IAQ relationship to human health

Air stands as a fundamental life-building element, and the quality of indoor air in settings like homes, schools, public structures, healthcare facilities, and private residences plays a pivotal role in people's well-being and overall health. Globally, household air pollution caused a staggering loss of 86 million healthy life years in 2019, with the heaviest burden borne by women and children in low- and middle-income nations. An estimated 3.2 million deaths in 2020 were attributed to household air pollution, including over 237,000 deaths of children under five. In the European Union, air pollution in its entirety emerges as the foremost environmental health concern, causing an estimated 400,000 premature deaths annually. Poor air quality is associated with a range of severe health issues, including asthma, chronic obstructive pulmonary disease, cardiovascular disorders, strokes, and lung cancer, among others, while also intensifying morbidity and mortality related to cardiovascular and respiratory conditions⁽²⁶⁾.

How indoor air pollution affects people

The concept of exposure

Both short-term and long-term exposure to indoor air pollution can give rise to various health complications⁽²⁷⁾. Short-term effects encompass symptoms such as eye, nose, and throat irritation, along with headaches, dizziness, and fatigue, which are generally transient and treatable⁽²⁸⁾. However, these symptoms can exacerbate pre-existing conditions like asthma⁽²⁹⁾. Conversely, certain health consequences may manifest only after prolonged and repeated periods of exposure⁽³⁰⁾. Sustained exposure to particulate matter and other pollutants in household air pollution can inflame airways and lungs, impair immune responses, and diminish blood's oxygen-carrying capacity⁽³¹⁾, potentially leading to respiratory diseases, heart ailments, and cancer⁽³²⁾.

Susceptibility to indoor air pollution

Furthermore, specific demographic groups, including children, women, the elderly, and individuals with pre-existing conditions, as well as socioeconomically disadvantaged households, are especially vulnerable to indoor air pollution⁽³³⁾. Vulnerability depends on the specific pollutant and a group's susceptibility to it⁽³⁴⁾. Studies indicate children's heightened susceptibility to pollutants like tobacco smoke, lead, and phosphorous-containing pesticides, which can cause coughing, bronchitis, worsened asthma, and other respiratory illnesses⁽³⁵⁾. Globally, almost half of all deaths from lower respiratory infections in children under five are attributed to inhaling particulate matter from household pollution⁽³⁶⁾. Elderly individuals might be particularly vulnerable to air pollution due to reduced chemical elimination capacity with age, though they may also exhibit reduced sensitivity to certain effects like eye or nose irritation. People with cardiovascular issues are more susceptible to particles, while those with respiratory ailments like asthma are more prone to various air pollutants⁽³⁷⁾.

Indoor air pollution, including particulate matter, allergens, endotoxin, and mould, has been linked to compromised health and performance in both children and adults⁽³⁸⁾. Certain chemicals may induce irritation of the eyes and upper airways, affecting cognitive abilities⁽³⁹⁾. Direct links have also been established between exposure to nitric oxide and adverse cognitive outcomes, including reduced verbal abilities and executive functioning⁽⁴⁰⁾.

Among the 3.2 million global deaths attributed to household air pollution, 21% result from lower respiratory infections, particularly affecting children⁽⁴¹⁾. Additionally, 19% are related to chronic pulmonary disease and 6% to lung cancer⁽⁴²⁾. The presence of mould and humidity levels, impacting mould prevalence indoors, correlates with long-term health effects, notably asthma severity⁽⁴³⁾. Moreover, household pollution exposure during pregnancy has also been linked to altered lung development, subsequently elevating the risk of pneumonia within a child's first year⁽⁴⁴⁾. Specific pollutants like radon, asbestos, arsenic, tobacco smoke, and others in indoor air have been associated with cancer, especially lung cancer⁽⁴⁵⁾.

Research has also shown that markers of cardiovascular disease can manifest even at ozone levels lower than WHO guidelines⁽⁴⁶⁾. In healthy adults, short-term exposure to both indoor and outdoor ozone has been linked to elevated blood platelets, a clotting risk factor, and increased blood pressure⁽⁴⁷⁾. Astonishingly, 32% of the 3.2 million global deaths due to household pollution exposure result from ischemic heart disease, while an additional 23% stem from stroke due to pollutants from solid fuels and kerosene in indoor environments⁽⁴⁸⁾. Evidence also points to connections between household air pollution and low birth weight, tuberculosis, cataracts, and cancers of the nasopharynx and larynx⁽⁴⁹⁾.

However, the complete scope of health effects stemming from indoor air pollution remains largely unknown, characterised by numerous gaps in knowledge. This issue exhibits a complexity and prevalence that surpasses the current grasp of research.

Health effects of indoor air pollution

Air pollution can have various impacts on human health:

1. Sensory impacts
2. Acute health effects
3. Chronic health effects
4. Carcinogenic effects
5. Mortality

Sensory impacts

These are primarily related to discomfort and irritation of the senses (e.g., eye, nose, and throat irritation, odors).

Immediate health effects

Short-term illnesses, such as respiratory infections and asthma exacerbations (short-term illnesses, such as respiratory infections and asthma exacerbations).

Long-term health effects

These include long-term (chronic) health problems, such as respiratory and cardiovascular diseases, lung disease, and diabetes.

Carcinogenic effects

Some air pollutants are known or suspected carcinogens, meaning they can cause cancer.

Mortality

In the most severe cases, air pollution can lead to death.

References

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(31) The United States Environmental Protection Agency, “Introduction to Indoor Air Quality,” The United States Environmental Protection Agency, 16 May 2023. Available online: https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality#:~:text=Indoor%20Air%20Quality%20(IAQ)%20refers,and%20comfort%20of%20building%20occupants.

(32) Maria del Carmen González-Caballero ET AL, “Pollution, Indoor Air,” Elsevier Reference Collection in Biomedical Sciences, 2023: https://www.sciencedirect.com/science/article/abs/pii/B9780128243152006801 ; The United States Environmental Protection Agency, “Introduction to Indoor Air Quality,” The United States Environmental Protection Agency, 16 May 2023. Available online: https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality#:~:text=Indoor%20Air%20Quality%20(IAQ)%20refers,and%20comfort%20of%20building%20occupants.

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(40) The National Institute of Environmental Health Sciences, “Indoor Air Quality,” 12 July 2023. Available online: https://www.niehs.nih.gov/health/topics/agents/indoor-air/index.cfm

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(42) The World Health Organisation, “Household Air Pollution,” 28 November 2022. Available online: https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health

(43) The National Institute of Environmental Health Sciences, “Indoor Air Quality,” 12 July 2023. Available online: https://www.niehs.nih.gov/health/topics/agents/indoor-air/index.cfm

(44) The National Institute of Environmental Health Sciences, “Indoor Air Quality,” 12 July 2023. Available online: https://www.niehs.nih.gov/health/topics/agents/indoor-air/index.cfm

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(46) The National Institute of Environmental Health Sciences, “Indoor Air Quality,” 12 July 2023. Available online: https://www.niehs.nih.gov/health/topics/agents/indoor-air/index.cfm

(47) The National Institute of Environmental Health Sciences, “Indoor Air Quality,” 12 July 2023. Available online: https://www.niehs.nih.gov/health/topics/agents/indoor-air/index.cfm

(48) The World Health Organisation, “Household Air Pollution,” 28 November 2022. Available online: https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health

(49) The World Health Organisation, “Household Air Pollution,” 28 November 2022. Available online: https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health