According to the U.S. Centers for Disease Control and Prevention (CDC), infectious diseases can spread when an infected person coughs, sneezes, talks, or breathes out droplets and tiny particles that contain viruses or bacteria. These droplets and particles can be breathed in by other people or land on their eyes, noses or mouth. An infected person can contaminate surfaces they touch. Virus particles and bacteria in the air can settle on and contaminate surfaces. Peoples can get infected by touching their eyes, nose, or mouth with hands contaminated by a virus or bacteria.

A study from National Institutes of Health (NIH); CDC; University of California, Los Angeles; and Princeton University scientists in The New England Journal of Medicine found that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that cause COVID-19 was detectable in respiratory droplets in the air for up to three hours.