In this brief article, I will provide you with a detailed guide on how to improve the air quality in your basement. I will also explain why the quality of air we breathe is very important.

How to improve the basement air quality?

You can improve the quality of air in a basement by doing a combination of the below things:

  • Control the moisture and temperature
  • Use Air purifiers
  • Source control

Why should we care about indoor air quality?

The average American spends 93% of their life indoors. 87% of their life is inside buildings, then another 6% of their life is in automobiles (Klepeis et al. 2001). 

Over the last several years, a significant amount of scientific reports provide evidence of air pollution inside buildings and homes, referred to as indoor air pollution (IAP), which is more serious than outdoor air pollution, even in industrialised cities and metropolitan areas (Weschler 2009; Kauneliene et al. 2016). 

Thus, a person has a higher health risk from indoor air pollution than from outdoor air pollution. 

Furthermore, people who spend relatively more time indoors are much more susceptible to the effects of IAP. “Sick building syndrome” is a term used for situations where building occupants exhibit acute health issues that appear to be linked to time spent within the building, but no specific illness or cause can be identified. 

The common pollutants linked with this are carbon monoxide, nitrogen dioxide, suspended particulate matter (PM10 and PM2.5), radon, and formaldehyde. 

A common characteristic of modern buildings and households is their tightness, (e.g.: using tight-fitting doors and windows), and inadequate ventilation can exacerbate IAP by not bringing in enough outdoor air to dilute emissions from indoor pollution sources, and not carrying indoor air out of the buildings. 

Basement areas are defined as enclosures placed directly under the building. These rooms are usually built below ground level, so they are prone to leakage problems, and usually lack adequate ventilation and heat. These factors play a major role in increasing the relative humidity of the room, which favours the growth of mold and mildews. 

The air quality in these rooms is primarily affected by factors such as (i) various items stored such as unused furniture, solvents and chemicals used for cleaning or hobby purposes, paints, and gasoline products (ii) moisture content, (iii) presence of mold and mildew, (iv) presence of furnace or boilers; and (v) dust and dander (Marć et al. 2018). 

Furthermore, these rooms usually have very limited air exchange, which causes a build-up of PM within these rooms. Certain products such as furniture release emissions more or less continuously, while other sources (e.g.: smoking, air fresheners) release emissions intermittently. 

Given the nature and origin of the emissions, they can be potentially harmful when inhaled and can cause serious respiratory issues in the long run, particularly to vulnerable groups such as children, older people, and people ailing from respiratory and cardiovascular diseases. 

Thus, it is important to ensure the air quality of the basement is well-maintained. In this article, we discuss various methodologies for abatement as well as improvement of air quality in basements.

To determine the best practical approach for improving air quality, it is crucial to identify the major contributors to IAP in the basement. A way to judge whether the basement has IAP is by identifying potential sources of pollution. 

For example, the characteristic “basement smell” is caused due to putrefaction processes that occur in high humidity conditions, and with the participation of microorganisms. 

Such conditions indicate poor ventilation and high relative humidity, which is characterised by the presence of molds on walls and articles such as clothes, shoes, etc., and the spores arising from this become a biological air pollutant. 

Sometimes, symptoms that are related to IAP (eg.: irritation of the eyes, nose and throat, headaches, fatigue, etc.), indicate the presence of dust, solvents, and other PM. 

Lastly, it is vital to look at the lifestyle and activities of the occupants within the basement. For example, smoking in the basement can lead to a rise in PM and carbon monoxide levels. The following methodologies can be employed for improving indoor air quality

Moisture and Temperature Control

The specific micro-climate conditions of high humidity levels and low temperatures in the basement directly contribute towards processes that lead to deterioration of indoor air quality. 

Elevation in humidity and temperature favours the growth of mold, which produce spores that act as biological air contaminants. 

Furthermore, such conditions also favour the release of formaldehyde from furniture and Volatile Organic Compounds (VOCs) from solvents, paints, and gasoline products, thereby making the indoor air quality of the basement even worse. 

