The measurement and focus of indoor environment quality [IEQ] is not new. But when it comes to schools, it seems that targeting the performance of our teachers is far easier than the quality of the built environment and its IEQ.

IEQ in commercial office buildings has been getting all the press recently, particularly as it relates to the emergence of building rating tools such as NABERS Indoor Environment, WELL Building Standard, Green Star Performance and others.

The World Green Building Council released a significant report in September last year, Health, Wellbeing and Productivity in Offices: The next chapter for green building, which has generated further interest across the property and construction industry.

But it can be argued that it is schools, together with healthcare, which have the biggest implications when it comes to the difference between a good and a poor performing IEQ. Students spend on average six hours a day, five days a week, 40 weeks a year, for at approximately 13 years in classrooms. The performance of these spaces is critical to their development.


ASHRAE 62 recommends a maximum 1000 parts per million (ppm) of CO2 for indoor environments and many commercial office buildings will target levels closer to 650 ppm, but according to Jack Noonan, senior consultant at technical risk management consultancy CETEC, they have recently measured levels in schools which far exceed this.

“Poor ventilation allows CO2 and indoor air contaminants to accumulate in occupied spaces,” he said.  “There have been a number of schools where we have measured carbon dioxide levels (as a proxy for ventilation effectiveness) at approximately 3,000 ppm. These have generally been occupied classrooms, often in winter, where the classrooms are closed off and clearly not adequately ventilated.”

These targeted levels for office buildings are considered to assist with employee concentration, strategy, performance and productivity. In fact, the 2012 study Is CO2 an indoor pollutant? Direct effects of low-to-moderate CO2 concentrations on human decision-making performance by Satish et al found that as levels increased from 600 ppm to 1,000 ppm to 2,500 ppm, there were statistically significant decreases in office performance; in some cases task performance was classified as “dysfunctional” at levels of 2,500 ppm.

Satish 2012 image

“Despite this, we are subjecting our students to carbon dioxide levels which are beyond 3,000 ppm and then telling them that they need to improve their focus, attention, and grades so that they can compete against our international counterparts in terms of literacy and other standards,” said Noonan.

Data compiled from the Wisconsin Department of Health Services, OSHA, NIOSH, and ACGIH found that a level of 1,000 ppm “indicates inadequate ventilation; complaints such as headaches, fatigue, and eye and throat irritation will be more widespread; 1,000 ppm should be used as an upper limit for indoor levels” and levels between 2,000 and 5,000 ppm are “…associated with headaches, sleepiness, and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.”

The authors of Is CO2 an indoor pollutant? Direct effects of low-to-moderate CO2 concentrations on human decision-making performance also contend that the impact of 2,500 ppm of carbon dioxide is roughly equivalent to a 0.08 blood alcohol concentration – beyond the 0.05 limit for driving in Victoria.

So what are typical CO2 levels in classrooms? A 2002 study of 120 classrooms in Texas found that 88 per cent of classrooms exceeded 1,000 ppm and, alarmingly, 21 per cent of classrooms exceeded 3,000 ppm.

“The focus on reducing class sizes should not just be about greater interaction between a teacher and their student,” said Noonan. “It should also be about keeping carbon dioxide levels low. Furthermore, a greater focus on adequate ventilation should also assist with this.”

Noonan adds that an additional consequence of poor ventilation is the accumulation of other indoor air contaminants such as volatile organic compounds, including formaldehyde.

VOCs can be found in a range of building and maintenance products used in classrooms including carpets, vinyl, paints, sealants, plastics, timber products, furniture, electronics, cleaning agents and many others.

The toxicity of VOCs vary. Many are known to have significant health effects: some are known irritants and others are known to cause cancer (carcinogenic), mutations, and other undesirable effects. In outdoor environments, VOCs may be easily dispersed before causing health effects, but in a closed, poorly ventilated space like a classroom in winter, VOCs can accumulate and create a health hazard.

In addition to significant health effects, a team at the University of California, Berkeley, led by Bill Fisk has found cognitive declines associated with exposure to VOCs that are at levels typical of an office that had been renovated in the past year

“There have been a number of schools within Australia which have previously had and subsequently rectified issues associated with VOCs,” said Noonan. “With a stronger focus on material selection and IAQ management, we hope that these issues continue to decline.”


Another major issue is the capacity of indoor air to spread viral and bacterial infections, with mould growth a particular contributing factor.

There is an increasing prevalence of chronic health conditions such as asthma, allergies and other sensitivities. Asthma is the leading cause of absenteeism in US school children.

A 2003 study found that the effects of mould contaminated schools in the US included significant immediate allergic reactions in students and teachers. Furthermore, more than two years after the exposure ended, many of these students and teachers continued to have reactions that were not present prior to the exposure.

“This has significant implications for our schools as our climate warms and there are more flooding events,” said Noonan. “The risk of mould issues in classrooms will increase and with it the consequences for the health of our school children.”

This issue is global.

A new World Health Organisation report has found poor indoor school environments to be a particular problem in many countries in the WHO European region, with issues including stuffy air, dampness and mould, uncomfortable temperatures and poorly functioning toilets.

Although the report says most high-income countries have policies to improve indoor air quality in schools, including ventilation standards, poor ventilation and stuffy air in classrooms, especially during the cold season, remains a common problem. This is having negative effects on respiratory health, absenteeism, academic performance and the well-being of pupils.

Exposure to mould and dampness is also common in some countries, while improving sanitation and hygiene in schools remains a challenge in countries with limited resources. Poor infrastructure and inadequate maintenance of facilities are reasons behind pupils’ low satisfaction with toilets and hygiene facilities and their scarce use of them.

“Our analysis shows substantial environmental problems in schools, which are largely overlooked. We hope that decision-makers take stock of the evidence and make sure that existing norms and regulations are implemented,” said Dr Marco Martuzzi, program manager, Environmental Health Intelligence and Forecasting at WHO/Europe.