Basements are notorious for their stagnant, stale air. The lack of air flow and windows in basements makes them prime locations for indoor air pollutants to accumulate. This not only leads to potential adverse health problems when you access your basement, but these pollutants may easily escape and contaminate the rest of the house. Which indoor pollutants can be found in a basement? How can an air purifier for basements protect us from negative health effects? Read on to learn more.

Basements: a unique microenvironment in the house

Basements are unlike most other rooms in the house. Typically used as storage spaces, for many, they are rarely or very occasionally accessed. They are known for their distinct ‘basement smell’, an unpleasant, musty odour unique to these types of spaces.

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Basement features

Why are basements often synonymous with poor basement air quality? Some factors include:

Use as storage

As mentioned above, individuals commonly store unused items in their basements. Some examples may be pieces of furniture, garden equipment, and do-it-yourself, home maintenance products like paints, lacquers, and petrol. All of these items emit significant levels of indoor air pollutants. Since it is a rarely-used part of the home, this also means that it is not cleaned as regularly as other rooms in the house. This ultimately leads to a build-up of dust, mould and mould spores, mildew, musty and unpleasant odours, and other contaminants that impact indoor air quality (IAQ) in basements.

High humidity levels

Basements are in direct contact with the ground, sometimes even being partially or completely underground. Water and moisture from rain or groundwater can gain entry to the basement through multiple mechanisms: liquid water flow, vapor diffusion, capillary suction, and air movement, as seen below. Moisture can also gain access through poor construction like inadequate grading, missing gutters, improper window wells, structural cracks, and foundation settling. Moisture and humidity in basements lead to proliferation of mould and mould spores and an unpleasant, musty odour.

Limited natural ventilation

Basements are known for their humid, stale air. This is due to the fact that most basements have no or few windows, making it impossible to properly ventilate the space. As a result, indoor pollutants accumulate and the air is rarely, if ever, renewed.

Stack effect

Did you know that upwards of 40% of the air you breathe in your home comes from the basement? Known as the ‘stack effect’, ‘pulling effect’, or ‘chimney effect’, the air in your home is constantly rising. This is a natural process and occurs from the temperature differences from the outside to the inside of your home. Due to the stack effect, you are likely unwittingly breathing in your dangerous basement air pollutants even if you keep your basement door closed.

Sources of air pollutants in your basement

According to a 2008 study, approximately 10 to 20% of the indoor air pollution found in homes are sourced from the basement⁴.

Poor indoor basement air quality may have a variety of sources. Biological air pollution, especially mould and mildew, is one of the most common air pollutants found in basements.  As previously mentioned, the conditions in a basement, particularly high humidity, damp environments, provide the perfect breeding ground for mould growth and spores. Black mould infestations are often a main cause of ‘sick building syndrome’. This is why it is highly recommended to dry as much excess moisture as possible if there is flooding in your basement.

Chemical pollution like volatile organic compounds (VOCs) is also very common in basements. A 2015 study found nearly 100 different VOC particle compounds present in basements. Some include benzene (a known human carcinogen), toluene, naphthalene, and limonene, most of which were sourced from gasoline-powered equipment, household cleaning products, air fresheners, solvents, and cigarette smoke. Most concerningly, the presence of VOCs was detected in 75% of the basements analysed, and those same contaminants had spread to 15% of living spaces. The study further states that ‘even if the basement is not part of the living area, air in the two zones is coupled’⁵.

Radon is also a concern in basement air quality. Based on figures from a 2002 study in Northern England, high concentrations of radon were found in 20% of homes⁶. Radon is particularly problematic in basements due to its proximity to the soil, where radon is found. A radioactive gas produced when uranium decays in soil, radon can penetrate a home directly through basements. It leads to serious health effects, and proper ventilation is crucial. Check your local radon maps to learn if you live in a high radon area.

Other indoor air pollutants are found in basements that have a negative impact on health like carbon monoxide, an odourless and tasteless gas known as the ‘silent killer’.

Health risks

Exposure to indoor air pollutants in your basement may be responsible for many unpleasant symptoms in both the short- and long-term. This is particularly the case if you store cleaning products, chemicals, and other VOC-causing products in your basement. Symptoms may include:

• Headache
• Allergy symptoms
• Irritation of the eyes, nose, and/or throat
• Difficulties breathing
• Cough
• Dizziness
• Fatigue
• General malaise and discomfort
• Nausea
• Problems concentrating

Long-term exposure to indoor air pollutants may lead to increased risk of respiratory disease, cancer (especially lung cancer), and nervous system and/or liver damage.

The benefit of an air purifier for basements

Installing a basement air purifier is an excellent way to provide clean air and protect you and your loved ones from the dangers of indoor air pollution in your basement.

Reduce air pollutant concentrations

An air purifier for basements that comes equipped with multiple purification technologies can combat all three of the main types of air pollution: fine particulate pollution, chemical pollution, and biological pollution. It is important to find a device that has a HEPA (high-efficiency particulate air)-certified filter, as this ensures that 99.97% of particles down to 0.01 microns are removed from your air. This includes:

• Particulate matter, or fine particle pollution, like PM10, PM2.5, and PM0.1
• Allergens like dust and dust mites, pet hair and dander, and pollen
• Mould and mould spores
• Cigarette smoke (first-, second-, and third-hand) and smoke particles
  

Do keep in mind that most basement air purifiers only contain one or two air purification technologies, and HEPA filters alone cannot remove VOCs from your basement’s air. For this, your device will require supplementary technologies. Eoleaf’s devices, for example, come equipped with 8 different filtration technologies, cleaning and removing all types of airborne pollution! Read more on this below.

