It is a bit tough to follow for the layman, but it can give you an idea.https://www.nejm.org/doi/10.10...Some info I have read show the highest concentration of viruses aerosolized found are 8-12 per cubic meter.

-The hot water tank is in this room in a closet but they put a nice door on that frame as opposed to the crappy particle board doors you usually see.

Check to see if it have particle board flooring which can give problems when it get wet.Joe Gore

Its somewhat indirect (not unlike particle physics.

I don't have to understand it in the slightest to be able to say "whoa... you want to build an unregulated, unlicensed, unsupervised particle accelerator in the basement?  

Sometimes, if we feel like a customer does not know what he wants, we would like to stay away, ie if we say how much per sf do you plan to buy on your tiles, we expect an answer like 1-1.50/sf and "not like oh I want a pretty one, not expensive but good quality", reversing the situation, I don't want a contractor to say "i have a friend who could build a beautiful cabinet that is cheap", you will probably get a particle board cabinet when you want all birch.

So it almost sells itself, or should I say "rents itself"I got idea a few years ago, I noticed a "Mom" and her son went to the locale Wal-Mart and purchased a dresser and desk, the particle board kind with a million screws.

Plywood or particle board underneath? 

If you have a serious issue, ongoing quarterly pest control, or aerosol "bombing" may be necessary.

@John Lindemann       If the house is safe (no fumes or particles), talk with the tenants.