As pollution, and threats of chemical warfare plagued the 20th century, the need to develop wearable air purifiers became necessary. Therefore, throughout the 20th century, respirators were developed to filter out vapors, gasses, fumes, or dusts from inhaled air. Two main types of respirators exist, with one only purifying the air, called an air-purifying respirator, and the other providing a fresh supply of air called an air-supplied respirator. Both, however, were developed for the same purpose: to ensure that the wearer is inhaling only clean air.
From the dawn of the current era, humans have worked to create technologies to purify the air in which they breathe and protect themselves against harmful toxins floating through the air. The first example of this is the use of animal bladders to protect Roman miners from lead dust during the first century AD. Leonardo da Vinci even proposed a respirator in the 16th century that was created from a woven cloth dipped in water and could be used to protect sailors against toxic weapons.
In more modern times, Lewis P Haslett patented the first respirator in 1848. This invention worked by filtering dust out of the air using moistened wool. He continued to develop other respirators, including the cup-shaped mask familiar today, throughout the 17th century. His company was so successful that the H.S. Cover Company remained in business until the 1970s!
Upon the introduction of chemical warfare, the need for more advanced respirators became immediately sought after. Therefore, after the Germans in World War I used chlorine gas for the first time, the military needed a way to purify the air. Canadian troops were the first to use respirators to defeat chemical warfare by using apparatuses that contained urine soaked cloths, which reacted with the chlorine and allowed for the breathing of the tainted air.
Today, modern respirators come in numerous shapes, sizes, and designs. However, all work by creating a seal along the face of the individual wearer in order to filter out breathable air. These devices continue to be used by the military, but also by concerned factory workers, or other individuals hoping to keep their lungs safe from harmful toxins and pollution.