" I have checked with some colleagues. They don't know of any health hazard resulting from the smoke smell after the fire is gone.
"While woodsmoke is potentially harmful because of polycyclic aromatic hydrocarbons ( carcinogens) I would think the residual smell would be more of an aesthetic problem than a health threat. Fire restoration companies typically get rid of such smells by using an ozone generator WHILE THE HOUSE IS UNOCCUPIED. This dissipates pretty quickly. The occupants may wish to look in to this."
The ozone is a health concern if you are breathing the air while it is being produced, so be careful with this. It is a possibility that might work. "