Drier indoor air may keep viruses active longer, increasing risk of long-range airborne transmission

UPTON, NY–A new model that tracks how expelled respiratory particles evolve suggests that drier wintertime indoor air allows virus particles in those exhaled droplets to remain active longer than is possible in moister summertime air. This finding may help explain wintertime increases in transmission of respiratory viruses like flu and SARS-CoV-2, the virus that causes COVID-19.

“This research is relevant to understanding COVID-19 and other airborne diseases that are really common, like the flu, as well as future novel viruses,” said Alison Robey, the lead author who conducted this research as an intern working with Laura Fierce, an atmospheric scientist formerly with the U.S. Department of Energy’s Brookhaven National Laboratory, now at DOE’s Pacific Northwest National Laboratory. “The ability to tease apart the mechanisms causing seasonality can help us figure out which safety controls—like distancing, wearing masks, and increasing/improving ventilation—are needed to reduce transmission risk in different situations.”

The study—published in a special issue of the journal International Communications on Heat and Mass Transfer focused on airborne pathogen transmission—was motivated by the question of whether the COVID-19 virus would follow similar seasonal trends as flu.

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