• Dr Shernice Johnson

The Heath Effects of Poor Indoor Air Quality


Air quality isn’t something that we think about often. When it comes to indoor air quality (IAQ) we usually tend to make a couple of assumptions:

  1. The air indoors is significantly safer than the air outdoors;

  2. Unless something in the air stimulates our visual or olfactory senses, it is safe to breathe.

This however, isn’t always the case. In this article we’ll explore some of the effects of poor indoor air quality on human health.


Indoor air quality is defined as the quality of the air within and around a building and its structures. Poor IAQ can have many adverse effects on human health. Many terms have been coined to describe the health effects of poor IAQ. The term "building related illnesses" refers to a group of disorders which have been linked to modern airtight buildings with a dependence on various mechanical systems for circulating air [1]. The term "sick building syndrome" has fallen out of use but refers to non-specific symptoms that occupants of a building may experience acutely. The cause of these symptoms is unknown and typically resolve soon after leaving the building.

Effects of Poor IAQ on Various Bodily Systems

In this section we’ll take systematic approach to identifying the various ways in which poor IAQ can affect the human body. In particular, we’ll be looking at the effects of particulate matter (PM), ozone (O3), carbon monoxide (CO), sulphur dioxide (SO2), nitrogen dioxide (NO2), lead, cigarette smoke and formaldehyde.

Respiratory System

The respiratory system the first point of contact of inhalable toxins, this means that the effects seen in this part of the body are numerous. Conditions which can result from poor IAQ include [2]:

  • Occupational asthma

  • Allergic Rhinitis

  • COPD (Bronchitis, Emphysema)

  • Respiratory Infections (e.g. Legionella)

  • Hypersensitivity pneumonitis

  • Inhalational fever

  • Cancer (nasal, leukaemia)

There are many ways in which poor IAQ causes respiratory problems. A common mechanism is when pollutants such as particulate matter irritate the lungs and cause an overproduction of mucus and inflammation leading to shortness of breath. Prolonged exposure to these chemicals leads to constant irritation of the airways and permanent damage to the respiratory system.

Nervous System

Several neurological symptoms and conditions can arise from poor IAQ. These include headaches, lethargy and difficulty concentrating, peripheral neuropathy in diabetics, memory impairment and learning disabilities. Lead, especially, is known to cause neurological impairment, especially in children. Formaldehyde has also been shown to cause impaired learning. Recent studies have implicated several air pollutants in the development of dementia. These pollutants include particulate matter (PM), carbon monoxide (CO) and nitrogen dioxide (NO2) [4, 5].

Cardiovascular System

Poor IAQ can have both acute and chronic effects on the heart [6, 7].

  • Acute (myocardial infarction, ischemic stroke, heart failure, cardiac arrhythmia, atrial fibrillation)

  • Chronic (arterial and venous disease, hypertension, coronary artery disease

There are many mechanisms by which pollutants affect the heart including inflammation, increased coagulability of blood and oxidative stress. The nerve supply to blood vessels can also be affected, this leads to poor blood pressure control. Here is a table showing how the various pollutants affect cardiovascular health.


Along with our nostrils, our skin is a common first point of contact for air pollution and poor IAQ is known to have damaging effects. Particulate matter, volatile organic compounds, oxides and paraldehydes can cause premature skin aging and hyper-pigmentation on the face. Sulphur dioxide is known to cause redness and blisters [2].


The effects of pollutants on the eyes can range from dryness and irritation to blindness [8]. Sulphur dioxide (SO2) is known to cause corneal opacification, a condition where the clear covering of the eye becomes cloudy causing blurred vision and eventual blindness. Cigarette smoke has been linked to cataracts, the specific compounds which lead to their development have not yet been isolated, however.


Exposure to air pollution can negatively impact a developing fetus. Studies have shown linkages between air pollution exposure, fetal head size, fetal growth and low birth weight [2].


Poor indoor air quality has a range of effects on various bodily systems. While it is true that the effects on the respiratory system are numerous and pronounced we must be aware that it can also affect the nervous system, heart, skin and eyes. The effects also extend to developing fetuses.

Given these findings it is evident that improving indoor air quality can lead to decreased morbidity and mortality. It is therefore imperative that systems to detect and reduce contaminants are put in place and constantly updated according to emerging evidence.

Official Statement from REgenTT Admin at 2/6/2019:

The May 29th 2019 blog post created by Dr. Shernice Johnson contained a conclusion which was not fully written by the author and included additional lines from REgenTT. If there was any confusion regarding the conclusion, kindly see above.


  1. Lara, A. R. (n.d.). Building-Related Illnesses - Pulmonary Disorders. Retrieved May 28th, 2019, from https://www.msdmanuals.com/professional/pulmonary-disorders/environmental-pulmonary-diseases/building-related-illnesses

  2. Ghorani-Azam, A., Riahi-Zanjani, B., & Balali-Mood, M. (2016). Effects of air pollution on human health and practical measures for prevention in Iran. Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences, 21, 65. doi:10.4103/1735-1995.189646

  3. Patelarou, E., Tzanakis, N., & Kelly, F. J. (2015). Exposure to indoor pollutants and Wheeze and asthma development during early childhood. International journal of environmental research and public health, 12(4), 3993–4017. doi:10.3390/ijerph120403993

  4. Allen, J. G., Macnaughton, P., Satish, U., Santanam, S., Vallarino, J., & Spengler, J. D. (2016). Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments. Environmental Health Perspectives, 124(6), 805-812. doi:10.1289/ehp.1510037

  5. Carey, I. M., Anderson, H. R., Atkinson, R. W., Beevers, S. D., Cook, D. G., Strachan, D. P., . . . Kelly, F. J. (2018). Are noise and air pollution related to the incidence of dementia? A cohort study in London, England. BMJ Open, 8(9). doi:10.1136/bmjopen-2018-022404

  6. Uzoigwe, J. C., Prum, T., Bresnahan, E., & Garelnabi, M. (2013). The emerging role of outdoor and indoor air pollution in cardiovascular disease. North American journal of medical sciences, 5(8), 445–453. doi:10.4103/1947-2714.117290

  7. Wang, M., Sampson, P. D., Sheppard, L. E., Stein, J. H., Vedal, S., & Kaufman, J. D. (2019). Long-Term Exposure to Ambient Ozone and Progression of Subclinical Arterial Disease: The Multi-Ethnic Study of Atherosclerosis and Air Pollution. Environmental Health Perspectives, 127(5), 057001. doi:10.1289/ehp3325

  8. Rozanova, E., Heilig, P., & Godnić-Cvar, J. (2009). The Eye - a Neglected Organ in Environmental and Occupational Medicine: An Overview of Known Environmental and Occupational Non-Traumatic Effects on the Eyes, Archives of Industrial Hygiene and Toxicology, 60(2), 205-215. doi: https://doi.org/10.2478/10004-1254-60-2009-1869

  9. West, S. K., Bates, M. N., Lee, J. S., Schaumberg, D. A., Lee, D. J., Adair-Rohani, H., … Araj, H. (2013). Is household air pollution a risk factor for eye disease?. International journal of environmental research and public health, 10(11), 5378–5398. doi:10.3390/ijerph10115378

  10. Cincinelli A, Martellini T. (2017). Indoor Air Quality and Health. International Journal of Environmental Research and Public Health, 14(11):1286. doi:10.3390/ijerph14111286

  11. Nielsen, G. D., Larsen, S. T., & Wolkoff, P. (2016). Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment. Archives of toxicology, 91(1), 35–61. doi:10.1007/s00204-016-1733-8

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