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Why indoor air quality matters in early childhood settings
Educators working with children are more exposed to illness than the general population. Despite strong evidence that improving indoor air quality (IAQ) reduces illness, many settings are not tackling this vital issue. IAQ refers to the condition of air within a building, which can be polluted with harmful gases, particles, and airborne pathogens. Unlike outdoor air, indoor air accumulates exhaled breath and pollutants, increasing infection risk from all airborne diseases (Greenhalgh et al., 2021).
Historically, figures like Florence Nightingale recognised the link between air and health. Yet in modern times, this wisdom has been forgotten and replaced by an overreliance on pharmaceutical interventions. It’s time to go back to basics and prioritise fresh, clean air indoors.
What we learned from COVID-19
The COVID-19 pandemic reshaped our understanding of disease transmission. Initially believed to spread mainly via droplets, we now know that SARS-CoV-2 primarily spreads through airborne aerosols which can linger suspended in the air for hours (Greenhalgh et al., 2021). Despite this new understanding, infection control routines in early years settings still focus primarily on handwashing and surface cleaning, both ineffective strategies against airborne spread.
HEPA air filters and improved ventilation are recognised as key tools in preventing airborne disease (Curtius et al., 2021). These not only reduce the risk of COVID-19 infections but also protect against all other airborne illnesses.
Which diseases are airborne?
Many of the common childhood diseases, COVID-19, flu, whooping cough, RSV, measles, mumps, norovirus, chickenpox, TB, and meningitis can spread through the air. Reducing their transmission through IAQ improvements will mean fewer sick children, fewer staff absences, and fewer disruptions to learning and care.
Importantly, contrary to popular belief, exposure to pathogens in early childhood does not “build” immunity. New research shows that a high burden of early-life infections in fact increases vulnerability to more severe illness later on in childhood (Brustad et al., 2025). Hence, fewer illnesses during early childhood should be the goal.
What do the government guidelines say?
UK infection prevention guidance already recommends that settings should monitor indoor air quality with carbon dioxide (CO₂) monitors and act when levels exceed 800 parts per million (ppm) (Public Health England, 2018). However, most settings do not follow these recommendations.
The invisible threat of Long Covid
Unfortunately, COVID-19 hasn’t disappeared. Reinfections remain common and all carry the risk of developing Long Covid, a condition affecting both children and adults with symptoms ranging from relatively mild long-term health issues to severe life-altering chronic illness (World Health Organization, 2023).
Between March 2023 and March 2024, Long Covid cases in children more than doubled, with over 111,000 affected across England and Scotland. It has also been found that some of the most vulnerable children are babies under 1 years old. Alarmingly, 1% of all babies under 6 months old required hospital care for COVID-19 between September 2023 and April 2024. Tragically, 8 of those babies died (Wilde et al., 2024).
Another large, recent, study estimates that Long Covid may have surpassed asthma as the most prevalent chronic childhood illness in America, with 5.8 million children affected. More specifically, their analysis revealed that 14% of infants and toddlers and 15% of preschoolers in the cohort showed symptoms consistent with Long Covid (Lorman et al., 2025).
Long Covid also affects early years staff. Education and teaching staff are among the professions with the highest rates of Long Covid (Kromydas et al., 2023), highlighting the urgent need for protective measures in early years environments.
Healthier children, healthier settings
What happens when we clean the air? According to one Finnish daycare study, the results were remarkable: fewer absences, better concentration, improved learning — and fewer infections sweeping through staff and children alike (Vartiainen et al., 2024).
In 2023/24, illness remained the top reason for school absences, it remains consistently 40% higher than pre-pandemic levels. Absence due to illness among teaching staff has also surged, with a 38% increase in spending on supply teachers. The government collects data about attendance and staff supply costs in schools, but the impact of illness in early years settings is largely invisible. The likely increased cost of staff absence in the early years sector will hit already stretched nursery budgets hard.
A competitive edge parents will love
Let’s not forget: many early years providers are also businesses. And what do parents want? To know their child is safe, happy, and thriving.
Improving IAQ has broader health and learning benefits. Clean air reduces asthma symptoms, enhances focus, and boosts cognitive performance (Allen et al., 2016). It supports clinically vulnerable children and staff to attend safely and reduces absenteeism. Improving air quality doesn’t just help children. It helps teams, business continuity, and reputations.
Offering clean indoor air is an innovative way to stand out in a competitive marketplace. It’s a simple message that reassures families: We care. We are proactive. We’re protecting your child’s health.
Do air cleaners work?
Yes. HEPA filters are proven to remove unwanted airborne particles (including viral particles, pollutants, mould, fungus and allergens). The UK’s Class-ACT study showed a 20% reduction in illness in classrooms using HEPA filters (Noakes et al., 2023). However, investing in the technology alone isn’t enough, staff do need to consistently use and maintain the equipment. Regular staff training is key to improving IAQ.
