I know it’s hard to say what to do without specific examples, so lets assume there are two lots: one which is level and zoned multifamily in an environmentally critical area; and another single family lot with a fantastic view on a cliff.

I'm pretty sure the 8.1 endorsement is for mortgagee policies only and indemnifies against loss related to environmental (superfund) liens which have been recorded in the public records. 

(a health, environmental, public nuisance and waste, liability among others issues,)Even if the lease doesn't directly disallow a business from R-1 there will be in contract something addressing tenant's responsibility to protect the landlord property , not creating waste, commit public nuisance, or damage.I would have no problem to a good, responsible tenant for use the residence address for ex. handyman or plumber since he does not physically conduct his business from the home, and all his tools might be in his truck or rented storage, but I still would make sure that I am not being liable for loss, damage to his tools...and request he has a rental insurance, compliance with city regulations.Conducting online seminars is not the same as doing a hair extension, or running car repairs shop from R-1.  

China -no one trusts their numbers, heavy pollution and heavy smokersItaly - largest population of elderly - this with highest risk.We can't get too hung up on stats because of testing.