I'm not a scientist, but KD has it right. Our air quality scientists have traced air masses back to the source using wind data collected throughout the country. Indeed, New England sees many of the air masses as they exit the U.S. Thus the "tailpipe" analogy.
The point that this drives home for me is that we live in an increasingly global society. Sometimes Chinese pollution even hits the west coast. Laws are the only thing that stops at the border!
Originally Posted by KD Talbot