Hmm, I recall an EPA chart showing expected performance of different MERV classes versus particle size that had the lower classes staying at zero for very small

Hmm, I recall an EPA chart showing expected performance of different MERV classes versus particle size that had the lower classes staying at zero for very small particles, but I’m not seeing it right now. But I found this — start at page 71. https://ordspub.epa.gov/ords/eims/eimscomm.getfile?p_download_id=499474 https://ordspub.epa.gov/ords/eims/eimscomm.getfile?p_downloa... You do want the higher MERV classes to get decent performance.