How to Improve Air Quality in Basement

Poor air quality is a common problem in basements. Being underground, the basement is typically colder and damper than the rest of the house. And without adequate ventilation, the humid air gets trapped inside, leading to a damp and musty basement space. 

Basements are often neglected, making the space susceptible to the growth of mold. Indoor air pollution also comes from some common household products. Without proper, immediate action, the poor air quality in your basement can easily spread throughout your home. This can have many negative side effects on the whole family, especially those who are vulnerable to respiratory illnesses and other health problems.

There are several ways you can improve the air quality in a finished or unfinished basement. You can use an air purifier to remove allergens, fans to promote airflow, or a dehumidifier to reduce humidity. But before you install any new appliance in your basement, you must remove the sources of poor indoor air quality. Below, you’ll learn why it’s important to improve indoor air quality, how to improve air quality, and the proper maintenance to keep healthy, clean air in your basement.

Why It is Important to Improve Basement Air Quality 

Good air quality in every part of your home is essential in ensuring everyone’s health and wellbeing. We need to make sure that we are always safe and we only breathe clean air inside our homes. Airborne allergens and harmful chemicals endanger your family, but they are actually common in any home. 

Dust, pollen, dander, and VOCs can be tracked into your basement from other parts of your home or even from outside. Depending on the condition of your basement, it can be hard to get rid of these allergens and chemicals once they settle on the space. Some tips that can help you are as follows:



1. Declutter your basement

Before you do anything else, you must first clean up all the clutter in your basement. Many of us treat our basements as storage units where we keep all our old stuff until we forget about them entirely. If you’re also guilty of this, it’s time to let go of some of these items that do not hold value to you anymore.

Remove old magazines, newspapers, books, clothes, toys, or any items where dust may settle. They can attract mold as well as dust mites and other pests. Once all the trash is gone and disposed of (responsibly!), organize your items into separate boxes for those you want to keep and those you can donate or sell. Make sure to wear a face mask and gloves when cleaning up a dusty or moldy basement.

2. Perform an indoor air quality test

Once you’ve cleaned up all the clutter you can see, you can test your indoor air to find out the root cause of poor air quality. You can conduct your own test by installing a detector or you can hire a professional.

You’d want to test for radon, a common source of indoor air pollution. This odorless gas forms when uranium breaks down from rocks, soil, and water and seeps into your home through the basement floors and cracks in the foundation. Radon exposure causes over 21,000 annual deaths from lung cancer.

Another common source of indoor air pollution is carbon monoxide, an odorless and colorless toxic gas. In high concentrations, it can be lethal when inhaled. Symptoms of carbon monoxide poisoning include headaches, dizziness, and nausea. If you have a fireplace, heater, or furnace in the basement, it’s especially important to install a carbon monoxide detector in the place. 

You may also want to test for volatile organic compounds (VOCs), fine particulate matter, and other common air pollutants. Professional testers will know what to test for and what possible steps to do next.

3. Fix and dry out water damage

Fix and dry out water damage

Water damage is a common problem in the basement. Because it’s underground, the basement often catches the groundwater that seeps into the soil. Rain or floodwater also flows into the basement, causing serious water damage without immediate action.

In case of emergencies, it’s best to hire a professional water damage restoration service. These companies use industrial-grade equipment to remove all standing water, dry out the moisture, and fix the damage. These equipment and tools include industrial dehumidifiers and blowers.

It’s essential to completely dry out the water in the basement to prevent mold and mildew that thrive in moisture. If the damage isn’t addressed immediately, it gives more time for these organisms to develop and spread, making it more difficult to get rid of them. Make sure that aside from the water, mold is also removed professionally to prevent it from spreading to other parts of your home.

4. Seal the cracks and gaps

After you fix the water damage, you will also need to seal the cracks and gaps in your basement to prevent polluted air from entering your home. To spot the tiny cracks, turn off the lights during the day and see where the sunlight shines through. You can mark the spots with tape and seal the gaps with a plastic cover or glass adhesive for glass windows. If there are gaps in the basement foundation, you can use caulk, cement, or expanding foam to cover them.

5. Keep the windows closed

Keep the windows closed

You may think that opening a window is the best way to provide ventilation in your basement, but this isn’t always the case. Opening the window lets in the outdoor allergens such as dust and pollen, along with humid air, especially during the summer. 

