How To Improve Basement Air Quality

Musty smell and air quality issues in a basement? You're not alone. The basement is one of the dustiest places in the home due to poor ventilation and lack of direct sunlight. In this post, we will look at the root cause and explore the many ways you can improve basement air quality with little effort. Whether it is a crawl space, finished or unfinished basement, this guide will cover it all.


how to improve basement air quality

1. Use An Air Purifier To Clean The Air

Skip the air freshener, bamboo charcoal deodorizer, or desiccant because an air purifier is the simplest, quickest, and most effective way to improve basement air quality. It continuously circulates clean air by trapping airborne contaminants into its filtration, thus preventing you from breathing the particles.

There are 2 common types of air filtration for basement use: 

  • Electronic Air Filters – Mainly focus on ionization technology to negatively charges airborne pollutants, merging and pulling them down for capture.
  • Mechanical Air Filter – Consists of 3 main filtrations starting with a pre-filter that traps dust and large particles. A True HEPA filter captures 99.97% of microscopic particles as small as 0.3 microns, such as lead dust, mold spores, pollen, pet dander, asbestos, and bacteria. An Activated Carbon filter, the air purifier removes smoke, odor, and chemical fumes such as radon, VOCs, formaldehyde, and carbon dioxide. Advanced models come equipped with ultraviolet light that kills microbes and germs with no chance of multiplying.

Before investing in an air cleaner, you need to calculate the basement size to ensure you’re getting the proper air purifier. Most manufacturers will include the recommended room size in square footage or CADR for the particular model. It is always better to go with a larger air purifier than a smaller one, even though it is more costly to own and maintain. While you’re at it, look for useful features such as an air quality monitor, timer, or auto mode that will enhance usability. Also, make sure the air purifier is equipped with a genuine True HEPA filter instead of a HEPA-type filter. A good gauge for the filter would be between MERV 17-20 rating system that traps even the finest particles. Depending on how bad the basement air quality is, you will need to wash or replace the air purifier’s filter before it is worn.

2. Install HVAC System To Improve Ventilation

Basements are infamous for poor air circulation, where dirty air gets trapped indefinitely, resulting in the stuffy feeling of everything you step foot in. Installing the ventilation system help exchange fresh air and prevents air from getting stale. Very useful in dealing with the basement’s poor ventilation, where dirty basement air can lead to adverse health effects. The downside with an HVAC or exhaust fan is the need for a qualified HVAC technician to perform the installation. You will have to incur the expensive cost along with the necessity of hacking and drilling. Again, an air purifier is a cheaper and quicker alternative to improve basement air quality. We highly recommend getting one, even if you have a good ventilation setup.

3. Keep It Dry (With A Dehumidifier)

A damp basement can lead to deteriorating air quality due to the limited ventilation with underground concrete built. Besides having to endure the musty smell, condensation, and moist feeling, a high-humidity environment also promotes mold/ mildew infestation in the ceiling, joists, trusses, dry walls, and floor. Mold exposure can cause allergic reactions like coughing, sneezing, nasal congestion, eye irritation, skin rash, headache, and other severe health problems. It will also make the air harder to breathe, which can be dangerous for those working or sleeping in the basement.

In comes a dehumidifier that helps reduce dampness in the basement and improve poor air quality. It absorbs excess moisture in the basement in order to maintain the ideal 30-50% humidity level. Without a favorable habitat for mold, the microorganisms will not spread and survive. However, not all dehumidifiers are created equal. Only use a refrigerant dehumidifier with enough moisture removal capacity to cover the entire basement area. Opt for models with a direct drainage option that diverts the water straight to a floor drain to save you the effort of emptying the water tank every 1-2 days. If the basement can reach a freezing temperature, ensure the dehumidifier comes with a built-in defrost function to protect the coils.

4. Seal Cracks And Gaps

An important but often overlooked step. To prevent polluted air from flowing inside or clean air from escaping, use masking tape, glass adhesive, or plastic cover to seal stress/ pressure/ impact cracks. Apply the same sealing on windows with condensation issues and leaky pipes. If gaps exist on the basement foundation wall or floor, seal it with cement, caulk, and expanding foam before the gaps expand over time.

5. Keep Windows And Doors Closed

Contrary to many beliefs that opening windows help with basement ventilation, you’re inviting more pollutants inside, particularly during the summer when pollens run high. Keeping the windows and doors closed prevents indoor air quality from deteriorating and humidity from rising. For a basement that lacks an air cleaner, the best time to leave it open is during winter.

6. Remove VOCs Sources

Avoid storing chemicals and solvents in the basement known for off-gassing VOCs, such as leftover paints, cleaning agents, dry cleaning fluid, varnishes, lacquers, and gasoline. Store them in the garage or outdoor shed with good ventilation instead. Also, use zero or low VOCs paint specifically designed for indoor use. Volatile organic compounds (VOCs) are high vapor pressure toxic that can build up quickly and pollute a poorly ventilated basement. For safety assurance, get a VOCs/ radon detector to monitor and detect the level of the chemicals in your basement.

