A micron is a millionth of a meter. A strand of human hair is approximately 50 microns wide while the red blood cell carrying oxygen in our blood is just 5 microns wide. One sneeze or cough may carry about 3,000 droplets, with each droplet being more than 5 microns across. When the suspended particle is smaller than 5 microns, it is called an aerosol.
New Virus Lasts Hours on Surfaces, in Air but Proximity to Patients Is Riskier
