Just read the box. They all say "this is not a respirator, does not protect against airborne bacteria" (this is paraphrased, since I have just seen my local products).
Even my local national health institute says that masks only protect against droplets from coughing, sneezing, or talking when in close proximity. Which I can grant you, but normal people shouldn't be coughing or sneezing into other peoples faces anyway. Which only leaves talking, but I don't see why grocery store is a place to socialize anyway.
IMO masks are only a thing because helpless people had the need to "do something" and masks are visible way of showing you are doing your part. Plus it didn't help that right wing nut jobs started a war against masks.
There is empirical evidence face coverings (of basically any fabric) reduce transmission rates. It's not like a respirator where there's a testing guarantee that if you're in an atmosphere full of infectious agents you'll be fine, but spreading or catching a virus is a game of probabilities and masks reduce those probabilities.
Even my local national health institute says that masks only protect against droplets from coughing, sneezing, or talking when in close proximity. Which I can grant you, but normal people shouldn't be coughing or sneezing into other peoples faces anyway. Which only leaves talking, but I don't see why grocery store is a place to socialize anyway.
IMO masks are only a thing because helpless people had the need to "do something" and masks are visible way of showing you are doing your part. Plus it didn't help that right wing nut jobs started a war against masks.