Before we had vaccines, there were few or no weapons in the fight against Covid-19. But there was one that might at least help reduce your risk of ingesting the virus – fresh air.
According to a study published by the government’s Scientific Advisory Group on Emergencies (SAGE) late last year, a well-ventilated room can remove 70 percent of virus particles in the air over time or leave them a little open, uninterrupted.
And now – as we are starting to socialize again indoors – a group of experts is calling for a change in the air quality in buildings, including our homes.
Before we had vaccines, there were few or no weapons in the fight against Covid-19. But there was one that might at least help reduce your risk of ingesting the virus – fresh air
In an article published in Science magazine last week, the panel of 39 researchers from 14 countries including the UK says the quality of our indoor air should be monitored to the same standards as food and water to prevent disease transmission protect.
“We all want to be sure that the air in our homes and in the buildings and restaurants we visit is clean, just as we are sure that the water that comes out of our faucets is safe to drink,” said Dr. Julian Tang, a clinical virologist at the University of Leicester and one of the report’s authors.
The experts demand that governments agree and enforce standards for indoor air quality and that monitors display the air quality in public buildings.
They argue that not only could this help prevent future pandemics, but it could also slow the spread of other airborne diseases like the flu and colds.
“This is particularly relevant given the emergence of new variants of Covid, which may be more easily transmissible: by taking measures now to improve ventilation, we can try to stop a new wave,” says Catherine Noakes, professor of environmental technology for buildings from the University of Leeds and another author on the report. Yet many of us don’t seem to have gotten the message.
The experts demand that governments agree and enforce standards for indoor air quality and that monitors display the air quality in public buildings
“Data suggests that most people feel that ventilation is less important than ‘hands, face, space’, but in many ways ventilation is most important,” adds Stephen Reicher, professor of psychology at the University of St Andrews, and a member of SAGE.
In fact, science is now showing that the coronavirus in droplets, or smaller particles known as aerosols, is far more likely to be transmitted through the air than, for example, through infected surfaces.
“We know that these aerosols behave similarly to smoke, but are invisible – and most virus transmissions take place indoors,” says Professor Noakes.
“When you’re infected with someone who is infected and doesn’t have fresh air, the particles can stay in the air for hours and build up over time.”
She says there are simple everyday actions we can take at home or in stores and offices – especially opening a window for ten to 15 minutes every few hours.
The crucial role indoor airflow plays in transmitting Covid was underscored in Western Australia, where the government recently closed a third of its quarantine hotels following an outbreak in January.
Investigations revealed that the virus had escaped from an infected person’s room in quarantine through a gap under the door and down the corridor where it infected a security guard whose post was several rooms away.
Why do we pay so little attention to properly ventilating our buildings?
“We have developed an ‘airlock’ culture, particularly in our air-conditioned, centrally heated offices where either nobody thinks about opening a window or it is impossible to open a window,” said Trish Greenhalgh, professor of primary care at Oxford University, said Good Health.
Our efforts to make our homes more energy efficient have come at the expense of good ventilation – “People often never even think about opening windows because they are worried about letting out heat,” adds Professor Noakes.
With indoor gyms and restaurants back on the agenda, the importance of fresh air in tight spaces where people speak loudly or breathe deeper is clear.
“This is especially true as the evidence shows that ‘superspreaders’ – people who can spread the disease to a disproportionate number of others – do so in enclosed indoor spaces like pubs,” says Professor Noakes.
As many offices are also preparing to return to almost normal business, experts say the quality of the fresh air in work areas must also be taken into account. According to the safety standards, employers currently have to ensure that workers are adequately supplied with fresh air in closed rooms. However, it is up to the company to decide how to deploy this.
“You see a lot of companies promoting their cleaning and disinfection efforts – but they’d better focus on making sure the air is clean and fresh,” says Professor Noakes.
“If a company has a mechanical ventilation system, make sure it works properly. If not, think about which windows and doors you can open to let fresh air into the building and let your staff know if this is guaranteed.
“An air filter might also be useful in a single room or an enclosed space.”
Portable air purifiers or air purifiers filter contaminants from the air around them – and some use ultraviolet light to destroy bacteria and mold particles.
“Air purifiers can be helpful in a certain area, but there is a very wide range of variable efficiencies. So take a look around,” says Professor Noakes.
While prevention of circulating viruses is paramount, experts might say that better ventilation could have bigger benefits – from improved sleep to less absenteeism from work and school.
One of the main problems with poor airflow in any building is that it can cause indoor air pollution to build up. These are gases such as nitrogen dioxide and carbon monoxide as well as particulate matter (PM) such as soot and dust.
Sources range from gas stoves and central heating to chemicals in cleaning and personal care products, adhesives, paints, and cigarette smoke.
These can contribute to a number of lung diseases, including chronic obstructive pulmonary disease (COPD), a group of progressive lung diseases like emphysema and asthma.
There is also evidence that air pollution damages your heart and circulation by affecting the inner walls of blood vessels, making them tighter and harder.
“We spend 90 percent of our time indoors, where the concentration of some pollutants can be up to five times higher than outdoors,” says Hasan Arshad, professor of allergy and clinical immunology at the University of Southampton.
Meanwhile, the benefits of improving ventilation are numerous. “There is even evidence that it helps you sleep better – and perform better the next day,” says Professor Noakes.
It is believed that the carbon dioxide we exhale can build up in a sealed space, making us sluggish and sleepy.
Carbon dioxide levels are measured in parts per million (ppm), with the general assumption that a well-ventilated interior is between 800 and 1,000 ppm. However, with the windows closed, the carbon dioxide levels in the bedrooms can rise to 2,500 ppm and more.
New buildings and offices are increasingly being equipped with MVHR systems (short for mechanical ventilation with heat recovery) that draw in air from the outside, filter it to remove many pollutants while the heat is stored, and then distribute it around the house.
However, they do not have to be legally installed and are difficult to incorporate into existing homes.
Professor Noakes wants people to get in the habit of opening windows (and using range hoods) for short periods of time throughout the day – especially when cooking or using chemicals like aerosols.
“It’s also a good idea to make an effort to reduce the amount of chemicals you generally use at home,” she adds. ‘Limit the aerosols you use – swap out a spray-on deodorant for a roll-on, for example, or try using much less of a product.
“Now is the time to apply the lessons we have learned from Covid-19 and examine how we can change our indoor air.”