Mobile Air Purifiers to Help in the Fight against COVID-19

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Mobile Air Purifiers to Help in the Fight against COVID-19

Other Governments provide funding, will Ireland follow suit?...

 

Ms. Dyani Lewis, writing for the Nature Portfolio, on ‘Why Indoor Spaces are still Prime COVID Hotspots’ as she opens her article with a compelling image of children learning with coats on inside a school in Germany that has open windows to improve ventilation, it was unnatural.

For months, health authorities have singled out indoor spaces with poor ventilation as potential infection hotspots, and on 1st March 2021, the World Health Organization (WHO) released a long-awaited road map to better ventilation. The document sets out specific targets and measures that businesses and other places can take to improve ventilation and make buildings safer.

Bluyssen and others are critical of governments’ failure to provide clear guidance or money for people to make indoor spaces safer. Some scientists say that has left large swathes of the population — from schoolchildren to office workers, restaurant goers and prisoners — at risk of catching COVID-19.

Ms. Dyani Lewis describes the slow recognition of the WHO in acknowledging that SARS-CoV-2 is an airborne virus. On 28th March 2020, two months after the WHO had declared COVID-19 a global health emergency, the agency broadcast a public-health message on Twitter and Facebook. “FACT: #COVID19 is NOT airborne,” it said, labelling claims to the contrary as misinformation. But evidence quickly established that the virus is transmitted by air, and researchers roundly criticized the agency.

The WHO updated its advice on SARS-CoV-2 transmission three months later, acknowledging the possibility that airborne transmission might occur in some community settings. Airborne transmission in “crowded and inadequately ventilated spaces over a prolonged period of time with infected persons cannot be ruled out”, the updated advice says.

When speaking about ventilation and the requirement and benefits of indoor air quality, the following statements were heard from various sources:

 

Philomena Bluyssen, a building engineer at the Delft University of Technology in the Netherland:

  • “ more needs to be done. “The WHO guidelines,” she says, “are the minimum.”

Yuguo Li, a building environment engineer at the University of Hong Kong:

  • “We would have saved a lot of people” if airborne transmission was recognized earlier.

Jose-Luis Jimenez, an atmospheric chemist at the University of Colorado at Boulder:

  • “The WHO and other health authorities have failed to clearly prioritise measures to improve indoor air quality to reduce the chance of catching COVID-19” and “They don’t emphasize how important it is. What the WHO needs to say is “fact, it goes through the air, we breathe it in.”
  • “One of the problems is that governments and businesses are still spending millions of dollars on surface disinfection, despite evidence that it is rare for SARS-CoV-2 to pass from one person to another through contaminated surfaces. By contrast, few countries have invested in measures to improve indoor air quality.”

 

 

  • “If we took half the effort that’s being given to disinfection, and we put it on ventilation, that will be huge,”. In October, Germany set aside €500 million (US$593 million) to improve ventilation in public buildings, including schools, museums and public offices.

Lidia Morawska:

  • “You imagine a busy bar,” she says. “In the reality, any place can become crowded and poorly ventilated. And people don’t realize this.”

Mechanical Ventilation and Drawbacks

A better method is to mechanically ventilate a space. This draws in virus-free outdoor air and removes contaminated indoor air, thereby diluting any virus present. In April 2020, ASHRAE and REHVA recommended setting HVAC controls to draw in as much outdoor air as possible and to filter recirculated air.

However, we note that few buildings, especially in milder climates such as in Germany, have systems powerful enough to use 100% outside air. Most office spaces and classrooms around the world are supplied with just 20% outside air, with the remainder recirculated to save on energy consumption for heating and cooling.

Another drawback of cranking up building ventilation is that rooms can become draughty and noisy, as existing systems have not been designed to accommodate these recommendations.

Air Purifiers_ The Ventilation Solution:

Mobile air purifiers that filter out viruses and other airborne contaminants could be readily deployed as part of the solution and would be more energy efficient than using extra heating or cooling on outside air. Filters in HVAC systems could also clean air that is recirculated.

Taking the lead in the provision of an affordable solution to the management of SARS-CoV-2 and other common pathogens, the government of Germany and South Korea, have provided funding to business to purchase mobile air purifiers that remove virus-laden aerosols. 

Researchers say that a greater focus on ventilation will yield benefits during the next pandemic — and even when there are no major disease outbreaks. Indoor air quality “has been very bad for a long time”, says Bluyssen. “This gives us the opportunity to improve not only the air quality for pandemic situations, but also the whole indoor environmental quality for the future.”

https://www.nature.com/articles/d41586-021-00810-9