Certain studies show that the air exchange rate in basements is higher in winters than in summers, which may increase the migration potential of VOCs to the living areas (Dodson et al. 2015). 

The best approach to this issue is to incorporate a dehumidifier to regulate moisture levels and increase the ventilation in the basement to keep it cool and dry. However, a downside of incorporating ventilation systems is the installation cost and the energy utilisation for its working. 

Air Purifiers

A major component of IAP is particulate matter (PM). These particles can originate indoors from various sources, or enter the basement from the outdoor air. PM has serious implications on health, depending upon its composition and abundance, and can also cause premature death in people ailing from respiratory and cardiovascular diseases. 

The best method for reducing PM concentrations is by using an air purifier. Depending upon the size of the basement, an adequate air purifier should be used. 

Air purifiers with HEPA (High-Efficiency Particulate Air) filters are best suited for indoor purposes. The presence of an activated charcoal filter and a UV light further increases the efficiency of the filters.

Air purifiers with HEPA I recommend 

NameWhy I recommend it
HATHASPACE smart true Air Purifier for HomeIt filters 99.97% of pollutants, as small as 0.3 microns, and has a coverage area of 700 sq.ft.
LEVOIT Air Purifiers for Home, Smart WiFi Alexa ControlCompact size and can be controlled with an Amazon Alexa or Google Home.

Source Control

One of the most effective ways of reducing IAP in basements is by identifying and eliminating the sources of these emissions.

For example, the presence of leakages in the basement causes an increase in relative humidity, which favours the formation of mold and mildew. 

This method is also a more cost-efficient approach for improving indoor air quality than increasing ventilation, as doing the latter can increase energy costs. 

Some common sources-specific emissions and methods to control them are given below.


Radon is a colourless, odourless, radioactive gas that originates from the radioactive disintegration of uranium present in the nearby soil or the rocks. 

Being a relatively heavy and radioactive gas is unique to basement pollution (Roulet, 2001) because of proximity to the soil, where this harmful element might directly penetrate through the building environment, through dirt floors, cracks in concrete walls and floors, floor drains and sumps. 

It does not have any short-term effects on health, but long-term exposure to elevated levels of radon can cause lung cancer. 

For smokers that live in such conditions, the risk is even higher. There are various kits for detecting and measuring indoor radon levels that are available easily and are inexpensive. Reducing radon requires technical knowledge, and can be addressed by contractors trained to fix radon problems. 

For residential complexes that rely upon well water and have detected elevated levels of radon in their basement, you should get the water tested from a certified lab or trained individual.

Commercially available radon detectors

1. Elifecity Portable Radon Meter, Long and Short Term Home Radon Monitor – Amazon.

2. RadonScreen Radon Test Kit for Home – Amazon.


Asbestos is a mineral fiber that was used earlier in a variety of construction materials since it acts as an insulator and a flame retardant. 

Although it is now banned in 55 countries, it is still used in major countries such as China, India, Russia, Canada, and the United States, although the EPA and CPSC have banned several asbestos products. 

Asbestos concentrates in the indoor air due to activities such as remodelling, cutting, and sanding of asbestos-bearing products. Elevated concentrations of respirable asbestos particles can cause lung cancer, mesothelioma (a cancer of abdominal and respiratory linings), and asbestosis (irreversible scarring of lung tissues). 

Elimination of asbestos particles can be done by repairing old asbestos-bearing materials by sealing or by covering them.

Carbon Monoxide (CO)

Carbon monoxide is generated as a byproduct of combustion, as well as tobacco smoke. 

It is a colorless, odourless gas that affects the cardiovascular system by forming a stable complex, carboxyhemoglobin, with the red blood cells (RBCs), thereby hampering the delivery of oxygen throughout the body. 

Exposure to lower concentrations of carbon monoxide causes a range of symptoms, such as dizziness, fatigue, headaches, nausea, and chest pain, but higher concentrations can be lethal.

