Smoking affects not only the smoker but also those around them. Additionally, while 18 year olds may be legally adults, many are also legally high school students. As such, they should not be allowed to buy cigarettes when they are still developing and may not understand the serious health consequences. Finally, while those under 21 may still be able to purchase alcohol, it is significantly more difficult for a minor to obtain alcohol when their peers cannot legally purchase it. It should be the same with cigarettes, especially considering the significant scientific evidence of serious health consequences associated with tobacco use.