State Health Department spokeswoman Holli Senior says she thinks business owners are ready.
Pennsylvania joins 32 other states with laws that ban smoking in most workplaces and public spaces. They include restaurants, office buildings, train stations and sports arenas.
Violators face fines of up to $250 or more.
But Pennsylvania's compromise measure comes with many exemptions - including the right to smoke in some bars, hotel rooms and nursing homes.
That's led the American Lung Association to decide not to endorse it.
On the Net:
Smoking ban info: http://www.health.state.pa.us/cleanindoorair