Buying an air purifier for schools

It is estimated that due to disruptions caused by the COVID-19 pandemic, students have lost about six months of schooling1. Many children have fallen behind in subjects like maths, reading, and writing as a result. Although the pandemic has subsided, children in schools are still at high risk of bacterial and viral disease transmission. Additionally, children are also one of the most at-risk groups of the negative health effects of indoor air pollution. Can an air purifier for schools provide protection from the dangers of poor indoor air quality for both children and staff? Read on to learn more.

Children sitting at desks in a classroom

Indoor air quality (IAQ) in schools

The effect of indoor air pollution on children

The World Health Organization (WHO) estimates that 93% of children (below the age of 15) around the world breathe air that exceeds its guidelines. In fact, the air is so polluted that it has a direct impact on a child’s growth and development, killing upwards of 600,000 children per year2. This is due to multiple reasons:

  • Children breathe more rapidly through shorter airways, breathing in more air (and pollutants) than adults
  • Children are smaller and live closer to the ground, meaning that they are more likely to breathe in pollutants at higher concentrations
  • Children’s respiratory systems (especially their lungs) and immune systems are not yet fully developed, making them vulnerable to organ damage and inflammatory diseases3

Moreover, children are more vulnerable to contracting respiratory diseases (like asthma), respiratory infections, and allergies at school. In the UK, asthma is considered to be the ‘most common long-term medical condition in children’, impacting around 1 in 11 young people. Rates of asthma in the UK are some of the highest throughout Europe with over one million children receiving asthma treatment nationwide4. Poor indoor air quality in schools and other indoor environments provide asthma attack triggers for many young asthma sufferers.

Studies have also linked poor indoor air quality to decreased academic performance and impaired cognitive abilities in young students. These studies found that exposure to chemical particles in classrooms (especially PM10, PM2.5, NO2, and ozone) leads to decreased academic achievement and working memory. The presence of these indoor air pollutants has a negative impact on concentration, reasoning, and test scores5,6.

A child walking down a hallway at school

Sources of indoor air pollution in schools

Indoor air pollutants in schools have a variety of sources that can lead to negative health effects. Some found in classrooms may include:

Although most indoor spaces are more polluted than outdoor spaces (typically 2 to 5 times), the indoor air of schools and educational institutions is often 8 to 10 times more polluted than outdoor air. Children spend 90% of their school days indoors, meaning that they experience an almost constant exposure to indoor air pollution.

Bacteria and viruses like COVID-19

Schools and classrooms are places where bacteria and viruses can proliferate with ease. This is due to the fact that children sneeze, cough, or talk within close proximity of one another, releasing aerosols into the air. During times of seasonal epidemics or pandemics like COVID-19, children also often find it difficult to respect social distancing measures put in place.

Environments that are closed with minimal ventilation and a high density of individuals lead to high transmission risk. As we have all learned from the COVID-19 pandemic, SARS-CoV-2 (as well as other airborne viruses) is transmitted via aerosol droplets. These droplets are released in indoor spaces like classrooms, and the rate of transmission is highest in places where there is limited air circulation and many people in close quarters. The coronavirus is spread when infected individuals exhale, talk, cough, sing, sneeze, eat, and even breathe within 1 to 2 metres (3 to 6 feet) of another person. These actions release microdroplets. The vast majority - upwards of 90% - of transmission events and viral exposure occurs in indoor spaces like classrooms7.

Two children wearing masks

The biggest problem faced by schools is the lack of ventilation in classrooms. Indoor spaces that are properly ventilated can push polluted, stale air out and replace it with fresh air (assuming that the outdoor air is not heavily polluted). Many schools operate in older buildings with heating and cooling systems (HVACs) that are unable to sustain sufficient airflow. Unfortunately, according to a 2021 study by the University of Leeds, ‘good ventilation can help disperse the aerosols that can cause infection, but in a busy classroom, ventilation alone will not be enough’1.

The above-mentioned University of Leeds study aimed to test the effectiveness of air purifiers, also called ‘air cleaners’ or ‘air sterilisers’, in reducing pathogen concentrations in schools. The results showed that many schools struggling to provide sufficient ventilation would require significant financial investment to improve ventilation in classrooms. Schools may not be able to ventilate properly for the following reasons:

  • Classroom windows do not open or only open partially
  • Schools are located in places with heavy outdoor pollution or noise
  • Opening windows would pose a safety risk to the children
  • Other adverse environmental conditions1

Under these conditions, an air purifier for schools can certainly help improve indoor air quality. Even in schools that are able to obtain proper air flow, an air cleaner can actively remove indoor pollutants from the air. This provides a more extensive layer of protection for school students and staff alike.

How does an air purifier for schools work?

An air steriliser works by pulling polluted air into the device, treating the air using one or more air filtration technologies, and recirculating the purified air back into the room.

