Has anyone ever studied the environmental impact of discarded cigarettes? Im constantly appalled at the number of drivers I see pitching their butts out their car windows. — Ned Jordan, via email
Its true that littered cigarette butts are a public nuisance, and not just for aesthetic reasons. The filters on cigarettes-four fifths of all cigarettes have them-are made of cellulose acetate, a form of plastic that is very slow to degrade in the environment. A typical cigarette butt can take anywhere from 18 months to 10 years to decompose, depending on environmental conditions.