Cautioning people to maintain social distance to prevent the transmission of the Covid-19 virus, the office of the Principal Scientific Adviser to the Government of India on Thursday said that aerosols, one of the key transmission mode of the SARS-CoV-2, can travel in the air up to 10 meters.
"Aerosols and droplets are key transmission mode of the Covid-19 virus, and while droplets fall within 2 meters from an infected person, aerosols can be carried in the air up to 10 meters," an advisory said.
The "Stop the Transmission, Crush the Pandemic - Masks, distance, sanitation and ventilation to prevent the spread of SARS-CoV-2 virus" advisory highlights the important role well-ventilated spaces play in diluting the viral load of infected air in poorly ventilated houses, offices and other closes spaces and said ventilation can decrease the risk of transmission from one infected person to the other.
Calling ventilation "a community defence" against the spread of the novel coronavirus, it says "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 land in the air, reducing the risk of transmission."
The Office of Principal Scientific Advisor in a release has advised introducing outdoor air in offices, homes and larger public spaces and said measures to improve ventilation in these spaces must be taken up on urgent priority in urban and rural areas alike.
"..recommendations for hutments, homes, offices and large centralised buildings are given. Simple strategic placement of fans, open windows and doors, even slightly open windows can introduce outdoor air and improve the air quality inside. The introduction of cross ventilation and exhaust fans will be beneficial in curtailing the spread of the disease," it stated.
In buildings with central air-management systems, improving central air filtration or increased filtration efficiency is especially helpful when enhanced outdoor air delivery options are limited.
The advisory recommended the use of gable fan systems and roof ventilators in offices, auditoriums, shopping malls and other closed public spaces. "Frequent cleaning and replacement of filters is highly recommended," it said.
The release stated that saliva and nasal discharged in the form of droplets and aerosols, by an infected person while exhaling, talking, speaking, singing, laughing, coughing or sneezing is the primary mode of virus transmissions, and an infected person who shows no symptoms also transmit the virus.
"People without symptoms can spread the virus. People should continue wearing a mask, wear double masks or an N95 mask," it added.
Notably, the SARS-CoV-2 virus infects a human host where it can multiply, in the absence of the host it cannot survive, and stopping the transmission of the virus from a person to another person will decrease the infection rate of the disease to a level where it can eventually die.
"This can be achieved only with the support and cooperation of individuals, communities, local bodies and authorities. Use of masks, ventilation, distancing, and sanitation, the battle against the virus can be won," the Office of Principal Scientific Advisor said.