RELATED: Virus Experts Have Stopped Going to These 4 Places as Delta Surges. Large, clear plexiglass partitions have become a common sight in the world, aiming to keep air flow down between customers seated inside at separate tables, create a barrier while speaking to a cashier, and even protect children at their desks in schools. But experts say the well-intentioned COVID precaution is completely ineffective for keeping anyone safe at best and potentially creating a dangerous situation at worst. While plastic shields can protect against large droplets emitted by coughs and sneezes, they do nothing to stop the airborne particles known to transmit COVID. “If you have plexiglass, you’re still breathing the same shared air of another person,” Marwa Zaatari, PhD, a building scientist and pandemic task force member of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, told Bloomberg.ae0fcc31ae342fd3a1346ebb1f342fcb Mounting research has found that the very shields meant to keep people safe could be putting them at an increased risk. In May, a team of researchers released a prepublication paper that found barriers between desks impeded airflow and ventilation in an office and led to an outbreak of COVID. The team found that removing the partitions and encouraging airflow by opening a window improved conditions. Another study published in the journal Science in June found that while assessing the risks of in-person learning at schools, using desk shields was associated with an increased risk of spreading COVID. And another study released in March found that partitions that used cubicle-style walls stopped smoke that researchers were using to test airflow from being taken up into an air filter, Bloomberg reports. RELATED: Don’t Eat Indoors If You Live Here—Even If You’re Vaccinated, Virus Expert Warns. “If you have a forest of barriers in a classroom, it’s going to interfere with proper ventilation of that room,” Linsey Marr, PhD, professor of civil and environmental engineering at Virginia Tech and one of the world’s leading experts on viral transmission, told The New York Times. “Everybody’s aerosols are going to be trapped and stuck there and building up, and they will end up spreading beyond your own desk.” Other experts agreed with the assessment. “I think this may be a particular problem in places like classrooms where people are present for longer periods of time,” Catherine Noakes, PhD professor of environmental engineering for buildings at the University of Leeds in England, told The Times. “Large numbers of individual screens impede the airflow and create pockets of higher and lower risk that are hard to identify.” Some experts explain that large partitions were an easy, early fix at a time when scientists were still trying to understand exactly how COVID spread inside certain places—all while giving the public a potentially dangerous false sense of security. “We spent a lot of time and money focused on hygiene theater,” Joseph Allen, an indoor-air researcher with the Harvard T.H. Chan School of Public Health, told Bloomberg. “The danger is that we didn’t deploy the resources to address the real threat, which was airborne transmission—both real dollars, but also time and attention.” RELATED: For more up-to-date information, sign up for our daily newsletter. Instead, experts argue that the money used to buy and install partitions or shields inside a business or office would be better spent improving air quality by adding filters, improved ventilation systems, or masks. Even once the threat of COVID diminishes, such changes could bring lasting benefits. “They’re good for seasonal influenza. They’re good for productivity. They’re good for mental health,” Allen explained. RELATED: You Must Do This to Protect Yourself From Delta—Even If You’re Vaccinated.