question: What is a cause of air pollution?
choices.text: death oxygen oxidation traveling swimming bacteria Thunderstorms rain
choices.label: A B C D E F G H
fact2: Vehicle emissions are a major cause of air pollution.
combinedfact: Traveling is a cause of air pollution.
formatted_question: What is a cause of air pollution? (A) death (B) oxygen (C) oxidation (D) traveling (E) swimming (F) bacteria (G) Thunderstorms (H) rain