Researchers at Abu Dhabi's Cleveland Clinic and Khalifa University have joined forces to launch a study to discover how long Covid-19 can travel through the air. Scientists in the emirate aim to better understand the spread of the contagion in an effort to drive down transmission rates and assess the effectiveness of masks and other personal protective equipment. The project will involve spraying a colloid comprised of silicon nanoparticles to simulate a patients' cough and aerosol generation. The nanoparticles glow red under ultraviolet light, allowing the team to see how particles spread. Researchers will test their model on mannequins at Khalifa University. The ability of Covid-19 to travel through the air was a source of keen debate in the early stages of the pandemic. In October, the Centres for Disease Control and Prevention said the virus can spread through tiny particles that can linger in the air for hours The CDC had not made a direct link about the role airborne transmission is playing in the spread of the virus until that point. The US public health agency's advice stated aerosolised virus particles can, and do, infect others under "certain circumstances". The capacity of Covid-19 to spread through minuscule droplets, which float in the air long after an infected person coughs, breathes, or sneezes, was noted by authorities in China in February, very early in the outbreak. The updated guidance acknowledged the virus can linger in the air – though it insists aerosolised transmission remains “uncommon”. “There is evidence that under certain conditions, people with Covid-19 seem to have infected others who were more than six feet away,” says the CDC guidance. “These transmission events appear uncommon and have typically involved the presence of an infectious person producing respiratory droplets for an extended time (greater than 30 minutes to multiple hours) in an enclosed space. “Enough virus was present in the space to cause infections in people who were more than 6 feet away or who passed through that space soon after the infectious person had left.” Circumstances where confirmed airborne transmission has occurred, according to the CDC, include in enclosed spaces, when people were exposed shortly after the infected person left. Aerosolised transmission has also occurred when infected people were shouting, singing or exercising, which increased the concentration of “suspended respiratory droplets in the air space”. In addition, inadequate ventilation can increase the risk of airborne transmission by allowing the build-up of “suspended small respiratory droplets and particles,” says the CDC. The agency said most people become infected by inhaling large droplets through close contact with sufferers.