Carbon monoxide emissions can be reduced by regularly inspecting central air handling systems present in the basement, such as furnaces, by increasing ventilation near stoves, and by refraining from smoking indoors.


Formaldehyde is a colourless, pungent-smelling gas, and is an important chemical used in a variety of building materials, household products, furniture, and is also generated as a byproduct of combustion and cigarette smoke. 

It causes watery eyes, burning sensation in the nose and throat, and can trigger attacks in people suffering from asthma. 

To reduce formaldehyde emissions, coating furniture with polyurethane, reduce or avoid combustion activities and smoking, and regulate humidity levels and temperature along with providing adequate ventilation. 

Studies show that under increased heat and humidity conditions, emission of formaldehyde.

Particulate Matter (PM)

PM is of two types – coarse particulate matter (PM10), and fine particulate matter (PM2.5). PM is a major issue in basements, as it can arise from various sources. 

They are generated from combustion activities, faulty air regulation units, and biological sources such as spores that originate from mould and mildew, pollen grains that entered from the outdoor air, animal dander, dust mites, and so on. 

PM2.5 can have serious implications for respiratory and cardiovascular systems since it comprises various elements such as nitrous oxide species(NOx), heavy metals such as lead (Pb), and so on.

Volatile Organic Compounds (VOCs)

VOCs refer to a variety of organic compounds that are emitted from certain materials in the form of a gas. These compounds are present in items commonly stored in basements, such as paints, solvents, cleaning products, cosmetics, and fuels. 

All of these products release VOCs when in use, as well as when they are stored. Exposure to VOCs can cause short term health effects such as irritation of the eyes, nose and throat, headaches, and nausea, while long term exposures can adversely affect the liver, kidneys, and the central nervous system. 

The most efficient way of reducing VOCs is by avoiding the storage of open paint and solvent containers and providing adequate ventilation in the basement.

Other FAQs about Air quality that you may be interested in.

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The air quality of basements is an important parameter that should be monitored regularly, to protect the health conditions of the building’s occupants. 

The majority of the IAPs in a basement can be dealt with by improving its ventilation conditions, by installing ventilation systems, and if that isn’t possible, then ventilation by frequent airing. 

This would lead to dilution of the pollutants or carry them away. Basements are primarily used as storage spaces, so it is vital to raise awareness about the common household articles that are usually stored which can contribute to the degradation of air quality. 

Furthermore, adequate care should be taken in doing so, which should be based upon the nature of the item being stored.

 Frequently Asked Questions (FAQs): How to Improve Basement Air Quality

How Can I check the air quality in my basement?

Nowadays various devices are commercially available that help in monitoring air quality in a room. You can purchase an Indoor Air Quality monitor (Airthings 2930 Wave Plus – Radon & Air Quality Monitor), which monitors several parameters such as temperature, humidity level, and some models also include carbon monoxide detectors. 

What symptoms indicate pollution in the basement?

The symptoms that indicate pollution in the basement are runny nose, irritation in the throat and eyes, difficulty in breathing, headaches, sneezing, chest pain, dry and itchy skin, tiredness, nausea, and other flu-like symptoms.

How can I improve ventilation in my basement?

If your basement has windows, it would be ideal to open them from time to time in order. For basements which have no windows, but have a central air system, installing exhaust fans attached to the ducts helps to circulate the air. Lastly, for basements which neither have windows nor a central air system, one could use table fans which would help to circulate the air within the basement, and promote air exchange from adjoining rooms.

Is it safe to sleep in the basement?

If your basement has adequate ventilation, it is safe to sleep in the basement. In the absence of ventilation, you can install an air purifier based on the space of the basement and types of items kept in it. However, if your basement has a furnace, you should refrain from sleeping, since combustion processes in the furnace emit toxic gases such as formaldehyde, carbon monoxide, VOCs, etc.


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