Coronavirus: 2 meters is not enough to avoid infections indoors

Is the 2 meter social distance enough to help avoid infectious aerosols? Not indoors, according to researchers in Penn State’s Department of Architectural Engineering who publish their study in the journal Sustainable Cities and Society.

The team found that interior distances of two meters may not be sufficient to adequately prevent the transmission of aerosols in the air.

“We set out to explore the air transport of virus-laden particles released by infected people in buildings,” said Gen Pei, leader of the work. “We investigated the effects of building ventilation and physical distancing as control strategies for indoor exposure to airborne viruses.”

The researchers examined three factors: the amount and rate of air ventilated through a space, the indoor air flow pattern associated with different ventilation strategies, and the aerosol emission mode of breathing versus speaking.

“The results of our study reveal that virus-laden particles from an infected person’s speech, without a mask, can rapidly travel to another person’s breathing zone in one minute, even at a distance of two meters,” explained Donghyun Rim. , co-author of the work. “This trend is pronounced in rooms without sufficient ventilation. The results suggest that physical distance alone is not sufficient to prevent human exposure to exhaled aerosols and must be implemented with other control strategies such as masking and adequate ventilation.”

That is, the aerosols traveled much farther and faster in rooms where fresh air flows continuously and pushes old air into a ventilation shaft near the ceiling, that is, the system installed in most residential houses, which can cause a concentration seven times higher than mixed-mode ventilation systems, according to the study’s findings.

Still, the likelihood of airborne infection could be much higher in residential settings than in office settings.

Referencia: Gen Pei, Mary Taylor, Donghyun Rim,

Human exposure to respiratory aerosols in a ventilated room: Effects of ventilation condition, emission mode, and social distancing, Sustainable Cities and Society,

Volume 73,2021,103090, ISSN 2210-6707, DOI: https://doi.org/10.1016/j.scs.2021.103090.

(https://www.sciencedirect.com/science/article/pii/S2210670721003735)