I have COVID. Tomorrow (Friday), I’ll be on day 6.
Turns out, I’ll have the house to myself tomorrow, all the way until Saturday at 2PM. If I want to roam the house free of any mask, how long before 2PM on Saturday do I have to mask up again or isolate again?
I’m not sure how well the answer to the OP is truly nailed down, but here’s something to start with from the University of Bristol’s Aerosol Research Center.
Link to the original paper from January 2022 – one might assume it’s undergone peer review by now, but I wasn’t able to quickly confirm that.
That’s interesting. Thanks! Absent additional info, I’ll give it two hours and open some windows.
FWIW, that research did undergo peer review and was published in the Proceedings of the National Academy of Sciences (USA) journal PNAS in June 2022 (Link).
Even better! If I know science, peer review makes it a fact! 
Seriously, though, thanks.
While testing using a Goldberg drum is not representative of real-world exposure conditions, it is a standardized way of assaying relative residual time of infectious and toxic aerosols and airborne particle contaminants. While close contact obviously increases the potential for contagion there are many instances of ‘superspreader’ exposure with SARS-CoV-2 (and other highly contagious airborne agents such as the measles virus and Varicella zoster virus) that occurs over long distances in enclosed spaces, often many tens of minutes after the exit of a contagious patient. Dilution over time and replacement with ‘fresh’ outside or filtered air is the most effective means of reducing airborne and aerosol contagion versus trying to sterilize using UV or antiseptic treatment.
Stranger
I’d suggest going for a bit longer than any test showed, in case there isn’t enough circulation or there is some other anomaly. Better to err on that side than the other.
It also wouldn’t hurt to do some sanitary wiping on often used surfaces, as the CDC recommends in the papers we got when Dad went to urgent care. (He’s over 60, diabetic, and has asthma, so I wanted him to get the antivirals. They wound up giving him multiple medications just to reduce any risks of complications and for comfort. Much more than my primary care doc would give.)