The three essential steps: Monitor, filter, ventilate
Monitor
Use a CO₂ monitor, aim to keep levels at or below 800 ppm. High readings indicate too much exhaled air in the room.
Filter
Invest in portable HEPA air filters. These remove viruses, bacteria, allergens, and pollutants. Choose carefully! Check out this website for reviews: https://housefresh.com/best-air-purifiers-we-tested/
Ventilate
Open windows and doors regularly to introduce fresh air. Air filters remove unwanted particles from the air but they don’t reduce CO₂. Natural ventilation supports both air quality and infection control.
A clean air revolution
The current UK regulations lag behind international standards. France, for example, now mandates an 800 ppm CO₂ limit in schools. Meanwhile, UK educational settings are told that a mean average of 1500ppm CO₂ is acceptable. Which begs the question, why are our government expectations for the quality of the air our children breathe set so low?
Policy change is desperately needed. Key recommendations from the SAMHE air quality project here include:
- Adopting WHO air quality guidelines
- Updating air quality regulations for educational settings
- Raising awareness and training for staff
- Funding improvements where needed
What you can do now
While we wait for improved IAQ legislation, early years practitioners and leaders can take action now:
- Buy affordable CO₂ monitors to monitor IAQ.
- Use HEPA air cleaners.
- Keep windows open regularly to improve ventilation.
- Train staff to understand and manage air quality.
We would never accept dirty water in an early years setting, so why accept dirty air?
Key takeaways
- Airborne diseases are a serious, neglected health concern in early childhood settings.
- Improving indoor air quality reduces illness and absenteeism.
- CO₂ monitors, HEPA filters, and ventilation are simple, effective tools.
- Children and staff remain vulnerable to Long Covid.
- Clean air enhances learning, health, and wellbeing.
Critical considerations
- Are you regularly checking CO₂ levels in your setting?
- Have you invested in a HEPA air filter appropriate for your room size?
- Are staff aware of how to use and maintain the air cleaners?
Explainer
- Indoor Air Quality (IAQ): The condition of air inside buildings, affected by pollutants and human activity.
- CO₂ (carbon dioxide): High indoor CO₂ levels indicate poor air quality.
- HEPA filter: High-efficiency filter that captures 99.97% of particles including viruses.
- Long COVID: Ongoing symptoms following COVID-19 infection, affecting daily functioning.
- Aerosols vs. droplets: Aerosols are tiny particles that linger in air; droplets fall quickly to surfaces.
References and further reading
Allen, J.G. et al. (2016) ‘Associations of cognitive function scores with carbon dioxide, ventilation, and volatile organic compound exposures’, Environmental Health Perspectives, 124(6), pp. 805–812.
Brustad, N. et al. (2025) ‘Early-life infections and later childhood health outcomes’, Journal of Pediatrics, 234, pp. 56–64.
Curtius, J. et al. (2021) ‘Testing mobile air purifiers in a school classroom’, Aerosol Science and Technology, 55(5), pp. 586–599.
Greenhalgh, T. et al. (2021) ‘Ten scientific reasons in support of airborne transmission’, The Lancet, 397(10285), pp. 1603–1605.
Kromydas, T. et al. (2023) ‘Occupational differences in long-COVID’, medRxiv. https://doi.org/10.1101/2023.03.24.23287666
Lorman, V., Bailey, L. C., Song, X., Rao, S., Hornig, M., Utidjian, L., Razzaghi, H., Mejias, A., Leikauf, J. E., Brill, S. B., Allen, A., Bunnell, H. T., Reedy, C., Mosa, A. S. M., Horne, B. D., Geary, C. R., Chuang, C. H., Williams, D. A., Christakis, D. A., Chrischilles, E. A., & RECOVER Consortium. (2025). Pediatric long COVID subphenotypes: An EHR-based study from the RECOVER program. PLOS Digital Health, 4(4), e0000747. https://doi.org/10.1371/journal.pdig.0000747
Noakes, C. J. et al. (2023) ‘Class-ACT: Air cleaning in schools’, Archives of Disease in Childhood, 108, A98.
Public Health England. (2018) Health matters: Air pollution. Available at: https://www.gov.uk
Vartiainen, V. A., Hela, J., Luoto, A., Nikuri, P., Sanmark, E., Taipale, A., Ehder-Gahm, I., Lastovets, N., Sormunen, P., Kulmala, I., & Säämänen, A. (2024). The effect of room air cleaners on infection control in day care centres. Indoor Environments, 1(1), 100007. https://doi.org/10.1016/j.indenv.2024.100007
Wilde, H., Harrison, A., & et al. (2024). Trends in pediatric hospital admissions caused or contributed by SARS-CoV-2 infection in England. The Journal of Pediatrics, 276, 114370
World Health Organization. (2023) Post COVID-19 condition. Available at: https://www.who.int
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