A cleanroom is a controlled environment where pollutants like dust, airborne microbes, and aerosol particles are filtered out in order to provide the cleanest area possible. Most cleanrooms are used for manufacturing products such as electronics, pharmaceutical products, and medical equipment. A cleanroom can be classified into different levels of contamination depending on the amount of particles allowed in the space, per cubic meter. Cleanrooms also control variables like temperature, air flow, and humidity.

Essentially, cleanrooms work to remove pollutants, particles, and contaminants from outside ambient air. Outside air is first circulated to a filter system. The filters (either HEPA or ULPA) then clean and decontaminate this outside air according to their specifications. The filtered air is then forced into the cleanroom. Additionally, contaminated air within the cleanroom is forced outside the room by registers, or it is recirculated back into the filters, and the process restarts.