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A IS FOR AIR QUALITY

Willow Aliento talks to indoor air quality (IAQ) experts about Australia’s stuffy, smelly classrooms – and why COVID-19 is not the only airborne issue.

School classrooms are notorious for being spaces where students often feel tired, irritable and generally out of sorts. No wonder teachers can find it hard to get kids to engage and pay attention. One of the main reasons this is so common is the indoor air quality in many classrooms is making them unhealthy places to be.

It is an issue indoor air quality (IAQ) and HVAC researchers and experts have been aware of for some time. Now, with COVID-19 still present in our communities and pupils returning to classrooms, education departments and schools are finally sitting up and taking notice.

HOW IAQ AFFECTS STUDENTS

UNSW School of Built Environment Associate Lecturer Dr Shamila Haddad led recent research into how IAQ affects student health and productivity. One of the major findings is that CO2 levels in Australian classrooms frequently exceed the recommended levels for indoor air quality.

High CO2 levels have a direct impact on learning performance, Haddad explains. Students are less able to concentrate and may also experience headaches, drowsiness, tiredness and changes in respiratory patterns. Schoolchildren exposed to CO2 levels above 1,000ppm face a significantly higher risk for dry cough and rhinitis. Low fresh air ventilation rates have also been linked to higher rates of absenteeism, poorer performance on academic tests, and teacher dissatisfaction.

“Poor indoor air quality (IAQ) and high indoor air temperatures in classrooms are critical problems worldwide,” says Dr Shaddad. “This is worsened when ventilation rates are insufficient to remove excessive heat or pollutants, particularly when windows are kept closed to avoid discomfort caused by external noise, weather, or to prevent drafts.”

Low ventilation rates also increase the concentration of other problematic pollutants in the classroom. Haddad says this is a major risk factor for asthma in children.

“Previous research has also demonstrated that the risks for upper and lower airways and systemic disorders in school children is significantly increased with the Volatile Organic Compounds (VOCs) score.”

Poor IAQ and high indoor air temperatures in classrooms are critical problems worldwide

WHERE OTHER INDOOR POLLUTANTS COME FROM

Gaseous pollutants can include:

• Bioeffluents emitted by occupants (burping and flatulence, for example)

• Emissions of Volatile Organic Compounds (VOCs) from building materials, furnishings and classroom equipment

• Pollution from outdoors, such as vehicle emissions that enter the indoor environment.

RMIT Associate Professor Priya Rajagopalan says the amount of time kids – and teachers – spend in the classrooms exacerbates the risks.

According to a report RMIT produced on Victorian classrooms, students spend up to 12,900 hours of their lives in school buildings from pre-school to Year 12 – or 25 per cent of their waking lives.

“Poor IAQ in schools impacts the cognitive performance of students and the health and wellbeing of teachers,” says Rajagopalan. “It is important to note that primary school students may be spending a whole year in a single classroom as they don’t change classrooms every period like in secondary schools.

“Sometimes the teachers may be spending their whole life in a single classroom, and if that room happens to be of poor air quality, it will have a long-term impact on their health. Some teachers are better aware of IAQ and sensitive to poor air quality and will be taking actions like opening doors/windows when they feel stuffy, but the majority of teachers keep working in the environment without realising the impacts.”

TAKING UP THE IAQ CHALLENGE

THE BENEFITS OF GOOD IAQ

The first step in improving indoor air quality is measuring CO2 levels, according to Preshit Fadnis, M.AIRAH, Sales Engineer at Panasonic Australia and a member of AIRAH’s recently formed Indoor Air Quality Special Technical Group.

In most schools IAQ is not measured at all, he says. CO2 levels are a good place to start as it is the easiest element of IAQ to monitor, and it is good general indicator for air quality.

Fadnis notes that in some systems, CO2 sensors are being retrofitted to air conditioning units in conjunction with technology that can control the amount of outside air brought in by the system. These systems can measure and monitor VOC levels and respond to elevated VOCs indoors. Such system also have wireless sensors, with a battery life of 5–10 years.

Air purification systems are available to remove mould spores, pollen, bacteria, viruses and odours from the air. Fadnis says this is now a standard inclusion in most of Panasonic’s air conditioning systems, including wall-mounted split systems, single split systems, VR systems, VRF cassette units and some ducted systems. In the near future it will be standard on all units. According to Fadnis, the technology requires no maintenance and has an operational life longer than the design life of most AC units.