It is worth noting that not all air purifiers are created equal! Air cleaners that contain HEPA (High Efficiency Particulate Air)-certified filters guarantee filtration of 99.97% of air pollutants down to a size of 0.01 microns (μm). For context, respiratory aerosol particles carrying SARS-CoV-2 typically measure between 5 to 10 μm in size. However, droplet nuclei have also been reported to spread COVID-19, and these measure less than 5 μm8. When battling fine particle air pollutants, HEPA-certified filters are the only filters on the market that can remove contaminants of this size.

Note: some devices claim to have ‘HEPA-type’ filters. HEPA-type filters do not undergo the same level of third-party testing as HEPA-certified devices do to ensure their efficacy.

HEPA-certified filters do have their limitations. This is why high-quality products like Eoleaf’s come equipped with 8 different filtration technologies, all of which are designed to tackle different types of air pollution. HEPA-certified air purifiers cannot eliminate VOCs, for instance. To account for this, Eoleaf’s devices also contain activated carbon filters and photocatalysis technologies, each of which remove VOCs from the air. Eoleaf products offer the following air purification technologies:

To learn more about each of these technologies and their functions, refer to our article here.

Eoleaf's 8-step filtration system

The benefits of an air purifier for schools

By installing an air cleaner in your school, you can provide a host of benefits to students, teaching staff, and non-teaching staff.

Protect student health

As a result of the COVID-19 pandemic, headteachers were provided little guidance regarding how to implement social distancing procedures in classrooms, especially with younger students. In a largely post-pandemic present, schools and other places welcoming large numbers of people are all looking for ways to ward off bacterial or viral epidemics and pandemics in the future.

Seasonal epidemics that touch classrooms and schools as a whole can have an impact on large percentages of students and staff. The flu, measles, bouts of colds and pneumonia, stomach bugs, and even non-contagious epidemics like pollen allergies can all have an annual presence in educational establishments. Providing purified air with an air purifier for schools is a great way to reduce contagion of bacteria and viruses. These devices also reduce airborne allergens that lead to unpleasant allergy symptoms.

The following heat map provides an example of how air purifiers installed in a classroom can reduce cross-contamination between students. The red area shows an infected student, and the purple and blue areas show where particles are removed from the classroom:

Heat map showing how COVID-19 spreads in a classroom

Source11

An air cleaner also protects students from the dangers of indoor air pollution. As mentioned above, children (alongside pregnant women, the elderly, and immunocompromised individuals) are one of the most at-risk groups in suffering the negative health effects of air pollution. In children, exposure to indoor air pollution can lead to multiple types of cancer (especially lung cancer), asthma, reduced lung capacity and function, respiratory infection and allergies, and increased risk of chronic disease in adulthood9. Some studies have even found that regular exposure to air pollution has been associated with more severe COVID-19 and other viral outcomes10. Furthermore, removing indoor air pollutants can improve academic performance and attention span amongst students.

Air purifiers designed for vehicles (like Eoleaf’s Pure CAR) are also ideal to protect students and drivers of school transportation vehicles.

Protect teachers and non-teaching staff

Equipping your classrooms with an air steriliser is the perfect way to provide better working conditions for your teaching and non-teaching staff. Staff working in a school experience the same level of risk of disease spread, cross-contamination, and negative health effects caused by indoor air pollutions as students do. In addition to the aforementioned health disorders, poor air quality in schools can cause headaches, fatigue, dizziness, and difficulties concentrating in adults. An air purifier for schools helps to reassure all members of staff who are in direct contact with students. The presence of an air cleaner also improves productivity, cognitive function, and reduces absenteeism amongst teachers.

Raise your school’s profile

Improving indoor air quality in your school can highlight your establishment in the eyes of elected officials and trade unions. This voluntary action also reassures parents by reducing the likelihood of disease outbreaks that could impact entire families.

Which factors should you consider when choosing an air purifier for schools?

Before making an air purifier purchase for your school, it is important to consider several factors.

Consider classroom size, ACH, CADR, and performance

Air purifiers are designed to filter the air of a classroom of a maximum size. Before buying your device, determine the volume of your classroom (length x width x ceiling height). Once you have calculated the volume of your classroom, you can use it to determine your ideal ACH and CADR.

  • ACH refers to Air Changes per Hour. It is the amount of times that a room’s volume of air is renewed with purified air. The Centre for Disease Control (CDC) recommends an ACH value of at least 5 for optimum efficiency, meaning that the is replaced five times per hour.
  • CADR refers to Clean Air Delivery Rate. This is a measurement of your device’s efficiency at removing air pollutants. It determines the volume of clean air diffused per hour. The higher the CADR, the more purified air it delivers per hour.
  • Calculate your CADR by multiplying your room’s volume (in metres cubed) by 5, the minimum recommended ACH value.
  • The CADR of powerful devices usually falls between 500 to 900 m3 per hour.

For more information on ACH and CADR, refer to our Buying Guide.

