‘Paradigm shift’ in ventilation needed to combat virus spread

Scientists from across fourteen different countries have today (Thursday) appealed to government for a ‘paradigm shift’ in improving indoor ventilation standards, as part of efforts to combat airborne COVID-19 virus transmission.

The call by 40 scientists comes days before further lockdown restrictions are eased on 17 May, as a scientific consensus continues to grow about the airborne transmission of coronavirus.

Published in the journal Science, the study highlights how building ventilation standards are now critical as a preventative measure to mitigate airborne transmission routes - likening ventilation standards in buildings to be where water sanitation was in the 1800s.

Dr Julian Tang, Honorary Associate Professor and Clinical Virologist of Respiratory Sciences at the University of Leicester is one of the scientists involved in the study: “Health authorities have singled out indoor spaces with poor ventilation as potential infection hotspots. They present a particular threat because the risks shoot up when virus particles accumulate in buildings.

“Bringing fresh air into a room and removing older stale air that contains virus particles reduces the chance of spreading COVID-19; the more fresh air that is brought inside, the quicker any airborne virus will be removed from the room.

“We all want to be confident that the air in our homes and the buildings and restaurants we visit is clean just as we are assured that the water coming out of our taps is safe for us to drink.

“If public places have a ‘ventilation certificate’, much like being health and safety certified, we will see restaurants more easily regaining diners’ trust, and employees more confidently returning to offices.”

Historically, public health regulations have concentrated on sanitation, drinking water and food safety, whereas the risk from airborne pathogens - whether flu or COVID-19 - has been according to the paper “addressed fairly weakly, if at all, in terms of regulations, standards, and building design and operation, pertaining to the air we breathe.”

The paper states: “A paradigm shift is needed on the scale that occurred when Chadwick’s Sanitary Report in 1842 led the British government to encourage cities to organise clean water supplies and centralised sewage systems.

“In the 21st century 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.”

Research during the COVID-19 pandemic has underlined the role that aerosols play in spreading disease. The paper states: “... community outbreaks for COVID-19 infection in particular most frequently occur at larger distances through inhalation of airborne virus-laden particles in indoor spaces shared with infected individuals. Such airborne transmission is potentially the dominant mode of transmission of numerous respiratory infections. We also have strong evidence on disease transmission, for example in restaurants, ships, and schools, suggesting that the way we design, operate, and maintain buildings influences transmission.”

Dr Tang further comments: “We must take action when it comes to better ventilation if we want to betterprotect present and future generations from unnecessary suffering and economic losses. It starts with a recognition that preventing respiratory infection, like reducing waterborne or foodborne disease, is a tractable problem.

“Our current response efforts to combat airborne viruses - such as mask-wearing and social distancing – are helping to reduce aerosol transmission, but specific, mandated guidance for buildings and private homes on improving indoor ventilation will ensure that we continue to reduce the number of COVID-19 cases, keeping airborne infection risk below an acceptable level.

“Ventilation systems that include higher airflow, filtration and disinfection rates, and monitors that allow the public to observe the quality of air around them, will mean we can be more confident as we come out of lockdown.”

The authors collectively note that the benefits of improved indoor ventilation go beyond infectious disease transmission and could significantly reduce the incidence of common colds, allergies and sick building syndrome-related illnesses that cost businesses billions in lost productivity through sickness absenteeism each year.

Dr Tang notes that there is further evidence that improved indoor air quality through increased ventilation improves office worker and classroom pupil performance.