When politicians and journalists use the phrase "carbon pollution," to which of the following substances are they typically referring?
Politicians and media outlets have been using the term "carbon pollution" to refer to carbon dioxide (CO2). This phrase is unscientific and misleading, because it conflates carbon dioxide -- a colorless, odorless, and relatively nontoxic gas -- with noxious substances like carbon monoxide and black carbon. There are more than ten million different carbon compounds, and the word "carbon" could refer to any of them. Calling CO2 "carbon pollution" is like referring to water (H2O) as "hydrogen pollution."