After the First World War, the military has a strong interest in using
 Respiratory masks showed as a defense mechanism against chemical warfare. This in turn led to the development of efficient and inexpensive filters in the 1930s that were made with resin-injected dust. Further developments led to filters made of very fine glass fibers that could remove particulate matter while providing little resistance to breathing.🎭

Wars have caused the development of other equipment, for example, the Internet was originally designed for military use