A clean room is an enclosed space in which airborne particulates, contaminants, pollutants, temperature, and humidity are kept within strict limits. In industry, clean rooms are used in the manufacturing and servicing of hardware such as integrated circuits, hard drives, LED, Filters, etc. In biotechnology and medicine, clean rooms are used when it is necessary to ensure an environment free of bacteria, viruses, or other pathogens.
Cleanrooms typically have a cleanliness level quantified by the number of particles per cubic meter at a predetermined molecule measure. The ambient outdoor air in a typical urban area contains 35,000,000 particles for each cubic meter in the size range 0.5 μm and bigger in measurement, equivalent to an ISO 9 cleanroom, while by comparison an ISO 1 cleanroom permits no particles in that size range and just 12 particles for each cubic meter of 0.3 μm and smaller.