A planning expert and adviser to government has called for changes to building standards for high-density and build-to-rent apartments because inadequate ventilation and crowded buildings pose an infection risk during a pandemic.

Orla Hegarty, Assistant Professor at the School of Architecture, Planning and Environmental Policy at UCD, said that "housing changes in recent years for more density may need to be reassessed in light of public health" and that in some cases people are living and working in what amounts to a "sealed boxes" which are not "adequately ventilated".

"We need to look at apartment standards again very closely - particularly for build-to-rent apartments. There is not a requirement for cross-ventilation. They are not required to have balconies which makes it very difficult to air out a room and the room sizes have got smaller with a lot of people sharing a long corridor," said Dr Hegarty, who is a member of an expert group that advises government on the Role of Ventilation in Reducing Transmission of Covid-19.

Speaking on RTÉ's News at One, she said: "That’s a very similar situation to what they have had in quarantine hotels in Australia where the internal corridor is poorly ventilated and where people were being infected between different rooms across the corridor. I do think some of the housing changes in recent years for more density may need to be reassessed in light of public health."

In February, a quarantine hotel in Melbourne had a Covid-19 cluster linked to air quality and the spread of the virus by aerosol transmission via a corridor between bedrooms.

The links between ventilation, architecture and public health go back a long way, according to Dr Hegarty.

"Architecture has always been about public health. Once people move indoors they need to be in sanitary conditions. They need to have water, fresh air and clean surroundings," she said.

"Ventilation has always been a part of architecture, particularly in buildings where people gather and where there are crowds. That goes back to the design of Cathedrals which had very high ceilings and air was drawn in at the bottom, just naturally, by having the doors open."

Public health emergencies of the past have influenced how buildings are designed and ventilated.

The Spanish Flu Pandemic saw authorities in Chicago avoiding a second wave by tackling ventilation in crowded public buildings.

"They closed all of the buildings where people congregated. Then they systematically did ventilation inspections on those buildings. It seems that there was an awful lot of building work going on for about six weeks when people were getting buildings up to scratch. They didn’t have a second wave. They opened in December of 1918," she added.

In Ireland, Tuberculosis (TB) had an impact on how buildings were designed, she said.

"People will be familiar with the older school buildings which had higher ceilings and very good ventilation - even windows between corridors and classrooms to increase the cross ventilation.

"We have some housing in Dublin designed in the 1940s where there were bed spaces on balconies for TB patients. We even have overcrowding regulations from the 1960s in housing which is to do with the amount of free air. Ventilation space in bedrooms was the basis of overcrowding regulations in housing. As we have moved in to the last 50 years or so we have moved away from that," Dr Hegarty said.

She said that in some cases today people are living and working in what amounts to a sealed box which are not "adequately ventilated".

"We have also been squeezing down our buildings and sealing our buildings and overcrowding our buildings more.

"As we have moved in to more modern homes, we have sealed up the drafts, we have triple glazed windows, and we don’t have chimneys on houses anymore. So, we are effectively living in a sealed box and a lot of them are not adequately ventilated," she said.

'Fresh air was our best friend in fighting infection'

Professor John Wenger, of the School of Chemistry at the University College Cork, and chair of the group that advises government on the Role of Ventilation in Reducing Transmission of Covid-19, said society needs to look at ventilation to keep indoor areas safe during the pandemic.

"Ventilation is important because the virus is mainly spread by the air. Looking back over history we know that fresh air was our best friend in fighting infection.

"The way that we do things now, we need to emphasise the importance of fresh air. If we are outside, great. But, we need to also bring the fresh air inside as well. It is especially important during Covid times," said Professor Wenger.

Dr Marie Coggins, an expert in Exposure Science in the School of Physics at NUI Galway, said ventilation is only one part of a number of measures to prevent viral spread in indoor settings.

"We need to think about a layered approach to improving indoor air. That includes ventilation, reduced exposure time, reduced occupancy indoors, distancing and masking.

"There are simple measures that we can all do now to improve ventilation and improve air flow through our buildings. We can make sure that our all vents and trickle vents are unblocked.

"We should also avoid recirculating of air. Then we can also invest in other systems like CO2 monitoring to help us identify when more ventilation is needed indoors."

While these are immediate solutions there are changes that could have a longer reach in to the future. Prof Wenger said this pandemic will have a lasting impact.

"This pandemic will lead to design changes. I think we need to factor in the possibility of future pandemics and that there will be a higher standard of regulation possibly on buildings in terms of ventilation and the filtration of air. The role of ventilation will be greatly improved in overall building design. I can see that being part of our future," said Prof Wenger.