The Belmont City Council on Tuesday night adopted a landmark ordinance regulating secondhand smoke in the city.

The ordinance passed on a 3-2 vote and will go into effect in 30 days, according to City Manager Jack Crist.

The ordinance was introduced by the City Council on Sept. 11, and then approved with a few wording changes at its Sept. 25 meeting.

Thought to be the first of its kind in California, the ordinance declares secondhand smoke a public nuisance and extends the city's current smoking ban to include multi-unit, multi-story residences.

Though Belmont and some other California cities already restrict smoking in multi-unit common areas, Belmont is the first city to extend secondhand smoke regulation to the inside of individual apartment units.

Smoking will still be allowed in single-family homes and their yards, and units and yards in apartment buildings, condominiums and townhouses that do not share any common floors or ceilings with other units.

The ban for multi-unit apartment buildings will not take effect for an additional 14 months after the ordinance is passed, so that one-year lease agreements will be unaffected.

Smoking will be permitted only in designated outdoor areas of multi-unit housing.

Additionally, smoking will not be allowed in indoor and outdoor workplaces, or in parks, stadiums, sports fields, trails and outdoor shopping areas.

Smoking on city streets and sidewalks will be permitted under the ordinance, except in the location of city-sponsored events or in close proximity to prohibited areas.

City officials have said that enforcement of the smoking ban will be complaint-driven.

The issue was first brought to the attention of the Belmont City Council last July, when residents at a senior housing complex complained of complications arising from secondhand smoke in their apartments.