Not sure why this hasn't been mentioned yet, but maybe in this case the woman has a health issue and that's why there's a smell when she's on her period. The vagina is full of microbes and yeasts that are normal and natural. If something is off about that, like dysbiosis, then the bacteria will be consuming menstrual blood and giving off a bad odor. Sorry if this description is gross but I'm just giving the facts.
I know that menstrual blood smell very well. It has a metallic, rotten egg kind of smell. It's not a normal smell and is a sign that either hygiene is lacking or there is dysbiosis. Often, tweaking the diet can help a lot with this.
As for sanitary product disposal, how hard is it to use a sealed receptacle if you're going to keep your used pads around? I've lived with plenty of women and most used tupperware to store used pads in between outdoor disposal in the trash. One roommate used an empty sanitary wipe container for this purpose, and then just tossed the whole container. You wouldn't store piss or shit stained toilet paper in an open garbage can, would you? Even in countries where you can't flush toilet paper, the bin next to the toilet has a sealed lid on it.
People are so gross. And before someone accuses me of misogyny or whatever, there are male equivalents of this issue. Stop leaving biohazards laying around, it's fucking disgusting. And if you want to sit around in your own filth, then do it when you don't have roommates.