“COVID-19 has created awareness of all of these indoor air quality topics,” he says. “In Australia there used to be very minimal data about IAQ in schools. Now we are looking at mitigating the risks associated not only with COVID-19 but with everything.”

Fadnis says that while Panasonic and others in the HVAC&R industry were promoting the need to address IAQ in schools long before COVID-19 emerged as a risk, the wider awareness is only just starting in Australia. This is in contrast to other nations, including the USA and Germany, where IAQ has been a priority for some time.

He welcomes the new focus in Australia. NSW, for example, has been installing CO2 monitors with some of the split systems being procured as part of the Cooler Classrooms program. In Queensland, Catholic schools are also taking up the challenge of improving IAQ with CO2 sensors.

“We don’t know what the long-term effects are for students of being in classrooms with 4,000ppm CO2 levels,” says Fadnis. “We are talking about our next generation – the future generation. We need to take care of IAQ right now.” ■

Dr Haddad says increased ventilation rates are associated with satisfaction with the thermal environment and IAQ, and have a protective effect on eye and skin-related disorders.

“Lowering CO2 levels and improving IAQ enhances comfort and reduces the feeling of tiredness, which increases students’ productivity and learning performance,” says Dr Haddad.

But isn’t there a standard?

Although there is a national regulation in Australia about the minimum supply of ventilation and the required levels of indoor air quality, Dr Haddad says the standard is rarely respected.

Australian school design complies with the National Construction Code and notes the need for naturally or mechanically ventilated classrooms with outdoor air to maintain adequate air quality. However, there is no requirement on how much and how often windows should be opened in naturally ventilated classrooms, and no strategy is provided for different spaces.

HVAC Hygiene ad - October 2019.pdf 1 19/9/19 2:44 pm

The National Construction Code sets out design requirements for mechanically ventilated buildings to control odours, particulates, and gases, aiming to achieve adequate IAQ. It requires a minimum ventilation rate of 10 and 12L/s per person for classrooms serving persons over and below 16 years old, respectively. It also specifies a minimum floor area required per occupant (2m²) in classrooms.

“So, the number of air changes per hour … is important in all learning spaces to achieve proper indoor air quality,” says Dr Haddad. “Ventilation is one component of maintaining healthy indoor environments and is an important COVID-19 prevention strategy for schools, learning spaces, and childcares.”

FROM THE HEALTH SECTOR TO CLASSROOM

Director of Viscon Systems, John Penny, M.AIRAH, specialises in building commissioning and indoor environmental control, predominantly in complex health buildings and scientific research facilities. He says that lessons learned in these facilities can be applied to IAQ issues being seen in many schools.

Penny has recently been looking at the issues with schools and IAQ and observes that COVID-19 is exacerbating an issue that has been around for many years.

“There was never enough ventilation in most schools,” he says.

The majority of classrooms in Australia have relied on windows and doors for natural ventilation, perhaps with ceiling fans added for cooling in hot weather. But windows and doors are not always left open. In some classrooms the windows no longer work properly, or are considered a security risk when left open. In many schools, split systems have been added as a quick and cheap solution to uncomfortable spaces.

Penny notes, however, that most of the HVAC systems simply recycle the air already inside the classroom – and outdoor ventilation is regarded as a “poor cousin” to HVAC.

“You can have around 30 kids within a metre of each other,” he says. “The CO2 levels can be acceptable if it is a windy day and the windows are open, but if it is a hot, still day, it is not so good.”

Penny says there has been a lack of recognition of IAQ in classrooms as a health issue. At the start of the pandemic, there was also reluctance on the part of authorities to recognise that COVID-19 was airborne, and AIRAH was one of the lone voices in Australia calling for an effective IAQ strategy to reduce risks.

A key part of addressing IAQ is ensuring there is someone at the school whose focus is on the health and wellbeing of students and the degree to which classrooms and other spaces support this.

“Fixing ventilation has other benefits,” Penny says. “Fresh air is good for people, and in classrooms, supports better learning outcomes.” Once the pandemic has abated, solutions that improve ventilation and minimise energy should be considered.

A WORKFLOW FOR FIXING IAQ

As a first step to short-term remediation, Viscon Systems Director John Penny, M.AIRAH, recommends testing with wireless CO2 monitors to check ventilation in the space. They can cost from $200 and can be moved around. Often no additional wiring or IT connections are required, and some IoT models can be integrated with a cloud-based monitoring and reporting platform.

