I don't think you're even gonna find HEPA filters anywhere. If that's your benchmark, I would do what someone else said earlier and just call up the gyms, but I would be very surprised if you found any doing more than just asking that people wipe down the equipment after using it.

My booster efficiency is starting to wane, so I'm planning on masking up again at the beginning of the month, but it's been made blatantly clear to the public that we're on our own - no one in charge gives a fuck about seriously trying to end this on a more permanent basis other than mitigation for those who aren't at risk.