9 Proven Indoor Air Pollutants You Need To Know About


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Clean air is a basic requirement for life. For this reason, we try to make sure that our surroundings are free from pollution: we grow plants outdoors, ban buildings that emit hazardous fumes, or avoid cigarette smokes. A lot of times, the bulk of our focus is directed in the outdoors that we even get paranoid to go outside thinking how toxic outdoors air can be, but what most of us are not aware of is that pollution may also be present inside our homes – the place where we spend most of our time.

According to the WHO (World Health Organization), outdoor air pollution should not only be our main concern as the indoor air may also wreak havoc on our health if it contains toxic levels of the following chemicals: benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons, radon, trichloroethylene, and tetrachloroethylene.

These substances labeled as hazardous by the WHO may come from construction materials, solvents from cleaning materials, human activities such as combustion of fuels for cooking or heating, or from leakages of substances from the soil.

Now let’s try to look more closely at some of the most common hazardous indoor pollutants in the world.

1. Benzene

Benzene is both present in outdoor and indoor air; however, studies have shown that indoor concentration of benzene is higher than those of outdoors, and this comes with the fact that indoor air circulation is poor in most buildings. Moreover, benzene is considered as a genotoxic carcinogen in humans and it predisposes conditions like acute myeloid leukemia.

2. Carbon Monoxide

Based on laboratory studies, the maximum concentration of carbon dioxide in houses and buildings should not exceed 2%. If you are continuously exposed to high levels of carbon dioxide – which in indoors are usually caused by the use of unvented stoves- your risk of getting heart disease also proportional increases.

3. Formaldehyde

Building materials and cleaning products may contain formaldehyde, an organic substance that may cause sensory irritations. At room temperature formaldehyde is colorless and it has a characteristic pungent and irritating smell.

4. Naphthalene

In a clinical study where subject mice were exposed to naphthalene 6 hours per day, 5 days a week for 104 weeks, severe inflammation was noted in almost all mice exposed to the lowest naphthalene dose of 53mg/m3.  In humans, continuous exposure to naphthalene may predispose respiratory tract lesions including tumors, and anemia. Inside the house, naphthalene is usually found in cleaning solvents and mothballs.

5. Nitrogen dioxide

Nitrogen dioxide belongs to a family of highly reactive gasses called nitrogen oxides (NOx). In households, it is produced when fuels are burned at high temperatures. It is believed that continuous exposure to nitrogen oxide supports the occurrence of respiratory diseases such as influenza. Some studies also conclude that though the short-term exposure effects to nitrogen dioxide are unclear, long-term exposure can cause acute respiratory diseases, especially in children.

6. Polycyclic Aromatic Hydrocarbons (PAH)

PAH are a group of organic contaminants that form from the incomplete combustion of hydrocarbons such as coal and gasoline. Tobacco smoking, smoldering fire places, wood stoves, unvented gas-burning appliances, kerosene spaces and heaters all contribute to the production of PAHs indoors. PAHs are generally hazardous as they increase the risk of cancer.

7. Radon

Radon is a naturally occurring radioactive gas that is emitted after the decay of radioactive uranium. Since uranium is all over the earth, radon can pose a problem almost anywhere. While radon from the soil can be easily dispersed by the air outdoors, radon that enters through the cracks in buildings and houses can be easily trapped inside making it a major health hazard. Exposure to radon gas is believed to be the second major cause of lung cancer after cigarette smoking.

8. Trichloroethylene (TCE)

Trichloroethylene is a manufactured, volatile organic chemicals that can be found on most cleaning solvents that are used to remove grease from metals. It can also be found as an ingredient in paints, varnishes, and paint solvents. You may come in contact with trichloroethylene indoors when TCE evaporates into indoor air during cooking and washing. TCE may also evaporate from groundwater, and immigrates through building foundations into the building indoor air. Constant TCE exposure predisposes you to several types of cancer.

9. Tetrachloroethylene

EPA’s Integrated Risk Information System (IRIS) has now classified tetrachloroethylene as likely to be carcinogenic to humans. Tetrachloroethylene is widely used indoors as dry cleaning products and metal degreasing solvents. Effects resulting from acute (short-term) high-level inhalation exposure of humans to tetrachloroethylene include irritation of the upper respiratory tract and eyes, kidney dysfunction, and neurological effects such as reversible mood and behavioral changes, impairment of coordination, dizziness, headache, sleepiness, and unconsciousness, while the primary effects from chronic (long-term) inhalation exposure are neurological, including impaired cognitive and motor neurobehavioral performance.  Tetrachloroethylene exposure may also cause adverse effects in the kidney, liver, immune system and hematologic system, and on development and reproduction.

In conclusion

You can hire experts to do a professional check to measure the level of pollution you have indoors, or you can check it yourself by using commercial test kits. But what is important though is that you take direct and precautionary measures to decrease or eliminate harmful chemicals in your indoor air, because, at the end of the day, clean air is a medicine… let it blow the dark cobwebs of your mind and body generated from the day’s toil.


Read next: 10 Simple And Easy Ways To Breathe In Clean Air Indoors

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