01/06/2021 09:39

What comes to your mind when you think of air pollution? You are not wrong to think of gasoline cars, trucks, or coal-based power plants because those are the sources of major air pollutants – outdoor air pollution. However, indoor air can be polluted up to 5 times more than outdoor air, as EPA says. Any harmful impurity that is present in the air can spoil the atmosphere indoors.

A report from the World Health Organization (WHO) tells that nearly 4 million people die every year from illnesses caused by indoor air pollution, making air pollution the most significant health risk in the world. In this article, we are going to discuss the typical indoor air pollutants, their sources, health effects, and how can we reduce the concentration in the air.

Common Indoor Air Pollutants

Organic Contaminants

Organic pollutants include viruses, bacteria, dust mites, pet dander, and pollen. Humans and pets are the primary carriers of germs and bacteria. Dust mites live in carpets, mattresses and grow by excess moisture in the house. Pollen can enter the house by cloths or through the air in the pollinating seasons.

Health Effects: Because these biological pollutants are small enough to inhale, they trigger allergic reactions, including sneezing, coughing, lethargy, watery eyes, fever, dizziness, digestive problems, and shortness of breath. Different viruses and bacteria cause various health issues.

How to Protect: To be safe, ensure that the house is well-ventilated and minimize the moisture level. A relative humidity level of 30% – 60% will help regulate mites and molds. Regularly wash your beddings and carpets with warm water. Keep yourself clean after coming to the house during the pollinating season.

Building and Paint Products/Formaldehyde

Formaldehyde is a chemical released from pressed wood products, building materials, and furniture, and can be found in large concentration both indoors and outdoors.

Health Effects: Common health effects of the chemical include skin, eye, nose, and throat irritation, as well as some types of cancers when the level of exposure is high.

How to Protect: For safety, ensure that building materials and pressed-wood products contain little to no emissions. Likewise, keep the house well ventilated when using the products.

Volatile Organic Compounds (VOCs)

Volatile Organic Compounds (VOCs) are fumes that find their way inside your house from paints, aerosol sprays, cleaning detergents and disinfectants, wood preservatives, stored fuels, automotive appliances, moth repellents, pesticides, and air fresheners. Other sources include copiers, printers, building supplies, and furnishings.

Health Effects: Low exposure to the gases can bring eye, nose, and throat irritations, head pains, light-headedness, and nausea. Extensive contact with the VOCs can cause harm to the liver, kidney, the central nervous system, and sometimes they can result in cancer in both humans and animals.

How to Protect: For protection, ensure that there is a lot of air distribution around the house when using materials that release VOCs, and keep the products away from children and pets.

Carbon Monoxide (CO)

Carbon Monoxide is a tasteless, colorless, and odorless harmful gas. The toxic gas is produced when fossil fuels do not burn completely. The gas can be emitted from unvented space heaters, gas stove, leaking furnaces and chimneys, automobile exhaust fumes, generators, and other equipment powered by gasoline.

Health Effects: At low concentrations, the gas can cause fatigue and chest pain; at average concentrations, the gas can cause weakened vision and decreased brain function. At higher levels, the gas can be fatal.

How to Protect: As a protective measure, it is crucial to ensure that combustion material is adjusted correctly and maintained, as well as ensuring that there is proper air distribution when high levels of CO are expected.

Nitrogen Dioxide (NO2)

The primary sources of this toxic and corrosive gas include unvented gas stoves, kerosene heaters, tobacco smoke, welding, and vented stoves with faulty installations. Living nearby highways will increase the exposure to NO2 as the gasoline-powered vehicles are the primary source of NO2 emissions.

Health Effects: When consumed, the gas causes respiratory infections, lung diseases, and chronic bronchitis. Lower levels of exposure decrease lung function and increase respiratory activity.

How to Protect: As a precaution, vent the NO2 appliances to the outdoors and ensure proper installation of vented gas stoves and other combustion appliances.

Lead (Pb)

Lead is a naturally occurring soft metal, whose use in household painting was barred in 1978. Lead particles are airborne and highly toxic when consumed.

Health Effects: Unsafe contact with lead causes impairment to the brain, the kidneys, red blood cells, and the central nervous system. Old lead paint remains to be the leading cause of lead (Pb) exposure in the US.

How to Protect: For protection, keep away from peeled paints and avoid removing paint by open-flame burning, sanding, or dry scraping. Keep the house mopped and clean and ensure that children never are exposed to lead particles because their bodies absorb more lead quickly than adults do.


The source of the semi-volatile organic chemicals in homes comes from sprays, liquids, powders, foggers, crystals, sticks, and balls that are used to kill and regulate pests.

Health Effects: Contact with these chemicals may result in eye, nose, and throat irritations, a higher risk of cancer, and injury to the kidney, including the central nervous system.

How to Protect: For protection, strictly use the pesticide according to the manufacturer’s instructions.


Asbestos is a group of minerals found in rocks and soils. Because these minerals have a high fiber strength as well as heat resistance, the minerals are used in building supplies, automobile parts, gaskets, coating, packing, and heat-resistant materials.

Health Effects: Asbestos unsafe because inappropriate attempts to extract asbestos materials can release asbestos fibers into the air at home. The fiber can then enter the lungs and cause asbestosis and lung cancer.

How to Protect: If materials at home contain asbestos, let them be like them and seek professional assistance when you need to remove them for remodeling or maintenance.

Radon (Rn)

Radon is an invisible and unscented gas present all over in low concentration. The gas comes from the earth when the uranium inside breaks down.

Health Effects: Contact with increased levels of radon exposes one to the danger of getting lung cancer.

How to Protect: To reduce the risk, have your house checked by a trained professional for radon level. Alternatively, you could purchase a radon testing kit and screen the home yourself. When you detect high levels of radon concentration, seek professional help for the elimination of the gas.

We do hundreds of activities at our house in nowadays, so air pollution is very probable. However, source control is the best way to keep the air pollution level to a minimum. Another measure you can take is to use air filters in your HVAC system and bring high-quality indoor air purifiers to improve indoor air.