Expert Panel: Indoor Air Quality

With the knowledge that Covid-19 mainly transmits via airborne particles, the pandemic has brought the issue of indoor air quality sharper into focus. But the debate about air quality stretches much further than this. We ask our Panel of Experts why good air quality in education settings is so important, as well as how schools can ensure clean air

Expert panelists: Tim Browning, head of business development, Fellowes Air Purifiers; Dr Andrew Larner, chief executive, Larner Associates; Chris Brown, head of public sector, phs; Jonathan Hunter Hill, sector manager for education, SAV Systems; and Jann Kirchberger, chief executive officer, youvee. Biographies at the end of the article.

Transmission of coronavirus mainly occurs through respiratory droplets generated during breathing, talking, coughing and sneezing. This makes enclosed spaces like classrooms breeding grounds for infection.

One of the important measures to reduce the spread of Covid-19, therefore, is through improving the air quality inside schools. Good ventilation and air purification in schools is recommended as it can remove or dilute air that contains virus particles.

In a bid to keep schools open during the ongoing pandemic, the Department for Education is currently providing schools with CO2 monitors to assess the ventilation needs of schools.

But while Covid-19 has brought the issue of indoor air quality to the fore, it is by no means a new issue. There are many other harmful pollutants and bugs in the air that can cause harm, especially to children as their lungs are not yet fully developed.

Covid in the air

As the Covid-19 virus mainly transmits via airborne particles, one of safety measures for schools is to increase ventilation and/or use air purifiers to remove or disperse virus droplets.

Jann Kirchberger, chief executive officer at youvee, explains how the Covid-19 virus can spread: “Covid-19 and other viruses are spread in the air by very small particles (aerosols) while breathing and speaking. These airborne particles can linger in the air for hours carried by air currents potentially infecting individuals when breathed in.

“Without suitable ventilation or air disinfection measures they can build up and thus increase the risk of infection for individuals. Therefore air ventilation as well as disinfecting indoor air reduces the concentration of viruses and germs in interiors.”

Tim Browning, head of business development at Fellowes Air Purifiers, adds: “Poorly ventilated classrooms can easily become breeding grounds for viruses with a single infected person introducing up to 70,000 infected particles into the air that can and do infect many other pupils.

“If choosing the right technology, adequate ventilation and air purification systems can remove over 99.99 per cent of germs and viruses – including Covid-19 / SARS-CoV-2, the H1N1 flu virus and other airborne contaminants.”

Tim Browning stresses that understanding how ventilation works is important: “When deciding which system to install, it’s highly important to check the number of air changes per hour (ACH) it will deliver. The more air changes per hour will ensure bad air is being replaced by good on a consistent basis. As rule, it’s wise to look for achieving between three to five changes per hour to ensure consistently clean air.”

Dr Andrew Larner, chief executive of Larner Associates, warns of other issues to be aware of. He says: “Poorly designed ventilation will increase transmission spreading virus particles all around the occupied space.

“To completely remove the risk of airborne transmission we would have to remove virus particles continuously as soon as they left the infected subjects mouth. As the air travels from the infected subject to the ventilation system, there will always be the risk of transmission if relying on ventilation alone. From experiments with Covid infected subjects in a chamber with three to four complete air changes an hour (ACH) has no appreciable effect on the level of viral load in the air. Air change rates of eight to nine ACH do have an appreciable effect.

“Most buildings do not have this level of ventilation. Mobile filtration or purification units have been proposed. Experiments have shown that two mobile HEPA filter units with a combined filtration of 1,000 cubic metre an hour have an appreciable effect on viral load in the air. However they do draw air horizontally across the room increasing transmission risk to those in the room with an infected subject.

“Even with 8-9 ACH, ideally the air is brought in at floor level and extracted at ceiling level to minimise cross transmission in the room. The only way to attack the virus particles as soon as they are exhaled is to use a high voltage (over 4,000 volts) ioniser. A small room filled with virus would take an hour to see an appreciable effect from ventilation at 8-9 ACH, but would be over 99 per cent clear in ten minutes with a high voltage ioniser.”

Jonathon Hunter Hill, sector manager for education at SAV Systems adds: “One of the primary causes of the rapid spread of Covid-19 was found to be recirculating ventilation systems, such as air conditioners without a fresh air supply. This was particularly evident in the bus and restaurant scenarios highlighted during the early stages of the Covid-19 pandemic. Consequently, the UK government required recirculating ventilation systems be put into full fresh air mode where possible and disabled entirely where not possible. Alternatively, natural ventilation was to be maximised by opening windows.

