My daughter read a book about smoking in the My Health series by Dr. Alvin Silverstein, Virginia Silverstein, and Laura Silverstein Nunn that would be a great book for any upper elementary aged child to read because it teaches about the health problems associated with smoking.
Back of books says:
Have you ever heard someone say, "at least I have my health?" Staying healthy is very important to us. If you've ever had a cold, the chickenpox, or a broken bone, you know that it's hard to be happy when something is wrong with your body. A cold makes you feel lousy, the chickenpox makes you itch, and a broken bone is very painful. The books in this series will help you learn more about the minor health problems we all face at one time or another. Along the way, you will also learn how all the parts of your body work together to keep you healthy most of the time.
This book has a questionnaire that children can give to friends and family to learn more about the effects of smoking. There is also a page that shares information from the American Cancer Society that describes how a smoker's health improves after he or she quits smoking.
My Health Series