How does second-hand smoke get from one unit to another?
Any way it can!
Due to differences in air pressure between units, between floors and between the inside and outside of a building, air (and second-hand smoke) can transfer through a variety of leakage paths:
- From a neighbour's patio or balcony, or from outdoor common areas;
- Through open windows or doors;
- Through electrical outlets, cable or phone jacks, or ceiling fixtures;
- Through cracks and gaps around sinks, countertops, windows, doors, floors, walls or dropped ceilings; and
- Through the ventilation or forced air system.
Research has shown that up to 65% of the air in a unit can come from other units in the building. Many people think that second-hand smoke infiltration is just a problem in older and leakier buildings. While it's true that such buildings do have air transfer problems, it's not unique to them. People living in new buildings also report unwanted second-hand smoke intrusions, although the leakage paths aren't as obvious to spot.
The Canada Mortgage and Housing Corporation has published a useful fact sheet on air transfer called Solving Odour Transfer Problems in Your Apartment.