“Ventilating using fresh air from outside is necessary to ensure that occupants are not breathing air that is carrying potentially dangerous viral particles. Increasing ventilation rates also leads to lower concentrations of particulates, because the existing room air is diluted by fresh air, reducing the risk of contamination and inhalation.”

Working in tandem

Chris Brown, head of public sector at phs, believes that optimal air quality will be more likely when combining ventilation and air purifiers. He said: “Air purifiers should not be a substitute for ventilation – both should work in tandem with each other. This is not always practical. Schools often have lots of environments which are poorly ventilated and have no way of improving ventilation. In these areas, an air purifier will make a significant improvement to that environment’s air quality.

“High-quality commercial air purifiers remove germs, viruses, and bacteria from the air. True HEPA filters are certified and can remove viruses such as Sars-Cov-2. In all settings, but particularly in non-ventilated areas, air purifiers are vital in the fight against COVID and other viruses

“In summary, any environment will benefit from an air purifier being installed whether there is ventilation or not, but high airflow will support a commercial air purifier even further. Higher airflow allows for germs and viruses to be removed from the air more quickly.”

The risk to children

Children are more susceptible to harmful air pollution as their lungs are still growing and developing. They also breathe more rapidly than adults and so absorb more pollutants. For children with asthma, high levels of air pollution are linked to increased asthma attacks.

Jonathon Hunter Hill from SAV Systems explains further: “Children are more susceptible to pollutants for two primary reasons: they are closer to the ground where denser pollutants achieve their highest concentrations, and they breathe at a higher rate than adults, absorbing more pollutants. Furthermore, as their lungs are still developing, their lungs are not able to filter out the pollutants that adult lungs may be able to.”

Chris Brown from phs adds: “Children between the ages of five and 16 are more susceptible to allergens such as pollen, mould, and dust mites, which are all pollutants you’ll find in most environments. Children with seasonal allergies, or hay fever, are also at a higher risk of developing asthma.

“According to the BSACI, allergies are more common in children than adults. Worldwide one in eight children suffer from allergic rhinitis and this figure is even higher in the UK (one in five). Not only does rhinitis reduce the quality of life for children, but it can also impair sleep and reduce school performance and attainment levels. High-quality commercial air purifiers will remove these pollutants and allergens from the air, as well as any seasonal viruses, providing the optimum environment for students to thrive.”

Tim Browning from Fellowes Air Purifiers highlights the issue of absenteeism which can be made worse by poor air quality: “It’s believed that over 42 million school days are lost to pupil absence every year – 22 million to the common cold. Fifty per cent of children in the UK have some form of allergy, with one in 11 suffering from asthma. As microscopic airborne particles rapidly spread all of these ailments, the ability to relieve these contaminants by consistently replacing bad air for good can only help to improve pupil wellness, performance and attendance levels.

“Effective air purification will drastically reduce germs, viruses, bacteria, allergens, VOCs (volatile organic compounds) and unpleasant odours, resulting in a healthier school environment.”

Jann Kirchberger from youvee adds: “Other substances like combustion products including carbon oxides, nitrogen oxides and perspiration of construction chemicals such as formaldehyde, in addition to dust and airborne germs and fungi are contributing to poor air quality in schools. Furthermore, high CO2 levels in the room air may lead to concentration and attention deficits, fatigue and headaches.

“However, indoor air quality is extremely important, especially for children that are still developing certain skills and cerebral developments. Higher air exchange and ventilation rates (causing cleaner air) have been associated with faster and more accurate student responses to colour, picture memory and word recognition.

“Natural ventilation with adequate air exchange rates monitored by CO2 sensors as well as mobile air purification devices wherever adequate ventilation is not possible are effective measures to continuously reduce the concentration of harmful substances in the air. Low CO2 values at the same time (<1000ppm) ensure a concentrated working atmosphere.”

Dr Andrew Larner warns that fresh air from outside may not always be the answer to improving air quality if the air outside is polluted. He says: “There are other factors that can have harmful effects on human health, whether that be gasses like carbon dioxide or ozone or particles like pollen causing hay fever or small particles that trigger asthma. Ventilation can reduce these factors by bringing in outside air, but depending on the quality of the outside air, can actually increase them. For example, a day with a high ozone count will draw in large amounts of ozone into the building. The addition of the right type of filter to the ventilation will remove particles and can operate on air entering as well as leaving the occupied space. Similarly a high voltage ioniser removes particles as air enters or leaves the occupied space but within the occupied space too.”

