Call for new indoor ventilation standards to fight COVID-19 spread

Queensland University of Technology (QUT) air-quality expert Distinguished Professor Lidia Morawska is leading an international call for a ‘paradigm shift’ in combating airborne pathogens such as COVID-19, demanding universal recognition that infections can be prevented by improving indoor ventilation systems.

Professor Morawska led a group of almost 40 researchers from 14 countries in a call published in Science for a shift in standards in ventilation requirements equal in scale to the transformation in the 1800s when cities started organising clean water supplies and centralised sewage systems.

The international group of air quality researchers called on the World Health Organisation to extend the indoor air quality guidelines to include airborne pathogens and to recognise the need to control hazards of airborne transmission of respiratory infections.

“We need to establish the foundations to ensure that the air in our buildings is clean with a significantly reduced pathogen count, contributing to the building occupants’ health, just as we expect for the water coming out of our taps,” Professor Morawska said.

“Mandated building ventilation standards need to include higher airflow, filtration and disinfection rates, and monitors that allowed the public to observe the quality of air around them. We should have virus-free air indoors.”

Professor Morawska said applying ventilation standards to food processing plants follows the same general principles as applying them to other types of indoor environments. “The key is that ventilation provided is sufficient and effective. Sufficient means enough of it. Effective means everywhere within the indoor space and such that air doesn’t flow from person to person.”

According to Professor Morawska, the amount of sufficient ventilation in relation to infection transmission in any particular indoor environment (including food processing plants) is assessed by using risk assessment models and tools, which take into account the characteristics of the space (in particular size), number of people, respiratory activities conducted (quiet breathing versus talking, etc) and the amount of time spend there. Based on this, ventilation requirements are calculated to keep the infection risk below the acceptable level, she said.

Professor Morawska said response efforts to combat airborne viruses were currently too weak because airborne infections were harder to trace than food or waterborne outbreaks.

“We’ve provided strong evidence that airborne transmission spreads infections, so there should be international ventilation standards that control pathogens,” she said.

“Most minimum ventilation standards outside of specialised health care and research facilities only control for odour, CO₂ levels, temperature and humidity.

“Ventilation systems with higher airflow rates and which distribute clean, disinfected air so that it reaches the breathing zone of occupants must be demand controlled and thus be flexible.

“Wide use of monitors displaying the state of indoor air quality must be mandated too, because the general public currently have no way of knowing the condition of indoor spaces they occupy and share with others.

“None of this means that every indoor space should become a biosafety facility, but a building should be designed and operated according to its purpose and activities conducted there, so that airborne infection risk stays below an acceptable level.”

While detailed economic analysis was yet to be done, Professor Morawska said estimates suggested necessary investments in building systems may be less than 1% of the construction cost of a typical building.

“The benefits are beyond infectious disease transmission. Improved indoor air quality may reduce workplace absenteeism, ‘sick building syndrome’ and allergic reactions.

“The reduction in productivity losses alone may cover the cost of any ventilation changes.”

Image credit: QUT