Ventilation in schools and colleges

Why is ventilation so important?

Effective ventilation may remove air-borne pathogens and improve air quality. Our 5-step guide includes practical measures to monitor and improve ventilation.

A collective approach

To ensure the importance of ventilation is understood and effective ventilation achieved, you should:

Meet with members to discuss ventilation in the workplace
Identify any concerns and, where possible, solutions
Raise them collectively with your employer.

Step 1 - Gathering evidence of poor ventilation

You can help draw attention to indicators of poor ventilation:

Do any areas feel stuffy or unpleasant?
Are there areas without natural ventilation, for example openable windows?
Do ventilation grids or airbricks appear dirty or blocked?

Feed any concerns through to management.

Step 2 – Workplace ventilation audit

A ventilation strategy to reduce the risk of aerosols and droplets transmitting Covid-19 and other respiratory infections should be part of your workplace’s overall risk assessment.

Ask your employer to undertake a ventilation risk assessment to identify any poorly ventilated areas.
If there already is one, ask for a copy to be displayed on the staff noticeboard.
Will it be revised at regular intervals?

Step 3 – Monitoring carbon dioxide levels

In response to pressure from the education unions, England finally invested an initial £25m in 2021 in providing all state-funded schools and colleges with one portable CO2 monitor for every two classrooms. This was followed by further Government funding in November 2022 to provide monitors for the remaining 50 per cent of classrooms.

The level of CO2 acts as a proxy for the microbe load as people exhale airborne viruses when they exhale. To check your workplace, ask that carbon dioxide monitors are used to check whether ventilation is sufficient to keep CO2 levels below 800 ppm. Indoor air at 600 to 800 ppm carbon dioxide indicates a relatively well-ventilated room.

Step 4 – Practical steps to ensure good ventilation

Examples of possible improvements to ventilation:

Airbricks should not be obstructed.
Windows should be able to be safely opened.
Ventilation grids need to be kept clean, so that the air supply is not obstructed.
Windows and internal/external doors should where possible be kept at least slightly open (noise, security/ thermal comfort and fire restrictions dependent).
To achieve a balance between ventilation and thermal comfort, uniform and dress codes should be relaxed in colder weather to allow staff and students to dress more warmly but, in addition, schools and colleges should, where necessary, have the heating turned up higher and for longer, starting earlier in the morning, to keep the temperature comfortable throughout the working day.

Step 5 – What if these measures are put in place but ventilation is still poor?

Air cleaning and filtration units are an effective means of reducing airborne transmission of aerosols where it is not possible to maintain adequate ventilation.

These units are not a ‘substitute’ for ventilation. They can, however, play an important role where ventilation has not proven sufficient. By filtering and trapping tiny particles of virus, pollution or pollen, they improve the air quality in each space. Research in the USA has shown that because of the improved air quality and the effect this has on cognition, the installation of an air filter in a classroom can improve test scores by as much as cutting the size of the class by a third.

Air filters – alongside good ventilation where available - helps reduce the transmission of respiratory infections. However, commercially available options are often unaffordable for a typical school budget – hence the attraction of build-your-own, Corsi-Rosenthal air filtration boxes which can be constructed for a fraction of the price of the commercial equivalent.

Moreover, pupils can be involved in the construction process, providing a valuable learning opportunity. To find out more about why we need clean air in classrooms, what air filtration is, and a brief guide to building a Corsi-Rosenthal box.

Ensuring clean air at external venues

Poor ventilation means that air-borne respiratory viruses like Covid-19, but also colds and flu, build up in the air and are more likely to infect participants at NEU training courses, conferences and other such events. Good ventilation helps to protect everyone from becoming ill unnecessarily.
In poorly ventilated workplaces, the exhaled air from people present causes a build-up of carbon dioxide which impairs concentration and thinking. This is an important consideration when running training courses as we want participants to remain alert and engaged, especially post-lunch and late afternoon when there can be a dip.
Even since the role of ventilation was understood in relation to the pandemic, the NEU has been pushing the issue in relation to schools and on numerous occasions we have called for more HEPA filters to be rolled out, so we should practise what we preach and deploy them in our own operations where they are needed.
Where a ventilation system cannot guarantee sufficient clean air changes, then portable High Efficiency Particulate Air (HEPA) filters should be used to clean the air, by trapping the harmful particles. Keeping windows open isn’t always possible in cold weather and if the outdoor air is polluted then the incoming outdoor air is going to be polluted and natural ventilation, via windows, won’t be sufficient. HEPA filters are particularly useful where outdoor air is polluted. They are also effective in removing allergens eg dust, smoke and pollen that trigger conditions like asthma and hay fever.
We are not alone in advocating for clean air. Sadiq Khan has recognised the importance of clean air for children by installing air filters in 200 of London’s most polluted schools.

Questions to ask venues:

Are there any areas where there is neither mechanical ventilation, nor natural ventilation such as open windows, doors, or vents?
If there are mechanical systems that provide clean outdoor air, temperature control, or both then does the system only recirculate air with no clean outdoor air supply? If so, the area is likely to be poorly ventilated and any pathogens in the air will just be moved around rather than removed.
Are there any indoor areas with fewer than 6 air changes per hour and/or a minimum of 10 litres per second per person of outside air?
Are any ventilation facilities obstructed or blocked by curtains or furniture?

If the answer to any of these questions is ‘yes’ or ‘we don’t know’, then HEPA filters should be used. Air cleaning and filtration units are an effective means of reducing airborne transmission of aerosols where it is not possible to maintain adequate ventilation.