Outdoor air pollution

Data from EarthSense shows that 27 per cent of all UK schools are located in areas which are above WHO air pollution limits for the pollutant PM2.5. But there are measures that schools, and indeed councils, can put in place to reduce the pollution levels around their schools. These include having no car zones around schools, anti-idling campaigns and encouraging active travel to school.

But to reduce external pollution, schools or councils should first understand the scope of the problem, believes Jonathon Hunter Hill from SAV Systems. He says: “Schools should find out how polluted the area in which they’re situated is. A combined effort would be required from all stakeholders to maximise the efficacy of the potential solutions.

“Clean air zones around schools could be established. For example, councils could enforce no parking zones around schools and limit local traffic. Parents can aid this by walking their children to school to minimise the use of vehicles. Planting has been found to mitigate a great deal of pollution, so schools could create a green boundary between the premises and the road.

“Where these methods are insufficient, the school should consider ventilating classrooms with filtered mechanical ventilation, which can remove damaging pollutants from the air.”

Chris Brown from phs agrees that schools need to understand the extent of the problem before deciding on what action to take. He said: “While promoting active travel to schools, encouraging children to walk or take public transport, closing roads during the school rush and switching to greener fuel options will all make a difference in the long-term, these steps will take time to make a collaborative impact.

“We would advise parents, schools and councils to assess the indoor air quality in their schools to understand the level of the problem and the potential risk to pupil and teacher health. Following this, familiarising themselves with the options available to combat the issues at hand will support schools to take appropriate action.

“These steps will mitigate and protect pupils immediately, while longer-term behaviour-change, and community action takes place alongside legislative change.”

Dr Andrew Larner comments: “PM2.5 particles, refers to any particle at or below 2.5 microns. Typically, these particles come from vehicle exhausts, and burning wood, heating oil or coal or natural sources such as forest and grass fires. Fine particles also form from the reaction of gases or droplets in the atmosphere from sources such as power plants. Chemical reactions can occur near schools that are miles from the original source of the emissions.

“Walking to school can reduce vehicle emissions but can increase exposure. Careful planning of routes to avoid places with high pollution counts is really important.”

Increasing awareness of the issue of air quality is crucial in order to spur action, believes Jann Kirchberger from youvee. He said: “Since poor air quality isn’t tangible it can often be dismissed easily. Driving awareness for this issue is crucial and can only be achieved by educating all parties involved - parents, staff and stakeholders.

“Mobile air purifiers provide an effortless measure to ensure that children are learning in a safe environment. Air purifiers operating with ultraviolet light are proven to eradicate many microscopic organic contaminants such as carbon monoxide, nitrogen oxides, formaldehyde amongst other airborne viruses and germs. Air purifiers based on HEPA filter technology significantly reduce the concentration of small particles (>100nm) in the air, but induce the risk of malfunction if not properly maintained or when the filters are not regularly changed – coming along with a potentially health-risky effort in time and costs.”

CO2 Monitors in schools

As we release CO2 when we breathe out, higher levels of CO2 means there is higher occupancy and lower ventilation, and can be an important red flag to identify areas of inadequate ventilation.

In August, the government announced that CO2 monitors will be provided to all state-funded education settings, so schools can identify where ventilation needs to be improved, and where it is working correctly. This, they hope, will reduce the transmission of the Covid-19 virus, thus keeping schools open.

Chris Brown from phs believes this is a step in the right direction, but it isn’t enough. He explains: “CO2 monitors can advise school leaders and teachers when further ventilation is needed, but they cannot combat the virus itself.

“Schools need further support and resources to better understand the very real impact of poor indoor air quality, and the huge range of measures that can be taken to make improvements to the air, rather than just highlight when there’s a problem.

“Governments should be speaking with academics and commercial organisations to understand what solutions are available and to provide insightful guidance to schools alongside funding to improve indoor air quality.

“Following these steps, we strongly believe governments should be moving towards implementing more stringent regulations around the quality of indoor air in education settings. Pupils should be provided with the best possible environment to learn and stay healthy.”

