Article is low on numbers "An air quality expert in Britain reported that much of it was “stale diesel” from traffic emissions generated in European cities."

Article is low on numbers "An air quality expert in Britain reported that much of it was “stale diesel” from traffic emissions generated in European cities." how much is "much of it" ? and big on personal observation like "As anybody who has seen the black smoke spewing out of the pipes of a big rig as it changes gears can testify, diesel has a fatal flaw." IMO a fluff piece.