Air filtration key to safe spaces: Experts

Aditi Tandon

Tribune News Service

New Delhi, August 21

Covid-19 vaccination by itself may not guarantee safety at workplaces and schools unless air filtration and indoor ventilation become part of the building design, says a new research as nations unlock and children return to schools.

Published today in The Journal of the American Medical Association (JAMA), the research calls upon the governments to alter building designs by fixing air changes per hour (a measure of room ventilation with outdoor air) and air filtration targets for indoor spaces like schools.

Authors say the majority of outbreaks involving three or more people have been linked with time spent indoors and evidence has confirmed that far-field airborne transmission (defined as within the room but beyond 6 feet) of SARS-CoV-2 is occurring. “Controlling the concentration of indoor respiratory aerosols to reduce airborne transmission of infectious agents is critical and can be achieved through source control (masking, physical distancing) and engineering controls (ventilation and filtration),” the research says.

“To reduce far-field airborne transmission of the virus in small-volume indoor spaces (classrooms, retail shops etc), we suggest targeting 4-6 air changes per hour through any combination of outdoor air ventilation,” the authors recommend.

They argue with Covid vaccine dose response unknown and debate about the dominant mode of transmission still ongoing, evidence supports engineering solutions if countries go back to opening offices and schools.

34,457 fresh cases

TOTAL DEATHS 4,33,964

ACTIVE CASES 3,61,340

375 deaths in 24 hours

Vax alone not enough

• Covid is transmitted from exhaled respiratory aerosols of infected individuals
• Smaller aerosols can stay aloft for 30 minutes to hours and travel well beyond 6 ft
• Vaccination alone may not guarantee safe workplaces and schools

Redo building designs

• Experts call upon governments to ensure buildings are altered for infection control
• They suggest 4-6 air changes per hour through any combination of outdoor air ventilation
• Air filtration is the process of ridding the air of airborne particles through the use of an air filter