I used to be a residential painter. AIUI (and I could be wrong here) biological and water-based molecules are larger than other chemical molecules so can be stopped by the particulate mask. This is why you can wear a dust-cup when spraying with acrylic (water-based), but need a respirator for oil or lacquer-based paint. TBH I'd expect the n95 to work better for infection than a surgical mask because you can get a better seal to your face