It proved to be quite a task to find a chart with accurate sizing of microns for the most common contaminants as well as common particles that are around us all the time (for comparison). This micron sizing chart is fairly complete. To the best of my knowledge, and by comparison to other particle size charts online, the list below is identical to numerous charts and data I found on the Internet – information is provided without warranty, or guarantee of accuracy of any kind. Hope this helps a little when it comes to understanding the size of these particles.
1 Micron = 1000 NanoMeters
Note the size range of viruses in this chart… .005 – 0.3
The .005 is much smaller than many water filters claim to remove! What is important to remember is the size of viruses that have proven to be harmful or deadly to humans. Smaller viruses exist according to scientists, but whether they are a risk to mankind or not, has yet to be determined —- it is also important to differentiate between water borne viruses and air borne (which can be much smaller).
Water Filters like the Lifesaver Jerrycan will filter out viruses to 0.015 microns (15 nanometers) in size, which includes all of the most common viruses found in water. Amazing technology when you think about it, a portable water filter that can remove such microscopic (and dangerous) particles from water.