Ventilation is there for a reason and removing it or sealing it up could lead to all sorts of other problems in common property, such as damp, for a start. In any case, as soon as the resident opens her front door, contained fumes will escape into common property.
There is a legal precedent in NSW where tenants in a flat were ordered to stop smoking inside their property becasue all efforts to stop the smoke spreading to other units had failed.
But before you get to that, perhaps you might want to look at strategies the would allow the resident to keep smoking in a place that isn’t going to affect other owners.
The new model by-laws allow Owners Corps to establish a smoking area for residents where they can smoke in peace provided the smoke doesn’t drift into common property or other units.
In any case, before issuing complaints and warnings, how about sitting down with the resident and discussing strategies that might work for all concerned.
But if that fails, strata law identifies smoke from smoking as a nuisance so the door is open to take it further if need be.
Meanwhile, rather than trying to contain the smoke, you could talk to these “air quality engineers” to see if they have any bright ideas.