Science journals have published at least 20 studies and analyses showing that Covid-19 and other contagious respiratory diseases are mainly spread by aerosols. The vast bulk of these aerosols are less than 1 micron in diameter. This is 1/17th the size of the pores in the finest surgical masks, and less than 1/80th the size of the pores in the finest cloth masks. For more than a year since the outset of the pandemic, the CDC and WHO downplayed and denied the threat of aerosol transmission. In the spring of 2021, both agencies quietly admitted that aerosols pose a major threat of transmission, but they have still not adequately updated their C-19 guidelines to reflect this reality This negligence has allowed countless preventable deaths to continue to this day. Ultraviolet disinfection systems are highly effective at killing airborne viruses and have been successfully used to control the spread of contagious respiratory diseases in hospitals and schools for more than 80 years.