"Eventually she got tired of trying, her research and life moved on, and the 5-micron mystery faded into the background. Until, that is, December 2019, when a paper crossed her desk from the lab of Yuguo Li.
An indoor-air researcher at the University of Hong Kong, Li had made a name for himself during the first SARS outbreak, in 2003. His investigation of an outbreak at the Amoy Gardens apartment complex provided the strongest evidence that a coronavirus could be airborne.
But in the intervening decades, he’d also struggled to convince the public health community that their risk calculus was off.
Eventually, he decided to work out the math. Li’s elegant simulations showed that when a person coughed or sneezed, the heavy droplets were too few and the targets—an open mouth, nostrils, eyes—too small to account for much infection. Li’s team had concluded, therefore, that the public health establishment had it backward and that most colds, flu, and other respiratory illnesses must spread through aerosols instead.
Their findings, they argued, exposed the fallacy of the 5-micron boundary. And they’d gone a step further, tracing the number back to a decades-old document the CDC had published for hospitals."
2003-2019 people.
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