system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why are cities banning e-cigs?
gpt
first off no city is banning them but many are treating them like "regular" cigarettes

e-cigs produce vapor, which is much better for you than smoke. but not a lot of data has been gathered on their potential problems also they still will effect nearby persons by exposing them to the nicotine vapor. Also many establishments have found that allowing e-cigarettes encourages "real" cigarette  users to smoke in places they are not allowed b/c they see the e-cig and think "well they are doing that so i can do this"