New Delhi | Jagran News Desk: A physical distance of two meters - about six and a half feet - may not be sufficient to prevent the transmission of airborne aerosols, according to a research team at Penn State Department of Architectural Engineering, US.

The results of the study, published online in 'Sustainable Cities and Society', an international journal focusing on fundamental and applied research suggested that physical distance alone is not enough to prevent human exposure to exhaled aerosols and should be implemented with other control strategies such as masking and adequate ventilation.

"We set out to explore the airborne transport of virus-laden particles released from infected people in buildings," said Gen Pei, first author and doctoral student in architectural engineering at Penn State.

"We investigated the effects of building ventilation and physical distancing as control strategies for indoor exposure to airborne viruses," he added.

The three factors that were examined by the researchers were the amount and rate of air ventilated through space, the indoor airflow pattern associated with different ventilation strategies, and the aerosol emission mode of breathing versus talking.

"Our study results reveal that virus-laden particles from an infected person's talking - without a mask - can quickly travel to another person's breathing zone within one minute, even with a distance of two meters," said Donghyun Rim, corresponding author and associate professor of architectural engineering.

"This trend is pronounced in rooms without sufficient ventilation. The results suggest that physical distance alone is not enough to prevent human exposure to exhaled aerosols and should be implemented with other control strategies such as masking and adequate ventilation," he added.

It was also found that aerosols traveled farther and more quickly in rooms with displacement ventilation, where fresh air continuously flows from the floor and pushes old air to an exhaust vent near the ceiling. Interestingly, this is the type of ventilation system installed in most residential homes, and it can result in a human breathing zone concentration of viral aerosols seven times higher than mixed-mode ventilation systems.

"This is one of the surprising results: Airborne infection probability could be much higher for residential environments than office environments," Rim said.

Finally, the researchers suggested that in order to reduce the transmission distance and potential accumulation of exhaled aerosols, increasing the ventilation and air mixing rates can prove to be effective.

Posted By: Sugandha Jha