[thaeli]

For particulates, media filters actually get more efficient as they get dirtier. They also get harder to blow air through, which means less air volume with normal fans or higher energy consumption with VFD fans. I'm simplifying a bit, but traditionally change intervals are based solely on keeping air resistance within acceptable values.

This paper presents a different mechanism by which IAQ can be negatively impacted by a dirty media filter. It's possible that this affects change intervals or other measures, and it's possible that this is a matter of theoretical concern but in practice doesn't matter much. It's cliche to say that a study's conclusion is that there should be more studies, but that's really the case here.