Indoor Air Quality and the Promise of Filtration

Attention to indoor air quality (IAQ) has increased, particularly considering that people spend up to 90% of their time indoors. Multiple studies have shown that indoor air can be more polluted than outdoor air due to high accumulation of pollution, the influence of outdoor and indoor sources, and the impact of human activities (Rathbone et al., 2025; Song et al., 2015; Yasmin et al., 2024). Typical indoor air pollutants include dust, mold, smoke, volatile organic compounds (VOCs), and bacteria, all of which can have a negative impact on human health. Poor IAQ is associated with various health issues, including respiratory diseases, cardiovascular and neurological conditions, fetal health issues, and even cognitive decline (EPA, 2024; Kumar et al., 2023; Van Tran et al., 2020; WHO, 2023). As our reliance on indoor spaces grows, ensuring the air we breathe indoors is clean has never been more critical.

In many lower socioeconomic communities, residents are exposed to higher levels of harmful air pollutants, which pose a particularly high risk to children, the elderly, and individuals with respiratory conditions (Bozzola et al., 2024). Many of these communities also live, study, or work near busy roads or industrial areas, which contribute to this dangerous pollution levels that often exceed the thresholds recommended by the World Health Organization (WHO, 2010). These thresholds are interconnected with several factors, including economic and social disadvantages, such as the quality of housing, limited access to resources for maintaining or improving air quality, heating and cooking methods, and increased exposure to environmental hazards.

One of the most effective ways to improve IAQ is the use of filtration systems. Various filtration technologies, such as HEPA (High-Efficiency Particulate Air) filters, activated carbon filters, and ultraviolet (UV) light systems, each target different types of air pollutants. These systems can significantly reduce the number of harmful particles in indoor spaces, thereby improving air quality and mitigating their health impact, with a particularly beneficial effect for communities with lower socioeconomic conditions.

A recent study published in Nature by Simona et al., (2025) examined the effectiveness of portable HEPA air purifiers in reducing air pollution in classrooms, particularly in schools situated in areas with high levels of ambient air pollution. This randomised trial found that when HEPA filters were used, the levels of fine particulate matter (PM2.5), which is a significant pollutant, were reduced by nearly 40%. Furthermore, the estimated infiltration of PM2.5 from outdoor sources was comparatively lower (~14-82%) in schools using filters than in those that did not use them. The addition of portable filtration systems has shown positive effects on classrooms already equipped with HVAC (Heating, Ventilation, and Air Conditioning) systems. This is a significant improvement, considering that high exposure to PM2.5 can lead to respiratory diseases, cardiovascular problems, and even developmental issues in children.

The benefits of air filtration systems extend beyond schools. Many families living in areas with poor air quality struggle with asthma, allergies, and other health problems that can be exacerbated by polluted indoor air. Studies show that children in low-income communities are more likely to experience chronic respiratory issues due to higher exposure to pollutants. Installing air purifiers in homes, schools, and community centres could be a simple and effective way to mitigate these health risks. Filtration systems are relatively affordable and easy to use, making them a cost-effective and accessible tool for improving indoor air quality in these neighborhoods.

In addition to improving respiratory health, cleaner air can have a significant impact on overall quality of life. Studies have linked good air quality to improved sleep, enhanced concentration, and better academic performance. For children, the benefits of cleaner indoor air are particularly important. They are still developing, and their bodies are more vulnerable to the harmful effects of pollution. By investing in air purifiers, families can create healthier environments where their children can learn, play, and grow without the added burden of pollution-related health issues.

The evidence is clear: filtration systems can play a key role in reducing harmful air pollution in lower socioeconomic communities, improving both physical health and quality of life. By addressing air quality in schools, homes, and other indoor spaces, it is possible to create healthier environments for those most at risk. With continued efforts to provide access to affordable air purification solutions, it would be possible to ensure that everyone, regardless of their neighborhood or income, has the opportunity to breathe cleaner, safer air. Nevertheless, improving indoor air quality in low-income communities, especially for children, requires a multifaceted approach that extends beyond air filtration and purifiers, encompassing access to better building materials, education, and cleaner cooking methods, as well as improvements in outdoor air quality control and reinforcement of public housing regulations.

For more detailed information, please refer to the following scientific publication: https://www.nature.com/articles/s41370-025-00743-9

Note: This article has been published on behalf of Andrea Cuesta-Mosquera, TROPOS – Leibniz Institute for Tropospheric Research, Leipzig, Germany.

References

Bozzola, E., Agostiniani, R., Pacifici Noja, L., Park, J., Lauriola, P., Nicoletti, T., Taruscio, D., Taruscio, G., & Mantovani, A. (2024). The impact of indoor air pollution on children’s health and well-being: the experts’ consensus. Italian Journal of Pediatrics, 50(1). https://doi.org/10.1186/s13052-024-01631-y

EPA. (2024, July 8). Indoor Air Quality. What are the trends in indoor air quality and their effects on human health? https://www.epa.gov/report-environment/indoor-air-quality

Kumar, P., Singh, A. B., Arora, T., Singh, S., & Singh, R. (2023). Critical review on emerging health effects associated with the indoor air quality and its sustainable management. In Science of the Total Environment (Vol. 872). Elsevier B.V. https://doi.org/10.1016/j.scitotenv.2023.162163

Rathbone, C. J., Bousiotis, D., Rose, O. G., & Pope, F. D. (2025). Using low-cost sensors to assess common air pollution sources across multiple residences. Scientific Reports, 15(1), 1803. https://doi.org/10.1038/s41598-025-85985-1

Simona, S. C., Bartell, S. M., & Vieira, V. M. (2025). Classroom air quality in a randomized crossover trial with portable HEPA air cleaners. Journal of Exposure Science and Environmental Epidemiology. https://doi.org/10.1038/s41370-025-00743-9

Song, P., Wanga, L., Hui, Y., & Li, R. (2015). PM2.5 Concentrations Indoors and Outdoors in Heavy Air Pollution Days in Winter. Procedia Engineering, 121, 1902–1906. https://doi.org/10.1016/j.proeng.2015.09.173

Van Tran, V., Park, D., & Lee, Y. C. (2020). Indoor air pollution, related human diseases, and recent trends in the control and improvement of indoor air quality. In International Journal of Environmental Research and Public Health (Vol. 17, Issue 8). MDPI AG. https://doi.org/10.3390/ijerph17082927

WHO. (2010). WHO Guidelines for indoor air quality: selected pollutants.

WHO. (2023). Household air pollution. Key facts. 15-12-2023. https://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health

Yasmin, A., Ahmed, I., Haider, M., Hossain, Md. K., Motalib, M. A., & Hossain, Md. S. (2024). Characterizing indoor air quality and identifying factors influencing air quality at home microenvironment in Dhaka city. Indoor Environments, 1(4), 100056. https://doi.org/10.1016/j.indenv.2024.100056