Echoing this thought, Tim Browning from Fellowes Air Purifiers believes that government has a role to play in helping schools fund air quality improvement measures. He said: “Budgets are extremely tight within most - if not all schools – and, in our experience, whilst improving indoor air quality via air purifiers is desirable with most leaders in education, it’s sadly unachievable for many due to inadequate funding being available.  

“Governments in the US, Germany and France have all provided central funding schemes/grants to the education sector to enable them to invest in adequate air purification systems. We believe it is essential for the UK government to follow suit and provide funding urgently to ensure the safest of environments for children and staff, as well as helping to enhance pupil performance and reduce absenteeism.”

Dr Andrew Larner said: “CO2 monitors will, unsurprisingly, identify where CO2 levels are high. This will identify areas that need increased ventilation. Reducing CO2 will have a positive effect on increasing attention span and learning outcomes. However, increased ventilation that draws air across the room risks increasing virus transmission. In one study or a classroom environment it doubled the number of students exposed to virus particles by introducing ventilation at the rear of the classroom with an infected subject at the front of the classroom. For virus transmission there is Coronavirus particle sensor about to be launched on the market.”

Commenting on the DfE CO2 monitors, Jann Kirchberger from youvee said: “This is definitely a step in the right direction. High levels of carbon dioxide (CO2) in indoor spaces have an adverse effect on the health and wellbeing for both students and staff alike. The main way indoor carbon dioxide affects our health is linked to our brains. As carbon dioxide levels in a room increase, the gas starts crowding out the oxygen, reducing the amount of O2 we absorb from each breath.

“In indoor areas across educational institutions, we are most likely to experience ranges of CO2 levels between 1,000 to 5,000 ppm. At that level, people often experience fatigue, develop headaches and struggle to concentrate. Adding CO2 monitors is a great way to combat this and ensure optimised  health and wellbeing of everyone.

“Despite this great initiative, reducing the levels of CO2 in an indoor environment does not prevent the spread of airborne viruses. For this, additional measurements need to be taken such as investing in long-term air purification methods and improving ventilation systems, which could be further supported through government funding.”
Building design

Jonathon Hunter Hill from SAV Systems comments on the effect of building design on air quality: “Studies have been done in recent years to quantify the effect of poor IAQ on the brain. Christian Bohr first documented the effect of CO2 concentrations on brain activity in 1904, but buildings of the 19th and 20th centuries had poor air tightness and therefore had a high air change rate. Consequently, the Bohr Effect has not had a great impact on building design. Modern buildings are relatively airtight. Hence, ventilation solutions that can manage indoor CO2 concentrations are now a permanent fixture. A more recent study by Harvard University document the effect in 2015, establishing that CO2 concentrations of above 900 ppm in rooms greatly inhibited cognitive ability. Therefore, it’s vital that CO2 concentrations and IAQ are managed in schools.

“The age-old solution has been to open a window, but this leads to draughts. Only mechanical ventilation with heat recovery (MVHR) can guarantee good IAQ regardless of external conditions.

“Whilst this is a step in the right direction, if the Department for Education wish to take this seriously, the regulations governing school ventilation (BB101) should be amended to guarantee that CO2 concentrations in classrooms never exceed 1,000 ppm, regardless of equipment type. Mechanical ventilation should be prioritised to ensure that classroom air is filtered.”

Wider benefits of clean air

The benefits of clean air are well known, although the Covid-19 pandemic has brought the issue into sharper focus.

So what are the wider benefits of good quality air inside classrooms?

“Many studies have proven that pupils perform better when they are working in clean, organised and well-equipped facilities,” comments Tim Browning from Fellowes Air Purifiers. “This improves concentration, behaviour and general health and wellbeing. And, because it’s not always practical to have windows open due to colder weather or outdoor pollution, or even permanently locked latches, localised purification of the air is important to keep replenishing bad air with clean air – especially in places where VOCs are being emitted from photocopiers and other machines. Open windows also allow entry of allergens that cause great irritation for sufferers of allergies such as hay fever.”

Jonathon Hunter Hill from SAV Systems comments: “Poor air quality is said to be the largest environmental threat to human health, so if we can appropriately manage indoor air quality, we should be able to reduce the threat that poor IAQ poses to our children for a large period of their lives: when they are at school. Assuming external pollution levels remain unchanged, ventilation systems that combine a high air change rate with filtration should be used.