7. Declutter Your Basement

Never treat the basement as a storage unit. Toss away old magazines, clothes, toys, unfinished paints, tools, or books that have no sentimental value. Do not keep chopped firewood inside, as the porous materials may contain fungi that multiply. For items that need safekeeping, store them in a box or bag and tuck them in a dry area. Vacuum regularly from top to bottom to remove surface dust particles. The fewer items you have cluttered in the basement, the less dust will accumulate, and the cleaner the basement air.

8. Test For Radon

Get a radon detector or hire a certified radon professional to test it once a year. Because radon is an odorless, colorless, and tasteless radioactive gas, most people don’t realize they are exposed to it until it is too late. Sealing all cracks, openings, and sump pumps is a good start. When a dangerous 4 picocuries per Liter (pCi/L) or higher radon level is detected, your only solution is radon mitigation systems. A costly solution that pumps out all the radon gases in your home via PVC pipe drilled into the floor.

Radon is a radioactive decay of uranium and a common source of basement air pollution that causes more than 21,000 lung cancer deaths every year. Naturally occurring in soil, rock, and water, radon will seep into your home through the basement floor, crawlspace, cracks in the foundation, building joints, water, or exposed soil.

9. Mindful Of Carbon Monoxide

Installing a CO detector in the basement can be a lifesaver. The carbon monoxide detector alarm will go off when it detects the CO level in your basement exceeding the OSHA limit of 50 parts per million (ppm). Without it, you’re at risk of carbon monoxide poisoning when exposed to a high concentration level of carbon monoxide above 150 to 200 ppm. Remember to change the carbon monoxide detector’s batteries for a more accurate reading.

CO is an odorless and colorless gas that can be lethal when inhaled. Many people don’t realize the danger until it is too late. One might experience headaches, fatigue, nausea, disorientation, unconsciousness, and death in a matter of minutes. A good telltale sign of carbon monoxide is the flickering flame on the furnace, rusty vent pipe, and increased moisture around the windows.

10. Keep It Clean

Routine maintenance is needed to ensure your basement remains clean, dry, and fresh for years to come. Thoroughly clean the basement every 3 days to reduce dust accumulation and improve air quality. Wear a face mask and gloves when performing housekeeping to minimize direct contact with the contaminants. Ensure all the air filters in the HVAC, air purifier, and dehumidifier are properly maintained based on the suggested interval time. Lastly, avoid smoking and eating in the basement.

Do air purifiers work in basement

11. Hire A Professional

If you have tried all methods above and have yet to come to fruition, it is time to call in the professional. Even though the cost could rise to thousands, it is a small price to pay in exchange for your health.

  • An HVAC specialist would solve most air quality issues in a basement, including installing gravels under the foundation, vapor barrier, waterproofing, extractor fan, ventilation repairs, and adding a sump pump downsloping lot.
  • If it is related to mustiness and mold issues, hire a mold remediation expert instead. Toxic fumes and gas leakage, reach out to a gas company for assistance.
  • For renovation, you will need a licensed contractor. Opt for non-porous materials that mold cannot feed off for an unfinished basement. Choose metal foil insulation instead of paper film, metal studs over wood studs, and ceramic tiles over laminate floors.

What Pollutants Are Found In A Basement?

It is critical to learn what's plaguing your basement air to have a better perspective on what you're dealing with. Here are the common air pollutant sources you need to look for.

  • Radon - Uranium breaks down that comes through cracks and gaps from the ceiling, tiles. floorings.
  • Carbon Monoxide - Furnace, faulty appliances, coal stoves, heaters.
  • Asbestos - Old homes before the 1970s. particleboards, insulations, adhesives, fire retardant foam.
  • Lead - Dust, old homes, and items from paint, toys, furniture, crafts, jewelry.
  • Volatile Organic Compounds (VOCs) - Composite wood products, aerosol products, paints, varnishing, household cleaners.
  • Microbial Volatile Organic Compounds (mVOCs) - mold spores, mildew, bacteria, viruses.
  • Particulate Matter - PM10 to PM2.5 e.g. dust, hair, dirt, fiber, lint, dust mite, smoke.

Again, get an air testing monitor if you feel the basement air quality doesn't sit right or is producing musty odors that can't be ignored. It measures the basement temperature, humidity level, particulate matter (PM), Volatile organic compounds (VOCs), and other toxin gasses. With the vital data, you can identify the cause of the air quality issue and plan the next course of action based on the severity.

Final Thoughts

We hope you will find the above guide useful in making your home more livable. With some effort, air quality in the basement can be restored to a healthy level. Keep an eye on mold, leakage, or nauseating smell that could quickly deteriorate the air. It is not a one-off job, as routine maintenance is needed to ensure your basement remains clean, dry, and fresh for the rest of the year.

No surprise here, an Air purifier is worthy of a spot in your basement and our top pick to improve air quality at a reasonable cost. However, not all models are up to the task. Instead of you scrambling the net for the right model, we have reviewed, compared, and compiled the best air purifier for basement use here.

Max Fernandez

A loving father and a dedicated reviewer for airfuji.com with more than 1000 air purifiers under his belt. Max Fernandez is also one of the million patients currently suffering from asthma. Feel free to nudge him if you have any questions.
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