The World Health Organisation (WHO) has belatedly acknowledged the threat posed by airborne transmission of the coronavirus following months of warnings from ventilation and air quality experts.
WHO officials said “evidence was emerging” that Covid-19 can spread through the air in enclosed spaces.
A number of scientists have, therefore, pointed out that building ventilation systems will be crucial in limiting the chances of “super spreader” events in enclosed environments that could spark a second wave of the pandemic.
Benedetta Allegranzi, the WHO's technical lead for infection prevention and control, said that evidence emerging of airborne transmission of the coronavirus in “crowded, closed, poorly ventilated settings…cannot be ruled out”.
The Building Engineering Services Association (BESA) said this supported the position taken by many indoor air quality (IAQ) experts that facilities managers should be revisiting their ventilation strategies to minimise possible transmission risks as more buildings reopen following the lockdown period.
“We have been arguing since the early days of the pandemic that ventilation can play a crucial role in reducing the threat of virus transmission,” said Nathan Wood, chair of BESA’s Health & Wellbeing in Buildings group. “We should also consider the wider deployment of air purification technologies, which are now being used more regularly in healthcare settings.”
The WHO’s change of stance was prompted by an open letter written by 239 researchers in the fields of virology, aerosol physics and epidemiology from 32 countries quoting evidence that showed tiny particles containing the virus could become suspended in the air.