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.
What shields your face eyes and respiratory tract from chemical and biological warfare agents and radioactive dust particles? A respirator, sometimes called a protective mask, shields your  face, eyes, and respiratory tract from chemical and biological  warfare agents and radioactive dust particlesâ¦ if used correctly. 7 people found this useful.