As to the question of rules regarding when and where peaceful protests may be held, that's highly dependent on the specific location of the protest.
The venturi mask, also known as an air-entrainment mask (and sometimes by the brand name VentimaskÂ®), is a medical device to deliver a known oxygen concentration to patients on controlled oxygen therapy.
Is a surgical mask an N95 respirator? No. Surgical masks are not designed for use as particulate respirators and do not provide as much respiratory protection as an N95 respirator. Surgical masks provide barrier protection against droplets including large respiratory particles.