> Hospitals have turned to portable air filters as an attractive solution when their isolation facilities are full. Woah! I knew that isolation rooms where ful

> Hospitals have turned to portable air filters as an attractive solution when their isolation facilities are full. Woah! I knew that isolation rooms where full-on filtered and with positive pressure. But I genuinely believed that all hospital HVAC units and major circulation ducts had HEPA filter stages. Is this true? Is it not mandatory for hospitals to add these filtering stages on all HVAC units or circulation ducts? Do they really just keep rotating the same contaminated air throughout the whole hospital?