Healthy indoor air is our fundamental need: the time to act is now
According to estimates by the World Health Organization, polluted outdoor air kills over 7 million people annually.1 In 2021, the WHO published new air quality guidelines to serve as the basis for setting or updating national ambient air quality standards.2 This document can also be the basis for setting national indoor air standards, as the recommended air pollution levels apply both to outdoor and indoor air. Will national jurisdictions update their indoor air quality (IAQ) standards? The shocking reality is that most countries, including Australia, do not have any IAQ standards or even plans to establish them. The handful of countries that have standards do not have the means and procedures to enforce them; therefore, they do not serve their purpose.3
What are the consequences of poor indoor air quality?
The burden of disease due to indoor air pollution in terms of disability-adjusted life-years in 26 European countries was demonstrated in the IAIAQ project.4 Numerous studies have quantified the negative impact of poor air quality in buildings on health, general wellbeing, and productivity.5 In Australia, the pre-pandemic costs attributable to respiratory, neurological and other symptoms and illnesses arising from exposure to hazardous gases and particles (both biological and non-biological) in the indoor environment were certainly above the $12 billion per year calculated in a 2001 study.6
In addition to pollutants from indoor and outdoor anthropogenic sources, other types of pollutants are those that humans emit. We continuously exhale carbon dioxide (CO2) and generate particles during all our respiratory activities, at a rate and size dependent on the activity.7 If pathogens (viruses or bacteria) are present in the respiratory tract, they are emitted as a component of the particles. The predominantly small size of these particles (most of them are < 1 μm) means that they can float in the air for prolonged periods and travel substantial distances within an indoor environment; if a susceptible person inhales these pathogen-laden particles, they can become infected. This process is called airborne transmission of respiratory infections, which the coronavirus disease 2019 (COVID-19) pandemic brought dramatically to our attention.8 Airborne transmission is considered the dominant mode of transmission of numerous respiratory infections.9 Of course, this is not a new risk, it has been with us forever, but was not considered, not recognised, and ignored. Globally, before the COVID-19 pandemic, acute respiratory illnesses such as colds and influenza accounted for an annual estimated 300 million lower respiratory infections, resulting in more than 2.7 million deaths and economic losses of billions of dollars.10 Similar to other countries, viral respiratory infections are a major cause of morbidity and mortality in Australia.11
The economic cost of these infections is high; non-influenza respiratory infections cost global communities tens of billions of dollars annually. The estimated cost of acute lower respiratory infections in the European Union totalled €46 billion in 2011;12 the economic burden from all lower respiratory infections in Australia exceeded $1.6 billion in 2018–19.13Although it is unlikely that we could eliminate respiratory infections by controlling airborne transmission in shared indoor spaces, we can substantially reduce them. If hospital admissions occasioned by these diseases could be halved by limiting airborne infections, tens of thousands of Australians would remain healthy, saving hundreds of millions of dollars each year.
Times of crisis expose the limitations of internal atmospheres. Along the Australian south-eastern seaboard in 2019–2020, buildings failed to protect people from bushfire smoke.14 In the COVID-19 pandemic, countless congregational settings (offices, schools, factories, residential aged care facilities, cruise ships etc), where most of the population spends a substantial fraction of the day working, studying, travelling, enjoying entertainment, resting or undergoing medical care as part of their daily lives, allow virus-laden particles to spread through indoor air.15 Inadequate management of internal atmospheres might not be obvious, but the disastrous consequences certainly are.
Why is indoor air quality so neglected?
Why is clean indoor air not considered of utmost importance to our health and wellbeing? After all, we spend more than 90% of our lives in buildings, breathing indoor air about 12 times a minute. The simplest answer is because IAQ is a regulatory “no man’s land”.
Globally, IAQ presents a complex political, social and legislative challenge, with lack of an open, systematic and harmonised approach. Even though the Australian Standard AS1668 and the National Construction Code specify ventilation system requirements, these are for new buildings and consider only outside air provision; they are not consistent with the WHO guidelines, do not consider air quality, and are not enforced. In Australia, as in most countries, there is no single national government authority with responsibility for IAQ, and any relevant legislation is at the discretion of individual states and territories, not the Commonwealth. In individual states and territories there are no bodies directly responsible for IAQ; responsibilities are spread between different organisations. For example, the Department of Education is responsible for IAQ in schools, and the Department of Health governs IAQ in health care facilities. It is a similar story for hospitality venues, office buildings, and retail. Further, occupational and residential environments are treated differently, and information on assessment of the indoor environment is often available only to building owners and treated as confidential.
Importantly, there are no performance standards for indoor air, only design and operation standards. Although outdoor air legislation is based on performance standards (through compliance with concentration levels of pollutants prescribed by the standards), indoor environment legislation is limited to design standards. Factors in the design include air exchange rate, filter specifications, and size of windows. Each factor is related to IAQ but is not the only one responsible for it; therefore, without actually measuring the performance of the building system, IAQ is unknown. This is not a new situation, the issue was raised more than 20 years ago,16 and despite the efforts of many air quality and public health experts, the situation has not changed.
What should be done?
Why is clean indoor air not considered of utmost importance to our health and wellbeing? After all, we spend more than 90% of our lives in buildings, breathing indoor air about 12 times a minute. The simplest answer is because IAQ is a regulatory “no man’s land”.
Globally, IAQ presents a complex political, social and legislative challenge, with lack of an open, systematic and harmonised approach. Even though the Australian Standard AS1668 and the National Construction Code specify ventilation system requirements, these are for new buildings and consider only outside air provision; they are not consistent with the WHO guidelines, do not consider air quality, and are not enforced. In Australia, as in most countries, there is no single national government authority with responsibility for IAQ, and any relevant legislation is at the discretion of individual states and territories, not the Commonwealth. In individual states and territories there are no bodies directly responsible for IAQ; responsibilities are spread between different organisations. For example, the Department of Education is responsible for IAQ in schools, and the Department of Health governs IAQ in health care facilities. It is a similar story for hospitality venues, office buildings, and retail. Further, occupational and residential environments are treated differently, and information on assessment of the indoor environment is often available only to building owners and treated as confidential.
Importantly, there are no performance standards for indoor air, only design and operation standards. Although outdoor air legislation is based on performance standards (through compliance with concentration levels of pollutants prescribed by the standards), indoor environment legislation is limited to design standards. Factors in the design include air exchange rate, filter specifications, and size of windows. Each factor is related to IAQ but is not the only one responsible for it; therefore, without actually measuring the performance of the building system, IAQ is unknown. This is not a new situation, the issue was raised more than 20 years ago,16 and despite the efforts of many air quality and public health experts, the situation has not changed.
The Medical Journal Of Australia – Written By Lidia Morawska, Guy B Marks, Jason Monty