"Concerns
Critics point to a 1997 study which found exposure to high levels of ozone ineffective at mold decontamination, and to the lack of studies showing high ozone shock treatment to be effective. They also point out that killing mold inside walls does not remove the mold, and that dead mold may continue to have adverse health effects on building inhabitants.
The Federal Trade Commission ruled in 1996 against a manufacturer of an Ozone generator, ordering them to cease representing their product's ability to "eliminate, remove, clean or clear any indoor air pollutant from a user's environment" [6]
Ozone is a powerful oxidizing agent which could damage rubber and other materials,[7] and ozone reactions with other material present in buildings could lead to increased levels of noxious chemicals such as formaldehyde.[8]"
High-ozone shock treatment - Wikipedia.
In the last year I had two chain smoking couples move out of apartments I own. In one case the painters had to scrub the walls, ceiling and cabinetry thoroughly before applying any paint as the tars from the cigarette smoke had coated all surfaces. I had all painted surfaces primed and then painted with two coats of paint as the drywall is no doubt saturated with smoke products and I wanted them to be sealed inside. I had the ductwork all scrubbed out with brushes and solvent. They had been there 19 years. I also removed all the carpeting and window covering fabric. The husband of the new couple smokes but he goes outside to do so.
The couple in the other apartment was there just three years but they had to have been spending upwards of $1,000 per month on cigarettes at $8/pack. I never saw them without lit cigarettes, ever. Walls scrubbed, a coat of primer followed by two coats of paint, ducts scrubbed out, pretty much the same drill. Turns out they had a pot farm in the bedroom, too.
In another case after a couple I knew passed away their house was to be sold so the executor had a crew come in to conduct an estate sale. A meth pipe was found in a dresser. One of their kids had been smoking meth in the house. The whole house was contaminated and had to be professionally cleaned.
Stench from pet waste is another matter. If urine has soaked into concrete it needs to be treated and likely sealed. Years ago a tenant was breeding small dogs in an apartment I own. It was second storey and had plywood flooring which I had to rip out and replace. Fortunately it was just one corner of a room.
3 Ways to Remove Urine Odor from Concrete - wikiHow.