Indoor air pollution means the physical, biological and chemical qualities of air inside a home, building, or facility that are harmful to health. Health conditions caused by indoor air pollution can be subtle, going unnoticed for a long time. It can lead to respiratory diseases, including cancer of the lungs and asthma.

What is Indoor Air pollution? Understanding Its Sources & Handling

A study carried out by the Institute for Health Metrics and Evaluation (IHME) called the Global Burden of Disease reveals that 1.6 million young people were killed in the year 2017 by health complications caused by indoor air pollution. This is four times more than the number of homicides that occurred that year. Some of these complications include pneumonia, heart diseases, stroke, and lung cancer.

Most of the cases of sicknesses and deaths from diseases caused by air pollution have been coming majorly from developing countries across Asia, Sub-Saharan Africa, and Latin America.

For these cases, the major culprit has been poor access to clean fuels for cooking. 

Most households in developing countries belong to low-income earners who depend on solid fuels for cooking such as crop waste, livestock dung, coal, and charcoal. They do not use clean fuels because they are either unavailable or too expensive. Burning these fuels in enclosed spaces in kitchens poses huge risks of respiratory diseases due to indoor air pollution.

According to the World Health Organization, the deaths caused by indoor air are categorized as follows:

According to the British Lung Foundation, humans spend up to 90% of their time indoors. This makes Indoor air pollution a cause of serious concern.

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Air pollution can occur in the following ways:

  • Heating a home
  • Cooking
  • Poor ventilation
  • Chemicals in building materials
  • Gas leakages

Sources of Indoor Air Pollution

The sources of indoor air pollution can be categorized as follows: 

  • Particulate matter: this refers to microscopic particles of dust and dirt in the air from outdoor and indoor sources. Indoor sources comprise smoking tobacco include (secondary inhalation), burning of candles, using wooden fireplaces, and kerosene heaters that lack vents.
  • Biological pollutants: this includes bacteria, fungi, viruses, pollen, mites, cockroaches, rat, and pet droppings. Stagnant water, wet surfaces, and materials damaged by water also provide perfect conditions to breed some organisms like molds, mildews, and some insects. House dust mites also thrive in this condition due to the humidity.
  • Volatile Organic Chemicals (VOCs) are emitted as gases from specific solids or liquids. Exposure to these chemicals may have short-term or long-term negative health effects depending on the degree of exposure during use and storage. VOCs are widely used as ingredients in household products such as varnishes, paints, disinfectants, cosmetics, and countless other products. 
  • Radon is a natural gas emitted from the soil. People living in modern houses that lack good ventilation are exposed to the dangers of this gas.
  • Asbestos is a building material notorious for causing respiratory diseases such as asbestosis and lung cancer. Asbestosis is a chronic injury to the lungs caused by asbestos fiber. Asbestos is most dangerous when it becomes easily disintegrated by hand. Certain activities in the home such as repairs or renovation can cause the easy disintegration of asbestos.

Also worthy of mention is Formaldehyde, a chemical widely used to manufacture building materials and several household products. It may be present in substantial concentrations both indoors and outdoors and exposure to humans can irritate the skin, eyes, nose, and throat. Formaldehyde also has the potential to cause some types of cancers.

Dealing with the Problem

Since we have established that indoor air pollution is a major problem, it is important that we mitigate it. While it is impossible to completely avoid pollutants, here are some of the steps you can take to reduce it to the barest minimum: 

1. Install and use exhaust fans and vents that help to expel unwanted gases outdoors. They should also be installed in kitchens and bathrooms to remove organic waste and excess humidity, especially from hot water in showers and dishwashers.

2. The humidity level in dark and cool areas such as the basement, cellar, or attic should be below 50%. This not only prevents water damage or condensation on building materials but also discourages the growth of mold and other biological pollutants. Spaces like this should be ventilated, and dehumidifiers should be installed for this purpose as well. 

3. Clean or replace every building material or furniture that has been damaged by water to prevent infestation of biological pollutants.

4. For people who suffer from allergies due to pollutants, special attention should be paid to the furniture and building materials installed in the home. Room furniture that accumulates dust and cannot be well cleaned with hot water should be avoided. It is also advisable that you leave a building whenever it is being cleaned with a vacuum to avoid sudden reactions from dust and mites. Central vacuums with high-frequency filters can also be installed. 

5. If you are to use woodstoves, choose the ones of proper sizes and ensure that all doors of the woodstove fit tightly.

6. Hire the service of a trained professional to examine, clean, and fine-tune the central service heating system comprising the furnace, chimneys, and flues annually. Repair any leakages or damages. You should also change or replace filters on central heating and cooling systems regularly following the manufacturer’s directives. 

7. Avoid smoking indoors. Also, do not use stoves or a fireplace that requires burning wood. They should be replaced with modern ones where possible.


While it might seem like people with asthma, COPD, and other respiratory conditions are the most at risk from indoor air pollution, pretty much anyone and everyone can be affected. This is why taking steps to correct pollution and poor air quality will help mitigate risks and make your interior space safer for everyone. 

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