The main effort is separating drinking water and waste water. Keeping them as far away as possible and preventing contamination. There is no way to do that with air. The air we breath in and the air we breath out will always mix. The best we can hope for is some amount of dilution with fresh air/filters, bit at the end of the you are never going to be able to achieve the same thing with airborne viruses that we did with waterborne illnesses. The flu, covid, etc are with us for the long haul.