Respirator

A respirator is a protective mask or device worn to prevent a wearer from inhaling hazardous substances such as fumes, vapors, gases, dusts, or airborne pathogens, and works either by filtering the surrounding air before it is breathed, an air-purifying respirator, or by supplying breathable air from an outside source, an air-supplied respirator. Early respiratory protection dates back to antiquity; the Roman writer Pliny the Elder, around 79 AD, described miners using animal-bladder skins to filter the air they breathed. The English physician Julius Jeffreys first applied the word respirator to a protective mask in 1836, and the physician Wu Lien-teh developed a direct forerunner of the modern N95 respirator in 1910 while responding to a pneumonic plague outbreak in Manchuria; the First World War then drove mass production of gas masks in response to chemical weapons. The 3M company introduced the first single-use disposable respirator in 1972, and a 1995 revision of the N95 standard required the mask to filter out at least ninety-five percent of airborne particles, the standard still in use today.