Respirator is a piece of headwear in DayZ Standalone.
A respirator is a device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, or gases.
Basis
Respirators are useful alternatives to gas masks, but like the gas mask, only works for a short time. In this case, the respirator is extremely short term, in the order of 1-2 minutes rather than 15 or more, and can only block particulate matter, having no effect on poisonous gasses or other dangerous inhalants.