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Greater understanding of the role of aerosols in spreading diseases.
- Control of airborne pathogens in buildings “addressed weakly, if at all” in regulations.
A group of the world’s leading experts in the transmission of airborne pathogens is calling for a tightened regulatory system to control air quality in buildings as a way of reducing the spread of COVID-19 and other illnesses.
The scientists who have contributed to the analysis include Cath Noakes, an IMechE Fellow and Professor of Environmental Engineering for Buildings at the University of Leeds. Cath is also a member of SAGE, the body that advises the UK Government on scientific emergencies.
Cath contributes to IMechE’s COVID-19 task force supporting the engineering approaches to improving ventilation in buildings.
Writing in the journal Science, the 40 scientists say: “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.”
Cath Noakes said: “Over the years, we have neglected the role that the air circulating inside a building plays in the way germs and viruses may spread between people. The pandemic has exposed that deficiency in our understanding and the way we seek to make buildings safer to use.
“We need to introduce new mechanisms that keep pathogen levels in the air flow in buildings and other enclosed spaces to a minimum. That approach can be achieved with technology backed-up with a requirement to meet new standards.
Frank Mills, Chair of Construction and Building Services Division at IMechE, said: “The world can only return to a normal and safe environment once mechanical engineers - who have expertise in the control and elimination of airborne infectious diseases – can apply their knowledge of effective ventilation systems, air sterilisation and air filtration technologies to reduce the risk of infection and to remove Covid from the air we breathe.
Recognising the risk of aerosol pathogen spread
Historically, public health regulations have concentrated on sanitation, drinking water and food safety, whereas the risk from airborne pathogens whether it is flu or COVID-19 is “... addressed fairly weakly, if at all, in terms of regulations, standards, and building design and operation, pertaining to the air we breathe”, say the scientists.
But research during the COVID-19 pandemic has underlined the role that aerosols play in spreading disease. When a person who has a respiratory infection speaks, coughs or sneezes, tiny infective particles are emitted from their nose and mouth. Indoors, those tiny particles are carried in the air and infect other people.
There are ventilation guidelines and standards which architects and builders must follow but the focus is on reducing odours and carbon dioxide levels and in maintaining thermal comfort. None provide recommendations on how to control the spread of pathogens.
The scientists are calling for World Health Organisation indoor air-quality guidelines, which cover pollutants such as carbon monoxide and other chemicals, to be extended to include airborne pathogens.