributor to background radiation is radon gas. It contributes more than half of the background radiation dose we are exposed to. Radon is a colorless, odorless gas that seeps into our homes from the ground. Unfortunately, it is an unavoidable presence in our lives.

The key takeaway here is that radon, while present everywhere, need not cause too much concern. Understanding how radon may cause diseases like lung cancer allows us to enjoy life’s simple pleasures, like savoring a banana on a tranquil afternoon, without any unnecessary panic.

We are exposed to naturally occurring carcinogens all the time, wherever we go. Yet, it doesn’t mean we will definitely get cancer. Radon gas that seeps from the ground and stays at your front lawn and school field disperses rapidly and dilutes to almost nothing.

It is trapped, concentrated indoor radon that is concerning. In man-made structures like workplaces, schools and homes, radon can accumulate significantly to a hazardous level. The risks from radon depend on two things:

1. Quantity: High radon levels are more dangerous, and
2. Duration: The longer you are exposed to radon gas, the greater the risk.

Indeed, recent studies suggest that prolonged, low-level exposure to radon may pose a greater risk compared to brief, high-level exposures. This is a phenomenon known as the "inverse exposure-area effect".

Our body has recovery systems like the immune system, DNA repair mechanisms and apoptosis (programmed cell death that eliminates cancer cells) that protect us against cancer when exposed to minute amounts of carcinogens in the environment.

However, prolonged exposure to high levels of carcinogens may overwhelm the recovery system such that it reaches the tipping point for cancer development. At this point, cancer cells can proliferate and, in a variable time frame, give rise to the disease.

Some may downplay the potential dangers of radon due to its misconceptions. While radon is biologically and chemically inert, it is important to understand why radon can still be dangerous. The primary issue lies in rapid radon decay. When inhaled, if radon undergoes radioactive decay, it emits energy in the form of alpha particles. This highly energized ionizing radiation is responsible for mutating DNA. Low dose irradiation does not cause much harm, but large amounts of radon lead to a higher dose of irradiation.

When radon starts to decay in the lungs, it goes through a rapid chain of transformation. The decay products (polonium-218, lead-214, bismuth-214 and polonium-214) have a very short half-life (hover function: the time it takes for half of a given amount of radon to transform into other non-radioactive elements). Alpha particles are released during the decay chain until they reach the next “stable” form, lead-210. Throughout the hour-long chain reaction, the emitted alpha particles hit the molecules in the lungs and disrupt their chemical bonds.

The alpha particles hit, mutate and damage the DNA in normal lung cells. Cancer may develop when the DNA is damaged and, due to the type or number of injuries, the repair systems are unable to properly do their job.

Who is at higher risk of developing lung cancer from radon exposure?

Although radon exposure is inevitable, it affects certain groups of people more than others. These individuals are more likely to get lung cancer from radon exposure:

• Smokers – Studies have shown that radon and cigarette smoking have a synergistic effect on lung cancer development. Very often, smokers get lung damage from carcinogens in tobacco. Exposure to radon makes it worse by further damaging the lungs with radioactive alpha particles. The combination of these factors dramatically elevates the risk of lung cancer in smokers exposed to radon. At the same time, radon seems to play a major role in lung cancer development in never smokers.
• Children - Children may be more vulnerable to the health impact of radon exposure. Their lungs are still developing, and any damage caused by radon exposure can have more severe and lasting effects. Similar to adults, children are at greater risk of lung cancer if they are exposed to radon and tobacco smoke at the same time. Many U.S. states are in discussion to mandate radon testing in schools and day-care centers.
• People with pre-existing lung conditions - People with chronic obstructive pulmonary disease (COPD) or asthma may be more susceptible to the harmful effects of radon exposure.
• Occupational exposure, especially miners - Miners, particularly those working in underground mines, are at an increased risk of radon exposure. The mining environments can have elevated levels of radon gas, which puts miners at a higher risk of developing lung cancer over time. Other occupations, for instance, construction workers, agricultural workers, and people working in confined spaces like basements or tunnels, may also face elevated radon levels. Occupational safety measures and proper ventilation are crucial to minimize this risk.

While radon gas is a common contributor to background radiation, it is important to understand that it is not something of immediate concern. Inhaling normal air every day carries minimal risk. The real concern arises when radon accumulates indoors, especially in certain situations mentioned above. Our bodies have defense mechanisms to handle small amounts of radon. It is when we have prolonged exposure to high levels that we need to be more cautious. With awareness and simple preventive measures, most of the potential risks can be managed effectively.

Read next: Understanding The EPA’s Radon Action Level: Is Your Home At Risk?