Ventilation lessons are good for child health

The lessons we have learned from the pandemic about how ventilation reduces the risk of diseases being spread around buildings will have positive implications for future generations of school children, says Nathan Wood, chair of the BESA Health & Well-being in Buildings group

If there is a silver lining from the Covid-19 pandemic, it has to be how much better we now understand the way airborne viruses spread inside buildings.

From the very earliest stages of the crisis, engineers spoke up about the importance of improving ventilation to protect building occupants. However, there was initial confusion about the nature of the virus which led to more emphasis being placed on surface cleaning and a refusal to accept that face coverings could help.

With the benefit of hindsight, some of those early arguments look somewhat embarrassing. However, we have moved on rapidly and the importance of building ventilation is now a key element of the government’s ‘Living with Covid’ strategy.

The focus on schools was intense from the outset, but the lack of available funding for mitigation measures put teachers and management at a major disadvantage. Once the information about the airborne nature of the threat was communicated, they were limited in most cases to simply opening windows. This ‘natural ventilation’ helps to an extent but is clearly not a complete response and is totally impractical during cold winter months and if the school is located close to a busy road or other source of noise or pollution.


There is a long battle ahead to deliver a comprehensive solution, but the knowledge we now have means the education sector understands the challenge it faces and is prepared to fight for the funding it needs to safeguard the long-term health of our children.
Six teaching unions recently ramped up the pressure on government to find more money to help schools tackle growing indoor air quality (IAQ) problems: The ASCL, GMB, NAHT, NASUWT, NEU and UNISON all expressed alarm at the extent of the air quality crisis in school buildings, which has been fully exposed since the government spent £25 million on classroom CO2 monitors.

Measuring the problem has only served to confirm what the building engineering industry had been pointing out for years that there was already a health crisis in schools fuelled by inadequate ventilation. Pre-pandemic this was responsible for a surge in asthma and other respiratory problems among school children – the failure of ventilation was simply fully exposed when Covid-19 hit.

In response, the government has pledged to supply 7,000 air purifiers for classrooms, but the unions agreed this was totally inadequate to address the scale of the growing air quality crisis.

Dr Mary Bousted, joint general secretary of the National Education Union (NEU), pointed out that this was little more than a token gesture: “Seven thousand more air purifiers is something, but it is completely inadequate for what should be a basic human right, the provision of clean air in every classroom,” she said.

“The fact that the Government has provided the extra purifiers shows that it recognises the problem but with over 300,000 classrooms in England it has failed to provide an effective solution.”

The unions are concerned that there will be further disruption to children’s education unless the IAQ problem is addressed and accused the government of offering rhetoric rather than solutions.

The Building Engineering Services Association (BESA), which represents ventilation providers and air quality experts, said there were a wide range of low-cost mechanical solutions available that could help schools take control of their air quality.
Supporting BESA’s indoor air quality campaign, Rosamund Adoo Kissi-Debrah, Co-Founder of The Ella Roberta Family Foundation and World Health Organisation advocate for clean air and child health said: “This is about saving the lives of children. We are in a public health crisis, and we must stop ignoring it.
“Nine years since the passing of my daughter Ella, the same number of children are dying from asthma every year – even though medications and expertise have improved while smoking has declined.
“Health professionals are clear that air pollution is an urgent but solvable problem – and the goal to lower PM2.5 pollution to 10 micrograms must be the first stop on the way to meeting the WHO’s new guidelines for protecting public health. 2030 should be the absolute latest that we achieve it.”

The NEU also reported on social media that 58 per cent of its teacher members said they did not have regular access to a CO2 monitor and, of those who do, 13 per cent said readings in their classrooms were regularly over 1,500 parts per million (ppm) and 32 per cent said they were over 1,200ppm.


The union said the government should carry out its own survey because “these levels indicate poor ventilation rates and make viral transmission and education disruption more likely”. The government’s own guidance is that all settings should have access to CO2 monitors and the ventilation should be able to keep CO2 below 800ppm in all occupied classrooms.

Sadly, this new level of understanding is not reaching everywhere. A story that recently appeared in the Sunday Times suggested CO2 levels of 1,500ppm in classrooms was “reasonable”. This is, at best, very unhelpful and, at worst, dangerously misleading. The article promoted the concept of using natural ventilation alone to provide adequate IAQ, but such a high level of CO2 would also indicate wider problems.

1,500 ppm is almost double the government’s recommended maximum and high CO2 is a clear indicator that the ventilation rate in the room is not adequate to support good learning conditions and protect health. That level of CO2 has been shown to reduce children’s concentration levels, but it also acts as a ‘canary in a cage’ for underlying threats from other pollutants.

Natural ventilation will play a part, but it cannot provide a complete solution and does not allow full control over the amount and direction of air in the space. It also cannot filter the air, which is necessary for buildings close to main roads and in other areas of high pollution to remove harmful particulates.

The need for much wider deployment of mechanical ventilation systems that ciruclate the air to where it is needed and remove harmful airborne particles is now widely accepted. Professor Cath Noakes, who is one of two engineer members the government’s Scientific Advisory Group for Emergencies (SAGE), is a powerful advocated for a national programme of building ventilation improvements.

She told the recent BESA National Conference that the impact of poor ventilation on human health and productivity had been clearly exposed by the pandemic. “Many of our buildings are under-ventilated and there is no excuse for it,” said Noakes, who is Professor of Environmental Engineering for Buildings at the University of Leeds.

“We know buildings can improve health and that poor indoor air quality reduces productivity by up to nine per cent – that’s half a working day a week.” She also pointed out that even before the pandemic 5.3 million working days were being lost every year to respiratory infections, according to the Office for National Statistics.


2021 was a breakthrough year for building ventilation because the pandemic increased the focus on how viruses are transmitted through the air. Our industry has been aware of this threat to children’s health for many years, but now everyone is talking about it, and we finally have a great opportunity to address it properly and for the long-term.

Many of the solutions are relatively straightforward and inexpensive, but every building is different so must be addressed individually. There are also a lot of ‘snake oil’ salesmen out there who are jumping on the bandwagon and offering ‘miracle’ air purification solutions that do not work.

Head teachers should approach local ventilation firms and ask them to survey their building before they do anything else. The first step is to understand the challenge including which parts of the building are not adequately ventilated before drawing up a strategy with a ventilation expert.

Guidance and advice on this topic is available for free via the BESA website:

Nathan Wood is chair of the BESA Health & Well-being in Buildings group and managing director of Farmwood M&E Ventilation.