The ban goes into effect 90 days after Tuesday's signing. That means that by this summer those who break the law could face fines of $50 per violation, although the city has said it plans to rely on signs and social pressure instead of active enforcement.
Health Commissioner Thomas Farley says the law will protect people from dangerous secondhand smoke. But some health experts question whether the smoke poses a serious danger in open, outdoor spaces. Critics of the law say the city is trampling on civil liberties.
Bloomberg's administration banned smoking in restaurants, bars and other public indoor spaces in 2002.