MUMBAI: Smaller aerosol particles can be carried in the air for 10 metres, the government warned on Thursday as it issued simple and easy to follow guidelines to prevent the spread of the Covid-19 virus, advising use of double masks and underscoring the need for well-ventilated spaces.
The advisory especially highlights the important role 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.
VENTILATION, USE OF TABLE FANS: Just as smells can be diluted by opening windows and doors and using exhaust systems, the dangerous concentration of the virus can be reduced by ensuring that outdoor air flows in, the advisory adds. So, strategic placement of table fans, open windows and doors, even slightly open windows, can introduce outdoor air and improve the air quality inside. Introduction of cross ventilation will be further beneficial.
AIR-CONDITIONERS: It also warns against running air conditioners while keeping windows and doors shut. “Running ACs trap infected air inside the room and increase risk of transmission from an infected carrier to others,” the advisory says.
COMMUNITY DEFENCE: Ventilation is thus a community defense that protects all of us at home or at work. 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. In offices, auditoriums and shopping malls use of roof ventilators are recommended. Frequent cleaning and replacement of filters is highly recommended.
DOUBLE MASK: Saliva and nasal discharged in the form of droplets and aerosols, by an infected person while exhaling, talking, speaking, singing, laughing, coughing or sneezing etc. is the primary mode of virus transmissions. Infected person who shows no symptoms also transmit the virus. People without symptoms can spread the virus. People should therefore continue wearing a mask, wear double masks or an N95 mask.
Those who do not have a surgical mask can wear two cotton masks together. “Ideally, surgical mask should be used only once, but when pairing, you can use it up to 5 times by leaving it in a dry place for 7 days after one use (ideally give it some sun exposure),” the advisory states.
SURFACE TRANSMISSION: Droplets emitted by an infected person land on various surfaces (where they can survive for a long time), the advisory said, calling for frequent cleaning of high contact points such as door handles, light switches, tables, chairs and the floor with disinfectants like bleach and phenyl.