WHO must ‘take action’ on indoor air quality to tackle coronavirus

Leading scientists from across the world have signed a petition launched that calls on the World Health Organisation (WHO) to take ‘swift and decisive action’ on indoor air quality in public buildings to help to curb the spread of coronavirus.

As Covid-19 continues to put pressure on health systems and the economy globally, the group calls on the WHO to review the research that shows an indoor humidity level of between the 40% – 60% relative humidity (RH) is the optimum threshold for inhibiting the spread of respiratory viruses such as influenza.

The petition is designed to not only increase global awareness among the public on the crucial role indoor environmental quality plays in physical health, but also to call on the WHO to drive meaningful policy change, which they say will be a ‘critical necessity’ during and after the coronavirus crisis.

The scientists point to research that shows that breathing dry air impairs our respiratory immune system’s ability to efficiently capture, remove and fight airborne viruses and germs, rendering us more vulnerable to respiratory infections such as Covid-19.

Also, when RH is lower than 40%, airborne droplets containing viruses, such as SARS-CoV-2, shrink through evaporation making them lighter. This enables the particles to float for longer in the air, increasing the likelihood of infection. 

Prof. Dr. Akiko Iwasaki PhD, Professor of immunobiology and professor of molecular, cellular and developmental biology at Yale, and an investigator for the Howard Hughes Medical Institute said: ‘90% of our lives in the developed world are spent indoors in close proximity to each other. When cold outdoor air with little moisture is heated indoors, the air’s relative humidity drops to about 20%.

‘This dry air provides a clear pathway for airborne viruses, such as Covid-19. That’s why I recommend humidifiers during the winter, and why I feel the world would be a healthier place if all our public buildings kept their indoor air at 40 to 60% RH.’

Sign the petition here.