Please let me know the difference between the description of the below PQRI codes



G8686 (currently a tobacco smoker or current exposure to secondhand smoke) and G8690 (current tobacco smoker or current exposure to secondhand smoke)
G8688 (currently a smokeless tobacco user (eg: chew, snuff) and no exposure to secondhand smoke) and G8692 (current smokeless tobacco user (eg: chew, snuff) and no exposure to secondhand smoke).
G8687 (currently a tobacco non user and no exposure to secondhand smoke) and G8691 (current tobacco non user and no exposure to secondhand smoke)