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January is Radon Action Month: What Air Filters Can Do

HVAC air filters cannot remove radon gas from your home. Radon is an invisible, odorless radioactive gas that enters homes through cracks in foundations. Because it is a gas (not a particle), standard MERV-rated filters, including HEPA filters, cannot capture it. However, air filters can trap radon decay products (also called radon progeny) once they attach to airborne particles, potentially reducing some health risks. The only proven method to reduce radon levels is professional radon mitigation, which typically involves a sub-slab depressurization system that vents the gas outside. January is National Radon Action Month, making it the perfect time to test your home.

TLDR:

  • Standard HVAC filters (MERV 8, 11, or 13) cannot remove radon gas, only the radioactive particles it creates after decay

  • Radon is the second leading cause of lung cancer and claims roughly 21,000 American lives annually

  • The only effective radon solution is professional mitigation

  • EPA recommends taking action if radon levels reach 4 pCi/L or higher

  • Testing your home with an EPA-approved kit is the first step to protecting your family

Every January, the U.S. Environmental Protection Agency (EPA) encourages homeowners to test their homes during National Radon Action Month. If you're wondering whether your HVAC air filter can help protect your family from this invisible threat, you're asking the right question. Here's what you need to know about radon, air filters, and keeping your indoor air healthy.

Who this is for: Homeowners concerned about indoor air quality, anyone buying or selling a home, property managers, and eco-conscious consumers looking to understand the limits and capabilities of air filtration.

Can Your Air Filter Remove Radon?

No, standard HVAC air filters cannot remove radon gas. Radon is an inert gas, and gas molecules pass directly through even the highest-rated MERV filters and HEPA filters. However, air filters can capture radon decay products (radioactive particles) once they attach to dust and other airborne matter, which may provide some supplementary protection alongside proper radon mitigation.

What is Radon and Why Should You Care?

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. It rises from the ground and can seep into homes through foundation cracks, gaps around pipes, sump pits, and construction joints. Once inside, radon can accumulate to dangerous levels, especially in basements and lower floors.

According to the EPA, radon is responsible for approximately 21,000 lung cancer deaths in the United States each year, making it the second leading cause of lung cancer after smoking and the leading cause among non-smokers. The Centers for Disease Control and Prevention (CDC) notes that people who smoke and are exposed to radon have a 10 times greater risk of developing lung cancer compared to non-smokers exposed to the same radon levels.

The National Cancer Institute estimates that about 1 in 15 U.S. homes has radon levels at or above the EPA's action level of 4 picocuries per liter (pCi/L). Since you cannot see, smell, or taste radon, testing is the only way to know if your home is affected.

Why Standard Air Filters Cannot Remove Radon Gas

To understand why your HVAC filter cannot capture radon, you need to know how air filters work and what radon actually is.

How Air Filters Function

HVAC air filters, whether rated MERV 8, MERV 11, or MERV 13, are designed to capture airborne particles. The EPA explains that MERV ratings (Minimum Efficiency Reporting Value) measure a filter's ability to trap particles between 0.3 and 10 microns in size. These particles include dust, pollen, pet dander, mold spores, and some bacteria.

Higher MERV ratings indicate better particle capture:

  • MERV 8: Captures particles 3 microns and larger (dust, lint, pollen)

  • MERV 11: Captures particles 1 micron and larger (mold spores, pet dander, fine dust)

  • MERV 13: Captures particles 0.3 microns and larger (bacteria, smoke particles, virus carriers)

Why Radon Escapes Filtration

Radon is a noble gas. Unlike particles that have mass and can be physically trapped in filter media, gas molecules are far too small to be physically trapped in filters. A radon atom is measured in angstroms (one-tenth of a nanometer), making it thousands of times smaller than even the smallest particle an air filter can capture.

This limitation applies to all mechanical filters, including HEPA filters, which are rated to capture 99.97% of particles 0.3 microns in size. HEPA filters excel at particle capture but are equally ineffective against gases.

What Air Filters CAN Do: Capturing Radon Decay Products

While air filters cannot capture radon gas itself, they may provide some secondary benefit by trapping radon decay products (also called radon progeny or radon daughters).

