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Indoor Air Quality

Indoor air quality (IAQ) plays a crucial role in public health, particularly since most people spend 80% to 90% of their time indoors. Modern building practices and lifestyle changes—such as airtight construction and limited natural ventilation—can allow a wide range of contaminants to accumulate without our immediate awareness. These pollutants include biological agents (e.g., mold, bacteria) as well as harmful gases (e.g., radon, carbon monoxide) that can contribute to respiratory issues, cardiovascular diseases, and even certain cancers. Understanding IAQ and adopting effective mitigation measures is critical for safeguarding health, especially in densely populated or industrial settings.

 

The amount of time spent indoors also raises overall exposure to toxic substances like benzene, formaldehyde, and fine particulate matter (PM2.5 and PM10). Vulnerable groups—including children, older adults, and individuals with chronic illnesses—are particularly at risk, as poorly ventilated or highly sealed buildings can trap contaminants, sometimes at concentrations exceeding outdoor levels. Moreover, particles linked to traffic or industrial pollution can infiltrate homes and workplaces through windows, doors, or inadequate filtration systems, further impacting indoor air quality.

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What Is It?

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Indoor Air Quality (IAQ) refers to the presence of various pollutants—chemical, biological, or physical—within enclosed environments such as homes, offices, and schools. In contrast to outdoor pollution, which is frequently publicized, indoor contaminants often remain invisible and undetected without proper measurement tools. These pollutants can include:

 

  • Volatile Organic Compounds (VOCs): E.g., benzene, formaldehyde, toluene

  • Fine Particulate Matter (PM2.5 and PM10): Microscopic particles able to penetrate the respiratory tract

  • Gases: Radon (radioactive), carbon monoxide (CO), nitrogen oxides (NOâ‚“)

  • Biological Pollutants: Mold, bacteria, viruses, dust mites, pet dander

  • Byproducts of Activities: Emissions from cooking, heating, or smoking

 

Because contemporary lifestyles involve spending extended periods in tightly sealed buildings, these pollutants can accumulate, sometimes reaching higher concentrations than outdoor levels. This accumulation poses significant health challenges—especially given that many of these pollutants (e.g., CO, radon, certain VOCs) are colorless and odorless.

Where Do They Come From?

  1. Everyday Household Activities

    • Cooking (particularly with gas stoves): Emissions include particulates (PM2.5), carbon monoxide, and nitrogen oxides

    • Cleaning and Fragrance Products: Many cleaning agents and air fresheners release VOCs when sprayed or evaporated

    • Tobacco Smoke: Over 7,000 substances, such as benzene and formaldehyde, can linger in the air and settle on surfaces
       

  2. Building Materials and Furnishings

    • Paints, Adhesives, Pressed-Wood Furniture: Potentially release formaldehyde and other VOCs as they cure or off-gas

    • Mold and Dampness: Thrive in poorly ventilated or humid environments (bathrooms, basements)

    • Radon: Naturally occurring, seeping in from the soil through cracks in foundations
       

  3. Insufficient Ventilation

    • Modern constructions emphasize airtightness for energy efficiency, often trapping indoor pollutants

    • Poorly maintained or unbalanced HVAC systems recirculate contaminated air without adequate filtration or fresh air exchange
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  4. Infiltration From the Outdoors​

    • Traffic- and industry-related pollutants (PM, nitrogen oxides) can enter through open windows or leaky ventilation systems

    • Seasonal allergens (pollen, spores) may also be carried in on clothing or through simple air exchange

How They Affect You

  1. Respiratory Impacts

    • Exacerbation of asthma, bronchitis, or COPD by elevated levels of particulate matter and allergens

    • Irritation of the eyes, nose, and throat, triggered by VOCs or by gases like ozone or NOâ‚‚
       

  2. Cardiovascular Risks

    • Long-term exposure to fine particles increases the likelihood of hypertension and heart disease

    • Certain combustion byproducts can induce systemic inflammation, affecting cardiac health
       

  3. Chronic Illnesses and Cancers

    • Radon: A leading cause of lung cancer, particularly for smokers in radon-rich areas

    • Benzene and Formaldehyde: Known carcinogens; prolonged exposure increases cancer risk

    • PM2.5 and PAHs: Associated with various chronic health conditions and potential carcinogenic effects
       

  4. Cognitive and Mental Well-Being

    • Fatigue, concentration difficulties, and heightened stress linked to poor indoor air, including high COâ‚‚ or VOC levels

    • Some VOCs (e.g., from solvent-based products) can affect mood and cognitive function over time
       

  5. Invisible Hazards

    • Many harmful agents (e.g., carbon monoxide, radon) have no color or odor

    • In the absence of detection devices, occupants often remain unaware of dangerous concentrations

How To Protect Yourself

  1. Regular and Proper Ventilation

    • Open Windows: Air out rooms daily, even briefly, to reduce stagnant air

    • Use Exhaust Fans: In kitchens and bathrooms to remove moisture and combustion byproducts

    • Check HVAC Systems: Ensure filters are replaced on schedule and ventilation ducts remain unobstructed
       

  2. Controlling or Reducing Pollution Sources

    • Choose Low-VOC Products: Opt for paints, adhesives, and furnishings labeled “low-VOC” or “VOC-free”

    • Avoid Indoor Smoking: Tobacco smoke is among the most significant contributors to poor IAQ

    • Maintenance of Appliances: Service gas stoves, furnaces, and water heaters annually to prevent leaks or improper combustion
       

  3. Monitoring and Maintenance

    • Radon Testing: Particularly crucial in high-radon zones; seal cracks and improve underfloor ventilation if levels exceed recommended thresholds

