Even if you don't have pets...vacuum bags will get that stale smell after a bit even before the bag needs changing... I always HATED that and would always change the bag before it needed it... but not anymore thanks to those activated charcoal pellets... years ago I bought this big canister of it for like $14 and I have over half of it left...Literally all you do is suck up a little bit every week or so...it takes 2 seconds and the bag literally never smells. Now, I can't say this would work with a dog... but it worked with my cats (which I no longer have)
I too hate the fragrances that mix with the bag smell and make it worse. Activated charcoal is the absolute best for me.
but even better is using my rainbow... It always smells soo good