Aerosols can be carried up to 10 meters, and following easy COVID-19 protocols like double masking, maintaining distance, improving the ventilation of indoor spaces etc would reduce transmission, a government advisory said on Thursday.
The advisory, issued by Union Principal Scientific Adviser K VijayRaghavan’s office highlights the important role that well-ventilated spaces play in diluting the viral load of infected air in poorly ventilated houses, offices etc.
“Ventilation can decrease the risk of transmission from one infected person to the other,” it said.
Just as smells can be diluted from the air through opening windows and doors and using exhaust systems, ventilating spaces with improved directional air flow decreases the accumulated viral land in the air, reducing the risk of transmission.
Here are the important points:
The virus spreads through saliva and nasal respiratory discharge. Mutations can make new ‘variants of concern.’ Some variants may have higher transmission and infection rates. Transmission of variants too can be crushed if we rigorously follow COVID Appropriate Behaviour.
One infected asymptomatic person can release enough aerosols to infect many. Symptoms can take up to two weeks to appear in an infected person, during which time they may continue to shed the virus to infect others. Some people may never show symptoms and yet be spreaders.
In closed indoor spaces, droplets, and aerosols become quickly concentrated, greatly increase the risk of transmission to people in the area. Just as smells can be diluted by ventilation, high concentrations of the virus can be reduced by ensuring that outdoor air flows in.
Spitting, coughing without covering, can cause virus-containing droplets to land on commonly used surfaces such as door handles, lift buttons, handles on buses, etc. If you touch such surfaces wash hands with soap before you touch your mouth, nose, or eyes.
Mask up, at home when with outsiders/those in contact with outsiders present. Double mask in congested spaces. Wear a surgical mask, then another tight-fitting cloth mask over it. If you must reuse a surgical mask, do not wash, read instructions. Cloth masks can be washed.
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.
Keep the door ajar and an open window on the other side. If even a low-power exhaust fan can be installed, it can greatly enhance circulation. In rooms set the A/C so that inside air is renewed. Keep windows and doors slightly ajar. Use gable/exhaust fans. Pay attention to ventilation in toilets. Mask up in toilets.
Improved central filtration/high filtration efficiency, especially helpful when outdoor air delivery options limited. Roof ventilators, HEPA/regular filters recommended in offices, auditoriums, shopping malls, etc. Clean/replace filters regularly: Don’t make them the problem.
Keep windows open in buses and trains where possible. Use exhaust systems to improve airflow in air-conditioned buses, vans, cars, and trains. Introduce HEPA/regular filters in air conditioning systems. These should be cleaned and replaced regularly.
ASHA/Anganwadi/Health Workers must be trained, protected for conducting Rapid Antigen Test. Help make Rapid Antigen Testing widely available. Health workers must be given an N95 mask even if they are vaccinated. To also be provided oximeters to monitor the infected person.