(CBS) — Starting Friday, you have to be 21 to buy tobacco in Chicago, up from the current age of 18.

Mayor Emanuel’s office says this is a good thing for Chicago’s young people, but some believe it’s bad for Chicago businesses.

Rob Karr, president of the Illinois Retail Merchants Association, says raising the tobacco-buying age will simply push people out of Chicago to buy cigarettes. It will also lead to more illegal cigarette sales in Chicago, he predicts.

“We think (the new law) will exacerbate those two problems and not accomplish anything that was intended,” Karr says.

Mayor Emanuel’s office says one of the objectives of the new law is that young Chicagoans will be healthier. Officials cite a report by the Institute of Medicine that says raising the tobacco sale age to 21 has substantial positive impact on public health and saves lives.

Karr says people will still buy smokes and health won’t be improved.

He also tells WBBM Chicago merchants are worried that raising the tobacco buying age will hurt their sales, saying that if people drive out of the city to buy cigarettes they’ll buy other things as well.

“Once you go (to a store) for one product, you typically don’t go just for that product, you’ll go for other things, whether it’s liquor or soda or food.  So it’s a loss of sales and frankly for the city sales tax revenue beyond just the sale of cigarettes,” he says.