“The additional benefit of high ventilation rates is management of indoor CO2 concentration, such that cognitive abilities are not inhibited. A study by the Danish Technical University (DTU) in 2019 showed that by controlling acoustics, lighting, and indoor air quality, educational performance could be increase by 10 per cent or greater, resulting in an extra year of education over a period of ten years.”

Expanding on this point, Chris Brown at phs said: “A study at the London School of Economics looked into the link between indoor air quality and exam performance. The study collected air particulate readings in examination rooms and found that exam rooms at the university varied considerably in terms of air quality, and that students performed worse when they were assigned to exam rooms with higher levels of air pollution.

“Other studies show that improving indoor air quality goes hand in hand with increased concentration levels and cognitive recall, and this is something we have heard anecdotally from teachers and heads at schools we work with.

“Most importantly, cleaner air quality will also unarguably reduce the symptoms of allergic rhinitis by removing the pollutants and contaminants that trigger these reactions, as well as drastically reducing the risk to students from Covid-19 and other airborne viruses.”

Jann Kirchberger from youvee said: “Many diseases can arise from exposure to airborne particles, this includes the infamous Covid-19, as well as diseases such as the common flu, mumps, measles, coughs and tuberculosis, amongst others. Therefore ensuring good air quality is vital to minimise the risk of long term health implications.

“One wider benefit of good air quality is reducing the absence of student’s and staff due to lower transmission risk of the cold and flu. This directly correlates to higher engagement in classes, and a better educational experience overall. It also has a great positive impact on students with asthma and hay fever, decreasing the physical burden and discomfort it causes them.

“When speaking about monitoring CO2 levels, this has a direct impact on students’ concentration during class. High levels of CO2 in an area can impact our health and wellbeing in a number of ways where one will start to experience fatigue, sleepiness, develop headaches as well as may struggle to concentrate.

“The best thing to take away from this is that optimised air quality is the best way to keep schools open and ensure a high level of education for children around the United Kingdom.”

Dr Andrew Larner highlights how poor air quality can aggrevate health issues: “Good air quality can removes the airborne causes of short term and long term health effects that include coughing; eye irritation; headaches and allergic reactions. Poor air quality can also aggravate asthma and/or other respiratory illnesses; and in rare cases, contribute to life-threatening conditions such as Legionnaire’s disease or carbon monoxide poisoning.

“In the UK, nearly one in 11 children and young people of school-age has asthma, which effects school absenteeism and learning performance. Indoor environmental exposure to allergens (such as dust mites, pests, and moulds) plays a role in triggering asthma symptoms.”

Panelist biographies

Tim Browning, head of business development, Fellowes Air Purifiers

Tim Browning is passionate about cleaning the air we share. As head of business development for air treatment at Fellowes Brands, he manages a national network of approved distributors and is responsible for providing air quality testing and tailor-made air purification solutions for education and other key sectors.

Dr Andrew Larner, chief executive, Larner Associates

Andrew is an acclaimed transformation expert not just in the UK but internationally, who has worked with many governments to solve big problems. Andrew has successfully delivered some of the most complex public sector programmes at times of crisis and has recently focused on finding the best solutions for the pandemic. Andrew is also CEO of not-for-profit company IESE.

Chris Brown, head of public sector, phs

Chris Brown is the head of public sector at phs. He and his team provide advice and support to public sector customers including schools and colleges across the UK. Chris sits on the Period Dignity Roundtable with the Welsh Government and supports the Access workstream for the Period Equality Taskforce, headed up by the Department for Education in Westminster. He has been instrumental in delivering phs’ period equality strategy.

Jonathan Hunter Hill, sector manager for education, SAV Systems

Jonathon Hunter Hill is the sector manager for education at SAV Systems, managing the AirMaster Smart Mechanical Ventilation (SMV) product group. Throughout his career, Jonathon has been a passionate advocate for improving indoor air quality in classrooms to improve our children’s health and educational performance.

Jann Kirchberger, chief executive officer, youvee

Jann Kirchberger has been appointed CEO of youvee® GmbH, where he is responsible for sales, marketing, product development, manufacturing and administration. He has also been responsible for the operational business of Frenell GmbH as chief operating officer (COO) since January 2020. Previously, he was a senior project manager for many years, playing a key role in the development, implementation and construction of solar thermal power plant projects in Australia, Spain, India and Italy. His technical focus is on thermodynamics, fluid mechanics, optics, process engineering and product development. Jann Kirchberger holds a degree in mechanical engineering from the Karlsruhe Institute of Technology (KIT).