Health workers already know that indoor air quality can be as important to human health as clean water and uncontaminated food. But before the COVID-19 pandemic, its importance in the prevention of respiratory illnesses outside of health circles was only whispered about.
Now, a team of nearly 40 scientists from 14 countries is calling for “a paradigm shift,” so that improvements in indoor air quality are viewed as essential to curb respiratory infections.
Most countries do not have indoor air-quality standards, the scientists point out in their recent report, and those that do often fall short in scope and enforcement.
“We expect everywhere in the world to have clean water flowing from our taps. In most parts of the developed world, it is happening and we take it completely for granted,” said lead investigator Lidia Morawska, PhD, of the International Laboratory for Air Quality and Health at the Queensland University of Technology in Brisbane, Australia.
But bacteria and viruses can circulate freely in the air, and “no one thinks about this, whatsoever, apart from health care facilities,” she said.
A first step is to recognize the risk posed by airborne pathogens, something not yet universally acknowledged. The investigators also want the World Health Organization to extend its guidelines to cover airborne pathogens, and for ventilation standards to include higher airflow and filtration rates.
Germany has been at the forefront of air-quality measures, Dr. Morawska said. Years ago, she observed a monitor showing the carbon dioxide level and relative humidity in the room where she was attending a meeting. The screen was accompanied by red, yellow, and green signals to communicate risk. Such indicators are also commonly displayed in German schools so teachers know when to open the windows or adjust the ventilation.
Monitors show carbon dioxide levels
But this is not yet being done in most other countries, Dr. Morawska said. Levels of carbon dioxide are one measure of indoor air quality, but they serve as a proxy for ventilation, she pointed out. Although the technology is available, sensors that can test a variety of components in a building in real time are not yet affordable.
Dr. Morawska envisions a future where the air quality numbers of the places people frequent are displayed so they know the risk for airborne transmission of respiratory illnesses. And people can begin to expect clean indoor air when they enter a business, office, or entertainment space and request changes when the air quality dips and improvement is needed, she said.
It is a daunting challenge to clean indoor air for several reasons. Air is not containable in the same way water is, which makes it difficult to trace contaminants. And infections transmitted through dirty water and food are usually evident immediately, whereas infections transmitted through airborne pathogens can take days to develop. Plus, the necessary infrastructure changes will be expensive.
However, the initial cost required to change the flow and quality of indoor air might be less than the cost of infections, the scientists pointed out. It is estimated that the global harm caused by COVID-19 alone costs $1 trillion each month.
“In the United States, the yearly cost – direct and indirect – of influenza has been calculated at $11.2 billion. For respiratory infections other than influenza, the yearly cost stood at $40 billion,” the team noted.
“If even half of this was caused by inhalation, we are still talking about massive costs,” said Dr. Morawska.