When the warm outdoor air comes into contact with the cooler surfaces in your basement, condensation occurs. Because the moisture has nowhere else to go, it accumulates in your basement and encourages mold growth. Opening your basement window is only helpful when the outdoor air is dryer and cooler. You will need a proper ventilation system instead.

6. Remove the sources of VOCs

Volatile organic compounds in high concentrations can be harmful to your health, but it’s nearly impossible to avoid these pollutants entirely. They can come from ordinary household products and spread through the air. VOCs can have a natural scent or they can be emitted as odorless and colorless gases from household items for cleaning, personal care, and hygiene products. Formaldehyde, one of the most common VOCs found in homes, can be found in daily items, fabrics, plastics, paint, furniture, cosmetics, and construction materials. 

With poor ventilation, the VOCs from these substances can reach toxic levels inside your home. While you cannot completely eliminate VOCs in your basement, high exposure can have adverse effects on your health. Inhaling VOCs can cause irritation to the eyes, nose, and throat, headaches, shortness of breath, and nausea. It can also damage the lungs, the central nervous system, as well as other organs like the kidneys and liver. Higher concentrations of some VOCs can even cause cancer.

To be safe, avoid storing products that are high contributors of VOCs in the basement. Use low-VOC paint and cleaners to reduce toxic gases. If you want to make sure, install an air quality monitor in your basement.

7. Remove plants from the basement

Remove plants from the basement

Houseplants have seen a growing rise in popularity in recent years, but remember that only certain types grow well in indoor settings, especially in a dark basement. While plants produce oxygen and can help reduce air pollutants, they also add humidity to the basement. If excess moisture is already a problem in your basement, growing plants in this space will only worsen its condition. It can also become a breeding ground for mold and bacteria, which can spread to the rest of your home if not controlled.

8. Maintain proper air circulation

Many basements have poor air circulation, causing stale air and unpleasant smells. To properly circulate air in your basement, you need the right ventilation system. You can install exhaust fans to vent out the damp air from your basement and replace it with cool, fresh air. You can also use portable fans like stand fans to circulate the air inside. These fans must be directed towards an open door to blow out the stagnant air from the basement. A ceiling fan installed near your basement entrance can also help circulate the air. 

9. Control the humidity with a dehumidifier

Control the humidity with a dehumidifier

Humidity is the amount of water vapor present in the air. The ideal relative humidity for your home is between 30 and 50 percent. Anything too low or too high can cause many problems for your health and the state of your house. Although, excess humidity is the usual worry in basements. 

High moisture levels paired with low-light conditions in your basement creates the perfect environment for the growth of mold. Mold spores, along with other allergens such as dust mites, are abundant in humid parts of the house, further decreasing the air quality in your basement. The best solution for severe dampness in basements is a dehumidifier. We have <this> guide to help you choose the best dehumidifier for your basement. 

It’s important to maintain humidity levels within the recommended range. To do this, you may not need to run your dehumidifier all the time. It’s commonly used in the summer when humidity levels are most extreme. However, in the winter, a dehumidifier may not be necessary at all. It depends on the climate in your region and it’s always best to consult a professional to know exactly what your basement needs. 

10. Use an air purifier

air purifier

Finally, to improve and maintain the air quality in your basement, invest in a good air purifier. The main purpose of basement air purifiers is to remove allergens, unpleasant odors, and harmful gasses in your basement, depending on the filtration system used. Air purifiers use different types of filters to catch tiny particles and VOCs.

The effectiveness of your air purifier relies on the type of filters used. Look for units with a True HEPA filter and activated carbon filter for maximum efficiency. Compare the CADR rating to see how effective each unit is against common airborne pollutants. To maximize performance, check the total area of your basement to choose the proper size air purifier. Here are some of the best air purifiers we recommend for large rooms such as your basement. 

When you find the best air purifier for your basement needs, you must observe regular filter replacements and proper maintenance as instructed by the manufacturer. This ensures optimum performance and a longer lifespan for your air purifier.


Whether or not you use your basement as a living space, basement air quality can greatly affect your health at home. We have outlined above the ten steps you can take to improve the air quality in your basement. Many issues with poor air quality in basement can be solved by simply cleaning and maintaining your basement properly. An air purifier is a beneficial investment for any basement. In most cases, you will also need a dehumidifier to balance humidity levels in your basement. If you notice more serious problems that you cannot solve with our tips, it’s best to contact a professional in HVAC to find the problem and its appropriate solution.