How to choose an air purifier for basements?

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Before making your purchase of an air purifier for your basement, it is important to consider a handful of factors.

Filter type

As previously mentioned, since there are a variety of pollutants found in basements, your basement air purifier should be adapted and designed to fight against and clean many different types of air pollution. A HEPA-certified filter is a requirement when combatting fine particle pollution and allergens. A HEPA filter is made to combat fine particles. HEPA filters can also remove mould spores from the air and stop mould proliferation in its tracks. Ionisation (negative ions) is also great for removing fine particles from the air.

• Keep in mind that there is a difference between ‘HEPA-certified’ and ‘HEPA-type’ filters! HEPA filters that are certified undergo rigorous third-party testing to ensure their efficiency.
  

A HEPA filter should not be the only technology included in your device, however! As mentioned above, although they are extremely effective against fine particles, HEPA filters do not remove VOCs. This is why it is smart to have supplementary technologies in an air purifier.

One of those supplementary technologies that you should seek out in a basement air purifier is an activated carbon filter. An activated carbon filter works to combat VOCs. Additionally, activated carbon filters removes stale, musty odours and smells from your basement’s air (not all air purifiers are designed to remove odours and smells!). Alongside an activated carbon filter, photocatalysis is another technology that works to remove VOCs. You will find all of these technologies and more in Eoleaf’s air purifiers: read more about our proprietary 8-step filtration here.

Size of your basement

Air purifiers are designed to filter the air of rooms of a maximum size. Be sure to consider your basement’s size when choosing your device. Eoleaf offers three different sizes depending upon the size of your targeted space:

• AEROPRO 40 air purifier: for small basements or rooms from 0 to 40 m² (450 square feet)
• AEROPRO 100 air purifier: for medium-sized basements or rooms from 0 to 80 m² (850 square feet)
• AEROPRO 150 air purifier: for large basements or rooms from 0 to 120 m² (1300 square feet)

Features and budget

A smart air purifier is a wise choice when fighting against basement air pollution. By having app compatibility and Wi-Fi connectivity, you can control your device without even having to go down into the basement. With a smart air purifier, you can enable smart scheduling, use voice commands, and learn more about your indoor air quality directly on your smart phone. Eoleaf’s devices are compatible with the Tuya Smart app and come with a convenient Automatic mode, allowing your device to automatically increase its fan speed when it detects new pollutants!

There are three parts to budgeting for an air purifier that should be considered: 1) the initial cost of the device, 2) maintenance costs, and 3) costs associated with energy consumption. Air purifier pricing varies significantly depending upon the options offered, but expect to spend between £500 to £1000 for a high-quality air purifier. All air purifiers require maintenance consisting of regular filter changes. This is absolutely essential if you want your device to function properly. Also, be sure to seek out an energy-efficient device to keep energy consumption and costs low.

The Eoleaf difference

Eoleaf’s devices offer some of the most efficient and modern air purification technologies on today’s market. They are designed to be durable and effective in providing clean air, safeguarding your health from the impact of indoor air pollution. Do not hesitate to reach out to our team of air purification experts for assistance in choosing the right model for you. Also feel free to refer to our in-depth Buying Guide.

Resources

¹ Marć M, Śmiełowska M, Namieśnik J, Zabiegała B. Indoor air quality of everyday use spaces dedicated to specific purposes-a review. Environ Sci Pollut Res Int. 2018 Jan;25(3):2065-2082. doi: 10.1007/s11356-017-0839-8. Epub 2017 Nov 30. PMID: 29192399; PMCID: PMC5773644.

² Carmody, J., Anderson, B., & Stone, R. (2018). Moisture in basements: Causes and solutions. UMN Extension. https://extension.umn.edu/moisture-and-mold-indoors/moisture-basements-causes-and-solutions

³ The stack effect. Innovative Basement Authority. (2023). https://www.innovativebasementauthority.com/services/foundation-repair/causes/stack-effect/

⁴ Dodson, R. E., Levy, J. I., Spengler, J. D., Shine, J. P., & Bennett, D. H. (2008). Influence of basements, garages, and common hallways on indoor residential volatile organic compound concentrations. Atmospheric Environment, 42(7), 1569–1581. doi:10.1016/j.atmosenv.2007.10.088

⁵ Du L, Batterman S, Godwin C, Rowe Z, Chin JY. Air exchange rates and migration of VOCs in basements and residences. Indoor Air. 2015 Dec;25(6):598-609. doi: 10.1111/ina.12178. Epub 2015 Jan 20. PMID: 25601281; PMCID: PMC4490136.

⁶ Wang, F., & Ward, I. C. (2002). Radon entry, migration and reduction in houses with cellars. Building and Environment, 37(11), 1153–1165. doi:10.1016/s0360-1323(01)00097-x