When radon decays, it transforms into solid radioactive particles, primarily polonium-218 and polonium-214. These decay products can attach to dust, smoke, and other airborne particles. Research published in the Journal of Environmental Radioactivity found that air purifiers can effectively reduce the concentration of attached radon decay products, though they cannot affect the radon gas concentration itself.

According to the American Association of Radon Scientists and Technologists (AARST), while filtration can reduce airborne radon progeny in the immediate area being filtered, this approach has significant limitations:

  • Radon gas continues to produce new decay products

  • Filtration may shift particle size distribution, potentially affecting lung deposition patterns

  • Consistent air circulation is required

  • AARST does not support air filtration as a primary radon mitigation method

The scientific consensus remains clear: air filtration should be considered only as a supplement, never a replacement, for proper radon mitigation.

The Only Proven Solution: Professional Radon Mitigation

If your home tests at 4 pCi/L or higher, the EPA recommends professional radon mitigation. The most common and effective method is sub-slab depressurization, which creates negative pressure beneath your home's foundation to draw radon gas out before it enters your living space.

How Radon Mitigation Works

A typical radon mitigation system includes:

  1. Suction pit: A small hole drilled through the basement floor or slab

  2. PVC vent pipe: Connects the suction pit to the exterior

  3. Radon fan: Creates continuous negative pressure to pull radon from the soil

  4. Exhaust point: Vents radon safely above the roofline, away from windows

The Minnesota Department of Health notes that properly installed systems can reduce radon levels by up to 99%. The Wisconsin Department of Health Services reports that average installation costs range from $1,000 to $2,000, comparable to other common home repairs.

Steps to Address Radon in Your Home

  1. Test your home using a short-term (2-7 day) or long-term (90+ day) radon test kit

  2. Review results and take action if levels reach 4 pCi/L or higher

  3. Hire a certified professional from the National Radon Proficiency Program (NRPP) or National Radon Safety Board (NRSB)

  4. Retest after mitigation to confirm levels have been reduced

  5. Test every 2 years or after major renovations

How to Test Your Home for Radon

Testing your home is simple, inexpensive, and potentially life-saving. The EPA recommends testing all homes below the third floor.

DIY Test Kits

Short-term test kits are available from several sources:

For the most accurate results, close all exterior windows and doors 12 hours before starting the test and maintain these conditions throughout the 48+ hour testing period. Place the test kit in the lowest lived-in level of your home.

Professional Testing

For real estate transactions or more precise measurements, consider hiring a licensed radon measurement professional who uses continuous radon monitors (CRMs) that provide hour-by-hour readings.

The Role of Good Air Filtration in Overall Indoor Air Quality

While air filters cannot solve a radon problem, maintaining high-quality air filtration remains essential for healthy indoor air. A good HVAC filter captures the many other pollutants that affect respiratory health, including:

  • Dust and dust mites

  • Pollen and outdoor allergens

  • Pet dander

  • Mold spores

  • Smoke particles

  • Some bacteria and viruses (higher MERV ratings)

Aerterra Product Spotlight: Eco-Friendly MERV 11 Filters

When you're ready to upgrade your home's air filtration, consider Aerterra's MERV 11 filters. Made from USA-grown corn and renewable materials, these filters capture particles as small as 1 micron while supporting sustainable manufacturing. With free shipping and convenient subscription delivery, you'll never miss a filter change.

Shop all Aerterra filter sizes to find the perfect fit for your HVAC system.

Sustainability and Clean Air Go Hand in Hand

Protecting your family's health and protecting the planet don't have to be separate goals. Traditional fiberglass air filters contribute to landfill waste and are made from petroleum-based materials. By choosing eco-friendly filters made from renewable resources, you're reducing your environmental footprint while maintaining clean indoor air.

Aerterra filters feature nanofiber technology that delivers superior particle capture without restricting airflow, helping your HVAC system run efficiently. Plus, every purchase supports reforestation efforts through Aerterra's partnership with One Tree Planted.

