Do Air Purifiers Help With Radon Gas?

Yes, air purifiers can help reduce the amount of Radon in the indoor space. However, not all purifiers work against radon and even the best HEPA air purifiers can prove inefficient against it. An air purifier with an activated carbon filter is the best choice when it comes to keeping radon concentration levels in check.

Radon is one of the noble gases that are more common in a household than one might think. Although inert, Radon can decay and cause damage to the inner lining of the lungs. As Radon decays easily you might wonder how it exists freely in the first place.

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Health Risks

Radon Testing Kit

Tips to Reduce Radon

Radon around you

Radon is rare because of its quick decaying nature but is given off by uranium and thorium that are commonly found in the Earth’s crust. The gas can make its way through cracks in walls, through underground water, basement cracks, or even through the soil, and because of its odorless, tasteless nature, it can go unnoticed.

Radon’s decomposition into radioactive particles can release powerful alpha radiation that can cause irreversible damage to the inner lining of the lungs. Constant exposure to noble gas can also lead to lung cancer. According to official stats from CDC, radon-based lung cancer claims as many as 20000 innocent lives in the US alone each year.

Radon is now on the watchlist of every environmental protection agency, but before its damaging effects became apparent there were a number of instances where daily use materials incorporated the element in some form unconsciously. Mattress manufacturers that used certain earth minerals in the production process unknowingly added the issue of radon off-gassing to their product. So did a bunch of accessories and building materials manufacturers that led to a spike in radon contamination.

Health Risks of Radon Gas

The United States Environmental Protection Agency (EPA) asserts that there is no safe radon level for an enclosed space, however, the agency suggests hiring a radon specialist if the level of radon reaches 4 pCi/L (picocuries per liter).

Excessive exposure to radon can lead to lung cancer and can permanently damage the inner lining of the lungs. The best bet against radon is to keep the space ventilated but it is hardly possible with the increasing populations and HVAC systems in our buildings. The indoor radon exposure levels are 48 Bq/m3 while as we move outdoors the value drops to just 15 Bq/m3.

Radon particles are responsible for as many as 21000 lung cancer deaths in the US alone each year. Even non-smokers can contract lung cancer from radon exposure.

Without serious exposure, radon poses a 0.45% risk of lung cancer and thankfully air purifiers can help keep these risks from spiking. Sadly, radon is a silent killer and symptoms like fatigue problems, wheezing, coughing, blood in cough, loss of appetite, and infections only surface when cancer has spread.

Radon Testing Kit

A qualified radon mitigation contractor can charge anything between $500 and $2000, or maybe even more depending on the size of your space and ambient radon levels. On the other hand, a radon test kit is relatively inexpensive ($10-50) and is readily available at hardware stores. As radon contamination can lead to health concerns, it is imperative that you test your indoor space to ensure optimal air quality.

Before you begin, it is important to understand a few things. As radon is given off by surface cracks and imperfections, the levels of radon near surfaces (walls, ceilings, floor) would generally be higher. The best way is to hang a radon testing kit from the ceiling where it hangs freely at eye level so it can measure the radon contamination levels in breathable air. Any closeness to surfaces will skew the test results.

In addition, test kits are rated for measuring radon levels over different time frames. Some short-term test kits can measure the levels in as little as 2 days and will give you a quick estimate if the radon levels in your space are dangerous. Long-term test kits are better for measuring the annual average radon levels, and the Minnesota Department of Health suggests spreading the 90-day test time of the kit over both heating and non-heating seasons. If two successive tests yield a 2 – 3.9 pCi/L result then a radon mitigation system should be considered.

Performing a test is suggested every 2-5 years or whenever there are any changes or improvements to the foundations or exterior walls.

How Do Air Purifiers Help with Radon Gas?

We already know that only some air purifiers work against Radon gas, here is a detailed breakdown of what each filtration stage of an air purifier brings to the table.

HEPA filter

A high-efficiency particulate air filter or a HEPA filter for short is excellent against particulate matter and can remove particles down to a size of 0.3 microns with a 99.97% efficiency. This number is backed by the United States Environmental Protection Agency (EPA) but as radon gas can be even smaller 0.5-3 nm, HEPA filters do not offer a viable solution to trapping the gas.
Radon decay products are larger in size and some of them can be trapped by a HEPA filter.

Activated Carbon Filters

HEPA filters are the recommended defense against particulate matter, but for most gaseous contaminants, activated carbon filters are the best choice. Radon is absorbed by the activated carbon that is commonly used to trap odors. Activated carbon filters also absorb VOCs, cooking odors, pet odors and can help neutralize harmful chemicals.

Ionic Filtration

Studies have shown that negative ions can significantly bring down the radon concentration in the air. This is true for both radon gas particles as well as for decay products.

UV Light chambers

UV-C light does not have any effect on radon or the decay products of radon. Hence, using a UV-C light air purifier just for tackling radon would be a waste of money.

Out of all the filtration stages and types, only carbon/activated carbon filtration works excellently against radon and its products.

Also Read: Best Air Purifier for Radon Gas in 2022

Tips to Reduce Radon Gas

If you don’t want to look into external remediation or want to keep radon levels within the safe threshold without using purifiers for radon gas, you can try:

1. Improving Ventilation

Radon is an odorless, tasteless gas and ventilation is the only real solution to bringing down chemical contaminants like radon gas. Ventilation helps, not only with radon but with toxic chemicals as well, and can significantly improve indoor air quality. Keeping a window open can help with indoor air pollutants and can even help in improving sleep quality.

2. Sealing Surface Imperfections

Sealing off cracks, openings, and other access points in a building can go a long way in reducing ambient radon levels. Using draft excluders will also keep other outdoor pollutants at bay that otherwise sneak into the indoor environment from under the door or through gaps between windows.

3. Improving Underfloor and HVAC system ventilation

If your building is equipped with underfloor ventilation, make sure it is not clogged as obstructions can impact ventilation. Similarly, a non-functional exhaust fan can also make the indoor air stale, increasing the number of airborne pollutants and radon levels.


Radon generation cannot be stopped and while the best bet against them is ventilation, air purifiers bring commendable protection against it where that is not possible. Air purifiers with highly activated carbon content work best against radon and its decay products. Some air purifiers sandwich HEPA filters in between carbon meshes or use a honeycomb design for carbon filters that increase the surface area in contact with the contaminants.

While the EPA recommends a long list of activities homeowners must carry out, the easiest and most feasible option is to use a good air purifier that uses activated carbon.