In recent years, numerous factors have been discovered by scientists to be impacting human health negatively. One factor that has come up several times and has been emphasized in many nations across the globe is the impact of indoor air quality on human health.

Indoor air quality refers to the air quality in enclosed spaces people live in or spend time in. The indoor spaces in reference can comprise houses, schools, offices, or any other buildings. 

Recent studies state that humans spend about 90% of their time indoors. With people spending this much time indoors, it is vital that their air quality is the top tier to ensure their health is not compromised. 

When looking to work on ensuring that the air quality of indoor places is good, it is first important to understand what causes poor indoor air quality.

Causes of Poor Indoor Air Quality

External sources or internal sources can cause poor indoor air quality. 

External Sources

External sources of poor indoor air quality refer to the factors outside the indoor spaces that cause poor air quality indoors. The most common external source of poor indoor air quality is the entrance of outdoor air pollutants through windows, ventilation systems, etc. 

Some homeowners sometimes complain of poor indoor air quality caused by external sources, yet they have HVAC systems. Well-maintained and serviced HVAC systems have filters that prevent indoor air pollution. Therefore, if indoor air pollution continues even with an HVAC system installed, one should seek HVAC repair services. In most cases, the required HVAC repair and maintenance procedure is the replacement of filters. This makes the HVAC repair cost relatively low. 

Another common external source of indoor air pollution is smoke. Smoke from the outside can get into indoor spaces through chimneys and other open spaces, compromising indoor air quality. If you reside in areas with common smoke outside, you should install an exhaust fan in your house. The exhaust fan will remove smoke fumes from the house that would have otherwise compromised the indoor air quality.

Another common external source of indoor air pollution often disregarded by many is dust and grime on shoes. Dust accumulated on shoes is a common cause of indoor air pollution that causes numerous. 

Internal Sources

Internal sources of pollution cause a huge number of poor indoor air quality cases. The most common internal source of air pollution is combustion byproducts. In houses, there are several uses of fire, for instance, cooking and heating the house. All these fires emit harmful byproducts that compromise the air quality in the house. 

Another indoor source of poor air quality in houses and indoor places is cleaning detergents, paints, pesticides, and other common household products. When used, these common household products contain harmful chemicals introduced into the air, among other volatile organic compounds. 

Old building materials, such as asbestos, also affect the air quality inside indoor places. It is vital to ensure that all possible indoor sources of air pollution are countered to avoid health complications. 

Effects of Poor Indoor Air Quality on Human Health

Effects of Poor Indoor Air Quality on Human Health

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As mentioned above, poor indoor quality leads to numerous health complications. Health complications caused by poor indoor air quality affect human health. 

Respiratory Diseases

Since poor-quality air in indoor environments first goes to the human respiratory system, this is where many complications start. The most common respiratory condition that emanates from poor indoor air quality is asthma. Asthma is a condition whereby a person often has difficulties in breathing. This is caused by inflammation, narrowing, and the production of extra mucus in the person’s airways.

Asthma is commonly found in people who have lived in indoor areas that have mold accumulation. Mold ruins indoor air quality when it reproduces, and its spores are suspended in the air. Mold spores in the air get into the human lungs and trigger asthma symptoms. Any reaction to spores in the air means a person is allergic to mold. While the condition can be treated, it can be fatal in some extreme conditions, especially if medical aid is not offered in time. 

Poor indoor air quality can also affect the prenatal lung development of an infant. A study discovered parent exposure to areas with poor indoor air quality was linked with impaired lung function in infants. This revolution denotes the dire situation surrounding the effects of poor indoor air quality, even for unborn babies. Therefore, expectant mothers need to ensure that they stay in places with perfect air quality. This will help ensure that the health of their unborn children is not compromised.

Areas with poor indoor air quality due to building materials using asbestos can also cause respiratory problems. When exposed to asbestos, one is faced with the risk of getting asbestosis. Asbestosis is a respiratory condition characterized by breath shortness and extreme coughing. Modern construction safety standards state that asbestos materials should not be used in construction. People residing in old houses with asbestos materials were instructed to remove them for their safety and health. 

Cardiovascular Diseases

While not common, poor indoor air quality can lead to developing cardiovascular conditions. The cardiovascular condition caused by exposure to poor indoor quality is characterized by oxidative stress, inflammation, and arterial stiffness.

These signs of cardiovascular diseases are caused by exposure to indoor air that has been ruined by ozone. Some air cleaners are the most common ozone source in houses, classes, and other indoor settings. 

Because ozone is the common cause of poor indoor air quality that causes cardiovascular conditions, one must work on preventing it. The best preventive method for avoiding this is to use air cleaners that do not produce or generate ozone. An easy way to know air cleaners that will generate ozone is by checking the type column. Air cleaners that are listed as electrical in the type column will generate ozone. You should purchase air cleaners listed as mechanical only to ensure you do not suffer from cardiovascular conditions caused by the ozone. 

Cognitive Impairments

The human brain is an extremely sensitive organ that requires optimum conditions to ensure none of its functions are affected. However, poor indoor air quality is not optimum for the functioning of the human brain. Exposure to air pollutants such as nitrogen oxides, endotoxin, mold, and particulate matter causes impaired mental performance in children and adults.

Nitric oxide is an example of a common air pollutant that affects cognitive performance. When exposed to high nitric oxide levels, one’s cognitive outcomes are significantly affected. Common tasks such as speaking and executive functioning become difficult due to the effects of nitric oxide on the brain. 

In some schools, poor air quality causes students to develop physical defects. Though quite rare, you must ensure you stay in areas with good-quality air to avoid such conditions, which can alter one’s life completely.

Work comparison is a common explanation used to demonstrate the negative effects of poor air quality on cognitive capabilities. In a study, professionals analyzed the work of two study groups. The study groups were divided into two, one placed in an area with necessary measures to ensure good air quality and the other in an area with poor air quality. The professionals set performance measures that they would use to compare the two groups. In the end, it was found that people working in the “green” area had higher performance measures when compared to the other study group.


In the 21st generation, cancer has proven to be a fatal disease that claimed the lives of about 10 million people in 2020. The lives claimed by cancer continue to rise as the years’ progress. Two of the most effective ways to prevent the occurrence of the disease have been early detection and using preventive measures. 

Lung cancer is among the deadly conditions caused by staying in areas with poor indoor air quality. Most of its severe cases were found in people living in areas with air quality ruined by secondhand smoke, arsenic, some forms of chromium, and asbestos.

With the possibility of getting such a deadly disease, it is paramount that one takes up several measures to improve indoor air quality


Our current generation is full of industries emitting exhaust fumes, harmful chemicals in household detergents, etc., so every person must be taught about poor indoor air quality. The effects of poor indoor air quality on human health should also be a well-known topic for everyone to ensure that human mortality due to this is reduced. 

Taking up easy measures such as installing an air purifier or regularly opening windows can help save lives and prevent poor health among many people. 


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