Why 0.3 micron HEPA filter is used in pharma industry, why not 0.25 or o.35 micron filter?
A standard air filter usually eliminates medium to larger particles from the air. However, they do not have capabilities to almost completely eliminate tiny micron size particles from the air. The HEPA filter is capable of doing so. Bacteria can be as small as 0.3 microns that is why 0.3 micron HEPA filters are used in the Air handling systems in pharmaceutical industry to eliminate bacteria in the clean rooms. This is because bacteria can contaminate pharmaceutical products. Therefore, it is essential in the healthcare field to ensure that smallest of particles including live bacteria are taken out of the air flow. Airborne diseases like Tuberculosis can be easily spread if proper air filtration is not used. In research Labs also where the research and medical scientists are working with bacteria and viruses, the air needs to be as clean as it can be to contain thesee particles. Virus particles though are smaller than 0.3 microns, but generally they travel through larger particles such as saliva or sweat or others.