Ventilation, CBRN filtration systems from Beth-El are versatile, customizable ventilation and CBRN filtration units that can be accommodated into container or mobile shelter. The systems incorporate a highly efficient cyclone-filter for heavy duty sand, dust, and fine dust extraction, followed by a prefilter in order to remove any remaining fine dust. A CBRN filter stage follows these dust filtration stages to remove nuclear, biological, and chemical particles from the air. The exceptional modularity of these systems allows them to be operated as ventilation systems and with a quick change of filter, can become life saving CBRN filtration systems.