City officials said enforcement of a new ban on smoking in cars with keiki will begin immediately without any educational or warning period.

Mayor Kirk Caldwell signed Bill 70 into law Tuesday at Waiau District Park in Pearl City. The site was chosen partly because it’s a park where people go to enjoy fresh air, something youths under 18 can’t do when sitting in a car or truck where an adult is smoking, he said.

“They have no alternative, and they have to breathe in that secondhand smoke, and we know it can cause huge health problems down the road,” Caldwell said.

The bill applies not just to tobacco, but electronic cigarettes as well.

The fine is a maximum of $100 for a first offense, $200 for a second offense within a year and $500 for a third offense.

While some have questioned how the new law will be enforced, Caldwell said it’s obvious that Honolulu Police Department officers will be able to see right away if there is an adult smoking in a car while in the presence of a child.

“If you’re caught breaking the law, you will be fined,” he said. However, he said, he’s hoping people will choose to abide by the law on their own.

City Councilman Brandon Elefante, the bill’s author, said smoking in a car emits 50 times more particles in the cabin of a car than are emitted by a car’s tailpipe.

He applauded groups who supported the bill, including the Coalition for a Tobacco-Free Hawaii and the Hawaii Public Health Institute. Also on hand at the signing were representatives from the University of Hawaii Student Health Advisory Council and the American Heart Association.

The Council voted 8-0 to approve the measure Oct. 11.

Opponents of the bill argue that it is an unnecessary intrusion into people’s personal lives. Among those who testified against it was the Hawaii Smokers Alliance and the local owner of a chain of electronic vaping shops.