Penny says facility managers or school maintenance and management staff can use the CO2 monitors to establish which classrooms are especially poor in terms of ventilation and CO2 levels to inform mitigation measures. These could include having fewer pupils in those classrooms, rescheduling the time of day those spaces are used to earlier in the day before CO2 builds up, seeing if windows require fixing, installing exhaust fans, or using portable air cleaning and purification units.

In well-ventilated spaces, CO2 levels should normally stay below a concentration of 800ppm. Best practice indoors is around 600ppm or below.

Portable air purifiers are part of the Victorian government strategy for COVID-safe classrooms and can also be valuable for managing the health risks of bushfire smoke and other pollutants. But Penny says they are not the ideal long-term fix for every school. ■

THOUGHT LEADERSHIP IN ACTION

The Sustainable Buildings Research Centre (SBRC) at University of Wollongong (UOW) holds Living Building Challenge Certification, an award that is given to buildings of significantly positive environmental impact and good indoor environmental quality. Its researchers also contribute to AIRAH’s own research, including the Innovation Hub for Affordable Heating and Cooling (i-Hub). SBRC researcher Dr Daniel Daly, Affil.AIRAH, says schools generally have some unique features that make IAQ a challenge, notably a high and varying occupant density that can cause CO2 to peak during certain periods.

“A lot of classrooms were designed for use with open windows and ceiling fans,” he says, “and not necessarily with split systems that do not have dedicated outdoor air supply.”

Schools are faced with a need to balance the desire for comfortable classrooms with the need to manage future costs, not to mention a desire to do the right thing for the environment. As air conditioning becomes more common in school classrooms, the importance of building envelope efficiency, energy-efficient HVAC systems, and solar PV increases. There is now a fresh focus on how the system may affect IAQ.

Daly describes the current focus on IAQ as potentially signalling a change in thinking, not only in reaction to COVID-19 but also in terms of the growing impacts of climate change. The bushfire summer of 2019/20 was a sign of things to come – highlighting another air quality issue that will require mitigation.

Adding more split systems to deal with high temperatures will not work, nor will simply opening the windows to let fresh air in if the air is full of smoke or pollen. There is a need to appreciate HVAC as being about more than just thermal comfort – it is also important to ensure adequate ventilation, Daly says.

Daly says decisions around appropriate HVAC systems should consider both monetary and non-monetary factors, for example improvements in the learning environment, or reductions in air pollution. They should also factor in broader governmental ambitions, such as electrification and net-zero strategies.

“There is an opportunity to break down siloed thinking,” Daly says. “We could see a real perception change, from thinking about HVAC as simply equipment to regarding it as a service that ensures the spaces we occupy are healthy.”

Viscon Systems director John Penny, M.AIRAH, showing off an air quality monitor – and a very reasonable level of CO2!

According to UOW Associate Research Fellow Clayton McDowell, Stud.AIRAH, public awareness of IAQ has been building.

“During the bushfires people wanted to understand about parts per million of pollutants,” he says, “and there was a massive rise in education around air pollution.”

But McDowell believes it will take a “paradigm shift” to address existing buildings, as it may not be as simple as bringing in the regular maintenance technician. Many schools have old equipment, and capital budgets for replacement or upgrade are planned many years in advance. Remedial work may be required on some buildings too.

Having air filtration installed as part of the air handling system as an add-on can help. Dr Daly notes, however, that schools can take other measures before installing a split system. These include assessing air tightness of classrooms, installing ceiling fans and ensuring insulation is effective to reduce the need for mechanical, split system-type cooling.

UOW SBRC Associate Professor Dr Georgios Kokogiannakis, M.AIRAH, says this current situation is a “moment to shine” for the HVAC&R industry.

“We see everywhere people are now having discussions about air quality,” he says. “We need to embrace this with an open mind and innovative solutions. We should also remember the other aspects of the building design such as energy use and acoustics.” ■

TESTING THE THEORY

Dr Shamila Haddad and the research team from UNSW School of Built Environment tested the application of a dynamic demandcontrolled ventilation (DCV) system with air extraction in classrooms where IAQ sensing technology was employed.

DCV systems utilise both natural and mechanical ventilation systems and control IAQ in school buildings by adjusting airflow rates based on CO2, Total Volatile Organic Compound (TVOC) and/or a thermal comfort parameter. The DCV supplied fresh air, based on the measured IAQ in the classroom to reduce exposure to air pollutants in the indoor environment.

The results showed CO2 concentrations may reach up to approximately 3,000ppm in the absence of proper ventilation in the classrooms.

“We found significant improvement in indoor CO2 and VOCs in classrooms after installation of the hybrid/DCV ventilation system,” says Dr Haddad. ■

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