Whether you’re a homeowner or a builder, you’ve likely heard of radon and the need for radon testing and mitigation services. But what exactly is radon, and why is it something we need to be wary of?
What Is Radon?
Technically speaking, radon is a naturally occurring radioactive gas. On the periodic table, it’s identified by the atomic number 86, and it is considered a “noble gas,” meaning it is chemically inert – in other words, it doesn’t react with other elements to form compounds.
What makes it particularly tricky for humans is that it is colorless, odorless, tasteless, and invisible. You cannot smell it in your basement or see it in your crawlspace. And because it has no electrical charge and is a gas, it moves freely through the soil, and even through many building materials like concrete.
Where Does Radon Come From? How Does it Form?
Radon doesn’t just “appear.” It is a byproduct of the Uranium-238 decay series.
- Uranium in the soil and rock decays into Radium.
- Radium (a solid) stays trapped in the earth.
- Radium then decays into Radon (a gas).
Because radon is a gas, it can migrate out of the ground and into the air we breathe. This process is governed by a half-life, the time it takes for half of the radioactive atoms in a sample to decay.
Why & How Is Radon Dangerous?
Radon is considered dangerous because is the 2nd leading cause of lung cancer after smoking. And in non-smokings, it is the leading cause of lung cancer.
It isn’t actually the radon gas itself that does most of the damage – it’s what the gas turns into. Radon decays into radioactive solids known as Radon Decay Products (RDPs), specifically:
- Polonium-218 and Polonium-214
- Lead-214
- Bismuth-214
These RDPs are chemically active and “sticky.” When you inhale, they attach to your lung tissue and emit Alpha radiation.
While alpha particles have low penetration (they can’t even move through a piece of paper), they have high mass. When they are emitted inside your lungs, they act like tiny cannonballs, slamming into the DNA of your lung tissue. Roughly 97% of the radiation dose to your lungs comes from these decay products, while only 3% comes from the gas itself.
the facts behind radon health risks
To understand the risk, we have to understand how we measure it. Radioactivity is the spontaneous transformation of one atom into another, releasing energy. We measure this in:
- Picocuries per Liter (pCi/L): The standard unit in the U.S.
- Becquerels (Bq): 1 Bq equals one radioactive decay per second.
The EPA estimates that radon is responsible for roughly 21,000 lung cancer deaths per year in the U.S. It is a known human lung carcinogen.
The risk is significantly amplified by smoking. For example, at a level of 4.0 pCi/L (the EPA’s “action level”):
- Never-smokers: 7 in 1,000 risk of lung cancer.
- Ever-smokers: 62 in 1,000 risk of lung cancer.
How does Radon Enters my Building? how do I prevent it?
Radon is a “path of least resistance” traveler. Buildings usually have lower air pressure than the soil surrounding them (due to the “stack effect” where warm air rises). This creates a vacuum that pulls radon in through:
- Cracks in concrete slabs
- Utility penetrations (pipes and wires)
- Sump pumps and drain tiles
- Crawl spaces
Crucially, radon follows air movement, not floor plans. Just because your neighbor has low levels doesn’t mean you do.
The good news? Radon is a solvable problem. We use two primary strategies to make homes safe:
1. Active Soil Depressurization (ASD)
This is the “Gold Standard.” We use a specialized fan to create a vacuum beneath the building. This reverses the pressure relationship, pulling the radon toward a suction point and venting it safely above the roofline before it can ever enter the house.
- Effectiveness: Can reduce radon by up to 99%.
- Goal: Often brings levels below 2.0 pCi/L.
2. Ventilation
Less common as a primary fix, this involves diluting the indoor air with fresh air. It is usually a secondary strategy used when soil depressurization isn’t fully feasible.
Depending on your home’s construction, a pro might use:
- Sub-slab depressurization: For homes with concrete basements.
- Sub-membrane depressurization: Using a plastic barrier in crawl spaces.
- Drain tile depressurization: Hooking into existing water drainage systems.
What a Good Radon System Looks Like
If you are hiring a professional or building a new home, a high-quality mitigation system should be:
- Safe: It shouldn’t cause “backdrafting” of your furnace or water heater.
- Durable: Built with high-quality PVC and specialized fans.
- Monitorable: It should have a gauge (manometer) so you can verify it’s working at a glance.
- Quiet: A well-installed system shouldn’t sound like a jet engine in your backyard.
Radon Mitigation: Knowledge Is Power
Radon can’t be seen or smelled, but it can be fixed. Whether you are a homeowner looking to protect your family or a builder looking to provide a healthier product, understanding the science of radon is the first step toward a safer indoor environment.
Testing is the only way to know your risk. Start there, and remember: effective mitigation starts with understanding the problem, not fearing it.