The air can be full of viruses in an enclosed space: how to make it healthy

Like the flu virus, the coronavirus what causes the covid It is mainly transmitted by air. If a person is infected (with or without symptoms), they can transmit the virus by exhaling, coughing, sneezing, talking, shouting or singing. For this reason, it is important to reduce the use of closed places or use the cross ventilation and standing as a way to have a healthy indoor environment.

To prevent the transmission of the virusventilation has become more in the eye of building constructors than world leaders and legislators.

Next July, in Belgium A law will come into force that will require public places, such as lays baremeet air quality objectives and view measurements in real time.

People will have access to information on carbon dioxide concentrations, an indicator of how much clean air is entering bars.

Later, in 2025, Belgian sports halls, restaurants and workspaces will also have to display the air quality classification via a certification system. In the event of a future pandemic, the Belgian classification system could determine whether or not a place is closed.

The law was signed into law in July last year and is the boldest in a series of steps countries have taken to make indoor spaces safer from infectious diseases like COVID and the flu.

Also in March last year, the US government launched the Clean Building Air Challenge to encourage building owners and operators to improve their ventilation and indoor air quality.

In October of last year, the state of California passed a law requiring all school buildings to provide clean indoor air. And in December, the White House announced that all federal buildings — some 1,500 in total — would meet minimum aviation security requirements.

Additionally, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) – a building industry organization whose recommendations are adopted into law through local building codes in the United States and in other countries – announced that it would develop standards that take into account the risk of infection by June 2023.

Meanwhile, in the UK, leading engineering bodies have released a government-commissioned report calling for mandatory clean air standards to keep buildings safe throughout their lifespan. Other countries are also taking action, such as installing air quality monitors in classrooms.

Argentina was the first country in Latin America to launch a public awareness campaign on the importance of carbon dioxide monitoring in enclosed spaces and ventilation. It is called Ventilar and it is still available on the website of the Ministry of Science, Technology and Innovation. From the National University of Hurlingham, the production of monitors was organized and knowledge was transferred to other public universities.

Kits for assembling monitors were also produced and distributed to the country’s network of science clubs. The province of Buenos Aires has developed a protocol on ventilation and carbon dioxide measurement in schools, 33,000 meters have been sent, accompanied by video and didactic material to be used in classrooms. Although not everyone uses them now.

“Although many advances have been made in raising awareness to prevent the transmission of infections and in the production and use of carbon dioxide meters in Argentina, the regulation of indoor air quality remains a challenge”, did he declare. GlobeLiveMedia physics doctor Jorge Aliaga, who was one of the promoters of the Ventilate campaign along with Conicet scientists Sandra Cordo and Andrea Pineda Rojas.

“Never in history has so much action been taken on indoor air quality,” said Dr Lidia Morawska, an aerosol specialist at Queensland University of Technology in Brisbane, Australia. But he warned that big challenges lie ahead, especially for schools, office buildings and other public places.

According to experts in the field, equipping them with the technology to produce clean air at sufficient levels will be a huge and costly undertaking. But the benefits would outweigh the costs. By one estimate, pandemic and seasonal flu outbreaks cost the UK an average of $27 billion a year. This country could save more than $206 billion over 60 years by improving the ventilation of buildings, according to the magazine Nature.

Researchers are still working to determine the best way to ventilate indoor spaces to prevent the spread of infections and what alternative technologies could replace or improve mechanical ventilation systems. But many say there’s already enough to start demanding safer indoor spaces.

According to Dr. Joseph Allen, a building hygienist at the Harvard TH Chan School of Public Health in Boston, “You can’t tell people to bring in more outside air without saying how much.” In June 2020, he and his colleagues recommended that schools wishing to reopen from lockdown perform four to six air changes per hour in their classrooms, during which the entire air volume in the room is replaced. . This equates to a ventilation rate of between 10 and 14 liters per second per person.

However, most schools received much less than that. A study of California classrooms, for example, found that most did not achieve this level of ventilation. The WHO released its own guidelines in March 2021, recommending a ventilation rate of 10 liters per second per person outside of healthcare settings.

However, health authorities have rarely considered ventilation when investigating major COVID outbreaks. Yuguo Li, a mechanical engineer at the University of Hong Kong, estimated fewer than 10 surveys measured ventilation rates in outbreak locations because airborne transmission was not on people’s radar.

Instead, researchers have tried to get clues through observational studies. Morawska participated in one that analyzed 10,000 classrooms in the Marche region of Italy. In the 316 classrooms with mechanical ventilation at rates of 1.4 to 14 liters per second per person, the risk of infection for students was reduced by at least 74% over a period of 4 months at the end of 2021, compared to that of students in classrooms that relied on windows for ventilation.

Last November, the work safety, school safety and travel safety working group of the COVID-19 Commission of The Lancet, chaired by Dr Allen, has issued specific guidelines on the rates of supply of clean air – through ventilation, air filtration or other means – to reduce airborne infections. To achieve what the report describes as the “best” air quality, it recommends more than 6 air changes per hour, or 14 liters per second per person.

For the doctor Morawska, carbon dioxide monitors should become widespread as a cheap and easily accessible tool that could be installed in all interior spaces, just like smoke detectors.

However, simply displaying carbon dioxide readings is not enough: room occupants are responsible for monitoring air quality and deciding if readings are high.

Last year, Morawska and her colleague Wei Huang of Peking University reviewed the air quality laws of more than 100 countries. Only 12 had national indoor air quality standards that specified maximum thresholds for pollutants. And only 8 of them – including China, South Korea, India, Poland and Hungary – set limits for CO2 concentration, the majority between 800 and 1,000 ppm10.

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