Learn more about why Aerterra is different and read our story.

This January, Take Action on Radon

National Radon Action Month is the perfect reminder to test your home, understand your indoor air quality, and take steps to protect your family. While your HVAC filter plays an important role in capturing airborne particles and allergens, radon requires a different approach.

Here's your action plan:

  1. Order a radon test kit from your local hardware store or online

  2. Test your home following EPA guidelines

  3. Contact a certified mitigator if levels exceed 4 pCi/L

  4. Maintain good air filtration with regular filter changes to address other indoor pollutants

  5. Choose sustainable options like Aerterra's eco-friendly filters

Ready to breathe easier? Shop Aerterra air filters by size or MERV rating, start a subscription for hassle-free delivery, or explore more indoor air quality articles on our blog.

FAQs

Can MERV 13 filters remove radon from my home?

No, MERV 13 filters cannot remove radon gas. Radon is an inert gas whose molecules are far smaller than any particle a mechanical filter can capture. MERV 13 filters are designed to trap particles 0.3 microns and larger, such as bacteria and smoke. While these filters may capture some radon decay products attached to dust particles, they cannot address radon gas itself. Professional radon mitigation is the only effective solution for elevated radon levels.

How often should I test my home for radon?

The EPA recommends testing your home for radon every two years, or after any major structural changes such as renovations, foundation work, or adding new living space in a basement. If you have a radon mitigation system installed, test it annually to ensure it continues working properly. Testing is especially important when buying or selling a home, as radon levels can vary significantly even between neighboring properties.

What is the difference between radon and radon decay products?

Radon (Rn-222) is a radioactive gas that cannot be filtered from the air. Radon decay products (also called radon progeny or radon daughters) are solid radioactive particles created when radon decays, including polonium-218 and polonium-214. These particles can attach to airborne dust and may be captured by air filters. However, since radon continuously produces new decay products, filtration alone cannot solve a radon problem.

Are eco-friendly air filters as effective as traditional filters?

Yes, eco-friendly air filters can be just as effective as traditional fiberglass filters. Aerterra's plant-based filters use advanced nanofiber technology to capture particles efficiently while maintaining proper airflow. The MERV rating system applies equally to all filter types, so a MERV 11 eco-friendly filter provides the same particle capture performance as a conventional MERV 11 filter. The difference is in the materials: renewable, plant-based fibers versus petroleum-based products.

How much does radon mitigation cost?

Costs vary based on home size, foundation type, and local labor rates. Most installations are completed in one day. Considering radon is responsible for roughly 21,000 lung cancer deaths annually in the United States, mitigation is a worthwhile investment in your family's health.

Why is January designated Radon Action Month?

The EPA designated January as National Radon Action Month because winter is an ideal time for radon testing. Homes are typically sealed up during cold weather, which can cause radon levels to rise to higher levels than during warmer months, when windows are often open. The winter timing also coincides with resolution-making season, encouraging homeowners to prioritize health and safety in the new year.

What radon level is considered dangerous?

The EPA recommends taking action to reduce radon if levels reach four picocuries per liter (pCi/L) or higher, and suggests considering action between 2 and 4 pCi/L. There is no known safe level of radon exposure, as any amount carries some risk. For context, outdoor air typically contains about 0.4 pCi/L, while the average indoor level in U.S. homes is approximately 1.3 pCi/L.

Can I install a radon mitigation system myself?

While DIY radon mitigation is technically possible, it is strongly discouraged. Improper installation can fail to reduce radon levels or even worsen the problem. Certified radon mitigation professionals have specialized training in system design, diagnostics, and installation. The EPA recommends using contractors certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB) to ensure your system is effective and safe.

Disclaimer

This article is for informational purposes only and does not constitute medical, environmental, or professional HVAC advice. Radon levels and risks vary by location, home construction, and individual circumstances. For specific radon testing and mitigation recommendations, consult with a licensed radon professional in your area. For health concerns related to radon exposure, please speak with a qualified healthcare provider. Air filter effectiveness varies based on HVAC system type, maintenance, and home conditions.

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