Should we cease to build new schools in cities? The importance of prioritising classroom air quality in school building design


A study investigating the impact of London’s air pollution found that children who grow up in the capital are at risk of developing long-term breathing disorders, while rising concerns over air quality and the impact it could have on children recently led doctors to call for a ban on the building of new schools in pollution hotspots. But given the ever-increasing demand for school places, is there a way we could mitigate the impact of air pollution without abandoning cities altogether?

As building services designers, we have an obligation to design buildings that meet the needs of those who occupy a building on a daily basis, and in this case, there is a lot more we could be doing for the school children of today. 

Currently, the UK has the highest prevalence of childhood asthma among all European countries and in 2016, it was reported that 443 primary schools in London were exposed to levels of nitrogen dioxide that breach EU legal limits, which the government accepts are harmful to health. This number dramatically increased to over 800 when other educational institutions, including nurseries, secondary schools and colleges, are included. 

Also read: The answer to cleaner air in our city centres is all wrapped up in the construction supply chain

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What if by improving air quality our kids could be healthier and learn faster? Expert research from the International Centre for Energy and Indoor Climate in Denmark concluded that improving ventilation rates in classrooms improved learning performance by 14%. These are significant findings and evidence of how improved indoor air quality can improve our children’s ability to be smarter and improve attainment levels in the UK’s schools. 

The recent updates to Building Bulletin 101 (BB101, 2018) is a welcome step in the right direction to improve indoor air quality in schools and as a result we will see more focus on passive design strategies and mechanical ventilation, as well as priority given to post-occupancy thermal comfort. 

Within BB101, requirements for CO2 levels have reduced to a maximum of 2,000 ppm for mechanically ventilated buildings and 1,500 ppm for naturally ventilated buildings. While this is good news, it will have a significant impact on school design. In recent times, the focus in the UK has been on natural ventilation and reductions in energy consumption rather than mechanical ventilation and indoor air quality. Because of the new limit, we will see an increased requirement for mechanical ventilation.

However, if more mechanical ventilation is used, there will be a capital cost penalty for construction as well increases to both maintenance and operational costs. The challenge for building designers is how we can guide schools to explore how best to implement such systems into their buildings in the most cost-effective way, and measure the social and economic benefits of improved IAQ.

Whether these new guidelines ‘go far enough’ could be up for debate. As a Danish organisation, Ramboll naturally looks at our peers for insight into their ways of designing. Danish schools have made significant steps to improve air quality in schools over the last 20 years, so we have naturally collaborated with colleagues in Denmark to learn how to further improve school design in the UK. Danish schools target a maximum of 900ppm of CO2 in classrooms, so most new build schools are mechanically ventilated: as this wouldn’t be ground breaking, we can all learn from the Danish way of doing things. Through this collaboration, we are ideally placed to work with our clients to find the best ways to implement good IAQ.

What is clear is that in order to support the implementation of mechanical ventilation systems our government needs to step in to support this initiative: they play a major role in ensuring that local authorities are able to make air quality requirements. If we were to incorporate mechanical ventilation into both new and existing school building design, there would no need to ban the building of new schools in cities and other pollution hotspots, and it cannot be done without leadership from the top. Banning schools in cities isn’t the answer – the incorporation of a new building services approach could ensure that students are able to thrive in a clean and safe environment.

Graeme McCutcheon is an associate at Ramboll