The prototype of an air filter is a respiratory protection device that people use to protect their breathing. According to records, as early as the 1st century in Rome, people used a mask made of rough linen to protect the mercury. In the long time since then, air filters have also made progress, but they are mainly used as respiratory protection devices in some dangerous industries, such as the production of harmful chemicals. In 1827, Brown discovered the movement law of tiny particles, and people have further understanding of the mechanism of air filtration.
The rapid development of air filters is closely related to the development of the military industry and the electronics industry. During the First World War, as a result of the use of various chemical agents, asbestos fiber filter paper as a layer of military gas mask came into being. Glass fiber filter media for air filtration was patented in the United States in October 1940. In the 1950s, the United States conducted an in-depth study of the production process of glass fiber filter paper, which improved and developed the air filter. In the 1960s, the HEPA filter was introduced; in the 1970s, the HEPA filter using fine glass fiber filter paper as the filter medium had an efficiency of 99.9998% for the particle size of 013 micron. Since the 1980s, with the advent of new testing methods, improved use evaluation, and improvement of filtration performance requirements, it has been found that there are serious problems in the HEPA filter, and thus a higher-performance ULPA filter is produced. Countries are still hard at work and it is estimated that more advanced air filters will soon appear.