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.
Surgical Mask and Eye Protection. In strict sterile situations, such as in the OR or with protective isolation, the mask covers the mouth and nose. The purpose of the mask is to form a barrier to stop the transmission of pathogens. In the OR or during other sterile procedures, the mask prevents harmful microorganisms in your respiratory tract from spreading to the client. When the client has an infection, the mask protects you from his or her pathogens.