Please keep in mind even a level 4 is the same as smoking 8 cigarettes a day or getting 200 x rays. 

Min Requirements:-Non-Smoker-Income must exceed 3x monthly rent-Min credit score 600-No evictions or unpaid judgements from previous landlords -Background check will be conducted on all applicants over 18-No more than two pets (dogs and cats) allowed.

are the people in the unit inside outside or non-smokers?...

Sure, if you are just the half-drunk artist living in the back of your buddy's garage, you'll do it for beer and cigarette money.

No pet, non smoker.   

Enough that we sold the home without it being a smoker house.Today, I will be trying out an even more powerful machine in a mobile home we are renovating that smells like the worst smoke smell you can imagine. 

It's difficult to prove, you can't force your way into the unit to find the smoking cigarette, you don't always know where smoke is coming from.

The $20 you gave him went to his favorite habit - cigarettes, liquor, drugs, cat food.

Tentatively investigator says it was an accidental fire caused by one of the tenants cigarettes.

BUT, they ignored the advice because of an anomaly.That being said, even the 80 year old chain smoker could have benefited by NOT smoking, despite being healthy.