The CDC has calculated how many air changes should occur to thoroughly clean a room after an infected patient was inside.
The table below (and located here) shows various ACH levels and the time required for removal of contaminants to 99% and 99.9% efficacy. For example, at an ACH of 10 (1 air change every 6 minutes) there needs to be 28 minutes to complete 4.666 Air Changes. At that point contaminants are 99% removed.
