Her Twitter feed is a daily exchange of ideas among fellow scientists, and it’s also peppered with questions from followers, which she tries to answer. Part of the reason Dr. Marr has become so popular in public forums is her ability to explain difficult scientific concepts in easy-to-understand terms.
She uses the visual of cigarette smoke when explaining viral plumes. To explain a concept called Brownian motion — and why masks can more easily filter the smallest microscopic particles — she uses the analogy of a drunken person stumbling into chairs and walls while trying to cross a room. “The particle is the drunk person, and the chairs are the fibers of the masks,” she says. “The fibers stop the particles.”
When people began asking whether their clothes could be covered in virus after going to the store or walking outdoors, she gave us all a lesson in aerodynamics. Just as bugs don’t smash into the windshield of a slow-moving car because they’re carried by air currents alongside the car, lingering viral particles also slip by the human body as we move, and don’t smash into our clothes, she explained.
And in the midst of a public health crisis that has upended our lives, Dr. Marr has used her knowledge to solve practical everyday challenges of parents and families. She used mathematical models to determine the safety of hugging during a viral outbreak, taking photos with her daughter in various hug positions to explain how to lower risk. She collaborated with Dutch researchers on how we can safely return to the gym. And her team is in the midst of research on the benefits of homemade masks.
But the demand for Dr. Marr’s expertise also highlights an alarming problem in the study of viruses and respiratory illness. There are, perhaps, fewer than a dozen scientists around the world with extensive expertise in aerosol transmission of viruses, but funding for their research often falls between the cracks of different disciplines. Basic science grants tend to view airborne viruses as a topic to be supported by health funds. But health agencies tend to focus on how a virus behaves inside the body, not how it gets there. Environmental scientists may study waterborne pathogens or air pollution, but they don’t typically focus on airborne transmission of disease.
“Somehow it hasn’t been on the radar screen,” Dr. Marr said. “I’m not the only one studying this. There are other people who do this, but not nearly enough to answer all the questions that everyone has right now.”
Dr. Marr is among a small but vocal group of scientists who are calling for more attention to be given to the airborne route of coronavirus transmission. Although the World Health Organization has been adamant that Covid-19 is not an airborne disease, a large body of evidence suggests people get sick by sharing the same air with an infected person. including outbreaks in a restaurant, during choir practice and when nearly half of 200 workers in a call center office fell ill.