Calls for indoor air quality mandate and $10 billion for school ventilation

A group of scientists, architects and other experts is calling for government action to mandate indoor air quality standards and improve "terrible" ventilation in Australian schools that can hamper learning.

Geoff Hanmer, an adjunct professor of architecture at the University of Technology Sydney, said since about the mid-1970s, Australia had made great efforts to clean up its outdoor air quality.

"And we've succeeded to a large extent," he said.

"But indoor air is something that we've neglected for many years … particularly in schools.

A recent study of 60 New South Wales public schools found if windows were shut, classroom carbon dioxide (CO2) levels easily exceeded 2,500 parts per million (ppm), which was "really bad ventilation", according to Mr Hanmer.

In Australia, outdoor CO2 levels sit at around 415ppm.

Australia's National Construction Code specifies indoor CO2 levels should not exceed 850ppm averaged over eight hours, but this is only a guideline.

Mr Hanmer said when CO2 went above 1,200ppm, it started to impair people's cognition, which was a big problem in a classroom environment.

"When we've measured schools, we find often that the quality of indoor air is pretty terrible," he said.

"It starts to affect [students'] … capacity to understand things, and consequently, their capacity to learn and participate in class.

"Afternoon rattiness [at school] is another by-product of this."

BTN High tested CO2 levels in three classrooms with about 20 children, including one room with a heating, ventilation and air conditioning (HVAC) system, one with a door and window open to outside air, and one with all doors and windows closed.

The classroom with the ventilation system peaked at around 1,500ppm of CO2 while the test was being set up, but then dropped and did not go above 800ppm once the system had been running for a while.

The classroom with a door and window open climbed up to around 2,000ppm and remained at about this level.

And the classroom with all of its doors and windows closed reached 3,500ppm, and was still going up when the test was ended.

Disease, mould also an issue

Poor cognition is not the only issue caused by poor indoor air quality.

Lidia Morowska, a professor and physicist from Queensland University of Technology, said high CO2 levels indoors usually indicated an issue with ventilation, which meant not enough fresh air was getting in.

And that's bad news when it comes to preventing the spread of disease.

Mr Hanmer said this was particularly evident during the second COVID-19 wave in Melbourne.

"We have a lot of information because there was track and trace in place," he said.

"For a lot of that period, quite a few schools were closed … but we can see that the schools that were open, if they had poor ventilation, they tended to have super-spreader events."

What are the rules in Australia?

Outdoor air quality is far more regulated in Australia than indoor air quality.

As Australia's industry, transport and population grew in the early 20th century, outdoor air pollution became a big problem in our major cities.

In response, state governments started monitoring outdoor air quality in the 70s and 80s.

And in 1998, the federal government mandated national standards for outdoor air quality, which included a list of pollutants and their allowable maximum concentrations over certain sampling periods.

These days Australian cities have some of the best outdoor air quality in the world, although Professor Morowska believes that's partly because Australia's population — and by extension, pollution — is spread across such a big landmass.

But for indoor air quality, there are no government-mandated standards.

The National Construction Code specifies that all buildings must include some kind of ventilation, whether it be mechanical — for example, via a HVAC system — or natural, via windows or doors.

Mr Hanmer said for historic reasons, most schools were ventilated using natural ventilation, and the only requirement was that the ventilating area (the windows and doors) was not less than 5 per cent of the floor area of the room.

Mr Hanmer said 98 per cent of NSW schools were naturally ventilated, "and the situation in other states appears to be similar".

The push for change

Mr Hanmer and Professor Morowska are both part of a national research group called Thrive, comprised of experts in aerosol science, engineering, architecture and business who want to improve indoor air quality.

Earlier this year, Professor Morowska led a paper from a number of scientists around the world that called for mandated indoor air quality standards.

Their blueprint for change recommends monitoring three pollutants, including CO2, particulate matter and carbon monoxide, which are good broad indicators of air quality.

Professor Morowska said all of these could be monitored with low-cost sensors.

"We had a meeting with the prime minister in the middle of August to present him with this blueprint."

A Department of Health spokesperson said the government was examining work by the National Science and Technology Council and the Australian Centre for Disease Control to develop policies for improving indoor air quality for Australians.

Investing in classroom air quality

Mr Hanmer's current focus is on improving air quality in schools.

"It is a problem we need to fix," he said.

Mr Hanmer said putting proper HVAC systems into schools was the best way to do this.

HVAC systems are different from the simple split-system air conditioners that already exist in some schools because they provide fresh air as well as temperature control.

Mr Hanmer said this would cost around $2 billion a year over five years — $10 billion in total — but that cost would be offset by how much the government would save.

Professor Morowska said poor air quality was already costing the country billions and the case for change was strong.

"There was a report published by the CSIRO in 1998 assessing that inadequate indoor air quality costs Australia $12 billion a year," she said.

"Now, if we translated this to the current value of the Australian dollar, it would be $24 billion a year — so it's a huge cost."