The Smoke-Free Ontario Act prohibits smoking in all indoor public and workplaces in Ontario, including work vehicles to protect the public from the hazards of breathing secondhand smoke.
While the Act applies to common areas of private dwellings such as hallways and lobbies of multi-unit dwellings, it does not apply in the actual home unit regardless of whether it is in a condominium or other multi-unit building or a single-family home.
A private homeowner or landlord can choose to make their units smoke free simply by specifying in the lease to be signed by the tenant/condo or co-op buyer acknowledging that they agree to abide by the No Smoking policy. This would need to be done prior to renting or selling the unit/multi-unit home to a new tenant.
Landlords or condo owners who would like to change their building/units to smoke free can choose to do so through attrition as tenants move out. Tenants who smoke and are not supportive of the policy to go smoke free, can continue to smoke as long as they live in the building.
Additional information for landlords, including practical information such as sample No Smoking lease language, a tenant survey to assess interest in smoke-free accommodations and more is available through Smoke-Free Housing Ontario or the Non-Smokers' Rights Association. Another good resource is Smoke-Free Housing BC.
Business case for smoke-free multi-unit dwellings.
How to implement a smoke-free policy for your apartment or condo building.