The Cook County Board of County Commissioners voted Thursday to raise the minimum age for tobacco sales to 21.
The law will go into effect June 1.
The minimum age to purchase tobacco products in Illinois and Cook County was previously 18 years old. However, dozens of municipalities throughout the state - including Aurora, Chicago, Evanston and Naperville - already enacted laws setting the minimum age at 21.
Just one year after Chicago raised the minimum purchase age, the city saw a 36 percent decline in the use of tobacco products among teenagers, according to the American Lung Association.