    • Carbon Monoxide Detectors: Essential wherever fuel-based appliances are in use

    • Air Purifiers: Devices equipped with HEPA filters can capture fine particles; activated carbon filters help reduce VOCs

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Even though modern homes and offices tend to seal out noise and weather, they also trap pollutants that can quietly compromise our respiratory, cardiovascular, and cognitive health. Without proper ventilation, regular monitoring, and effective source control, these hazards often remain invisible to occupants. Fortunately, devices such as indoor air sensors, radon test kits, and carbon monoxide detectors can shed light on otherwise unseen problems. Yet, in many cases, awareness remains the first and most pivotal step. Educating household members, coworkers, and the broader community can significantly enhance prevention efforts and long-term outcomes. While total elimination of indoor pollutants is not always feasible, diligent maintenance, informed choices, and mindful habits can substantially lower risks and foster safer indoor environments.

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Additional Key Recommendations

  1. Indoor Air Sensors: Connected devices can measure COâ‚‚, PM2.5, VOCs, and other metrics in real time — rendering invisible pollutants visible.

  2. Humidity Control: Keep indoor humidity at 30–50%. Use dehumidifiers in damp areas, and promptly address leaks or water damage to prevent mold growth.

  3. Awareness and Education: Spread knowledge among family, neighbors, and colleagues. Often, the very first step is recognizing the issue, as many remain unaware of invisible indoor pollutants.

  4. Hidden Problem: Despite available technologies (sensors, ventilation systems, healthier construction materials), indoor air pollution often flies under the radar, leading to prolonged or repeated exposure to unhealthy conditions.

References

  1. Adegunwa, A. O., Oyekunle, J. A. O., & Ore, O. T. (2025). Distribution and source apportionment of polycyclic aromatic hydrocarbons in indoor dust of an emerging residential city in Nigeria: Implications on human health. Environmental Pollution and Management.

  2. Damilos, S., Koumoulos, E. P., & Saliakas, S. (2025). Computational fluid dynamics for indoor air quality management. Materials.

  3. Posani, M., Voney, V., Odaglia, P., & Du, Y. (2025). Low-carbon indoor humidity regulation via 3D-printed superhygroscopic building components. Nature Sustainability.

  4. Spengler, J. D., & Sexton, K. (1983). Indoor air pollution: A public health perspective. Science, 221, 9–17.

  5. World Health Organization. (2010). WHO guidelines for indoor air quality: Selected pollutants. WHO Regional Office for Europe.

  6. Jones, A. P. (2008). Indoor air quality and health. Atmospheric Environment, 42(1), 1–13.

  7. Qi, P., Zhu, S., & Sun, Y. (2018). Real-time indoor air quality monitoring using low-cost sensors and IoT platforms: A pilot study in Shenzhen. Building and Environment, 136, 128–136.

  8. Haverinen-Shaughnessy, U. (2012). Socio-economic differences in indoor air quality and housing characteristics in the context of health disparities. Indoor Air, 22(5), 360–367.

  9. Chen, C., & Zhao, B. (2011). Review of relationship between indoor and outdoor particles: I/O ratio, infiltration factor and penetration factor. Atmospheric Environment, 45(2), 275–288.

  10. Goyal, R., & Kumar, P. (2013). Indoor air quality in primary schools of different socioeconomic status in Delhi, India. Atmospheric Environment, 67, 187–201.

  11. Weschler, C. J. (2009). Changes in indoor pollutants since the 1950s. Atmospheric Environment, 43(1), 153–169.

  12. Sherman, M. H., & Hodgson, A. T. (2004). Moisture control guidance for building design, construction, and maintenance. Lawrence Berkeley National Laboratory.

  13. American Lung Association. (2024). Indoor Air Quality and Health.

  14. Apte, M. G., & Erdmann, C. A. (2002). Indoor carbon dioxide concentrations and SBS in office workers. Proceedings of Indoor Air 2002.

  15. Environmental Protection Agency. (2021). Indoor Air Quality Basics.

  16. Godish, T., & Spengler, J. D. (2012). Relationships between ventilation and indoor air quality: A review. Indoor Air Quality and Climate.

  17. Mendell, M. J., & Heath, G. A. (2005). Do indoor pollutants and thermal conditions in schools influence student performance? A critical review of the literature. Indoor Air, 15(1), 27–52.

  18. Mendell, M. J., Mirer, A. G., Cheung, K., et al. (2011). Respiratory and allergic health effects of dampness, mold, and dampness-related agents: A review of the epidemiologic evidence. Environmental Health Perspectives, 119(6), 748–756.

  19. Sundell, J. (2004). On the history of indoor air quality and health. Indoor Air, 14(S7), 51–58.

  20. U.S. Department of Health and Human Services. (2023). Guide to Healthy Homes.

  21. World Health Organization. (2020). Indoor Air Quality Guidelines.

  22. Zhang, X., Weschler, C. J., & Salthammer, T. (2017). Indoor Air Chemistry and Health. Atmospheric Environment, 185, 25–35.

Work with a naturopathic doctor / naturopath to help you assess for environmental pollutants and to understand how they may be affecting your health. The information on this website is a guide for ways to protect you and your family from environmental pollutants.  It is not meant to replace advice from a healthcare professional.

Committee Members

Dr. Moira Fitzpatrick, ND (USA), Chair

Dr. Iva Lloyd, ND (Canada)

Merciful Ananda (USA)

Dr. David Lescheid, ND (Germany)

Pedi Mirdamadi (USA)
Charity Thiessen (Canada)
Dr. Dwan Vilcins, Environmental Epidemiologist & Naturopath (Australia)

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