Mandating indoor air quality for public buildings


An international group of experts are calling for indoor air quality standards to be introduced around the globe.

More than 40 scientists have joined forces to recommend setting levels for three key indoor pollutants: carbon dioxide (CO2), carbon monoxide (CO) and PM2.5 – particles so small they can lodge deep in the lungs and enter the bloodstream; as well as standards for ventilation rate – the number of times per hour that the entire air volume of an area is changed. 

They have set out the standards framework in an article published in the prestigious journal Science

Cath Noakes, the paper’s co-author and Professor of Environmental Engineering for Buildings in the University of Leeds’ School of Civil Engineering, is among those calling for change as medical experts fear dirty air in buildings may contribute to nearly as many deaths as outdoor air pollution. 

“Introducing standards for air quality in public buildings recognises the right for those using the buildings to expect a safe and healthy environment, in the same way they should have confidence in food hygiene or fire safety.

Professor Cath Noakes, School of Civil Engineering

Indoor air matters 

Professor Noakes, who specialises in airborne infections and the transport of airborne pathogens, was appointed OBE in 2020 for services to the COVID-19 response.  

She said: “We need to raise awareness that indoor air matters. Many indoor places are public, where individuals have little control over the quality of air they breathe.  

“Introducing standards for air quality in public buildings recognises the right for those using the buildings to expect a safe and healthy environment, in the same way they should have confidence in food hygiene or fire safety. 

“There are multiple studies that indicate that improving indoor air in public spaces is cost effective in terms of health, wellbeing and productivity.” 

Supporting evidence for change 

The team of experts hope policy makers in the UK and worldwide will use these suggested standards to support the evidence for making changes in regulations, guidance and standards for indoor air. 

People living in urban and industrialised societies spend more than 90% of their time indoors, yet there are few controls over the quality of the air they breathe there. 

The scientists behind the paper found that technologies for measuring ventilation already exist in most modern, mechanically-ventilated buildings but monitoring ventilation rates – in terms of clean air delivered to the space – requires consideration of the number of people and their activities, to ensure adequate IAQ. 

They recommend that CO2 sensors should be used to measure pathogens and CO2ventilation during human occupancy in a public space, as they are readily available, inexpensive and robust. 

Limiting CO2 levels 

Professor Noakes said: “CO2 is one of the easiest parameters to measure and can be used to effectively assess ventilation quality. By limiting levels of CO2 indoors, we can reduce the spread of diseases spread by respiratory pathogens, like COVID-19, colds and flu.” 

The paper states that mechanical ventilation systems should remove and dilute human-emitted pollutants – such as body odour – and other indoor-generated pollutants at a higher rate than they were produced, so they would not accumulate in indoor air. 

And the team agreed that additional measures, such as air cleaning and disinfection, could greatly reduce the need to increase the outdoor air supply, which carries a heavy energy demand.   

The research was led by Professor Lidia Morawska – from Queensland University of Technology – who is also Vice-Chancellor Fellow at the University of Surrey

Social and economic benefits 

Professor Morawska, who led the appeal to the World Health Organization to recognise the airborne transmission of the COVID-19 virus early in the pandemic, said: “Most countries do not have any legislated indoor air quality performance standards for public spaces, that address concentration levels of indoor air pollutants. 

"To have practical value, indoor air quality standards must be implementable by designing new buildings that are built, operated and maintained to standard or retrofitted to meet the standards. 

"While there is a cost in the short term, the social and economic benefits to public health, wellbeing and productivity will likely far outweigh the investment in cost in achieving clean indoor air." 

This research demonstrates the University of Leeds’ contribution to the United Nations Sustainable Development Goals (SDG). These include SDG 3 (Good Health and Wellbeing) and SDG 11 (Sustainable Cities and Communities). 

Further Information 

The paper – Mandating indoor air quality standards in public buildings – was published in Science at 6pm GMT on Thursday March 28. 

DOI: 10.1126/science.adl0677 

For media inquiries pls email the University of Leeds press office via