Aerosols from Covid-19 infected person can travel in air up to 10 metres: Centre

'In closed un-ventilated indoor spaces, droplets and aerosols become quickly concentrated and greatly increase the risk of transmission to people'

Mask up in toilets, use table fan systems and roof ventilators in offices, auditoriums and shopping malls and double masking in congested spaces are some of the suggestions in the Centre's new advisory, which, highlighting the extent of airborne transmissibility of Covid-19, said, nasal droplets fall within 2 metres from a Covid-19 infected person and the aerosols can travel in the air up to 10 metres.

The other recommendations made in an advisory by the Office of the Principal Scientific Advisor (PSA) K Vijay Raghavan said saliva and nasal discharge in the form of droplets and aerosols carry the virus from one person to another. Larger size droplets fall to the ground and on surfaces, and smaller aerosol particles are carried in the air to greater distances.

It recommended keeping windows open in buses and trains where possible, use exhaust systems to improve airflow in air-conditioned buses, vans, cars, and trains, and introduce HEPA/regular filters in air conditioning systems.

"Better the cross-ventilation, lower the risk of transmission. Let outdoor airflow in to displace indoor air. This directional airflow and improved ventilation can lower the potential for infection from accumulated viral load in closed spaces," the advisory said, asking for measures to improve ventilation to be taken up on priority in urban and rural areas alike, recommendations for hutments, homes, offices and large centralised buildings.

Also Read | Modi govt busy managing Covid narrative rather than addressing issues: Former bureaucrats in open letter to PM

"Simple strategic placement of fans, open windows and doors, even slightly open windows can introduce outdoor air and improve the air quality inside. Just as smells can be diluted from the air through opening windows and doors and using exhaust systems, ventilating spaces with improved directional airflow decreases the accumulated viral load in the air, reducing the risk of transmission," it said calling ventilation a "community defence" that protects all at home or at work.

The advisory on “Stop the Transmission, Crush the Pandemic - Masks, distance, sanitation and ventilation to prevent the spread of SARS-CoV-2 virus,” suggested, " Mask up, at home when with outsiders or those in contact with outsiders present. Double mask in congested spaces. Wear a surgical mask, then another tight-fitting cloth mask over it. Pay attention to ventilation in toilets. Mask up in the toilets."

The advisory highlighted the important role well-ventilated spaces play in diluting the viral load of infected air in poorly ventilated houses and offices and how proper ventilation can decrease the risk of transmission from one infected person to another.

"In buildings with central air-management systems improving central air filtration, increased filtration efficiency is especially helpful when enhanced outdoor air delivery options are limited," it said.