Ideally, you should find an air cleaner that blows air upwards, not frontwards. This helps to avoid cross-contamination.

Consider an air cleaner’s filter, cost, and lifespan of replacement filters

Be sure to choose the most effective filters available. Generally speaking, this means a device with a wide range of action against many types of pollutants. A HEPA-certified air purifier for schools will guarantee purification of fine particles and the tiniest of viruses like COVID-19. However, be sure to find a device that also removes VOCs, such as one that includes an activated carbon filter. Activated carbon also helps combat unpleasant odours in the classroom!

Air purifier costs can vary significantly. Whilst the upfront price tag is important to consider, ensure that you also keep maintenance costs in mind. All air purifiers require regular filter replacements. Lower-quality filters, although cheaper, generally need to be replaced more often, thus racking up your annual bill. Higher-quality filters, like Eoleaf’s, require replacements just once annually. It is also important to invest in durable devices with low power consumption that are built to last in a school, guaranteeing an eco-friendly and economical user experience.

Consider the noise level

Air purifiers for schools that make a lot of noise can lead to distraction and, if the noise level is extreme and persistent, hearing loss. It is always advisable to avoid products with a noise level exceeding 70 decibels (dB) for indoor environments like schools and classrooms. Eoleaf’s air purifiers are quiet but powerful, making them ideal for a classroom setting. Their sound level ranges from near-silent on their lowest fan speed to the sound level of regular office noise on their highest fan speed. This ensures the least classroom disruption whilst providing exceptional air purification.

For assistance on choosing the right air purifier for you, do not hesitate to reach out to our team of air purification experts. Also feel free to consult our Buying Guide for more information on how to choose the perfect device for your needs.

A child playing next to Eoleaf's AEROPRO 40 device



Resources

1 Lewis, D. (2021, November 5). Can air cleaners reduce COVID-19 in schools?. University of Leeds News. https://www.leeds.ac.uk/news-health/news/article/4953/can-air-cleaners-reduce-covid-19-in-schools

2 World Health Organization. (2018, October 29). More than 90% of the world's children breathe toxic air every day. World Health Organization. Retrieved December 2, 2022, from https://www.who.int/news/item/29-10-2018-more-than-90-of-the-worlds-children-breathe-toxic-air-every-day 

3 Singh, M. (2022, November 7). Air pollution: Here's How You Can Safeguard Yourself from the Adverse Effects. NDTV.com. Retrieved December 2, 2022, from https://www.ndtv.com/health/air-pollution-heres-how-you-can-protect-yourself-your-kids-from-air-pollution-3491135

4 NHS. (n.d.). Childhood asthma. NHS 75. https://www.england.nhs.uk/childhood-asthma/

5 Lu W, Hackman DA, Schwartz J. Ambient air pollution associated with lower academic achievement among US children: A nationwide panel study of school districts. Environ Epidemiol. 2021 Nov 3;5(6):e174. doi: 10.1097/EE9.0000000000000174. Erratum in: Environ Epidemiol. 2022 Feb 25;6(2):e202. PMID: 34909554; PMCID: PMC8663889.

6 Gartland N, Aljofi HE, Dienes K, Munford LA, Theakston AL, van Tongeren M. The Effects of Traffic Air Pollution in and around Schools on Executive Function and Academic Performance in Children: A Rapid Review. Int J Environ Res Public Health. 2022 Jan 10;19(2):749. doi: 10.3390/ijerph19020749. PMID: 35055570; PMCID: PMC8776123.

7 Bromage, E. (2020, May 6). The risks - know them - avoid them. Erin Bromage PhD. https://www.erinbromage.com/post/the-risks-know-them-avoid-them

8 Lee BU. Minimum Sizes of Respiratory Particles Carrying SARS-CoV-2 and the Possibility of Aerosol Generation. Int J Environ Res Public Health. 2020 Sep 23;17(19):6960. doi: 10.3390/ijerph17196960. Erratum in: Int J Environ Res Public Health. 2021 Nov 09;18(22): PMID: 32977575; PMCID: PMC7579175.

9 Air pollution and children’s health. European Environment Agency. (2023, April 24). https://www.eea.europa.eu/publications/air-pollution-and-childrens-health 

10 Hernandez Carballo I, Bakola M, Stuckler D. The impact of air pollution on COVID-19 incidence, severity, and mortality: A systematic review of studies in Europe and North America. Environ Res. 2022 Dec;215(Pt 1):114155. doi: 10.1016/j.envres.2022.114155. Epub 2022 Aug 27. PMID: 36030916; PMCID: PMC9420033.

11 Messer, S., & Bernabe, A. J. (2021a, July 22). Researchers find air filtration systems provide an added layer of protection in classrooms. Good Morning America. https://www.goodmorningamerica.com/wellness/story/researchers-find-air-filtration-systems-provide-added-layer-78961394

Eoleaf's range of air purifiers

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