I think you should be able to smoke cigarettes when you are old enough and responsible enough to clean up your own mess. I worked in a supermarket back in the '80's when there were no restrictions, and I had to fish cigarette butts out of the urinal even when there was an ashtray right there! on top of the urinal! I had to sweep up the ones people left in the parking lot. Some people would take the ashtray out of their car and dump it in the parking lot for someone else to clean up. People flick them out of cars in drought areas and start forest fires.
With rights come responsibilities. If you can't dispose of your butts/ashes properly, you don't belong smoking cigarettes. I don't care if you're 13 or 103. The world is not your ashtray and we are not your maids.