For decades, respirator researchers have been asked whether filters need to be tested with aerosols similar to those encountered in the environment. Common sense suggests that viruses or bacteria are collected differently from engineered nanoparticles, silica dusts, oil mists or other types of workplace aerosols. But that is not necessarily the case.
For more information, including further scientific reading on this topic, please see
http://www.cdc.gov/niosh/npptl/partic...