A legitimate question: How much "dirt" is negligible, and how much is harmful? Anyone who's eaten anything has pretty much consumed some number of bugs or rat hairs, which is OK with the FDA if not one's own body.
Can we relate to the amount of dirt that actually gets through these filters? Remember, we're talking about enough introduced to suffocate the filter pretty well. That's some poor car maintenance - likely several oil changes, even in a reasonably dusty environment.
Take any given number of grams of dirt, remove the amount that the oil filter would remove, and divide it by the number of oil changes that your properly maintained car would have before its air filter was restricted to over double its resistance as new? Not much.
FWIW, I don't care how much the test stand cost. That seems like fluff, and in a third party article, it seems to want you to believe it's honest. That's shaky as a debate tactic. I'm not saying it's untrue; I'm saying that it seems to be trying hard to be seen as true. Please see disclaimer below.
