Closed systems, whether made of reusable or single-use parts, must be designed so that GMOs cannot be released into the facility. The guideline notes this includes release through any ventilation of the closed system, and suggests that a filter with a pore size of 0.2 µm or less is generally suitable for containing aerosols in ventilation lines when fermenting bacteria or cell cultures.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.